Thread: What second batteries do people use ???

Clean32,
If you have a 144Ah starter battery, for 10% discharge you'd get 14Ah usable, for 20% discharge 28Ah. You need to look at the battery specs to see what a particular regular discharge pattern of use does to its recharge cycles. It might cut them down by half possibly (I have no idea; its battery dependent). For a deep cycle giving 28Ah usable based on 70% discharge you'd need a 40Ah battery (in theory).

What you need depends on what type of camping and motoring you do and how many things you connect to it. So, like Adonuff, if you are usually driving every day then a smaller battery will suffice and a large starter battery will probably be OK. An advantage of 2 starter batteries is that, if your main crank battery does cark it, you are likely to be able to start the vehicle with the second battery if its not too discharged. You usually can't do it with a standard deep cycle battery, even if its fully charged, because you can't get the amps out of it.

If you do a lot of camping for days at a time and don't start the car, then a large deep cycle is probably best. Either way, in my view, you need to get the biggest (in Ah) battery you can fit in and afford, which ever type suits your use and risk profile.

Just a technical note so we're all on the same page, an Amp is the rate at which the current flows (like water in litres per second) and AmpHours is the volume or amount of electrical energy used/needed (like 50 litres of water).

Cheers
Mundy

i have two starter batteries would not waste my money on a deep cycle one , when i am out in the caravan i put the second starter battery in the caravan and use a generator for charging etc

Originally Posted by Mundy

Clean32,
If you have a 144Ah starter battery, for 10% discharge you'd get 14Ah usable, for 20% discharge 28Ah. You need to look at the battery specs to see what a particular regular discharge pattern of use does to its recharge cycles. It might cut them down by half possibly (I have no idea; its battery dependent). For a deep cycle giving 28Ah usable based on 70% discharge you'd need a 40Ah battery (in theory).

What you need depends on what type of camping and motoring you do and how many things you connect to it. So, like Adonuff, if you are usually driving every day then a smaller battery will suffice and a large starter battery will probably be OK. An advantage of 2 starter batteries is that, if your main crank battery does cark it, you are likely to be able to start the vehicle with the second battery if its not too discharged. You usually can't do it with a standard deep cycle battery, even if its fully charged, because you can't get the amps out of it.

If you do a lot of camping for days at a time and don't start the car, then a large deep cycle is probably best. Either way, in my view, you need to get the biggest (in Ah) battery you can fit in and afford, which ever type suits your use and risk profile.

Mundy

thanks for that.

funny thing, we drove up charging the new battery say 1.5 hours, and that night only running the fridge ( which was on mains untill we left and every thing inside was frozen anyway). the next day no start, switched over started then switched back a couple of klms down the road. never had a problem after that.

we ussaly drive everyday eather on the move or doing the traps, we are not much for sitting around ( not with minime)