has anyone put dual batteries in the stock location on a 07 f150 5.4?
or dual alternators?

 

i was just wondering if anyone else had done this before. i have been playing around for a couple of hours and this is what i come up with for the dual batteries in stock location.
and i wanted to add these are not the batteries i am going to put in here just using them to fab this up one is the stock and the other is a 75s that was in my car they are basically the same size though the 75s is about a half inch taller.




edited to remove the pics of a everstart and the factory motorcraft that was used to fab up the bracket there was confusion that i was using 2 different batts wired in paralell without an isolator.

i had to move the winshield washer bottle about 3 inches forward and make new brackets for it and the batteries fit right in i still have to paint it and do the wiring for them.
i want to say again these are not the batteries i am going to use im still looking for some batts something cheap for now.
also i was wondering if anyone has done a dual alternator set up in one of these trucks?
if anyone has could you point me in the right direction for the wiring diagrams and harness connectors and maybe a picture of the alts mounted and the bracket they use.

 

a few minites ago i came across styxnpicks thread on this very thing from back in 07.
https://www.f150online.com/forums/20...llow-tops.html

 

this is the finished pics of it with 2 bci 34s batts 750 amps each cheap walmart batts i had laying around till i get some good ones to put n here. they are a pretty tight squeeze in here at 10 1/4"L x 6 13/16"W x 7 7/8"H each.



the first thing is i noticed is damn the starter turns over fast. but now some alts to keep up the voltage.

 

You may want to think about installing a battery isolater. So you are only using one bat for starting. That much amperage can cause premature starter and ring gear wear from the starter slamming into the ring gear twice as hard and fast.

 

what about using a 12v soleniod that is nc and wire it to the starter solenoid wire so that when the starter is activated it opens solenoid and disconnects one batt for starting only. i found some like this rated at 1500 amps continuos duty i think would be more than enough .

hey styx if you come across this how is your starter holding up to the way you had the optimas wired it looked to be wired in parallel to with no solenoids or isolators.

 

That should work. Just make sure all the factory bat connections are on the same bat. All other extras are on the other bat. Nice thing about an isolater is both bats wont go dead if lights or any thing get left on.

 

check these out http://www.pac-audio.com/products/pr...#37;20Products

 

thanks but after thinking about it i disconnected one battery and put a dc amperage clamp on the starter wire and then cranked the truck over got the reading and then connected the other battery and cranked the truck and got that reading and there is not a significant differance to warrant a battery isolator installed for the starter it was pretty close to the same amperage each way but the volts were just a little more with both of the battery's so im just going to leave it the way it is. besides i have a 100k mile bumper to bumper warranty on my f150 if it breaks its free to repair.

 

The starter is not going to draw more amperage with 2 batteries hooked up. The increased amperage will engage the starter harder and faster and spin faster. Swing a ten pound sledge hammer lightly. Then swing it harder. Which will do more damage to object struck? You are the battery, the sledge is the starter. Hammer still only takes so much strengh to swing. A battery with more strength can swing the hammer harder and faster. This may or may not ever become an issue for you. But it can happen. I work on diesel semi trucks and have seen this happen when more than required batteries are installed.

 

nice job

 

You need an isolator or two identical (same batch, voltage, etc) batteries.

 

they are the same Low-e Red they both have the same date code and batch number stamped into the top of them and are both group 34.

 

Then how in the hell is one an EverStart and the other Motorcraft? If the motorcraft came in the truck, it will discharge faster being it is older and been used more. This will also cause the Batteries to discharge each other trying to recharge the other.

 

lol i was just using the old ones in the pics in first post to fab it up i posted the pics of the ones that are in here in post #4 they are 2 everstarts 34 bci 660 cca i know better than to use 2 different types or ages of batts in the same vehicle when they are connected together i had problems in my car doing that when i had 4 batts in it.

i edited the first post to remove the pics of the everstart and motorcraft since it was confusing people.