therock

iTrader: (2)

The Scenario,

Dual Odyssey AGM PC1500 batteries in parallel.

A three way switch that will connect the batteries via a contactor solenoid with a "Key Off" situation.

Switch Positions
(1) Ign-on energizes relay-both connected.
(2) No relay connection with key on or off.
(3) Relay connected at all times.

An Odyssey OMAX-25A-1B charger.

When planning to not use the vehicle for weeks at a time, would connection the charger with the toggle in (3) both connected at all times be OK and charge and maintain them without issue?

Thanks

FatherSonSS

You can make it work but a couple factors come into play.

First off i'm assuming that you will be connecting the batteries in parallel.

Depending how you hook them up determines how you will have to charge them, for example if you hook them up in series you will need a 24v charger, or if you do it in parallel and only want to use one charger you will need to hook the negative of the charger to a ground rather than to the battery to help stabilize the voltage between the two.

Not sure what your application is but I run two batteries and love my battery isolator I recommend that you run one too. Its basically a huge diode so you can use it to have one battery only be able to charge and start your car so that you can run your battery all the way down but still be able to start your car. Theres also some devices out there that are similar except they base their cutoff on voltage.

Let me know if you have anymore questions on the subject

EDIT: re-read your post, glad you chose parallel sorry I missed it, make sure to use that stabilizing wire


-Matt

therock

iTrader: (2)

Thank You,

I have been researching since my last post and got busy.

I'm using THIS CONTACTOR with a double pole / double throw three position toggle.

Switch Positions
(1) Ign-on energizes relay-both connected.
(2) No relay connection with key on or off.
(3) Relay connected at all times.

It will stay in position (1) 99% of the time. Position (2) will be for jumping others off or running my accessories, Laptop, Lights, Audio and so on when parked. Position (3) will be to start myself in the event the Main is dead.

The photo below is a first pass. I ran out of high temp non-split looming and heat shrink. The red wire is not touching the AC line. I used 2GA wire. The other line is going to the starter where the main ends its run. I'll eventually replace that with 2GA to match.
Both batteries are DieHard Platinum AGM's - AKA the Odyssey PC1500DT.
As you can see I have no switch wire on the contactor yet. I did test it with a jumper.

I have an unused connector I found lurking back in the shadows near by that is ign-on 12v & ground. I may make use of it.

What is the female counterpart called and the best place to get one if not the dealership counter?

Thanks Again!

FatherSonSS

I'm not sure what to call it but I think a 9005 bulb connector would work for that. At your local auto parts store go to electrical and they have stuff that might work for that they also have some connectors like that by the clips and weird bolts sometimes.

If you can't find it there a junkyard would defiantly have the other half of that.

Or you could always just cut it off and solder it up


Whats the second battery for ? You've got some serious power there wheres it all going ? haha


-Matt

therock

iTrader: (2)

Getting ready for a winch to be added on a front and rear receiver with off-road lights, radio, and such for search and rescue.
Camping too.

I found the connector on Rock Auto for a wheel sensor but I imaging its used all over the vehicles.

FatherSonSS

Nice thats going to be an awesome setup when its all done, I really enjoy being ready for everything.

Yeah I figured that connector would be pretty universal, the side of the NV4500 has the same thing for the reverse light switch among many other applications.



-Matt

therock

iTrader: (2)

Thanks,

I have heard some GM trucks that shipped with Dual Batteries were configured simply for ign-on connected / ign-off disconected. This may be the pigtail for it.

3rd One Down Is For Me

therock

iTrader: (2)

While I have your ear, two subjects,

1.) I plan on doing the so-called "Big Three". I will replace the OE Battery to Starter, and OE Ground to Block, with 2GA cable. I want to keep it like OE with better wire.

But the Alternator Wire upgrade has me perplexed. Some say leave it be in fear of not having a fusible link feed wire.
I don't want to do a hasty move. I am treading thin ice on this one. I Google and search and get all kinds of different configurations, theory's, fusing size and ratings sugestion inconsistencies.

Can I get your words on it?

2.) Fusing the batteries when both are short runs under the hood. I read differences here too.
Some say they do not if its as stated in the above, as long as one has installed and routed with great care and consideration.
And again with fuse type and ratings, Mega/ANL..... Heck when a Winch stalls it can get to 400A. So if you want to protect a 145A alternator with a 150A fuse..................

Do you have any words on this one?

Thanks

FatherSonSS

1.) Big 3 is awesome I was just telling someone else about it, defiantly a must with all that you are trying to do.

The alternator wire defiantly needs to be upgraded or else everything else is for nothing. Lets knock out the easy part first, the alternator is the central ground for your whole system so make sure to upgrade the engine blocks ground strap, no fuse needed obviously. For the positive side of the alternator, the whole point of a fuse is to protect your truck from fire, damage in the event that the wire is shorted out. I assume one of your batteries is still in the stock location and that you still have that little red junction box between the alternator and batter. If your running a foot of wire to that box and than a foot from the box to the battery and they wire is tapped and loomed like it should be than what do you think the chances that the wire will short out? I'm thinking almost impossible unless you do something really weird and I don't like to plan for the worst. You have big fuses down the line for anything that happens with your system so the only thing that a a fuse would be protecting is approximately 2ft of wire thats loomed and taped. I don't think its necessary

I run a 0 gauge lead from the core support, to the alternator, to the wiper cowl, it has split loom and tape closing the loom the entire length and I've been running this way for years with no problems because I ran the wire smartly without a chance of it grounding somewhere.

All that being said the alternator wire is the biggest one todo out of the whole upgrade and I highly recommend that you do it. I've done it to many cars over the years and never had a problem. I have however seen a circuit breaker's positive side ground out on brake lines and cause a wreck from fire/loss of braking. Luckily no one was hurt but it was ironic nonetheless.


2.) Same concept on your batteries, your install looks great very clean and out of the way. You said you were out of loom and I assume you plan to put it on once you get more. Your runs are short and unless you see a potential for your positive wire to ground out there is no need for a fuse. And if you do think it will ground out move it !!! haha

If your ground wire grounds out.... good, more power to it


-Matt

therock

iTrader: (2)

Thanks,

To confirm, a larger alternator wire from the alternator to the junction box carefully done is what you practice?
That little red box is getting crowded eh?

Thanks for the complement. I am an industrial high speed maintenance technician and machinist (not CNC) of more years that I want to admit.

I'll post more pics soon.