# Leisure Battery Power Monitoring Systems



## ivecotrucker (Jul 7, 2012)

Greetings All,
I would appreciate everyone's comments, views, ideas & any actual experience of 12v battery power monitoring systems such as basic AmpHour Counters, the Nasa B1, SmartGauge etc.
How reliable are their predictions of State of Charge & remaining available AmpHours ? 
Do their various algorithms actually work or are they just an approximate guess ?? 

Thanking you in anticipation.


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## Admin (Jul 7, 2012)

I have a NASA BM1 fitted which works very well, it also monitors the starter battery.
I never run my batteries to low, about 25% so it is nice to see.


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## oldtech (Jul 7, 2012)

ivecotrucker said:


> Greetings All,
> I would appreciate everyone's comments, views, ideas & any actual experience of 12v battery power monitoring systems such as basic AmpHour Counters, the Nasa B1, SmartGauge etc.
> How reliable are their predictions of State of Charge & remaining available AmpHours ?
> Do their various algorithms actually work or are they just an approximate guess ??
> ...



Thanks for a very stimulating question Ivecotrucker !!!  ( ... ha ha  !!  ) 
Let's hope we gets lots of response on here  ....hopefully before I go and buy one !  :lol-053:
... and thanks to Phil for starting the ball rolling !.
Regards 

Oldtech


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## ivecotrucker (Jul 7, 2012)

Greetings Oldtech,
I followed your suggestion to make this subject into a new thread. We don't seem to be exactly swamped with useful answers yet (apart from good old No 1 !), even though it's a wet Sat afternoon - perhaps everybody all watching football; do they play this time of year ??.


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## AndyC (Jul 7, 2012)

I use a Sterling Power Management Panel: Sterling Power Products: Power Management Panel

As far as I can tell it's reasonably accurate.

Actually I only fitted it because I got it for free, it was a swap-out under warranty for one of my customers, because one of the monitoring channels wasn't working, and Sterling didn't want it back 

Previously I always relied on a voltmeter to show the state of charge of my batteries, when they got down to around 12.2v (with no load) I reckoned they were about half charged. I always tried not to let them get much lower than that.

I know some boaters who have the SmartGauge fitted, they all seem to think it's quite accurate.

AndyC


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## oldtech (Jul 7, 2012)

AndyC said:


> I use a Sterling Power Management Panel: Sterling Power Products: Power Management Panel
> 
> As far as I can tell it's reasonably accurate.
> 
> ...



Hi Andy

Thanks for your input

Coming from an electronics background , I too have always relied on my trusty DVM
to tell me everything .
The problem is that voltage doesn't really tell you that much when it comes to batteries ....
.... sure ...less than 12volt is not good .... and 13volts or more IS good but this doesn't
really tell us ANYTHING about how long we can expect to have a good supply of CURRENT .

You were certainly lucky to get a Sterling unit free !  .... from what I know about this subject ,
these are top quality units .... they are certainly at the top-end of the price range
... and people I know who are serious about boats seem to swear by them.

all the best 

Oldtech


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## oldtech (Jul 7, 2012)

AndyC said:


> I use a Sterling Power Management Panel: Sterling Power Products: Power Management Panel
> 
> As far as I can tell it's reasonably accurate.
> 
> ...



Hi Andy

Thanks for your input

Coming from an electronics background , I too have always relied on my trusty DVM
to tell me everything .
The problem is that voltage doesn't really tell you that much when it comes to batteries ....
.... sure ...less than 12volt is not good .... and 13volts or more IS good but this doesn't
really tell us ANYTHING about how long we can expect to have a good supply of CURRENT .

You were certainly lucky to get a Sterling unit free !  .... from what I know about this subject ,
these are top quality units .... they are certainly at the top-end of the price range
... and people I know who are serious about boats seem to swear by them.

all the best 

Oldtech


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## Byronic (Jul 7, 2012)

Oldtech, if you put a moderate load on a new(ish) battery at its maximum charge say 50W for 2 or 3 minutes then take a voltage reading this will give you a more accurate measurement say about 12.8V. If you assume that a nominal 12V battery is completely flat @ say 10.7V then by comparing voltage readings (as you use the battery) with the Amp Hour rating of your battery you  should get some idea of remaining capacity. Eg if your battery reads 11.7V then you have used approx. 50% of your battery's Amp Hour rating.  

Naturally with an old battery the full charge reading will be below 12.8V and an adjustment has to be made. 

Admittedly this is only gives a rough approximation but a bit more use than solely a Volt reading. As you're in the electronics game I'd suspect this would'nt be accurate enough.

But I'm not so sure that my fairly sophisticated battery management unit is all that accurate either, algorithms or not.


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## ivecotrucker (Jul 7, 2012)

Thanks Byronic,
Your "moderate load for a few minutes" is the correct way to remove the 'surface charge' from a newly charged battery before testing the voltage; this surface charge is a false reading & does not reflect the real electrochemical reactions within the battery plates.
I hope you don't mind me saying but I think your voltage:% discharge figures are a bit optimistic. According to various battery manufacturers an indicated voltage of 12.1v = 50% discharge & 11.7v = 75% discharge.


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## Jojo (Jul 7, 2012)

While you're on this topic... do any of you happen to know anything about this control panel? Or ideally where I could find a handbook for it?



BTW Turns out the problems channa and Firefox offered to help me with stem from a failed leisure battery, so I've bought a pair of replacements and my dad is getting very excited thinking about charging circuits 

Best wishes all!


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## ivecotrucker (Jul 7, 2012)

Sorry Hamsha, I've not seen one like that.


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## Byronic (Jul 8, 2012)

My power manager is now 15 years old so the following may not apply to the latest equipment.
The device monitors the leisure batteries and controls charging  from solar panels, the mains to 12V transfiormer and via voltage droppers (vehicle is 24v) 12V charge from vehicle alternator, ie 3 sources.

When I installed the unit I found  unrealistic readings displayed. As per the instructions I had set the jump pins so the unit did all the things it was supposed to do such as monitor battery temp, volts, amps remaining, management regime  giving extra boost charge when required to desulphate the plates etc

Contacted the German Manufacturer and described my installation, the reply was that the device was really intended for a single supply source in order that the processor would learn to work out a management pattern and that if I kept switching the unit between differing power sources then this could/would make the device go crazy...their words. 

I had to reset the jump pins so these days it's just a glorified Voltmeter but still very useful,the agitation regime still operates and I attribute long battery life to this.


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## AndyC (Jul 8, 2012)

hamsha said:


> While you're on this topic... do any of you happen to know anything about this control panel? Or ideally where I could find a handbook for it?



There are contact details on the Ace Caravans website: ACE Caravans 
You could try asking them if they could send you a copy of the manual.

AndyC


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## ivecotrucker (Jul 8, 2012)

Hi Byronic, what make is your (German) power management system please ?.


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## Jojo (Jul 9, 2012)

AndyC said:


> There are contact details on the Ace Caravans website: ACE Caravans
> You could try asking them if they could send you a copy of the manual.
> AndyC


You're right. I emailed them a few weeks ago, no reply, but you've prompted me to try again


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## Byronic (Jul 9, 2012)

ivecotrucker said:


> Hi Byronic, what make is your (German) power management system please ?./QUOTE]
> 
> Hi Ivecotrucker, The make is Steca..... Batterieladesysteme+Prazisionselktronik GmbH. The model I have can handle up to 20Amp @ 18V solar panel output. There are lesser and greater capacity options available.
> It more accurately can be described as a battery management system plus rather than power management system which may deal with 240V mains transformation/alternator output etc.
> ...


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## ivecotrucker (Jul 9, 2012)

Thanks for the details Byronic. I'm looking into altering our electrics  & thought if I researched and collated all the info that I & others could find that it might also make a useful M/Home Knowledge thread but there doesn't seem to be a lot of interest out there - a bit too esoteric perhaps.


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## Byronic (Jul 9, 2012)

Hi Ivecotrucker, you probably already know....but the online English version of the REIMO catalogue is very good for info and  all the latest gear expensive (naturally) they are light years ahead of suppliers here TBH info.
I once converted a brand new T25 VW van using furniture kit and all components sourced ex Reimo. It turned out better in finish and equipment than the VW Westfalia factory job. In truth though it ended up costing more as well!


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## ivecotrucker (Jul 9, 2012)

Thanks Byronic. It's years since I saw any of their stuff so I'll look them up online, as you suggest. 
Mrs IvecoT is fond of saying "you get what you pay for" so I expect your conversion must have looked the biz (as they say).

(Edit) I've just looked up the REIMO catalogue. What looks like two fairly standard AmpHour counters; little useful technical detail; may not be able to monitor leisure bank AND starter ?. Their prices are way over the top !.


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## Byronic (Jul 10, 2012)

I can only imagine you are looking at the English sourced catalogue set up by their various UK agents? The actual German (English Version) site has just about everything available for motorcaravans.


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