Dual Battery How-To (Pics & Instructions)

[Harley#356]

And the finished product :k


any questions, just post them up. sorry for all the pics and the long load time for dialup guys, but pics help out alot more than just a bunch of words in a post IMO

[cpharley]

Is there a particular kind we should get? Which yellow top did you get?

[Harley#356]

I would just get the 2 post yellowtops if you are going with a dual setup. My original yellowtop is a 4 post which was nice when i only had one battery because the top posts were for the truck and i used the side posts for my stereo and neons and stuff.
With the dual setup, the side posts dont fit on the 4 post optimas so you can't use them anyway, and not like you really need 6 or 8 posts total between the 2 batteries ;t thats a LOT of wires the 2 post optimas are cheaper by a little bit too

[HarleyDammitt]

Do the accessories shut down when the ignition is in the off position when using the accessories terminal on the isolator?

[Harley#356]

not quite sure what you are asking

it acts pretty much like stock. neons and alarm works when the trucks off, and the stereo and other accessories need the key in on acc. in order to work just like stock setup.
i think since the HID's are wired up separately from the stock wiring, they wont work unless the keys in, but haven't really messed around with the stuff that much to see.

[2002GreyHD150]

Hey Dammitt... the reason for the solenoid is so Josh can jam in the parking lot until the stereo battery goes dead & not affect/effect the starting battery. The solenoid only connects the 2 batteries during charging. the stereo & lights/accessories have power from the 2nd battery all the time, as long as the battery is chraged/charging.

Rob W.

[HarleyDammitt]

Kinda related...

So... When I disconnect the MAIN battery (the one that starts the truck), the accessory battery remaiins hooked up... right?

I ask because my stereo (Sony) looses my station presets when I unhook the battery ground at the track to reset the computer... It'd be nice to do this mod for that alone...

[Hoffmann]

Part two of the How To above- http://www.nhtoc.com/vbforum/2000-20...revisited.html

Josh, you have to fix the description on the picture #19b post #13 of the first How To, pic bellow.



The way you described the connection of the solenoid, "to the accessory", you will be running the two batteries together every time the ignition is either ON or OFF because the ACC can be ON when the engine is OFF thus discharging both batteries when parked listening to some tunes, e-fan, etc... and if you kill both batteries, the main purpose of this MOD is useless.

The correct way to connect this type of solenoid is:

Battery #1 (large pole)
Battery #2 (large pole)
Ground (small pole)
Ignition* (small pole)

Usually solenoids can be connected either direction, (negative/positive) that's why I only mentioned the sizes of the poles.

*With an override switch connected to the battery #2, use a three way switch so you can separate the batteries even when the engine is running (to save the alternator), with this override you can also connect the auxiliary battery when the main battery is dead or you want to run both of them with the engine OFF.

[Harley#356]

thats actually what I meant by 12v accessory. Its a switched 12v ignition source.

I'll probably rewrite that how-to eventually though. The pics are hard to read the writing on, and I did write that in 2004, right before I started college for my electrical engineering degree Can defintately spiff it up a bit now being done 4 out of 5 years of my degree being its an electrical mod lol

[truckpilot]

Not that I'll ever do this mod, but nicely done Josh, a big help to those who will.

[JHein]

Where did you guys run the wire from the solenoid to that has power during cranking and in the "run" position?

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