# Rapid leisure battery charging via vehicle alternator/solar?



## Talbot (Nov 6, 2012)

Has anyone had experience of the CTEK Battery to Battery Charging solution with integrated Solar MPPT and is it a potential solution for rapid charging of the leisure battery while driving? Or is there a better solution out there?

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New: CTEK Battery to Battery Charging with integrated Solar MPPT. The excellent new D250S Allows two DC power inputs - for example solar panel plus alternator and automatically selects the input giving the most power. It uses MPPT technology for maximum solar input under lower light conditions and also provides solar overspill to the starter battery to keep that well maintained too. Conveniently it works just fine even without a solar panel! With CTEK's usual top class multi stage charging and continuous output up to 20A it gives fast charging of the leisure batteries, and longer battery life too. Equally important this is part of a system so by adding a Smartpass it is possible to boost the maximum B2B charge up to 80 Amps. Various configurations are possible with just one example illustrated left.


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## FULL TIMER (Nov 6, 2012)

unless you need the solar input side of things I would rather use the sterling B2B charger a bit further down the page not saying the Ctek is no good just that I dont know it, I have used Sterling products for years when building vehicles for the emergency services and know they are reliable.


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## shortcircuit (Nov 6, 2012)

Fitted the  D250S this year and it appears to do exactly as described.  I have an 80w solar panel attached and it is keeping both the leisure and starter batteries topped up at the moment.  When using the MH the batteries were again topped up with little running and I had no real need for EHU.  In addition I upped the cable size from the alternator to the unit as existing wiring inadequate


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## noarlunga (Nov 6, 2012)

I have a relay switch between the van battery and the leisure battery (which is a modest 60Ah temporarily while I fit the van out, 2 x 110Ah planned). I didn't realise that the charge would drop before the leisure battery was fully charged, if what the motorcaravanning.co.uk site says is correct. It sounds as though I might need to compensate for this as I'm running a Webasto Airtop, LED lighting and I plan to add a tv and possibly a coolbox in summer.

If I fit one of these B2B chargers, would I keep the relay in or strip it out?

Johnny A


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## Gee (Nov 6, 2012)

noarlunga said:


> I have a relay switch between the van battery and the leisure battery (which is a modest 60Ah temporarily while I fit the van out, 2 x 110Ah planned). I didn't realise that the charge would drop before the leisure battery was fully charged, if what the motorcaravanning.co.uk site says is correct. It sounds as though I might need to compensate for this as I'm running a Webasto Airtop, LED lighting and I plan to add a tv and possibly a coolbox in summer.
> 
> If I fit one of these B2B chargers, would I keep the relay in or strip it out?
> 
> Johnny A


Hi Johnny,
When I fitted my b2b I just removed the fuse on the relay, and kept all the relay wiring in place in case i wanted to swap  back. So far so good, and much better charging to my 230ah LB.


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## thegoodlookingbloke (Nov 6, 2012)

Save your money. Solar power is nowhere near the claims of these companies that are out to sell their products so they try and baffle you with technological crap that just doesn't stand up. 

You don't get 'ought for nought' and solar power can only give you a fraction of what your batteries need for normal use.

Your alternator is the mighty powerhouse so unless you are marooned in the Sahara with no engine, forget all this Solar hype. :wave:


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## Talbot (Nov 6, 2012)

Sotar is only an extra.

What I really want to know is - is there a solution out there to rapidly charge my leisure battery from the vehicles alternator even on short journeys?


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## shortcircuit (Nov 6, 2012)

The Ctek range offers two rates of charge at 20A or 60A, depending on model.(Hope these figures are correct).  The length of your short journey will depend on how much you have taken out of the leisure battery  and the output of the alternator.

The Ctek charger is a multi stage charger which does a lot more than a simple relay/switch to the alternator which benefits the batteries.

Solar power opens a big can of worms.  I was very cynical at their usefulness up until I fitted one.  In France this summer I had no problems with batteries and it was not particularly sunny but had I had a heavy discharge on the batteries it would not have coped.  I also no that in this past at this time of the year I would put charger on occasionally  to keep batteries up to ensure I can start MH, I can forget about that now as I no they are fully charged


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## maingate (Nov 6, 2012)

So solar power is crap?

Well it is in winter.

My onboard charger puts up to 18 amps (from the alternator) when I am driving. With 2 x 110 Ah batteries, that is as much as I want. If I was putting 60 amps into them, they would be Donald Ducked pretty quickly, due to boiling up and warped plates. A battery only takes what it requires anyway so 60 amps is a pipe dream. As was said, you don't get 'owt for nowt' in this life. Rapid forced charging knocks the life out of batteries.

BTW, I manage for months on end with one 90 watt solar panel. I now have a 100 watt panel as well and the 11 or 12 amps they put in to the batteries doesn't sound crap to me.


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## Talbot (Nov 6, 2012)

maingate said:


> So solar power is crap?
> 
> Well it is in winter.
> 
> ...



I wouldn't do without my 100 watt solar panel as it usually does me proud. However, I was wildcamping last week and never saw the sun once so I was relying on the vehicle alternator to charge my LB and it wasn't very effective. Just spoken to the dealer who said to turn the fridge off as it runs directly off the Leisure Battery when driving. If this is the case, thats why I've got problems keeping charged. So what's the solution? If I was able to get 18 amps from the alternator I don't think I would have this problem. Is the 18 amps directly from your alternator or do you have a B2B fitted?


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## maingate (Nov 6, 2012)

Talbot said:


> I wouldn't do without my 100 watt solar panel as it usually does me proud. However, I was wildcamping last week and never saw the sun once so I was relying on the vehicle alternator to charge my LB and it wasn't very effective. Just spoken to the dealer who said to turn the fridge off as it runs directly off the Leisure Battery when driving. If this is the case, thats why I've got problems keeping charged. So what's the solution? If I was able to get 18 amps from the alternator I don't think I would have this problem. Is the 18 amps directly from your alternator or do you have a B2B fitted?



My van is German and has an Electroblock unit fitted. Part of this is the charging unit which charges the leisure batteries at 16 amps max and puts a 2 amp float charge back into the van battery while driving. This also happens when on 240 volt hookup.

I would think that you need to check the max charging rate of your onboard charger. From what I have read on various forums over the years, some vans come with pretty poor chargers. Also, I would disregard what your dealer said. Your fridge gets its 12 volt supply from the alternator, not the leisure batteries. An alternator is capable of putting out 80+ amps. The fridge will take a fair amount (but not always if the fridge is already cold) but there should still be enough for the batteries. Any limitation will probably be down to the charging unit. 

There is nothing wrong with upping the charging rate to your batteries but 60 amps is a bit ridiculous. Even at 18 amps, it takes my batteries a while (therefore a good long run) to be fairly well charged up after a night or two of wilding (unless the solar panels had put some back).

The real secret is to be aware of how much power your various accessories use, how long you use them for and how much power you are putting back into them when driving. Constantly running the battery below 50% will shorten their life. You could add an extra battery but then, if you have a low power onboard charger, it will take twice as long to recharge them. Lets say you wanted to put 60 amps back into one battery. It would just not work. Now if you had 3 fairly big batteries, each one could take 20 amps if they were quite low and 60 amps of charge does not sound daft.

The way I look at it, it is possible to avoid ripoff campsite prices by wilding BUT it costs money to set a van up to be able to do that. Ah well, that's life.


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## landydriver (Nov 6, 2012)

.


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## Somelier (Nov 6, 2012)

thegoodlookingbloke said:


> Save your money. Solar power is nowhere near the claims of these companies that are out to sell their products so they try and baffle you with technological crap that just doesn't stand up.
> 
> You don't get 'ought for nought' and solar power can only give you a fraction of what your batteries need for normal use.
> 
> Your alternator is the mighty powerhouse so unless you are marooned in the Sahara with no engine, forget all this Solar hype. :wave:



Can't agree with you there. We had a 75W solar panel fitted to our new van and it keeps the batteries topped up a treat.

If I were you, I'd ignore advice from ANYONE who owns a Landrover - shows they have absolutely NO idea about decent engineering at all.:lol-053::lol-053::lol-053:


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## Neckender (Nov 6, 2012)

I have 2-80watt solar panels, mmpt controller, 3-110 amp leisure batteries plus vehicle battery, 1000watt and 150 watt invertors 240volt slow cooker and 240volt tv.  never short of power.

John.


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## Kontiki (Nov 6, 2012)

For nearly four years we managed fine with a 80 watt panel with a Exide 85 amp gel battery, never once had any problems with lack of power but then it all depends on how much you use as well. New van has a 130 watt panel & 2 x 90 amp batteries, the new van is likely to be a bit more power hungry with a Camos sat system (on the old van we just had the suit case type satellite so never used to bother sometimes)

It is a case whatever set up you have it's all about managing the resources, you are not living in a house where you can get limitless power/gas/water, in a motorhome you have finite capacity & as long as you are aware of what you have then adjust how you use them you can get by.


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## landydriver (Nov 6, 2012)

.


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## Talbot (Nov 6, 2012)

Have read the last few replies, I think better to clarify my situation. Firstly it's NOT about solar. I have a 100 watt panel and I never have any power issues when its sunny. In fact when its sunny I could watch TV for 5 hours a night, have the whale blown air heater on for a couple of hours, run several lights and the solar would charge my 105 amp battery to full by 11.30am next day. Its brilliant and I would recommend their use.

However when in DULL Northumberland last week for 7 days with NO SUN, I only managed to use the TV and heater for 3 hours on first night which dropped my battery down to bar 3 on my sargent control panel (bar 5 is full and bar 1 is critical) so I was midway on my marker. The next 6 nights I did not dare use the TV so resorted to crosswords and conversation with OH. Had to be careful about using the heater also probably max 2 hours per night and had to rely on down jackets or the pub to keep warm. I only put one of my 10 lights on. Apart from the fridge display light (which must draw something) no other appliances were drawing power. By keeping moving every other day, I managed to get some charge into my battery but not much and this is probably because my MH uses the LB to charge the fridge on 12 volts whilst driving so much of the charge will have been diverted to the fridge instead of the LB. The use of LB to run fridge is rare I understand, but that is what I have.

Trust me, we coudn't have used less power than we did. You may say, why did I not go on EHU? and my answer is that - rarely can I find a campsite in such a fine location as on the beach or clifftop overlooking the sea. So I was happy to compromise for my personal benefit. But what I am trying to ascertain is the best solution to increase the power to my leisure battery whilst driving and I believe it lies with some form of B2B chaging device (Sterling or CTEK have been mentioned). Van is new (6 months old), batteries are all tested and in excellent order. I am new to this 12 volt power technology and trying to navigate my way through it and not make an expensive mistake. Anyone lese been here??


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## yorkslass (Nov 6, 2012)

we had problems with losing power fairly quickly so increased our leisure batteries from 2 to 4and put in a sterling B to b . no problems since, touch wood.


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## Talbot (Nov 6, 2012)

yorkslass said:


> we had problems with losing power fairly quickly so increased our leisure batteries from 2 to 4and put in a sterling B to b . no problems since, touch wood.



Sounds good. How much to install and can you recommend an installer? Thanks


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## sparrks (Nov 6, 2012)

Go with a Sterling B2B, good piece of kit. A battery will only take the charge current it needs. 
One overlooked advantage with the B2B, is that being an inverter it charges at the same rate whatever the starter voltage. In other words on a cold wet night, with the lights, heater, demister, wipers all on the altenater/starter battery voltage can drop to around 13.3 volts. This will slow down the rate of charge to the batteries both starter and leisure. The B2B will still charge at 14.4 or 14.8v (or less) depending what you have set it to, even with a lower input voltage. I have one of the remote control units sited next to the drivers seat and gives all sorts of info on voltages, currents, temps, etc. When my batteries are quite low the input current reaches 50A for about 2 mins and after about 5 mins drops to about 20 - 25A.
I think it was Maingate who said something along the lines of check your requirements and then see if you can lower them. Go for Max power in, Min power out.


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## wildcamp (Nov 7, 2012)

Hi Talbot,
It is unusual to have your fridge connected to the LB circuit.  Are you sure this is as intended by the maker?

Current would not be 'diverted' (that's not how it works) but if it is connected as you say then the current used to operate the fridge will cause a voltage drop in the wiring to the LB and therefor it will never get the full alternator voltage when the fridge is on and the battery will never charge fully.  Maybe this is your problem.  (Fridges can draw around 10Amps at 12V but this is very dependent on the make and type of fridge.)

To my mind the fridge and LB should have separate wiring back to the relay.  This is what I have done on my self build.

Can you check if this is supposed to be this way with the manufacturer or do you have a wiring diagram you can consult?


Anyway:
The max current available for charging is dependent on:
1) the current the alternator can supply - normally 60A or more
2) the internal resistances of the starter B and LB - normally < 0.002 ohms
3) the resistance of the wiring between the starter B and LB.  - depends on wire diameter and length.

The major restriction here is simply the wiring and this is the only thing that you can change easily.  (Although you can fit larger alternators or have twin alternators if your engine can take it.)

You can charge the LB at a very high current by using short and/or fat wiring but be warned that the relay will have to be up rated to carry the extra current and everything will have to be fused and wired correctly and appropriately.  Of course as the LB charges the voltage quickly approaches the alternator voltage and the current drops off and will eventually reach near zero amps.


Indeed, the sizing of the wiring may be selected to control the maximum charging current and there are a few reasons why a manufacturer may want to restrict the charging current in this way.  e.g. to protect the battery (high charging currents can damage a LB) or simply to keep the cost down.  Maybe also be safety reasons like to prevent any gas generation in the LB and reduce risk of explosion!


Anyway, it may just be the way your fridge is wired.  You can experiment by switching your fridge off.  Also if you have a multimeter you could check the LB terminal voltage with the engine running (after the relay has clicked in) with the fridge on and with it off.

All this assumes that you have a split charge relay system of course!

Cheers


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## FULL TIMER (Nov 7, 2012)

If I was the OP I would re wire the  split charger which is aready fitted to provide power for the fridge when traveling from vehicle battery/alternator , and then fit the Sterling B2B charger to charge the leisure battery, wire the solar panel direct to leisure battery via regulator,


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## wildcamp (Nov 7, 2012)

Hi Fulltimer,
It's all about the voltage drop down the wires.  In my view as an electronics bod they should be wired back to the relay separately otherwise the LB will NEVER get full alternator voltage when the fridge is on;  This can be mitigated by using heaver wire BUT there will still be an unnecessary voltage drop.

It's all down to Ohms law really.  :cheers:


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## FULL TIMER (Nov 7, 2012)

Yep I was then sitting there thinking about that and edited my post while you wrote yours , I have always wired them seperate anyway and for the fridge I normally use 65 strand wire to the fusebox and. 44 strand to the fridge from there. for the charging relay I normally use 120 strand , I also use the durite or  amber valley chargeguard  self sensing relays not the crappy things that you see in caravan stores


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## wildcamp (Nov 7, 2012)

Ha Ha :lol-053:

No worries 

I've heard that alternators on new cars and vans may now produce 14.2V (or something like that) rather than the 13.8v we are used to.  If this is the case then the B to B chargers are a little bit more difficult to justify.  Of course they work by stepping the 13.8V up to something above 14V to make sure that the LB is 100% charged, but if you have over 14V anyway...


I dont think that 13.8V is really enough to charge a LB to 100% but is fine and safe for a starter battery (and just about OK for a LB, just takes longer).  I guess advances in batteries means that they can now safely up the alternator voltage and I recon this means that they can fit a smaller starter battery to save weight.

Anyway, not come across one myself but something to look out for.


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## sparrks (Nov 7, 2012)

wildcamp said:


> Hi Talbot,
> 
> Current would not be 'diverted' (that's not how it works) but if it is connected as you say then the current used to operate the fridge will cause a voltage drop in the wiring to the LB and therefor it will never get the full alternator voltage when the fridge is on and the battery will never charge fully.  Maybe this is your problem.  (Fridges can draw around 10Amps at 12V but this is very dependent on the make and type of fridge.)
> 
> ...



That's the disadvantage of a split charger, the B2B will compensate. For example I run a 12v compresser fridge off from the leisure batteries 24/7 when using the van, this draws approx 3.5A, say the batteries are charging at 9A and the fridge cuts in the load going into the batteries rises from 9A to 12.5A, if I now put my small roadpro electric oven on, another 10A, the load from the B2B going into the leisure batteries rises to 22.5A, switch the additional loads of the current drops back down to what the batteries need. It appears to me that that the B2B will compensate for any load (up to it's max output) that is on the leisure battery whilst the engine is running.


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## wildcamp (Nov 7, 2012)

Yes, I hear what you are saying B2B systems are good but are expensive and a good split charge system can charge your battery just as quick if you want.  Although a B2B system can adjust its output voltage up or down to facilitate a 'multi-stage' charger if you pay enough money and this may be better for and help extend the life the LB.

Some people get confused over current and what it is.  In your post you mention how the B2B is compensating because the current is going up.  This is not strictly true.  I could replace your B2B with a split charge relay and an ammeter.  As you switch your loads on and off the ammeter will read the same way as you have described with your B2B, this is a simple fact of electric circuits and not a function of your B2B.  However it may be more complicated as your B2B may be increasing it's output voltage, especially if you have 'remote sensing' of the battery TERMINAL voltage.

It starts to get complicated quickly and is difficult to explain fully in a few sentences.

In short your B2B charger is NOT generating extra current.  You cannot directly generate current, you can only generate voltage.  Current is a product of a potential difference across an impedance.

Rubbish right?  Well no it's not.   In our case when charging a battery the potential difference is the difference in voltage between the generator (alternator or B2B charger) and the battery terminal voltage and the impedance is the addition of all the resistances (as we are only dealing with DC) between the two voltages.

I=V/R


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## Firefox (Nov 7, 2012)

thegoodlookingbloke said:


> Save your money. Solar power is nowhere near the claims of these companies that are out to sell their products so they try and baffle you with technological crap that just doesn't stand up.
> 
> You don't get 'ought for nought' and solar power can only give you a fraction of what your batteries need for normal use.
> 
> Your alternator is the mighty powerhouse so unless you are marooned in the Sahara with no engine, forget all this Solar hype. :wave:



During the summer 1x100w solar panel can supply 50-60 Ah per day (or more). It's enough to restore a 100Ah leisure battery discharged to 50%. In the winter you may need 2 or 3 times the solar capacity due to lower sun angle, shorter daylight hours and more cloud cover.

"You don't get 'ought for nought' " is a summary of the first law of thermodynamics and refers to a closed system. It's therefore a misquote as applied to solar power which is not a closed system as there is an external source.


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## sparrks (Nov 7, 2012)

wildcamp said:


> Some people get confused over current and what it is.  In your post you mention how the B2B is compensating because the current is going up.  This is not strictly true.  I could replace your B2B with a split charge relay and an ammeter.  As you switch your loads on and off the ammeter will read the same way as you have described with your B2B, this is a simple fact of electric circuits and not a function of your B2B.  However it may be more complicated as your B2B may be increasing it's output voltage, especially if you have 'remote sensing' of the battery TERMINAL voltage.
> 
> It starts to get complicated quickly and is difficult to explain fully in a few sentences.
> 
> I=V/R


You're right, it is difficult to explain fully in a few sentences. The point I was making, albeit badly, was as the load increases on the starter battery the voltage decreases thus lowering the charge capability as the potential difference lowers between the starter and the leisure battery. The "compensation made by the B2B" is that it's an inverter and raises the output voltage increasing the potential difference and increasing the charge rate. This output voltage is fixed by the setting selected by battery type. In normal use I have my vented unsealed lead acid batteries set to european gel at 14.4v, if I need a higher rate of charge I set it to the wet lead acid setting at 14.8v. With a split charge system if you have a load like a fridge off a starter battery along with other loads this can lower the starter battery voltage and reduce the charge rate. The output of the B2B in normal use is not affected by the input voltage whereas a split charge system is depedant on it.


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## wildcamp (Nov 7, 2012)

Yes, I agree with everything you said here.  It sounds like you have a very decent B2B charger and know what you are doing.

One thing is that the alternator does a very good job of maintaining the voltage on the starter battery due to the heavy gauge wire and the fact it is a regulated output.


I guess the point that I am trying to make and getting back to the subject of this thread is that there are split charge systems and split charge systems.  Talbot to have a compromised system and it could be vastly improved with nothing more than a bit of rewiring at very little cost if he can do it himself.

It is possible to get a good result and rapid charging from a split charge system but as I said and you have pointed out the output from an alternator is not really of high enough voltage to make a perfect job of it.

I guess it all depends on how much money you are willing to spend.  If you are full timing and are often off the grid than a B2B system may make sense as it will fully charge and protect your battery rather than just 80 to 90% you may get from a split charge system.  On the other side you can beef up the wiring and relay and buy another battery to double the capacity for a cheaper price.

Anyway, I reckon Talbot should test his system to see what is really going on before spending any significant money.  :cheers:


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## maingate (Nov 7, 2012)

This is an interesting debate and it has raised one issue which means anyone with a German van using the Electroblock unit will not need a B2B charger.

There is no effect on the charging rate of my leisure batteries when the fridge is switched on. I know this from previous observations on my control panel. What you say must only apply to other charging units.


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## sparrks (Nov 7, 2012)

I certainly agree that the most cost effective upgrade can be to the wiring, I use welding cable of approx 25mm csa with many hundreds of strands. My main reason for commenting was that for anyone needing a large amount of charge in a short space of time cannot go wrong with a Sterling B2B charger or simliar. It also works well as previously stated under poor input voltages. It would also appear that a decent solar panel or two would be a valuable addition.
I notice your comment about adding another battery for extra capacity, this is all well and good, but if you're not charging the first one successfully  how would adding a second help matters?, although would be helpfull on long journeys.
Which comes back to this point - reduce your Amp/hrs requirements. For example my music system in my van uses about 250mA on full volume. I use a creative labs 2.1 surround system  which I converted to 12v and an mp4 player with about 130 albums recorded in flac.
OP, good luck with whatever you choose.


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## wildcamp (Nov 7, 2012)

Sparks,
I reckon if you have a decent split charge system then you may get to 90% of the charge form a B2B system (just my guesstimate mind you) 

My thinking is that 2 batteries at 80% are better than 1 battery at 100%

A decent split charge system will get you to 80% pretty quickly.  Of course batteries should always be fully charged for their health,  but if you have solar or plug in from time to time to top them up then...

Cheers


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## Firefox (Nov 7, 2012)

I see you edited your post... I wondered why you were referring to me before, LOL!

My split charge is just a manual 45A trip switch and a 100A wire, I didn't bother with a relay. I think I only get 80-90% of charge from alternator compared to a 240v hook up smart charger judging by how long the batteries last till they drop to 12v. Alternators on their own are not brilliant at charging. To top up the charge on the plates needs alternating periods of constant current and constant voltage together with sensing of leisure battery voltage whereas the alternator is a blunt sword, it just chucks out the same output regardless!

But combined with a constant top up from solar and plug in occ, they are not bad.


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## wildcamp (Nov 7, 2012)

Exactly Firefox, Exactly.

Sorry for the mistaken identity.

Just out of interest, how many miles do you reckon it takes to charge your LB to 80% with your setup?


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## Talbot (Nov 7, 2012)

Wow, just got to say I'm overwhelmed by the responses and a particular thanks to Sparrks, Wildcamp, Firefox, Maingate and Fulltimer for providing extensive information. There's a lot to take in and it gets incredibly complex for me to fully understand, although I think I'm with it.

Yes, the manufacturers claim they have been wiring fridges directly to the LB for years with all their models. Quote from recent email _for as long as I have worked for (Manufacturer) the fridge has always worked off the leisure battery and not from the vehicle battery. The relays, when the engine is started,  switch the 12v off in the rear, put power to the leisure battery from the vehicle to charge and also allow the fridge to operate from the leisure battery. _

I agree with your comments regarding a full test to evaluate what is going on, how much charge is going to the fridge and to the LB, so I will do this first. However, I'm confused as to the best solution to resolve this, whether B2B or enhance the split charge configuration. Also a little concerned that its a new MH and has a 3 years manufacturers warranty so will I be able to modify the electrics and keep within warranty? I'm not able to do this myself so would need to buy the service from a supplier.

If I install a B2B charger does it charge directly to the battery via the alternator or would the additional power go via my onboard Sargent 155 charger. If so, could it cope with the increase of power to charge the LB or is it likely to be a bottleneck? I don't think the 155 is a particularly powerful charger. 

Greatful for a little more explanation and what you would do next if it were you. Additionally, my MH is a conversion based on a LWB Boxer van, so I don't really have additional room for a second LB and I can't get another solar on my roof.

Thanks in advance for everyones input and advice.


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## FULL TIMER (Nov 7, 2012)

the STERLING B2B is only connected to your batteries there is no connection to the alternator it would be totally seperate from any other device on your motorhome, to work out what your fridge is using just look for the wattage  on info label probably 120w, so devided by 12v gives you 10 amps more information on the B2B here. Sterling Power Products: Battery-to-Battery Charger Information


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## wildcamp (Nov 7, 2012)

I've just had a look at the sargent website and could only find the user manual for the EC155, I guess it is this one that you have.

It looks like this unit is supposed to look after everything for you and has an internal split charge relay.  Although it is not exactly clear.

On page 10 it shows the battery connector with pin 1 as the "Fridge 12 V output" and pin 7 as the "Fridge power in / Engine run"  

So it seems to have a separate fridge input for when the Engine is running which makes sense as apposed to the fridge being connected to the leisure battery.

I would try to find out how this connector is wired to your van and then phone Sargent and check that it is correct and explain your problem,  they may be able to offer a solution or advise on a different charging solution.

Also, I stick by my voltmeter test on the LB terminals.  Connect the voltmeter across the terminals (or get an assistant) note the voltage and start the engine, after a short while the relay should click (you may not actually hear it) and the battery voltage should jump up as the charging starts, note this voltage and switch the fridge on or off and note how the voltage changes.  You will need a volt meter with a resolution of 2 decimal places on a 20V scale.  You can get a cheep multimeter from Maplin or of ebay for about £8.

Please post your findings 

Cheers


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## sparrks (Nov 7, 2012)

Talbot said:


> ............Also a little concerned that its a new MH and has a 3 years manufacturers warranty so will I be able to modify the electrics and keep within warranty? I'm not able to do this myself so would need to buy the service from a supplier.
> 
> If I install a B2B charger does it charge directly to the battery via the alternator or would the additional power go via my onboard Sargent 155 charger. If so, could it cope with the increase of power to charge the LB or is it likely to be a bottleneck? I don't think the 155 is a particularly powerful charger.
> 
> ...



Your warranty concern is one of the reasons I chose to install the B2B as my van was 6 months old at the time, (not sure what it did to the warranty by cutting two holes in the roof though) there is a temp sensor to fix to the alternator mount. Sorry can't help you with the Sargent 155 unit.

Personally if it was me I would see if the current setup is actually working properly, if it's not get it fixed and see if I can live with it, whilst trying to reduce the load requirement. Have you got room for a larger capacity battery to replace the existing? How much longer does the warranty run for?
Best of luck


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## Talbot (Nov 8, 2012)

wildcamp said:


> I've just had a look at the sargent website and could only find the user manual for the EC155, I guess it is this one that you have.
> 
> It looks like this unit is supposed to look after everything for you and has an internal split charge relay.  Although it is not exactly clear.
> 
> ...



Have done as you suggested and phoned Sargent explained problem and clarified the wiring situation. Very fortunate as I spoke to the very person who designs the wiring looms for this manufacturer and he was surprised at what they told me. He clarified the position that the industry standard is to charge the fridge from the engine battery and he had the wiring diagrams in front of him for my vehicle and confirmed that I am powering the fridge via the engine battery. He also explained that Peugeot lay a 50amp supply to behind the drivers seat and the MH manufacturer pick it up from there. At this junction I have an 8mm cable capable of carrying in excess of 50amps which is regulated by a 20amp fuse. So he says I should not have any probleems with the wiring size. He has asked me to drop test the LB and take a meter reading on the EB and LB with the fuse removed from the Sargent EC155 Control Unit to see what the alternator is producing. He thinks it could be the LB not able to hold charge or a problem connection. I have booked this in to the dealer next week and shall report back. Thank you everone for your ideas and suggestions and it does sound like I will also benefit from a Sterling Alternator to Battery charger as well. Happy camping


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## wildcamp (Nov 8, 2012)

Glad to hear that you are on your way to getting it sorted.  Always best to speak with someone familiar with the setup 

So the MH builder said that your fridge is running from the LB and Sargent say that it should run from the engine battery.  I hope that the MH builder have not fudged the installation and were just confused when you spoke to them earlier.

Those Alternator to Battery chargers are quite expensive.  The B to B ones are a bit cheaper.  Either will probably do a great job though.

Cheers


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## Firefox (Nov 8, 2012)

wildcamp said:


> Exactly Firefox, Exactly.
> 
> Sorry for the mistaken identity.
> 
> Just out of interest, how many miles do you reckon it takes to charge your LB to 80% with your setup?



Probably about half an hours driving per battery. Say 30 mins each  for the two leisure and 15 mins for the starter 1 hour 15 mins total. By all accounts of B2B chargers, that could be reduced considerably. If one is doing lots of short trips between camps and B2B could be a useful purchase.


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## wildcamp (Nov 8, 2012)

Yes, I coming around to the idea now.

If you have a split charge system it's wise to make it as good as you can.  After all they do a fair job and are cheep.

A B2B system will do a better job, charging to 100% and keeping your batteries in better health.  Maybe even extending the useful life of your batteries and then maybe paying for itself in the long run.  It's just the initial cost is a bit prohibitive, for me anyway.

Good thread this.

Cheers all.


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## Firefox (Nov 8, 2012)

My estimates are probably on the low side. It depends how much my batteries are discharged. But an alternator at 20 Amps for 90 mins would only put back 30 amp hours. Enough for a nights wilding but If I'm 60 or 90Ah down it would take a run of 3 hours or more.


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## oldtech (Nov 8, 2012)

This is a really interesting thread with many good comments.
Sorry if this comment muddies the waters somewhat !

I decided , some time ago to have the alternator ONLY charging the starter battery.
Sounds dumb doesn't it ?
Some would say that once my vehicle's battery was charged I would be just  "wasting" 
available alternator current.

Here's why I decided .
Every bit of current from the alternator costs money in terms of extra fuel used.
You don't "feel" the drag of the alternator when you are driving , but it's there !
The drag is at it's lowest when all batteries are fully charge , then the alternator is under "no load "

If you ever had a dynamo on your pushbike you will know what I mean.
When you turn your lights on you can feel the extra effort needed to maintain a certain speed.
It doesn't matter if it's a hub dynamo or one that rubs against the tyre rim , the result is the same.
There is no such thing as free energy , and ALL conversion processes waste a proportion of that energy.

If you turn on your headlights in daylight , you may well be safer , but you WILL pay for it in terms
of fuel consumption.
Turn on your Air-con ( if you have it ) and you REALLY start paying for it , because you are using 
mechanical energy to spin the compressor , in addition to spinning the alternator.

There is only ONE thing that is truly free in a motor vehicle and that is heat .
That's because it is an unavoidable by-product of a running engine , and so is noise.

OK , for many vehicles , there is no choice but to use alternator power to charge auxilliary batteries,
.... unless you have solar !!!

But don't think that an alternator gives a "free" charge .... it's simply not so !

*Oldtech*


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## Firefox (Nov 8, 2012)

This is correct:ditto:

The more current you draw from the alternator, the more load you put on the drive belt. It stands to reason as the wires carrying the current produce a magnetic field and this field has to interact with the permanent magnets as the alternator spins.

There's no free power unfortunately, the engine needs to work for it. This concept of "free" alternator power is what made the HHO scams so successful. You can produce hydrogen gas using a current, and you can burn it for power, but the current does not come without drag on the engine via the alternator drive belt. Fortunately for the scammers most of the public don't understand the physics, hence a tidy profit selling plans and kits for HHO generators emerged!


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## maingate (Nov 8, 2012)

This is why I make sure my batteries are fully charged from home hookup before I set off on a trip.

After that we are all at the mercy of the weather and our solar panels. My 190 watts of panel are freestanding because I can still get power in Winter (assuming the Sun is out). I have had 4 amps at 10.30 am (ish) on a February morning from a 90 watt panel.

The way we use our vans is a balancing act. Different people do it different ways. My overall view is that the cost of setting up for successful wilding is soon recouped by avoiding sites (as much as possible, or at all). You need a bit of luck and you need some flexibility with your planning but it can be done.


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## Firefox (Nov 8, 2012)

With the modern panels you can still get some current when it is cloudy and even more so if you angle them and sun follow in winter. With 200W of panels, you can still get 10-30Ah depending on conditions. Not brilliant but worth having, and if you are frugal with power, that can last you the evening.


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## oldtech (Nov 8, 2012)

*Well said Firefox !
*
You are singing my song .. ha ha !

My Golden Rules for Green living are :-

1)  Do everything possible to get *ALL* of your " solar harvest " into your batteries
     most charge controllers / regulators switch out of bulk-charge mode *FAR* too early,
     .... and a lot of the solar energy is wasted before it even gets *near *to the batteries.

2) Change your lifestyle , if necessary , so you only use the power you *REALLY* need and
    use it only *WHEN* you really need it .

3) Buy the best batteries you can afford , and the best batteries for our kind of lifestyle
    are 6 volt "golf-cart" batteries , no question  .... most "so-called" leisure batteries are junk .
    If they appear cheap then it's just "false-economy "   ...* " Penny wise and Pound stupid "*

4) Be nice to your batteries and *they* will be nice to you !
    There is no reason why quality batteries shouldn't give you 8 years or more of faithful service.
    But *ONLY* if you keep them FULLY charged  and *DON'T* deep-discharge them .

Happy Green living everyone 

Regards 

*Oldtech*

PS  Hey Phil ! .... have you got a sort of " Sunshine " smiley-type thing to add to the list ?


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## Talbot (Nov 8, 2012)

oldtech said:


> This is a really interesting thread with many good comments.
> Sorry if this comment muddies the waters somewhat !
> Every bit of current from the alternator costs money in terms of extra fuel used.
> But don't think that an alternator gives a "free" charge .... it's simply not so !
> ...



Fully appreciate your comments, but that doesn't really concern me. I want to achieve the maximum performance from my alternator when I am driving to my next wild spot. Might be 5 miles or 20 miles, but I'm not one to sit in the same spot for more than one or two days anyway. I like to keep moving and see new places and afterall is it not wildcamping ethics to move on from a 'wild camping' spot after one or maximum two days at any one time. I'm certainly not driving around just to charge my battery and I agree that it would be bonkers for anyone to do that with the cost of diesel.

The other interesting thing is that I have a built-in computer that records my trips, mpg, length of trip, time etc and I have never noticed any difference in mpg with air con on or air con off, windows open or windows closed my vehicle does 34mpg at 60 and 31mpg at 70 on average over the trip. I did 4000 miles through France in August and achieved an average of 31.4 on the trip. I'm pleased with that, but back to the main point, when I do drive my short journey I need to put as much charge back into the battery as I can. Hence the thread and I really have learned a great deal from everyones contribution.


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## Talbot (Nov 8, 2012)

oldtech said:


> *Well said Firefox !
> *
> 
> My Golden Rules for Green living are :-
> ...



Hi Oldtech, are you saying there is a solution to stop controllers turning off too early?


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## sparrks (Nov 8, 2012)

Info from Sterling power  Sterling Power Products: How effective is advanced battery charging on a battery and can it damage the battery?



oldtech said:


> Here's why I decided .
> Every bit of current from the alternator costs money in terms of extra fuel used.
> You don't "feel" the drag of the alternator when you are driving , but it's there !
> The drag is at it's lowest when all batteries are fully charge , then the alternator is under "no load "
> ...


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