D90mitch
Well-Known Member
Thanks for the tip, I will have a look when I am back at the weekend.
Going to be a bit of a bitch for the cables to link the two though?
Any piccies from people that have dual batteries?
joshremlin
Active Member
How you doing are you buying the brain as such what does a auxiliary battery straight from the alternater are you just going for a normal car battery with wires off the existing to charge it... I only ask as I need a dual battery for a c.b and some flashing lights so I can leave them on without the car running and killing the battery.
D90mitch
Well-Known Member
Deep cycle battery, Haven't decided on wiring yet - for a winch.
D90mitch
Well-Known Member
Ok that would be appreciated.
joshremlin
Active Member
Ive got a brand new normal car battery I think ill get away with that for now as the flashing lights and cb isn't high watts/amps
forkliftfred
Member
I made one recently. 100 amp relay operated from a switch which also switches on a voltage meter so I can monitor it. I've also wired the relay from the D+ on the alternator so the relay will only switch on when the engine is running!!
ronsealdeath
Sagging Member
B+ mate. D+ is always live so your batteries will be constantly connected with that setup which is not good.
If your going to be using a winch I would suggest the biggest single battery you can get in your main tray, say at least 1000CCA job, and when you winch just idle her up a bit or put in some kind of hand throttle. Dual batteries is only really useful for fridges and spotlights and so on. If you want to winch with the engine off it would be a help but that won't make your batteries last too long before they go flat! Having said that, dual batteries are cool.......
main thing innitTwo Optima yellowtop dual starter/deep cycles would be a sweet setup.
Wish I knew how to connect the 2nd battery in a proper way - I got this car with two batteries already there, connected parallel, I think. So they were draining each other ot something, I don't know for sure as I'm a bit of a dumbass when it comed to automotive wiring/electronics and so on. I've disconnected my second battery and removed it. Sometimes I drop it back in as a spare, without connecting it. Both are 65 Amh or whatnot. So together way over 100. The alternator is what, 75? So isn't it bad dor it to charge two bayteries at the same time?
Datatek
Well-Known Member
Unless one battery is faulty, one will not discharge the other and it's fine to connect 2 batteries of the same type & AH together, they will just take longer to charge fully. You need to check the voltage you are getting from the alternator at 2K rpm, you need around 14.2 volts to fully charge a modern battery.
If the second battery is just for a winch for example, you can fit a relay to seperate it from the main battery except when the engine is running by using the D+ on the alternator to energise the relay.
