Battery to Battery

Dorwyn

Dorwyn

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I've replaced my failing 110 ah Platinum battery with a new one, which is now working fine. The original that was taken out has been has been revived and is now showing a no load voltage of around at least 12.9 volts for the last 8 or 9 days. I'm thinking of connecting it to the new one as an auxillary, but think that it would not work directly connected, since the performance of the two would be different. I don't want to go for a full B2B set up, due to the expense. I just wonder if this unit would do the job?

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I would put it under load to see what happens befre thinking of adding it.
 
I had a quick look but couldn't see what type of battery t is suitable to charge.
Where as this quality unit will charge four types lead acid, AGM Gel or Lithium.
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Dorwyn said:
. I don't want to go for a full B2B set up, due to the expense. I just wonder if this unit would do the job?

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You standard split charge relay in the van will give a higher charge than that providing it is wired with correct size wiring.

Edit:
Just noticed you have an Auto Trail the wiring will be woefully undersize.
Rewire the split charge circuit with 16 mm sq cable check the relay and replace if rated at less than 40 amps. A much cheaper option.
 
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Point taken about putting under load to test. On reflection it's cheaper to buy another new battery and wire it directly. It's just that I'd like to find a use for a (possibly) good battery. Maybe use it to light the house garage.
Lenny HB said:
You standard split charge relay in the van will give a higher charge than that providing it is wired with correct size wiring.

Edit:
Just noticed you have an Auto Trail the wiring will be woefully undersize.
Rewire the split charge circuit with 16 mm sq cable check the relay and replace if rated at less than 40 amps. A much cheaper option.
Click to expand...
The existing cable looks reasonable, and it's very short. Of course were I to use an additional battery, I'd need a few metres of cable and I would use something much thicker. I think the van was built abroad, while they were still Trigano. It was built in the year production was swapped over to Grimsby, and is AT in name only.
 
If you connect the two together, the good battery will always be discharging into the other one until they balance out, like having a full bucket of water connected to another which is only 1/4 full, they will balance out.
 
I expect the old battery has lost its capacity. Doing a check will confirm that. Why carry such an extra 'lump' around for just a couple of Ah? Besides that, I wouldn't put an old battery with an old one.
 
Dorwyn said. Point taken about putting under load to test. On reflection it's cheaper to buy another new battery and wire it directly. It's just that I'd like to find a use for a (possibly) good battery. Maybe use it to light the house garage.


I have used 3 old batteries that are kept in charge with an ancient 40w solar panel on top of my storage shed and a cheap 10amp solar regulator. When needed they charge my battery drills, screw driver, carpet cleaners, hedge trimmer and grass cutter as well as the lighting.
 
hymerman said:
If you connect the two together, the good battery will always be discharging into the other one until they balance out, like having a full bucket of water connected to another which is only 1/4 full, they will balance out.
Click to expand...

It will only do that if the old battery is faulty (Or not fully charged when you first connect the two together in which case you will have a one-off ‘balancing’ situation not an “always be discharging” scenario).

If its capacity has reduced but is otherwise healthy it will be perfectly fine. It’s no different to connecting two new batteries of different capacities; they will act as a single bank with a total capacity of the summation of the two batteries.

Ian
 
Yes bigtwin, that's what I meant, I just didn't explain it correctly.
 
Lenny HB said:
Edit:
Just noticed you have an Auto Trail the wiring will be woefully undersize.
Rewire the split charge circuit with 16 mm sq cable check the relay and replace if rated at less than 40 amps. A much cheaper option.
Click to expand...
Just a shot in the dark! Where would this relay be on an Autotrail (Fiat) ?
 
PhilandMena said:
Just a shot in the dark! Where would this relay be on an Autotrail (Fiat) ?
Click to expand...
I think it's inside the Sargent unit. probably best to bypass it and fit a new relay.

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