Dual battery how-to

Sorry for the extra subject padding but I feel it's important.

Here are a few links to help you understand how to install the isolator.

I'm sure there are more than a few newsgroupers out there with dual setups that can help you further...

-- DougW

Here you go:

Although this is good advice, it has been very common in the RV field to connect the batteries together, even when they were not exactly the same type. This includes mixing of deep-cycle and starting batteries. A special solenoid was used that kept the batteries separated until the engine was running. Then they were connected directly together for charging. I'm not talking about isolated instances here, but large manufacturer's like Winnebago. The isolator is a safer approach if the voltage drop across the diodes isn't of any concern.

Dick

look at

Its not hard to install....I managed it with minimal supervision. I didnt use their tray (got Kilby's) or their batteries (got R & Y Optima's), but I did get their isolator and wiring. I didnt bother with the battery manager - too much fuss (and $).

Uh... *ahem*, is it me or is this getting uncomfortably familiar?

Cool. Thanks for all the advice. This jeep forum has been really useful in learning about all this stuff!

It looks pretty simple in the diagram. I notice that you still run the - to - between the two batteries but I guess as long as the + is isolated it doesn't matter.

Any suggestions on what voltage/amperage isolator to get? I poked around on the web and there are TONS of different power ratings. I would have thought that everything on a vehicle would need to be 12v, but I didn't even see any 12v isolators... most everything was much higher voltage. As for amps, I have *no* idea what to look for.

This reminds me of something else I was wondering about. I installed an in-line fuse between my battery and my aftermarket stereo because I ran the power wire for the stereo straight from the battery myself and just figured I might oughta protect the stereo. Anyway, I knew I needed a 15amp fuse because that's waht the stereo instructions said. But when I went to radio shack to buy a fuse, all the "automotive" rated fuses of every amperage were 32v. Again, it seems to me they all should have been 12 volt. Why would 32v fuses be standard on vehicles when virtually 100% of cars have 12v power?

Cars don't 'really' have a 12 volt system, it is closer to 14-15 volts when the alternator is in play and can spike up higher on occasion.

The volts are just the speed of the electricity, the amps are the power part.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

The voltage rating on a fuse has more to do with how much voltage it can stop if it blows. If you put a 32v fuse in a 120v circuit, the power might jump the fuse when it blew, thus preventing the fuse from opening the circuit effectively. You should use a fuse with at least 2-3 times the voltage rating as your operating voltage. A 32v fuse is entirely appropriate for a 12v circuit.

Yes I did ask a little about this last month but we never really got deep into the technical aspects of topic. Now I actually have the second battery and am starting to make progress on the install so I needed some more info.

Thanks. Somehow I knew just wiring things together would have to be too easy.

Thanks. Somehow I knew just wiring things together would have to be too easy.

ROTFLMAO!

You are learning there boy....

If it 'seems' too easy, usually it is eh...

;-)

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Joshua Nels>

Agreed, if I can put one in for my system, then any idiot can put one in.

(not calling anyone an idiot, but I hate electronics, dont know much about it, and dont do as much wrenching as I should either, and I still managed to do it).

-jenn

Oh, wow. I know exactly what you are talking about, as I read many of those posts. Egads, am I really coming off the same way? I would hate to think I'm creating the same kind of atmosphere here. I will do my best from this point forward to stop rising to Cal's bait, however infuriating it is. I guess I will just killfile him. I know everyone says the best action is not to respond to a troll, but it's hard when you're the one victim he's selected to antagonize.

I really am trying to learn about four wheeling and get going on a very limited budget so I don't want people to quit helping me or answering my questions.

What's wrong with radio shack fuses??? They're clearly marked "For automotive use" and so I figured they would do the job. Are radio shack parts inferior or something?

The reason I am going to radio shack is because it is within walking distance (2 blocks) of my house. This is especially important right now because I am still grounded from using the car due to off-roading without supervision. (a.k.a. the infamous stuck-to-the-axles-and-the-winch-won't-help incident.)

I use radio shack for lots of parts and a fuse is a freaking fuse. If it is rated the same, then it is the same. I mean radio shack sure doesn't 'make' fuses, they just buy them the same place as the auto store and usually in more bulk so their prices are lower.

Oh, just so you know A Jeep sure ain't no 'car'!!! LOL!

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Yeah, yeah, I know. Don't think I'm some kid, I'm actually way too old to be grounded. I'll be 17 soon.

What can I say. I live in a ridiculously strict household.

I don't even consider 17 too old to ground my son if he deserves it and I'm not that strict. :)

Jerry

OK, so you're 16, and live in a strict household. According to Google you either now have or in the past have had...

an 81 CJ (presumably a CJ8 "which has about $25,000 worth of performance and off road modifications on it") a 69 Dodge a "new" TJ a 4x4 monster truck

a 2- year old child

and a desire to play Hulk Hogan in Des Moines, IA.

I do not make this up, just a quick Google author search...

Methinks thou art a troll...

• * * Matt Macchiarolo
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