Author Topic: Dual batteries on the cheap?? (Read 4120 times)

DeMented Toys · « **on:** Jan 12, 2007, 08:59:38 PM »

Is there a cheap way to set up dual batteries? Without a kit from Painless wiring, ect?

Duffil · « **Reply #1 on:** Jan 12, 2007, 10:16:11 PM »

how do you want to set 'em up? just a solenoid separating them or with a battery isolator as well. I've got a schematic here for a solenoid/isolator system, but I can't scan it till tomorrow at work. The solenoid and isolator can be had from any parts house(NAPA

). If you want, I'll scan and post with part numbers, etc. tomorrow.

DeMented Toys · « **Reply #2 on:** Jan 13, 2007, 06:28:37 AM »

Cool, that would be great. I wasn't quite sure how to wire them up. I was just thinking of hooking them together and adding one of those solar chargers to help keep them charged... Or maybe just using the extra one for running the extra stuff and using the solar charger with it... What do the isolator and solenoid do?

Duffil · « **Reply #3 on:** Jan 13, 2007, 06:52:55 AM »

The isolator only lets one charge at a time, that way your alt can keep up. Once your primary battery reaches full charge, it switches to charging the secondary. The solenoid keeps the batteries separated until you flick the switch.

DeMented Toys · « **Reply #4 on:** Jan 13, 2007, 09:12:34 AM »

Oh, okay, that makes sense... So the solenoid keeps both batteries from being drained, and keeps the primary battery fully chargaed via the alternator...
So a solenoid is an important part of the setup I guess.
But what about the isolator? What are the benifits of keeping the extra battery seperated? Has anyone used a solar charger, with a solenoid being used, to help keep the secondary battery charged?

kneedownnate · « **Reply #5 on:** Jan 13, 2007, 11:28:31 AM »

Quote from: Duffil on Jan 13, 2007, 06:52:55 AM

The isolator only lets one charge at a time

Odd, that's not how ours work. Basically, what it does is isolate each battery from each other so if one draws down it doesn't draw the other down with it, but both still charge. We've used nearly the same type of isolator you can get at kragen for years and they work pretty well, though the new style we're running seem to rob too much of the alt output and charge too low.

DeMented Toys · « **Reply #6 on:** Jan 13, 2007, 12:00:47 PM »

hmm... So what I am needing to know... Is just how to hook up my other battery. Whether I need a solenoid or isolator or whatever... I just want it to work.

I mean, I read about it online... But most articles are using a kit from painless, or wherever... Right now the other battery is just hanging out under the hood, charging off a solar charger for a spare, or backup battery... I figured I may as well hook it up. But am not sure how exacty to go about it...

kneedownnate · « **Reply #7 on:** Jan 13, 2007, 01:23:50 PM »

There are a couple of easy ways to do it. Get an isolator (kragen has a little blue one, about 3.5"x4", has 3 posts probably), mount it somewhere in the engine bay as far from heat as possible. I don't know if toyota alternators offer an auxilery output post that you could hook up to, but if so you could run a minimum 10 gauge wire up to the isolator input post. You then run another 10 gauge wire from an output post to your spare battery.

If your alternator doesn't have another post you can hook into then you can run a 10 gauge wire from the positive battery post to the isolator input, then run another from the isolator output to your spare battery.

Either way you do it, neither battery will be drawn down by the other if one gets discharged or goes bad, and you'll always have a spare!

kneedownnate · « **Reply #8 on:** Jan 13, 2007, 01:24:50 PM »

I'm going into work tomorrow, so if I remember to bring my camera I can snag a pic of the isolator and how it's wired in.

DeMented Toys · « **Reply #9 on:** Jan 13, 2007, 01:25:49 PM »

Thanks.

Gewehr43 · « **Reply #10 on:** Jan 13, 2007, 03:36:51 PM »

Why not just run an Optima or something similar?

DTB · « **Reply #11 on:** Jan 13, 2007, 03:53:34 PM »

Quote from: Gewehr43 on Jan 13, 2007, 03:36:51 PM

Why not just run an Optima or something similar?

if i had my choice i would run 2 optimas! not cheap by any means though! 12voltguy sells some nice isolators and gear

Cheesemaker · « **Reply #12 on:** Jan 13, 2007, 04:09:28 PM »

Here's how they wire up! Go to Jcwhitney they have alot of them. Or 12 volt guy, or your local parts house! And if your main battery dies you can jump it off the back-up! This is my future battery plans!

kneedownnate · « **Reply #13 on:** Jan 13, 2007, 06:51:10 PM »

That's how we run em, but that would entail taking the factory harness out of the equation wouldn't it?

Duffil · « **Reply #14 on:** Jan 13, 2007, 07:05:28 PM »

OK, to have a dual battery system that is selectable, you run a solenoid as well as the isolator. Nate, you are right that the isolator will isolate each battery and not allow one to draw the other down, but a good one(the ones I sell, and what this kit came with) will charge the primary battery up full, then switch to charging your aux battery. Otherwise, a heavy diode could be used.

here is the link to the schematic: http://i26.photobucket.com/albums/c139/duffil/scan0001.jpg

Operation is as follows:
"Center off: the batteries are isolated from one another. Each is charged independently and provides power independently to the load connected to that battery. That is the normal position.

Parallel Batteries, Key on: The batteries are connected together when the ignition is on, typically with the engine running. Commonly used when under heavy load, ie, winching. The switch should be returned to Center Off whe the high current mode is no longer needed.

Emergency Jump Start: The batteries are connected together with the ignition off. It enables you to jump start the vehicle if the primary battery is dead. NOTE: be sure to return the switch to center off when completed; failure to do so will leave the solenoid energized with the key off, which will drain the auxiliary battery."

Duffil · « **Reply #15 on:** Jan 13, 2007, 07:07:55 PM »

The instructions this kit came with(foothill offroad products, 530-889-2021, Auburn, CA) calls for a 200A solenoid. Those are spendy. A NAPA ST95 is continuous duty, rated at 80A. Also, if you have the cash, an ST34? is rated continuous duty for the full 200A.

Duffil · « **Reply #16 on:** Jan 13, 2007, 07:09:03 PM »

Quote from: kneedownnate on Jan 13, 2007, 06:51:10 PM

That's how we run em, but that would entail taking the factory harness out of the equation wouldn't it?

I have been thinking(not too deeply) and I think you could just modify the stock harness and it'd work just fine, and still turn the charge light off and be clean.

yotaweelr · « **Reply #17 on:** Jan 13, 2007, 07:10:46 PM »

I have been running dual orbitals for 3 years with no isolator. never had a problem. just hook them parallel. isolator is to stop the batteries from draining each other. but this is not as much an issue if you get the batteries at the same time (and same numbers) from the store and hook them up. the problem occurs when you use one old battery and one new one. or a pair of old ones.

Duffil · « **Reply #18 on:** Jan 13, 2007, 07:21:09 PM »

OK, I just re-read this again. Apparently I have had my head up my ass, you guys are right. The isolator just prevents them from draining each other.

The batteries will charge simultaneously.

Duffil · « **Reply #19 on:** Jan 13, 2007, 07:24:06 PM »

Quote from: yotaweelr on Jan 13, 2007, 07:10:46 PM

I have been running dual orbitals for 3 years with no isolator. never had a problem. just hook them parallel. isolator is to stop the batteries from draining each other. but this is not as much an issue if you get the batteries at the same time (and same numbers) from the store and hook them up. the problem occurs when you use one old battery and one new one. or a pair of old ones.

But then you have no selectability...all the cool guys have switches!

kneedownnate · « **Reply #20 on:** Jan 13, 2007, 07:33:17 PM »

Quote from: Duffil on Jan 13, 2007, 07:21:09 PM

OK, I just re-read this again. Apparently I have had my head up my ass, you guys are right. The isolator just prevents them from draining each other. The batteries will charge simultaneously.

I just didn't feel like arguing

If you were so inclined you could run the wire to a switch and turn the power off to your second battery. No sense in constantly charging a second battery if you're not draining it some, but I guess that depends on what type of batteries you run. When I do it I'll be runnin 2 or 3 yellow optimas, but only cause they were given to me :grin:

yotaweelr · « **Reply #21 on:** Jan 13, 2007, 07:42:24 PM »

Quote from: Duffil on Jan 13, 2007, 07:24:06 PM

But then you have no selectability...all the cool guys have switches!

it's kinda on the cheap, being I didn't have to buy too much battery cable, or an isolator. But i did spend 300 on the 2 batteries. If I want to select which battery gets used I will pop a couple wing nuts off the marine terminal clamps and switch to one battery. I carry 2 for welding on the trail reasons and winching. I really don't care about anything else that is good about dual batteries.

DeMented Toys · « **Reply #22 on:** Jan 14, 2007, 04:08:31 PM »

So I can just hook them up parallel and they will both charge until I can get an isolator?

Duffil · « **Reply #23 on:** Jan 14, 2007, 07:27:02 PM »

yep. I dunno how hard it will be o the alt though. I'm not saying it won't last, obviously yotaweelrs has, I just mean it'll probably be charging at a higher amperage than normal.

DeMented Toys · « **Reply #24 on:** Jan 18, 2007, 03:48:18 PM »

Thanks. I think I'll just hook it up parallel and see what happens.

Vic stuff · « **Reply #25 on:** Jan 18, 2007, 05:26:34 PM »

i have mine hooked up in paralel I haven't had any probs yet. Red Top and Water Battery for now till i can afford another blue top. I have an isolator in the works with a bling switch just gotta start workin on it but its been cold here so...

kneedownnate · « **Reply #26 on:** Jan 18, 2007, 06:16:26 PM »

Quote from: Vic stuff on Jan 18, 2007, 05:26:34 PM

i have mine hooked up in paralel I haven't had any probs yet. Red Top and Water Battery for now till i can afford another blue top.

Can't remember why just now, but it's supposedly a big no no to hook gel and wet together.

Vic stuff · « **Reply #27 on:** Jan 18, 2007, 06:30:59 PM »

Quote from: kneedownnate on Jan 18, 2007, 06:16:26 PM

Can't remember why just now, but it's supposedly a big no no to hook gel and wet together.

hmm could be havent had any probs yet "knock on my wooden desk" but i plan on doing a new red and blue top when funds can afford it, my trays are sized for optimas already

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