Running different batteries?

[corsetts]

Hi all,

The leisure battery died in our caravan whilst on holiday recently. The surf is fitted with two Optima deep cycle batteries so I took one of those for the caravan and put the caravan battery in the Surf.

I must admit I forgot all about it and the caravan battery is still on the car.
Will it do any harm to anything running batteries of differing capacities or should they be matched?

Cheers,

Chris

[MattF]

Won't make a monkeys.

[wishbone]

I thought if you mixed a 'dead' battery with a good one the dead one would pull the good one down ? (when the alt isn't charging)

[MattF]

I thought if you mixed a 'dead' battery with a good one the dead one would pull the good one down ? (when the alt isn't charging)

Yup, you're correct. I had misread his question. I thought he was referring to differing capacity batteries. My blonde moment for the week there.

[corsetts]

Yup, you're correct. I had misread his question. I thought he was referring to differing capacity batteries. My blonde moment for the week there.

No, no you were quite right. Sorry, my bad, I didn't phrase it very well.

Yes I was refering to different capacities, although the caravan one was flat it didn't pull the ampage down enough that i couldn't start it so i was just wondering what the implications were long term.

Thanks for the help, I'll leave it as it is then

Cheers

Chris

[Maverick]

If I remember correct you'll knaker the caravan battery. I think they are not desinged for the high starting amp that a car requires, but more for long low draws.

I could be wrong of course.

[Tallyman]

As Maverick said, not really a good idea. A Leisure Battery is designed to provide a small current drain over a long period of time, whereas a car battery is designed to take a big drain (starting) and to recover quickly in case it's needed again. Giving the leisure battery a charge via the car's alternator isn't a problem if it's dead but you'll knacker it completely if you leave it in there too long and use it to start the car, even if the second battery id still connected with it.

[corsetts]

Thanks for the advice, much appreciated.

I'll hoik it out then and replace with the original.

Cheers,

Chris

[Maverick]

What I did when I ran out of charged batteries in Scotland this year, was I connected the grey electrics cable to the truck and started her up, then connected the other battery via jump leads and left the truck running whilst I cooked (OK she cooked) tea (about half an hour). This put enougth charge in the two batteries to last me another four days (the solar panels were not getting enougth sunlight).

For next year I plan to use the split charge circuit I found in the shed and make up a charging circuit in the boot with quick release caravan clamps, that way once the first battery is dead it can go in the car for charging whilst the others run through.

[corsetts]

Thanks for that, I did wonder how long I'd have to run it off the car to give it a useable charge.

Annoying thing is that I wired my auxhillary so that if the battery did go flat in the caravan I could just plug the car in and run off that as I gave it a permanent live.
It all worked fine when I did it and tested it, then when I needed it, there was nothing there.
The battery indicator in the van showed that there was plenty of juice but as soon as I switched even a light on, the voltage would drop off the scale.
Dunno whats gone wrong there, I'll have to have a dig and see whats happened.

cheers

Chris

[Maverick]

I noticed that the caravan charger circuit only allowed 13volts to go to the battery, whereas the battery that was connected via the jump leads was getting just over 14.5v. But then there is a hughe difference in wire between my jump leads and the caravans wiring.

[wishbone]

When I was reading up on split charge systems they said it was a poor connection between the car and caravan that gave the biggest probs with voltage drop. If I was going that route I'd look for a secondary connection (military maybe ? ) just to run the battery charge from the car to the van and use 0 gauge wiring throughout to minimise voltage drop. In my surf I'm using 4 gauge to run from the main battery to the leisure, and upgrading all the earth leads too.

Rob.

[Maverick]

What I intend to do before next year is run some 50amp cable to the boot, and install a split charge circuit in the cubbyhole that houses my rear fuse board. So when the first battery is flat I can just connect it to the car and it will charge whenever we go out for a drive.

[MattF]

Are caravan/leisure batteries more along the line of a typical SLA battery then? Charging finnickiness and all?

[darkdezigns]

Thanks for that, I did wonder how long I'd have to run it off the car to give it a useable charge.

Annoying thing is that I wired my auxhillary so that if the battery did go flat in the caravan I could just plug the car in and run off that as I gave it a permanent live.
It all worked fine when I did it and tested it, then when I needed it, there was nothing there.
The battery indicator in the van showed that there was plenty of juice but as soon as I switched even a light on, the voltage would drop off the scale.
Dunno whats gone wrong there, I'll have to have a dig and see whats happened.

cheers

Chris

that'll most likely be poor earth,when i take van i always take my jump pack,if van goes flat run it on that,then when u go out take it with u and charge it up in the car