Adding a Battery to Battery (Sterling Type) Charger to Leisure Battery Bank (1 Viewer)

Camping Gaza

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If this was to be done would you have to disconnect the existing charging circuit from the batteries?
(ie charge from the split relay from alternator)

Or do you simply add the BtoB into the existing system:

Source: Vehicle Battery/ Cables to Battery to Battery Charger/ Cables from charger to the target battery bank leaving the existing charger in place?

I'm guessing it should not make a difference....
 

Al1

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It's what I did, after all you add solar and don't remove anything.
Al
 
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Camping Gaza

Camping Gaza

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Thanks Al, I was wondering this tho... As the BtoB "tricks" the alternator into delivering a higher current, would the split charge if still connected "untrick" the alternator?

I'm guessing that if you put one in Al, and yours works all ok, it does not. Hope you could confirm this for me. Cheers

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Steve and Denise

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When I fitted our B2B I fitted a relay to disconect the standard charger as the B2B takes care of all the charging.To find a feed for your relay I used the +d from the fridge of step signal when the engine was running. A good man to ask is Jon @jonandshell or Andy @Techno they both have experience in this area
 

Techno

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What do you mean by the standard charger ?
The rapido simply parallels the batteries when the engine is running, if you isolate the battery parallel the fridge won't get 12 volts
 
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Robert Clark

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It's says in our owners handbook that the leisure batteries will never be fully charged by connecting them to the engine batteries via the split charge relay - however a good solar regulator and some solar panels will add the little extra required.

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Camping Gaza

Camping Gaza

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@Techno ... So if I connect a BtoB and don't touch the charging circuit that's there, will it have any adverse effects or will it charge the leisure bank at full charge still tricking the alternator?
 

Techno

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I found sometime after buying my van that someone had previously removed the battery parallel fuse on my CBE distribution panel
The consequence of this was that my AES fridge was switching to gas without my knowledge which was a potential disaster if going for fuel
 

Techno

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IMG_5894.JPG
 
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Is that display showing amount of Amps being fed into your leisure battery ?

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Steve and Denise

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Hi Andy
I did try to explain this as I had done it with the advice given by members who are more familier with this type of system than me ie YOU & JON and it has worked a treat ever since. By the way I have added a third battery now and am monitering the results.(y)
 

Al1

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Thanks Al, I was wondering this tho... As the BtoB "tricks" the alternator into delivering a higher current, would the split charge if still connected "untrick" the alternator?

I'm guessing that if you put one in Al, and yours works all ok, it does not. Hope you could confirm this for me. Cheers

Mine has been working fine, fridge works on battery and hab battery getting good charge.

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Camping Gaza

Camping Gaza

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Update: Bought a Ring b to b charger, (cheaper than sterling) connected to battery, and solar panels to the b to b charger cos its got one built in. All working charging from altenator via cab battery, shuts off at set voltages, solar charging all good great bit of kit!

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A few months on from the start of this thread I have a question that I just can't straight in my head...
So @Techno can you please talk me through this?
  1. Lets say the leisure batteries have a 50% charge - around 12 volts
  2. You start the engine, the alternator provides a charge to the vehicle battery (let's suggest this is 14.4 volts). The split charge relay parallels the leisure battery and if you put a meter on the leisure batteries it will read 14.4 volts.
  3. The B2B charger is connected to the vehicle battery and the leisure batteries
So what makes the B2B charger (in my case a ctek D250S) think the battery needs a full charge of 20 amps?

Surely the split charge relay needs to be removed?
 

haganap

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I can only speak from experience and from usage. But when I done my first one @Sidney a relay was fitted to bypass the split charge but allow the fridge to continue to work, my solar panels went through the relay so to not confuse the B2B in the manner you describe. Result was it worked perfect.
Fast forward several years and now fitting on my rapido in the way described. parallel to the normal charger, no isolated solar etc and I am convinced it is not as effective and I dropped a battery at Chester that was only 3.5 years old.
However, I have not entirely looked at the problem yet but I think the issue maybe that my Hab batteries are at hte back of a van which is nearly 8 meters and the cab battery is right at the front. Whether or not I am experiencing some voltage drop or not I am unsure but I have yet to see my NASA BM indicate more than 20a going in.

probably complete coincidence but I ought to investigate it.
 

two

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The reason you install a B2B is to improve the charging regime of your habitation battery from the engine alternator. Leaving the split charger in place will not help. It will interfere with and confuse the B2B. The B2B will still “work” but not as effectively as intended.

You should remove the split charge relay if add a B2B charger. You are replacing a simple charging method with something far more sophisticated and the split charger becomes superfluous.

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jonandshell

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Removing the standard split charge relay will mean your fridge will not run on 12v.
Adding a five pin relay at the leisure battery, utilising the normally closed contacts and an ign or D+ trigger, will keep power to your fridge and habitation electrics on the move.
The leisure batteries being charged are then isolated from everything but the Sterling b2b which will the look after them properly.
 
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A few months on from the start of this thread I have a question that I just can't straight in my head...
So @Techno can you please talk me through this?
  1. Lets say the leisure batteries have a 50% charge - around 12 volts
  2. You start the engine, the alternator provides a charge to the vehicle battery (let's suggest this is 14.4 volts). The split charge relay parallels the leisure battery and if you put a meter on the leisure batteries it will read 14.4 volts.
  3. The B2B charger is connected to the vehicle battery and the leisure batteries
So what makes the B2B charger (in my case a ctek D250S) think the battery needs a full charge of 20 amps?

Surely the split charge relay needs to be removed?

See post #30 in this thread for what I did with my CTEK D250S Dual.

http://www.motorhomefun.co.uk/forum...ing-b-to-b-charger.150719/page-2#post-2303641
 

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