Need to wire a second battery in the plumbing truck. Going with a deep cycle in the back.
I've never set up dual batteries before.
In my mind, i run an auxiliary cable from the positive terminal of the factory battery to the positive terminal of the auxiliary battery in the back. Ground the second battery to the frame.
Still 12 volts, right?
In reply to Dusterbd13 :
Yes. If you wire them in parallel it remains 12V. If you wire in series you'll have 24V. And use a good sized cable because that second battery will be feeding the starter along with the first one. I used welder cable in my race cars.
Cool. We have 00 cable for it. Just wanted to double check my head before i fried something with 24 volts by being wrong.
wiring a standard battery and a deep cycle in parallel might be a bit odd, i mean even replacing one battery in an old battery bank with old batteries isnt great, i cant imagine 2 entirely different types of batteries together is great.
Why do you need the 2nd battery?
Battery isolators are a thing. But like antihero says, why?
More reserves for inverter and task lighting.
I honestly assumed deep cycle was the way to go. Apparently not?
Batteries will kill each other so I've always been told.
Use a continuous duty solenoid to connect the two +12v sides together while the ignition is on and separate the two when it's turned off.
Easier and cheaper than an isolator.
This also means that you can't kill both batteries while using +12v stuff when the ignition is off .
In reply to Trans_Maro :
Have a link to a good one? May be a wise investment here. And i assume the second will charge off the alternator while truck is running?
I think Mr. Maro has it right. Run your non- vehicle load off the remote battery, vehicle off the other.
the offroad expeditionary people are all over that.
Dusterbd13 said:More reserves for inverter and task lighting.
I honestly assumed deep cycle was the way to go. Apparently not?
Deep cycle is the way to go....just not connected to your standard battery too.
What are you running with the inverter?
You want one of these.
Wire the deep cycle to run the non-vehicle load, keep the existing battery as-is. This doodad will charge the deep cycle when things are running but will prevent your non-vehicle load from sucking down the starter battery. If you do run down the starter battery, you can flip a switch and this thing will gang the batteries together to start the truck. Got one in my Vanagon, although in that case it also lets the solar system charge the starter battery.
I wouldn't hook up two batteries in parallel unless they're identical batteries, same brand, same model, same size, same chemistry, same date code. Even then, you're replacing them in pairs, so you've set the lifetime of the pair to be whichever one dies first.
You can use a separate charger to isolate the deep cycle and charge it off the normal 12v circuit, but then you need to decide which power bus you're running which accessory off.
If you want more reserves and a single power system, then I'd go with a pair of identical semi-deep cycle batteries like Optima yellowtops or similar.
I think we may be overthinking the hell out of this like the internet tends to do. Dad had a diesel truck with two batteries since 93. When any of our other cars would have a battery go bad, dad would take a battery out of the diesel to fix the car, then use a new battery in the diesel. So the batteries were always mismatched, old and new, different brands, etc. The batteries always seemed to live a long happy life in this situation, sometimes ten years or more. So wire it up the way you originally thought, it will work. Or use the thing Keith suggested if you are worried about discharging the starter battery, that seems like a solid idea.
The "best" solution would be to use a rv type battery solenoid with a true deep cycle battery - think a 12v golf cart battery. Those are not very good at doing things like turning starters, but they are great at providing a constant load for a long time and being drained down. The marine deep cycles that you find out there are a compromise battery that has some drain down capability but retains some starter-turning capability. Ideally, you would have a continuous solenoid (look up a Cole Hersee 24213) that connects the positive terminals on the two batteries. Wire the solenoid engagement to a +12V that only has power in run and not in crank. That way, the battery will always charge when the vehicle is running but will be totally isolated at other times and you won't put a cranking load on it. Then wire the 12VDC outlets or devices directly to the deep cycle.
Edit: the combined that Keith linked would be a good upgrade from the old school continuous solenoid.
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