Bill

I've been thinking about dual batteries, and have seen several ways of rigging them up
1: simple parallel hook up
pro: cheap, easy, lots of amps
con: batteries can drain each other if not exact same charge

2: hooked up with some kind of solenoid
pro: no battery drain, and "auto" charging
con: expensive, more wiring

I've also been looking at installing a HO alternator (min 140 amps), so I'm not sure if it's been done, but:
Can anyone forsee any major problems with simply hooking up 2 batteries to the same alternator, as if it were only one? I know that with both batteries hooked up I would only get half(ish) the current to each battery, which is why I'd go with the min 140amp(/2 = 70amp = stock).

Once I have the batteries hooked up, run all the normal truck stuff off the starter battery, and run the second battery with a deep cycle, and run all my "toys" off it(lights, bigger stereo, winch, etc).

I'm sure I'm over looking something...I don't like electrical junk. So any thoughts would be appreciated.

4Crawler

iTrader: (3)

Not much more wiring actually and much more robust and functional with a solenoid:
http://www.4crawler.com/4x4/CheapTri...atteries.shtml

You can disconnect the batteries, say in camp, and drain the aux. battery w/o touching the main battery.

And if you kill the main battery, you can power the solenoid and do a self-jump-start off the aux. battery (have used this more times than I can count).

No need for a bigger alt. unless you want a bigger one for some other reason. 1 or 2 batteries will work off the stock alt., but I do run mine with a 160amp alt.:
http://www.4crawler.com/4x4/CheapTri...orInstallation

W/o a solenoid or isolator, your two batteries are really just one big battery. Sure, it'll take longer to drain, but when drained, they are just as dead as one battery.

Bill

Yeah, after reading that, it doesn't quite get accross what I want to ask.

I'm thinking about having the batteries completely isolated from each other. Each battery will have a seperate positive cable running the the Alt, and each will be grounded to the frame.

Thats why I was thinking about the bigger amp, as each battery would only see 1/2 what the alt is putting out.

I'm just trying to think of ways around a $300 solenoid

4Crawler

iTrader: (3)

Makes no difference if both batteries have separate wires between the + terminals and the alternator. At the alternator, those two wires connect together and that means both batteries are in parallel all the time. You can get a dual battery solenoid kit (similar to what I used) for a little over $100.

waskillywabbit

iTrader: (-1)

There is a "Dual Battery FAQ" thread on Yotatech.

I use the Painless Dual Battery kit and it works very well and easy to install.

Bill

hmm...that kit is a whole lot cheaper than the Marine solenoids I've been looking at, thanks.