# Battery monitor



## Chrisb1701 (Nov 27, 2018)

I am thinking of installing a battery monitor 
Does anyone have one installed are they worth installing any recommendations for make or model ? 

I was looking at the vitron 712 with Bluetooth


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## vanmandan (Nov 27, 2018)

suspect you're looking for something a little fancier than this,....I find it very handy.
I keep mine pugged in all the time....interesting to watch the voltage changes under various conditions.
hard to beat at £4.

Digital 12V/24V LED Car Cigarette Socket Voltmeter: Amazon.co.uk: Electronics 

should check against a known acurate volt meter.... mine reads 0.2V under the true voltage.


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## Wooie1958 (Nov 27, 2018)

Quite a few on here have Nasa BM 1 & 2 monitors    Battery Monitors - Nasa Marine Instruments

They seem to be liked a lot    :dance:


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## iampatman (Nov 27, 2018)

I have a BM1. Does what it’s supposed to do.

Pat


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## wildebus (Nov 27, 2018)

Chrisb1701 said:


> I am thinking of installing a battery monitor
> Does anyone have one installed are they worth installing any recommendations for make or model ?
> 
> I was looking at the vitron 712 with Bluetooth


the NASA BM models have a lot of fans and one of the key features with them is the Big Display.  they are a fair bit easier to see then the Victron BMVs (the display on the BMV is perfectly readable still.  you just have to scroll through to see the different info).
The Victron BMVs however are more capable and flexible and via the Bluetooth App all the info is available on your Smartphone or Tablet.  That to me trumps the NASA units.

I have the BMV-712 and find it very good and worth the money.  It is the unit I recommend over the NASA Marine BMs  in the design builds I do.  
A nice feature of the Victron BMVs is the built-in Relay which allows you to control devices based on battery parameters you choose (I have mine setup so the [electric] water heater will not have power if the battery bank is below a certain SOC)


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## mistericeman (Nov 27, 2018)

Yup went for the BM2 as the display is very clear and easy to read.... Been good as gold over the nearly 3 years since I fitted it.


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## Chrisb1701 (Nov 27, 2018)

Thank you all for your reply’s given me a lot to think about I do like the bigger display and more information on the screen on the BM models 

Back to reading some more reviews


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## Deleted member 38440 (Nov 28, 2018)

Hello
I've an Auto-sleepers fitted Sargent ec480, are the mentioned displays superior in any way?
Graham




The voltag


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## wildebus (Nov 28, 2018)

grahammay2 said:


> Hello
> I've an Auto-sleepers fitted Sargent ec480, are the mentioned displays superior in any way?
> Graham
> 
> ...


No question.  MUCH SUPERIOR.


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## cliveandann (Nov 28, 2018)

hairydog said:


> It depends what you want to monitor. Monitoring the voltage is easy, but pretty useless on its own.
> 
> The voltage of a battery is only an indication of its remaining charge if no current has flowed in or out of the battery for the last hour or two. Which makes it an impractical measure, even though many people on WC seem to think it tells them something.
> 
> ...



Amp hour counters such as the Victron are excellent for measuring the amounts of power used by the batteries or received by them from a charger over time. However they aren't very accurate for measuring the state of charge of batteries even when using modifications to the calculations for Peukert's formula (as does the Victron).  I use a Smartgauge which is from experience the most accurate readily available instrument for measuring the state of charge of a battery.  It does this without the need to install a shunt.  However it does not perform the other functions of an amp hour counter for which I have a separate unit.  For a detailed explanation why the Smartgauge is better for measuring the state of charge please have a read of this webpage. SmartGauge Electronics - SmartGauge compared to Amp Hours Counters


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## wildebus (Nov 28, 2018)

hairydog said:


> I've not used a smartguage, but although I accept most of their criticisms of amp counting meters, I consider their smoke and mirrors calculations to be dubious at best.
> Far better to accept that no battery monitor is 100% precise, and to try to get the batteries up to (and past) 100% full on a regular basis. That way the "counting meter" resets itself and is far more accurate than the smartguage which is only guessing.
> Of course, the capacity of your battery bank is an unknown in the first place. *Yes, each battery may be.nominally 100Ah, but that will only be when it is brand new, at a temperature of 25°c and a discharge current of exactly 5A,* and subject to production line variations.
> Those conditions cease to apply as soon as it is installed and/or used. You have to use an informed guess to decide what your battery bank's capacity is. You could never be 99% accurate in that, so their quibble that ammeters can often be 1% out is silly.



In fact, when it comes to leisure batteries, most sellers publish the C100 Rating for the battery as being the 'nominal' capacity and not the C20 one - so assuming a 2A discharge current.  So when configuring the monitors, you end up using a value that is lower than the 'headline' value (so my AGM batteries are advertised as 110Ah units, but that is the C100 value.  For the Victron BMV, I entered their C20 value (95Ah).  
And of course no one draws exactly 5A or 2A or anything anyway, so the theoretical available capacity is constantly varying.  I pull anything from 1.5A minimum to 180A+ maximum in my setup.

I find the Victron BMV very good in the way its algorithm works out the SOC percentage.  I can look at the data in the VRM portal, see precisely how much power has been used, the Ah drawn and when looking at a chart of Discharge current as a 'C' level, the SOC drop looks spot on for that 'style' of usage (be it just a few Amps with the fridge running, or a heavy draw when the Induction Hob or Water Heater is on.
Once I had done that a few times to confirm the data, I no longer need to worry about if the SOC value displayed is correct as I am confident it is - and I occasionally check that by seeing how much net power is going in to get the battery bank upto 100% again.


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## jagmanx (Nov 28, 2018)

*Despite all the complicated stuuf*

We have a simple voltmeter connected to the LB

We only have a 85AH battery and we only use vehicle in the summer

A) The meter shows to over 13V and even 14V mid morning if it is sunny
B) Evening it goes down but never below 12.6 V

For us it does the job £5

I sometimes use an inverter (150Watt) off the EB
The onboard meter for the EB is a lighted lozenge display
I only star to use the inverter when all 5 lozenges are showing..once is goes down to 3 I switch the inverter off and wait..
On a moderately sunny day the solar recharges the EB up to 5 lozenges at which point I can use the inverter again
This is a sunny day only procedure...BUT IT WORKS
It I want extended use of the inverter I do so whilst travelling as the alternator and the solar will keep both batteries fully charged.

You do not need anything fancy..Except common (electrical) sense


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## wildebus (Nov 28, 2018)

hairydog said:


> I'm sure you are right. To be quite honest, I wouldn't buy a "leisure" battery in the first place. Normal batteries tend to be a far better buy, if you can't afford Deep Cycle.


I use the term "leisure" battery to distinquish between Starter Batteries and Traction batteries and the ones targetted to the RV & Marine industries rather than a specific subset.
I don't blame the makers as it is one of these things where people generally compare by price and size and if one company used the C20 rating they would appear less competative for what might well be a better quality battery.  The only company that comes to mind that quote the C20 by default is Victron.

(I have a feeling that in the US, the standard measure when Ah are quoted is the C20 rating - but they also have this obsession of quoting batteries by their 'group', which makes things a bit confusing as the capacities within a group can vary a fair bit)


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## wildebus (Nov 28, 2018)

hairydog said:


> *I've not used a smartguage, but although I accept most of their criticisms of amp counting meters, I consider their smoke and mirrors calculations to be dubious at best. *
> Far better to accept that no battery monitor is 100% precise, and to try to get the batteries up to (and past) 100% full on a regular basis. That way the "counting meter" resets itself and is far more accurate than the smartguage which is only guessing.
> Of course, the capacity of your battery bank is an unknown in the first place. Yes, each battery may be.nominally 100Ah, but that will only be when it is brand new, at a temperature of 25°c and a discharge current of exactly 5A, and subject to production line variations.
> Those conditions cease to apply as soon as it is installed and/or used. You have to use an informed guess to decide what your battery bank's capacity is. You could never be 99% accurate in that, so their quibble that ammeters can often be 1% out is silly.


I had a read of the Smartgauge link.  I've never used one either and felt the write-up was heavily biased towards a "we're great, the rest is rubbish" angle and was hardly impartial.  I would like to read an independent review on the product.

The write-up reminded me of the Charles Sargent video I watched last year talking about running AC fridges via inverters and how his inverter jobby is 10 times better than every other one on the market.


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## wildebus (Nov 29, 2018)

hairydog said:


> .....
> 
> The one I use (which works brilliantly, and has done for many years) looks exactly like DC Battery Monitor Positive Negative Current +/- 30A Voltage 120V Car Volt Meter 754610748905 | eBay which costs less than £15. But if you would rather pay more than ten times as much to be able to open an app instead of looking at a display, that's fine by me!
> 
> [Later] Mine must be a bit different because it measures charge currents way over 30A. Perhaps mine is a 50 or 60 amp one. I don't remember, to be honest. It was installed many years ago.



This looks the same as yours, but with a higher 150A current rating
DC 0-120V 0-150A Volt Amp Watt Meter Capacity Percent Battery Monitor Test Meter 754610748950 | eBay

And one with a 500A Rating!
DC 0-120V 0-500A Dual Voltage Current Capacity Power Watt Meter Battery Monitor  | eBay

They all LOOK the same - I guess it is just the shunt that is different about them. They do look very neat I have to say and at the price could well be worth a punt.

Here are some other options which in price and/or features sit between a basic voltmeter and a NASA Marine or Victron BMV unit:

As far as other meters/monitors go, I tried these in-line on some Solar Panels so I could monitor what has happening
Digital Monitor LCD Watt Meter 60V/100A DC Ammeter RC Battery Power Amp Analyzer 712190256203 | eBay
They worked as expected but ...  when I took it apart to check the innards the quality of the build was not very good.  if the metal case was slightly pressed it would touch the the solder blob (rather than joint) on the positive connection and short.

These are good  units which used a fair bit on general monitoring and solar panel monitoring
AC80-260V 100A LCD Digital Volt Watt Current Power Meter Ammeter Voltmeter BI507 4894663039127 | eBay
The one above is an AC monitor - there are identical ones for DC and for different maximum current limits 
I'm using one of these (DC version) in my van on the input to the Victron inverter which is on 24/7 so I can see how much power that (and the stuff connected to it) is using.
It is great for that kind of specific job but the one Hairydog has is better featured if monitoring a battery.


Once which looks very interesting and I am going to get to see how the info matches my BM-712 is this device
https://www.ebay.co.uk/itm/Wireless...T-AMP-AH-SOC-Remaining-Capacity/142637245664?
It doesn't use a shunt, you simply route the battery -ve cable though the sensor.  It looks promising, would be very easy for anyone to install I suspect, and is cheap for what it promises.  (just like HDs one, there are different options with different current ratings at slightly diffrent prices).  There are monitors identical to the one above that DO use a shunt however, so need to check carefully if you want one type over the other.


(PS. None of the links and sellers are anything to do with me.)


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## wildebus (Dec 18, 2018)

I bought one of the units above to test and compare to my Victron BMV

This is the Unit I am checking out:



Battery Monitor w/Hall Sensor by David, on Flickr

And the Victron BMV-712 BT Screenshot



BMV-712 by David, on Flickr

The Voltage is quite a bit different - that is my error really as I am getting the voltage from the top device from a different pickup and AFTER some heavy cable loading.
The Current reading is a wider variation then I would have expected - 173.2A vs 180.0A - so around 5% difference.  It could be down to the voltage but it really shouldn't matter for current.
The Wattage is different, but that WILL be down the different voltage reading (P = V*I).

I do like the info on the top monitor - the Ah in the battery counts down in use and the very visual battery gauge is nice as well.  
Overall, I think it is a nice unit and worth the £30 odd it costs


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## trevskoda (Dec 18, 2018)

So to top things off 90% of folk on here are battery gauge watchers rather than go out play,if mine die i buy new ones,but im still going out to play,na na  na na.:drive:


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## wildebus (Dec 18, 2018)

trevskoda said:


> So to top things off 90% of folk on here are battery gauge watchers rather than go out play,if mine die i buy new ones,but im still going out to play,na na  na na.:drive:


A fair observation, but for me, analysing is a hobby of mine :idea-007:, so me doing this (and getting 'toys' etc, that are not maybe really neccessary) is part of the fun and enjoyment of the whole campervan thing. 



Because of the way the forum quote system works, my replies (in red) will only make sense when referenced back to hairydogs post I am quoting


hairydog said:


> I think mine is probably a 60 amp one. It seems to be OK.
> 
> I have one of those. Seems to work OK for the things I've tested through it, but it is really more of a test tool than a thing to use as a display.
> 
> ...







hairydog said:


> I wonder how similar that is to this one: Battery Monitor 6in1 300V 100A State of Charge SOC AH VOLT AMP Charge Discharge 732140263808 | eBay which seems to be more what I wanted. They do look quite similar in the display, but yours has one button and the one I found has two. What do you think?


That looks good.  On my similar monitor, the only setting needed was to select the shunt size (50A or 100A), so one button was good enough.  Your linked one will of course need setting up for battery bank size so I guess the buttons will feature as up and down amongst other uses.

I wonder how long the cable to the hall sensor is?  that could be a big limiting factor on placement. That could potentially be extended, but could also screw the readings as will change cable impedance (so probably not extendable in reality).

The seller in the above link was the same seller for the monitor I just got.  It arrive in good time and well packaged, so that is a good sign.


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## st3v3 (Dec 18, 2018)

Whilst it's a great piece of kit, I may have a BM-1 for sale at/after the New year meet at Hereford, for £50. I need to have a chat to Phil 


Just in case that helps anyone out...


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## wildebus (Dec 18, 2018)

st3v3 said:


> Whilst it's a great piece of kit, I may have a BM-1 for sale at/after the New year meet at Hereford, for £50. I need to have a chat to Phil
> 
> 
> Just in case that helps anyone out...


£50 for a BM-1 is a great price


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## peter palance (Dec 19, 2018)

*you*



Wooie1958 said:


> Quite a few on here have Nasa BM 1 & 2 monitors    Battery Monitors - Nasa Marine Instruments
> 
> They seem to be liked a lot    :dance:


you  did,pj ok


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## chas142 (Dec 23, 2018)

*Many Other Versions 50/100 amp.*



hairydog said:


> It depends what you want to monitor. Monitoring the voltage is easy, but pretty useless on its own.
> 
> The voltage of a battery is only an indication of its remaining charge if no current has flowed in or out of the battery for the last hour or two. Which makes it an impractical measure, even though many people on WC seem to think it tells them something.
> 
> ...




Good explanation Many different sizes of that meter on ebay, (once you find them), the 30amp version look like you would need to run your main input and outputs through the monitor, ok if your are fitting meter by battery or somewhere near those main cables, perhaps you had a shunt with your gauge. Another option I found there, following your link was:-

Battery Monitor Meter Wireless DC 120V 100A VOLT AMP AH SOC Remaining Capacity%%  | eBay

Wireless and £25


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## wildebus (Dec 23, 2018)

chas142 said:


> Good explanation Many different sizes of that meter on ebay, (once you find them), the 30amp version look like you would need to run your main input and outputs through the monitor, ok if your are fitting meter by battery or somewhere near those main cables, perhaps you had a shunt with your gauge. Another option I found there, following your link was:-
> 
> Battery Monitor Meter Wireless DC 120V 100A VOLT AMP AH SOC Remaining Capacity%%  | eBay
> 
> Wireless and £25


If you got to post #19 in this thread you will see a photo of that one in use that I posted (https://www.wildcamping.co.uk/forum...base-/73267-battery-monitor-2.html#post984540)


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## chas142 (Dec 23, 2018)

*Ahhh*



wildebus said:


> If you got to post #19 in this thread you will see a photo of that one in use that I posted (https://www.wildcamping.co.uk/forum...base-/73267-battery-monitor-2.html#post984540)



No I didn't get that far. I must study 19> lots of information in there.  Should have read it first.


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## wildebus (Dec 23, 2018)

hairydog said:


> I suspect that there is a hall sensor that the cable goes through, a box of cleverness on a short wire that can't be extended, and also a longer (extendable) wire to the dsplay. So the box of cleverness will need to be near the sensor.
> 
> The one I have that uses a shunt is fine with a few metres of flex between the display and the shunt, though it was far from happy when I tried it with multicore telephone cable. It just happened to be what was to hand, but it was no good.


That is right - and the longer cable on my unit is the USB Cable.

The one you just ordered looks like the cable from the sensor goes into the meter  (3 wires from hall sensor, 3 pin port into meter) so you might be stuck with display positioning?

On the units with the shunts that don't come with specialist wiring, I typically use 3-core 1mm flex as the neatest option.  The meters usually need Vin, GND and the two sense wires - so I bring in the 2 senses, plus power from battery bank and then just pick up a local ground.


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## chas142 (Dec 23, 2018)

hairydog said:


> Yes, any meter can only monitor one point where all the current passes through. The one you linked to can only monitor current in the wire passing through its hole. My experience of these hall effect sensors is that they are not reliably accurate, but I have ordered one of these: Battery Monitor 6in1 300V 100A State of Charge SOC AH VOLT AMP Charge Discharge 732140263808 | eBay, so when the Slow Boat arrives, I'll be able to compare.
> 
> The shunt or sensor doesn't have to be anywhere near the meter's display. Mine is installed in the earth cable to the battery bank, with a very long wire to the meter in the dash.



I know what you mean about hall effect ammeters, I was a Auto Electrician 25 years ago, then it seemed the more you paid and the age of the meter made a big difference. Not been involved much for some time and always used my old meters mostly. Updated a few bits recently, everything is much cheaper now, even if on a paddle steamer from the other side of the world.

Yes, shunt or sensor can be well away from the gauge, with a long wire. I looked at the 30 amp unit like your link, well one of them on ebay, (it was saved earlier as it was the cheapest, ha ha), and that didn't show a shunt,  showed it in line with a charger / alternator, without a shunt or sensor, you would obviously have problems if you had to cut into the wires and run them half way around the MH. 

Are you finding much of a volts drop across the shunt ? One reason why I never fitted Split charge diode systems, if I found them on the trucks that I maintained they would automatically be removed and replaced with a heavy duty relay system.

Let me know how you get on with the Chinese monitor, there is a post above with a picture of the monitor I linked, (just seen you linked to a different type again, so many options), and their link for I suspect the same unit for about £32, that shows more details than the link I posted. I've got to go back to it at some point but I don't know if it's a bit of over information. I've got to read it all to understand it and decide if I want that much info. Brain slowing down as I get older.:beer:


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## chas142 (Dec 23, 2018)

hairydog said:


> I think they are nearly all the same: the meters work on a 75mV difference across the shunt.
> Mine is a 50A meter (I think: I've had it longer than the eBay purchase history goes back) so the voltage drop should be 1.5millivolts per amp. Not enough to worry about, I reckon.



Yes, I agree to that, on some of the trucks that I worked on you could lose 2 or 3 volts in the system, if they had batteries mounted on the trailer for tail lifts etc. No chance of them charging up!!


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## chas142 (Dec 24, 2018)

wildebus said:


> If you got to post #19 in this thread you will see a photo of that one in use that I posted (https://www.wildcamping.co.uk/forum...base-/73267-battery-monitor-2.html#post984540)




Re the ebay monitor with the hall sensor it has connections for Vext Power, any idea ? I'm assuming from the diagram that it could show voltage of say the starter battery, could be handy, I wonder if that set up with the relays would also give you the option of cutting off the radio power, on the starter battery side when voltage low. Mind you can buy separate low voltage cut off for that for a few pounds, or wire the radio into the leisure battery side. I keep taking out the fuse when parked up but sometimes forget. The solar controller charges both starter and liesure batteries and can be changed for priority, % wise.


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## st3v3 (Dec 25, 2018)

hairydog said:


> Generally, the external power connection is so that the meters can monitor a wider range voltage than they can run on. They cant monitor two separate voltages.



Generally, but I did find this, that looked interesting...

Wireless 2 Dual Battery Monitor Main Aux 400V300A SOC Charge Discharge Motorhome 732140331415 | eBay


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## st3v3 (Dec 25, 2018)

I suspect it's chinglish for needs no external/additional shunt...


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## wildebus (Dec 25, 2018)

hairydog said:


> That claims not to need a shunt. So how does it work? Perhaps the shunt is built into the black things.


Looking at the size of the studs on them, I reckon you are right.


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## witzend (Dec 25, 2018)

Chrisb1701 said:


> I am thinking of installing a battery monitor I was looking at the vitron 712 with Bluetooth


   Thats some money for a battery monitor just a occasional dab with the multi meter does what I want 



Wooie1958 said:


> Quite a few on here have Nasa BM 1 & 2 monitors They seem to be liked a lot



Are they part of the Rothschild family


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## jagmanx (Dec 26, 2018)

*Simple Voltmeter*

I use the above Only £5.
Cheap and very cheerful.
The led display is always active.
By monitoring the voltage..with regard to which items are in use I believe it ensures my battery never suffers.
Ok if the truma heating and fan are in use I can see the voltage drop to say 12.7 so turn the fan off and the voltage rises (dependent on solar). Then once the voltage is up to say 12.9 I can use the fan again if needed. I also KNOW that the EB does get topped up.
Finally I sometimes use a 150 watt inverter for a laptop again mabe using the inverter for 10 mins then pausing enables the laptop to be fully charged on most days.
Ps I also use a 12V dc to 19v dc adapter for laptop.
Only 1@ 85AH battery but no issues (6 months Summer only)

PS1 I have used the above to "maintain" my LB for the last 4 summers (2015) having purchased a new LB.

I think LBs (and EBs) can often be neglected over the winter solar will usually solve this
Before I had solar 1 winter (2014-15) when I was not able to "Plug in at home" knackered the LB but it was 8 years old !


PS2 I needed a new EB in 2018 original one from 2006 !

I appreciated some may need a more complicated setup especially those with Electric fridges and more so be it
But in general KISS Keep It Simple (and) Sufficient


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## chas142 (Dec 26, 2018)

wildebus said:


> Looking at the size of the studs on them, I reckon you are right.


Yes the black box is the shunt and wireless connection RF, you can see the shunt wires across the 2 bolts. 

The relay connections are shown in both 2w and 3w, so I assume that would let you use the relay function on both battery circuits, but for one of the protection options on each system only. For me the 2 battery system would work well as I could set up low voltage protection on both systems to protect both systems from under voltage. 

This would allow me cut off radio memory drain on main battery and to cut off, (none essential), output sockets on leisure battery when using dehumidifier in rear, approx. 2hrs a day, set up on timer. When solar brings batteries back to normal voltage, (set), systems would be reactivated.

This type of monitor would give lots of useful information on both systems. Mmm I am almost sold on it. Less than £40 is a good price and think it can save your batteries as well with the additional relays.

To answer another question on here, not all meters need a shunt or monitor, if the main power cables are run through a coil in the back of a meter that will work an standard analogue swing type meter, or a digital meter if shunt and electronic control fitted in the back of the meter, like I assume what appears here:-  DC Battery Monitor Positive Negative Current +/- 30A Voltage 120V Car Volt Meter 754610748905 | eBay


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## wildebus (Dec 26, 2018)

You mention drain from the radio a lot - just how much power is your radio using when it is off?  it should be so small to not care UNLESS it has been wired up incorrectly.


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## chas142 (Dec 26, 2018)

wildebus said:


> You mention drain from the radio a lot - just how much power is your radio using when it is off?  it should be so small to not care UNLESS it has been wired up incorrectly.


 I'll get back to you on that one with the details, it is small but it is tied in 24/7, like some other systems, alarm, immobiliser, clock. They all add up to enough to drain the battery if not used for a couple of weeks. The solar and dual controler will have probably solved that issue but not getting much out of that, (140w panel), at the moment.


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## wildebus (Dec 26, 2018)

chas142 said:


> I'll get back to you on that one with the details, it is small but it is tied in 24/7, like some other systems, alarm, immobiliser, clock. They all add up to enough to drain the battery if not used for a couple of weeks. The solar and dual controler will have probably solved that issue but not getting much out of that, (140w panel), at the moment.



All radios are connected 24/7 - otherwise all the settings (radio presets, etc) would be lost everytime the power is disconnected. Removing power to that and to the clock would be a PITA as everytime you would need to reset them.
Removing power to the alarm would probably - depending on alarm - set it off as it would see it as a tamper.
I don't think the immobiliser uses much power at all when the ignition is off either. If you did disconnect the immoliser on a low voltage situation, then you would not be able to start the engine and get the charge back up.


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## Deleted member 38440 (Dec 27, 2018)

chas142 said:


> Yes the black box is the shunt and wireless connection RF, you can see the shunt wires across the 2 bolts.
> The relay connections are shown in both 2w and 3w, so I assume that would let you use the relay function on both battery circuits, but for one of the protection options on each system only. For me the 2 battery system would work well as I could set up low voltage protection on both systems to protect both systems from under voltage.
> 
> This would allow me cut off radio memory drain on main battery and to cut off, (none essential), output sockets on leisure battery when using dehumidifier in rear, approx. 2hrs a day, set up on timer. When solar brings batteries back to normal voltage, (set), systems would be reactivated.
> ...



Hello Charlie
Could the wiring come straight from the already existing Sargent ec480 ? displayed


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## chas142 (Dec 28, 2018)

wildebus said:


> All radios are connected 24/7 - otherwise all the settings (radio presets, etc) would be lost everytime the power is disconnected. Removing power to that and to the clock would be a PITA as everytime you would need to reset them.
> Removing power to the alarm would probably - depending on alarm - set it off as it would see it as a tamper.
> I don't think the immobiliser uses much power at all when the ignition is off either. If you did disconnect the immoliser on a low voltage situation, then you would not be able to start the engine and get the charge back up.



The drain across the fuse in the fuse box is 195ma, I am going to pull out the centre dash section to remove and check the radio memory draw separately. If my maths is correct that is just under 5amps a day.


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## chas142 (Dec 28, 2018)

grahammay2 said:


> Hello Charlie
> Could the wiring come straight from the already existing Sargent ec480 ? displayed



I doubt it, but I don't know the Sargent EC480, I have had a quick look on ebay and no wiring diagrams for the ones there, no thick connectors, you might be able to link it in to tell you what the draw is when you switch items on. Have a look at the following link, the various pictures, it show in effect how it would be fitted in-line without a shunt for the basic 30amp unit. I think it the same meter as the other link, less info and slight difference in price. It shows a charger but that could also be your alternator. Battery Tester DC LED 90V30A Digital Voltmeter Ammeter Voltage Gauge Panel Meter 754610748905 | eBay


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## Deleted member 38440 (Dec 29, 2018)

chas142 said:


> I doubt it, but I don't know the Sargent EC480, I have had a quick look on ebay and no wiring diagrams for the ones there, no thick connectors, you might be able to link it in to tell you what the draw is when you switch items on. Have a look at the following link, the various pictures, it show in effect how it would be fitted in-line without a shunt for the basic 30amp unit. I think it the same meter as the other link, less info and slight difference in price. It shows a charger but that could also be your alternator. Battery Tester DC LED 90V30A Digital Voltmeter Ammeter Voltage Gauge Panel Meter 754610748905 | eBay


Hello Charlie The image shows just 4 light weight connections + - In  & Out. If not connected to existing Sargent wiring, which feeds should be used.
https://i.ebayimg.com/images/g/AvUAAOSwgY9XcpiB/s-l400.jpg
Many thanks to yourself or others that have the answer. Graham


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## chas142 (Jan 3, 2019)

grahammay2 said:


> Hello Charlie The image shows just 4 light weight connections + - In  & Out. If not connected to existing Sargent wiring, which feeds should be used.
> https://i.ebayimg.com/images/g/AvUAAOSwgY9XcpiB/s-l400.jpg
> Many thanks to yourself or others that have the answer. Graham








Yes it shows 4 connections, light or medium, it appears the makers use that system for 10/20/30 amp meter, this is what they feel is suitable up to 30 amps, above that they use a separate shunt in the system, that way lighter cable can be run to the monitor and the monitor can be fitted further away from the connection point, that's with a separate shunt, the price goes up but allows a meter with a higher amperage to be used. I assume you are using this on your leisure battery ? If I was fitting this I would probably connect it in near the leisure battery on the + & -, I might even mount it near the leisure battery as it's under the passenger seat, at least as a test, you don't want to run the cables to far with the 30 amp unit. As I said I don't know your set up. I also don't know this meter, it was mentioned  by someone else initially, but it turned out that they had a larger meter with a shunt.

You may find that this 30amp unit is to small for your system, that will depend on your vehicle, size of alternator fitted, size and type of batteries fitted, AGM batteries can accept a higher charge amperage than gel batteries. My gel battery take approx  25amps when low but soon cut back to 10 amps, so I would get away with using the 30amp meter, I would be more likely to buy a higher amperage version with a shunt as the 30amp version wouldn't work for me if I doubled up on my batteries or changed to AGM.

I have one of these Sealey SPECIAL Clip-On Ammeter 0-30 Amp any direction 5024209003018 | eBay   Handy as a quick test, not that accurate but there are other clamp type meters on ebay.


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## chas142 (Jan 3, 2019)

wildebus said:


> You mention drain from the radio a lot - just how much power is your radio using when it is off?  it should be so small to not care UNLESS it has been wired up incorrectly.


The drain across the permanent feed fuse in the fuse box is 195ma, it turns out that 10ma is what is supposed to be the memory feed and 185ma, (unit switched off), is a drain on what should be the ignition feed through the radio. As there is no auxiliary key position or override on the radio, (like some more modern systems), the standard procedure was to cut the ignition feed into the radio and join the feed into the radio to the permanent memory feed; That way allowing the radio to be used when parked up. Never a very satisfactory way of wiring a radio in, ok with none memory push button radio systems or if the set didn't draw power when turned off, apart from minor memory (10ma) as you correctly stated.  Unfortunately mine does draw this 185ma.

Incidentally it also turned out that the feeds in the Fiat wiring loom were reversed according to the German Radio Manufacture's ISO wiring layout, they point this out in their manual that some Manufacture's reverse the wire the radio plugs.

So looking at the issue again:idea-007: I will fit a delay timer relay with a trigger switch, the radio is now wired up to ignition only. When set up with timer in standby mode the timer draws 20ma, in working mode its 50ma, the timer I have ordered is adjustable but will be set for about 4hrs. After that time it will drop back to the 20ma and cut the radio out. Working it through the battery monitor system would have drawn more power, the 185ma down to the set voltage, hours and hours, then 50ma to operate the cut off relay and monitor power till the battery was flat. So on the radio side in stand by mode, I will in effect go from 195ma down to 30ma, that will make me

I had no intention of cutting everything off, I was just making the point that there are many other types of drains upon the batteries. At the moment I can't check it at the battery as the front of MH is against a wall and the back just fits in the drive, I will do that another time to see what the other items are drawing, I hope not to much.
:have fun:


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## Floridaphill (Jan 3, 2019)

vanmandan said:


> suspect you're looking for something a little fancier than this,....I find it very handy.
> I keep mine pugged in all the time....interesting to watch the voltage changes under various conditions.
> hard to beat at £4.
> 
> ...



and mine didn't read 12.5 volts at all when tested with a bench supply and Fluke meter, cheap and cheerful.


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## wildebus (Jan 3, 2019)

chas142 said:


> The drain across the permanent feed fuse in the fuse box is 195ma, it turns out that 10ma is what is supposed to be the memory feed and 185ma, (unit switched off), is a drain on what should be the ignition feed through the radio. As there is no auxiliary key position or override on the radio, (like some more modern systems), the standard procedure was to cut the ignition feed into the radio and join the feed into the radio to the permanent memory feed; That way allowing the radio to be used when parked up. Never a very satisfactory way of wiring a radio in, ok with none memory push button radio systems or if the set didn't draw power when turned off, apart from minor memory (10ma) as you correctly stated.  Unfortunately mine does draw this 185ma.
> 
> Incidentally it also turned out that the feeds in the Fiat wiring loom were reversed according to the German Radio Manufacture's ISO wiring layout, they point this out in their manual that some Manufacture's reverse the wire the radio plugs.
> 
> ...



ref the Radio, I had a feeling that the signal/ignition +12V into the radio was wired to the permenant +12V.   And with newer radios, the "Off" button on the radio does not actually turn the radio fully off in most cases, so there is a much larger drain then there should be.
This is a common issue with aftermarket radio installations on newer vehicles.  See this a lot in the VW Transporter world where the standard radio is a Canbus connected unit via the new-style Quadlock connector found on newer vehicle, and the Quadlock connector has no ignition feed signal, so often DIY (and 'professional' for that matter) just connect the radios ignition +12V to the permanent +12V as it is easy to do.

I actually have a wiring kit especially for VWs (and other VAG vehicles) that deal with this, and also what I call a "Drive/Camping Radio Loom" kit which allows you to use a 3-way switch to feed the radio ignition with the Ignition signal (the "Drive" mode), or from a permanent +12V signal (the "Camping" mode), or just off  (handy if you want to turn your ignition on late at night/early morning on a campsite and don't want to blast the neighbours).

Interesting comment about the Fiats wiring being reversed according to the Germans   I think it is more likely that the German Standard is the one the wrong way round   As when installing any aftermaket radios , if you are installing into a German vehicle with ISO plugs you have to swap over the red (ignition +12V) and yellow (perm +12V) wires, but on any others it is still red-red and yellow-yellow   (these are the radio industry standard colours)


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## chas142 (Jan 6, 2019)

wildebus said:


> ref the Radio, I had a feeling that the signal/ignition +12V into the radio was wired to the permenant +12V.   And with newer radios, the "Off" button on the radio does not actually turn the radio fully off in most cases, so there is a much larger drain then there should be.
> This is a common issue with aftermarket radio installations on newer vehicles.  See this a lot in the VW Transporter world where the standard radio is a Canbus connected unit via the new-style Quadlock connector found on newer vehicle, and the Quadlock connector has no ignition feed signal, so often DIY (and 'professional' for that matter) just connect the radios ignition +12V to the permanent +12V as it is easy to do.
> 
> I actually have a wiring kit especially for VWs (and other VAG vehicles) that deal with this, and also what I call a "Drive/Camping Radio Loom" kit which allows you to use a 3-way switch to feed the radio ignition with the Ignition signal (the "Drive" mode), or from a permanent +12V signal (the "Camping" mode), or just off  (handy if you want to turn your ignition on late at night/early morning on a campsite and don't want to blast the neighbours).
> ...



I will check the drain on the car as that has one of the, what I am calling the ignition/auxiliary override button on the radio, that is over ridden by the ignition switch again so automatically goes back to normal operation, a much better system, original fit in my Peugeot and the Co-Pilots Citroen.

I think my unit has a much higher current draw on the ignition feed circuit even when switched off than most, but I can't  really remember now what the norm was. When I was fitting radios some 25+ years ago most of them were just standard push button radio cassettes, I did a lot of work on trucks, when I did fit the type of unit that I have in the same situation, (as a professional), I hoped it had an auxiliary feed. Most vehicles get driven every day so not a real issue. It has to be my MH that has to be wired into the permanent, been meaning to sort it out for ages. I could have fitted a switch in the system but I would have probably left that in the on position and still flattened the battery, as I said I hopefully remembered to pull the fuse out when parked up at home.. So I think the timer relay is a good way for me to go, and its adjustable from a few second up to several hours. 

I was surprised to hear you say that you thought it was the Germans who got the wiring wrong,:raofl: I used to know the head of a UK Technical Dept of a well known German Auto Electrical Manufacture, and he had the opinion that it was all the other countries, (well England as that was where he was based), that were well behind the Germans and implied we didn't know what we were doing.:mad1:


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## Deleted member 38440 (Jan 10, 2019)

*How to connect display monitor?*

Hello all
I've just purchased and thought it would be simple to wire. However I need some help with the wiring. It seems that the monitor can be wired to show either the charging state or the usage but not both,is that so? 
Looking forward to hearing from you soon. Many thanks Graham


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## Deleted member 38440 (Jan 10, 2019)

*How to connect display monitor?*

Hello all
I've just purchased and thought it would be simple to wire. However I need some help with the wiring. It seems that the monitor can be wired to show either the charging state or the usage but not both,is that so? 
Looking forward to hearing from youhttps://www.wildcamping.co.uk/forums/redirect-to/?redirect=https%3A%2F%2Fwww.ebay.co.uk%2Fitm%2FBattery-Tester-DC-LED-90V30A-Digital-Voltmeter-Ammeter-Voltage-Gauge-Panel-Meter%2F142142090671%3F_trkparms%3Daid%253D111001%2526algo%253DREC.SEED%2526ao%253D1%2526asc%253D20131017132637%2526meid%253Dfebba087561e48258d30dc5fa75593f5%2526pid%253D100033%2526rk%253D2%2526rkt%253D8%2526sd%253D142142090671%2526itm%253D142142090671%26_trksid%3Dp2045573.c100033.m2042 soon. Many thanks Graham


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## st3v3 (Jan 10, 2019)

Hopefully a link that works for you...

Battery Tester DC LED 90V30A Digital Voltmeter Ammeter Voltage Gauge Panel Meter 754610748905 | eBay


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## chas142 (Jan 11, 2019)

grahammay2 said:


> Hello all
> I've just purchased and thought it would be simple to wire. However I need some help with the wiring. It seems that the monitor can be wired to show either the charging state or the usage but not both,is that so?
> Looking forward to hearing from you soon. Many thanks Graham



Hi Graham, so you have the 30amp unit, if you look at the pictures on the link provided by st3v3 in post 60, you will see that you have input and output connections, *+* & *-* on each. It shows you in both pictures that the battery goes to the input side of the of the monitor, the wires that go to the vehicle wiring go to the output side. 

Have you wired it in yet ?

You should decide where you want the meter to fit, then and more important you should decide how you are going to run the cable and what cable you are going to use, or are you going to fit it near the battery, is you battery under the passenger seat?

As I said earlier you don't want to be running cables around the MH, it causes volts drop in the cable and you end up have to use thicker wire because of this. So I don't know how good your DIY skill are. I would say that fitting it near the battery on my vehicle would be the best and easiest option on my MH, but difficult to see it when down by the seat. So that is the easiest way to connect it in unless you want to cut into the main wiring by the electrical box, (dependant on your vehicle which I don't know), I could do that as I was an Auto Electrician, so pulling the box apart wouldn't be beyond me. But the better option would have been as I thought I broached earlier was to buy the slightly more expensive meter that had a separate shunt.

But you have it now, if you don't feel confident in fitting it you should get a professional to fit it for you, you don't want to set you MH on fire. I've seen it all before. If you do it yourself disconnect the *-* side of the battery first and that should be the last connection you put back. If I were you I would connect it using your existing wiring by cutting into it *+* & *+* and connecting that then *-* & *-* and connecting that. With your meter you would need to use yellow eyelets I suspect of the correct size for the screws, or you could make up 4 short cables, min 30amp cable, with eyelets attached at one end then you could use a H/D screw down connection block, that way you can remove the meter and put the wiring back to as was if you like or to swap the meter around the other way if you needed to. I have a watt meter that is reversed like that for different tests but I don't think you would need to do that with your monitor. As I said earlier I don't know your meter so you need to follow the information given in the instructions and from hairydog in post 61, who has a similar meter. It's basically plug in and play to understand it.:goodluck::goodnight:

Make sure everything in insulated so it can't short out.


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## Deleted member 38440 (Jan 11, 2019)

Thanks for your replies hairydog & Chas. I would fit near lbatts which are under hab bench. The battery monitor just doesn't look like it is substantial enough to carry the full load of current through it. I've an auto sleeper 2013 with Sargent kit. Further comments very welcomed. Graham


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## wildebus (Jan 11, 2019)

hairydog said:


> The 30A meter has to be wired in line with the main cable, but the 50A, 60A and 120A ones do not. They use a shunt (a strip of metal of precise resistance) in line with the cable, and a flex to where you fit the meter. I would buy a 60A one if I were you. I'm pretty sure that's what mine is.


Like wot he says 
Even if you think the lower amperage versions will be sufficient in terms of power terms, I would always recommend a Monitor that has a seperate shunt (or sensor) as it almost invariably allows much more flexibility in cabling and display positioning.


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## ScoTTyBEEE (Jan 11, 2019)

hairydog said:


> The 30A meter has to be wired in line with the main cable, but the 50A, 60A and 120A ones do not. They use a shunt (a strip of metal of precise resistance) in line with the cable, and a flex to where you fit the meter. I would buy a 60A one if I were you. I'm pretty sure that's what mine is.



I have this one and it’s 50a, I think it then goes 100,200,400

It works really well though, but the instructions are a bit Engrish and need a bit of nous.

This is the one you want and you wire it up as the first picture (internal power supply)
DC 120V 50A Voltage Current Ah Time Meter Battery Charge Discharge AGM SLA LEAD 754610748943 | eBay


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## Deleted member 38440 (Jan 12, 2019)

hairydog said:


> It is a 30A meter, so ought to be capable of carrying at least 30A.
> 
> Unless you have an inverter bigger than about 600 watts, you probably won't have a current bigger than 30A going in or out of the habitation batteries at any time. What Sergent kit do you have?
> 
> However, I expect that the terminals on the 30A meter will be rather fiddly and small.


 Sargent EC 480 & ec500.  I do have a 2k inverter fitted  directly to the lbatts which wouldn't go through the meter. 
Graham


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## wildebus (Jan 12, 2019)

grahammay2 said:


> Sargent EC 480 & ec500.  I do have a 2k inverter fitted  directly to the lbatts which wouldn't go through the meter.
> Graham


If you have a battery monitor that is fitted and bypasses what would be by far the biggest load on the battery when running, it kind of defeats the point of fitting the monitor doesn't it?


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## Deleted member 38440 (Jan 12, 2019)

wildebus said:


> If you have a battery monitor that is fitted and bypasses what would be by far the biggest load on the battery when running, it kind of defeats the point of fitting the monitor doesn't it?




Yes I suppose so, on occasions when invertors has been used.


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## mistericeman (Jan 12, 2019)

Use of our 3000w inverter (running microwave pulling 80 amps or so)
Was the main reason I bought our NASA.... 
To keep an eye on the 3 x 100ah batteries


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## jagmanx (Jan 14, 2019)

*Indeed*



hairydog said:


> That's daft. Unless you monitor all the use, there is no point in doing it at all.
> The meter may be able to monitor slightly higher currents than it can display, but of course you can't run a 2KW inverter (max current around 200A) through a 30A meter. That's overloading by an order of magnitude.
> You need to buy a monitor that can monitor everything.



Simple maths (ignoring inefficiency issues)

2 KW at 220 V is say 10 amps @ 220V (yes I repeat)
OK AT home a kettle may run at 3KW =  15 amps and not blow the 13 amp fuse 
( 240V puts it on the limit 240V x 13 Amps = 3KW plus)

12 V needs to be at 15amps x20 =300amps
Burning leads !!!!


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## mistericeman (Jan 14, 2019)

That's why I went for the BM2 so it could cope with our 3000w inverter..... And the 80 amps or so from the alternator when the batteries were down to just above 50%


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## wildebus (Jan 14, 2019)

hairydog said:


> I just got home from a trip away to discover that the one of these I ordered has been delivered via the Slow Boat. But sadly, there is no user manual with it. Any chance of a photo of the user manual you were sent?


If you PM me an address I will send you a PDF   (I can't recall where I got it from on line so easier to send the file then search for the link)


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## wildebus (Jan 14, 2019)

jagmanx said:


> Simple maths (ignoring inefficiency issues)
> 
> 2 KW at 220 V is say 10 amps @ 220V (yes I repeat)
> OK AT home a kettle may run at 3KW =  15 amps and not blow the 13 amp fuse
> ...


won't pull 300A for very long though with most battery setups 


FWIW, I am - or will be in around an hour now my ring terminals have arrived- running 70mm cable from my 2400W inverter


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