main battery and 'leisure' battery CCA question

[fairwynds]

Afternoon everyone, cold innit?!
As van not been run for a few weeks, due to ongoing resto work, I thought I'd better give my batteries some tlc.
Both my main and leisure (under pax seat) batteries are no older than 18 months.
The main one is the older style, with removeable caps and you can top up with distilled water etc. It has a sticker on top which states
"CCA SAE 620 amps AH (20h) 65 amps"
The leisure one I put under the passenger seat (following various advice here re the pros and cons of proper leisure v ordinary car batteries) is an ordinary, non leisure battery which has a sticker on it which states
"CCA SAE 700 amps AH (20h) 70 amps"

My question is, is it best practice/worth it to swap them over so the higher CCA (Cold Cranking Amps) battery is used as the engine starter battery?
Will my current set up be an issue for the split charger, perhaps not being able to fully charge the second/leisure side battery?

As you will appreciate, electrickery not a strong point!

Thanks for your help...

FW

[California Dreamin]

Afternoon everyone, cold innit?!

My question is, is it best practice/worth it to swap them over so the higher CCA (Cold Cranking Amps) battery is used as the engine starter battery?
Will my current set up be an issue for the split charger, perhaps not being able to fully charge the second/leisure side battery?

As you will appreciate, electrickery not a strong point!

Thanks for your help...

FW

Firstly, these two batteries are similar sized (not like having a 65ah starter and a 110ah leisure) so charginging disparity won't be dramatic.
Secondly, once running and charging through the split charger it doesn't matter which is in which position as both are directly connected and being charged as one combined battery.
Obviously the higher CCA is better for those really cold starts but again there isn't that much difference between the two batteries you have.
As yours is Petrol engined I wouldn't bother changing them over, I would be tempted if it was a diesel, just to give the better battery to the glow/plugs and higher demanding diesel starter motor.
Standard split charge system... then it's likely to be fairly basic and low rated split charge setup but they do work and your leisure battery isn't particularly big.
Unless you have a reason to believe there is an issue?
Obviously if you were replacing the relay or wiring it would be a good time to upgrade whilst your at it.

Martin

[fairwynds]

Martin, thanks alot - makes sense, and means I don't actually have to do anything!
Ive got one of those itelligent charger systems which I plug in periodically. But because of the intense cold at the moment, and the fact that van hadnt been started for several weeks (due to ongoing work taking longer than expected!) I thought Id give them both a charge.
Initially the main (NON maintenance free) battery kept coming up with 'error F01' which the instructions say means 'check battery OR too low a charging current set'. I topped up electrolyte and charged at higher rate and all ok. BUT the leisure side one is maintenance free, so cant do electrolyte and still getting error message - will check later with a digital multi meter (just had to buy one as the one I had was old fashioned analogue and not up to job!)
Hopefully this second battery is not defunked!
Cheers
Jonathan

[California Dreamin]

Hmmmm yeah......well you know as well as I do that car batteries just don't like being sat fully discharged...infact they die within a few weeks as the plates become sulphated.
Hopefully you caught yours before any permanent damage was done.

A further thought....the battery with the removable tops is best as 'leisure' because it is likely to be worked harder during camping/recharging/discharging and so will benefit from the ability to top up the cells as water is used.

Martin