Dual Battery Install
 

Hey guys:

I did a pretty primitive dual battery install today and it turned out well and really cut down on the voltage drop at low RPM's. It took some research to find a battery that will work and fit where I wanted it to.

I welded up a bracket for the battery to sit in and bolted it into the spot where the factory jack used to sit on the inner fender. Then I unbolted the vacuum canister and smog filter. They were bolted to the inner fender by 2 bolts each. I drilled new holes and relocated the smog set up closer to the battery.

Then the vac can I made a new L shaped bracket bolted it to the fender and reattached it.

I ran them in parallel because all I was after was a little more oomph for the -20 winters here and for low rpm amperage. I am fully aware that all i did was make one giant battery and if I leave my lights on they both will go dead. Some day down the road I will put in an isolator but for now this will do juuuuuust fine.

PS I did clean everything up and make it nice n tidy before calling it done.

Not too bad - the only thing I would have done is kept the red for red and black for black, only for consistency ... but it's your truck and you know what's what so really it's a non issue.

Totally wanted to! I live in the sticks and our Napa only had black 1 gauge. So it was bout all I could get...i supposed they do sell red duct tape

ok im totally curious...how is this different from connecting two nine volt batteries together? i mean are there issues with the power switching back and forth or double voltage? i dont know this much about DC current haha

Its the same but it differs in how you hook them up: series or parallel.

http://www.zbattery.com/Connecting-B...es-or-Parallel

What I did was just made on giant battery. You could take 2 6V and wire them in parallel to make em 12V.

No issues with power switching back and forth as it is a constant 12V with no fluctuations in power. If I were to go parallel I would have ended up with 24V and smoked my wiring.

That's pos to pos and neg to neg right? Seems easy enough.

What size Alternator?

hey man you better be carefull cuz i dont think you installed a battery isolator and if one the batteries has a lower voltage when you shut ur truck off they will discharge each other, unless the batterys came from the same plant at the same day they usually will have a problem unless a isolator is installed, check my thread i started about my dual battery install

Wont this stress both of your batteries?

In a parallel circuit each component shares equal intensity.

If you alternator is meant to put out 13.8-14.2 volts when running --lets just average it to 14 volts-- then that means your battery receives a 14 volt charge.

If you place two batteries in parallel this means each battery is only getting a 7 volt charge! True they are only each putting out 7 volts apiece but doesnt the battery have a 'optimal' recharge happiness rating? In other words is a lower charge on each battery damaging the cells in some way?

Or does it act kind of like a trickle charger.

Not knocking yourset-up - I love it in fact! I love anyone who does anything DIFFERENT with their cars - just curious! :thumbsup:

y: 135 out of a stang.

Mike: no isolator...yet. Not too concerned with it at this point as both batteries are new. The only thing I needed them for at this pt is for the -20 temps we have been having and getting enough juice to crank it over. Also this absorbed a lot of the load that my dual fans pull. Paired together they sit and hold a solid standing 12.6V. What isolator did you go with?

I will eventually go for a switched set up but for now this will do mighty fine.

DJ: as I see it this set up acts (and I always stand to be corrected) not as 2 separate batteries but 1 giant bat. The same could be said of a single batt that if one cell gets weak it pulls down all the others. Its still a 12V set up and gets the same amount of charge just a much longer load capacity and cranking duration due to increased size of batt. Like swapping out a 10 gallon gas tank for a 20 gallon tank...fuel still flows out at the same rate just more of it there.