Relocating battery and relays on F350

[ponyboy88]

I plan on moving my battery to the rear if the truck, and possibly converting to dual batteries. I currently have a 3G alt, and Taurus fan wired with relays under the hood. If I remember correctly when installed the relays the instructions said to mount near the battery, should I relocate them to the rear as well?
Goal is more underhood room, less bouncing battery, more weight on rear of truck.

[psychlopath]

I'm sure you've thought about this, but running the batteries to the rear of the vehicle is going to require some pretty hefty starter cable.

I dont know what sort of amperage the starter actually pulls but I know that I accidentally hooked my starter cable to the wrong side of my 160A maxi fuse and it blew it when I tried to start up.

According to this chart (which is just the first one I found, nothing official) it looks like you'll need two gauge wire for 200 amp at 10 feet. Youre not running that far, but you will very likely be pulling more than 200A at startup.

Just something to keep in mind.

What do you need more room under the hood for?

Originally Posted by ponyboy88

I plan on moving my battery to the rear...

[jowens1126]

I dont think your doing this for the right reason. Get the proper equipment to secure your battery in the front where it belongs. If you want more weight in the back. A big heavy tool box full of tools would be much more effective and useful.

[sackman9975]

Originally Posted by jowens1126

I dont think your doing this for the right reason. Get the proper equipment to secure your battery in the front where it belongs. If you want more weight in the back. A big heavy tool box full of tools would be much more effective and useful.

[war1ock]

Broncos have an almost 50/50 weight distribution as is.and that just sounds like a big pain in the ass.

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[Steve83]

Originally Posted by ponyboy88

I plan on moving my battery to the rear if the truck...
Goal is more underhood room, less bouncing battery, more weight on rear of truck.

What do you plan to put where the battery is now? If your battery is loose, just clamp it down. What will more weight on the rear do for you?

I agree with everything that has been said so far: extending the battery cables is expensive, risky, and counterproductive to good starting & charging. If the big battery cable gets pinched & shorted, it can set the truck on fire &/or explode BOTH batteries. I got mine nearly free at a JY & routed it very carefully to minimize the risk, but I'm still conscious of it. But I kept the stock one & put the aux.batt. where the weight would actually HELP by lowering the CG - not shifting it rearward.

. .

Moving the fan relays won't help them, or the fans. If you move the stock battery, you need to move the starter relay & fusible link wires with it.

[bluebolt]

As others have said this can be expensive for the amount of gain you get. If you are determined to I have put batteries in the back of a few cars and can offere some tips.

1. Use at least 1 or 0 gauge wire.
2. I highly recomend a cutoff witch. Do NOT buy the cheap $20 ones form Summit or Jegs, they don't have the amperage rating for a starter cable. Get one with at least 175 amp continuos and 1000 amp surge rating.
3. As Steve83 mentioned moving the solenoid to the back can be a good idea. This works best with an old style starter that has only one larger starter cable to it. This is how I do it.
A. Put a junction block up front where the solenoid currently is. All your wires to the main harness will go there. Run a #4 or #6 gauge wire back to your cutoff switch to a terminal I will call "OFF".
B. Run another #4 or #6 gauge wire from the output of the alternator to the back to the cutoff switch to the other terminal which I will call "ON". Somewheres in this wire run use a Megafuse that is larger than your alternator rating, the closer to the battery the better. For a 140 amp alternator I use a 175 amp fuse.
C. Mount your starter solenoid switch in the back near the battery. Extend your small "start" wire from the front to the back. If you have an older vehicle that still needs the second small terminal for "boosting" the ignition output you will have to extend that as well. Make sure the solenoid is grounded!
D. Run a short #4 or #6 wire from the cutoff switch "ON" terminal to the normal large "battery" terminal on the solenoid.
E. Run a short #1 or 0 gauge wire from the battery "positive" terminal to the large battery terminal on the solenoid.
F. Run your long #1 or 0 gauge wire from the large "starter" terminal on the solenoid to your starter.

This is one of the safest ways to do a rear mount battery. It isn't cheap. It has 3 different "safeties"

1. The large long starter wire is not "live" except when starting, much safer in an accident.
2. The long alternator wire has two benefits. If you or someone else have to shut down the vehicle while running using the cutoff switch your electrical system will not have a voltage surge from the alternator, potentially frying expensive electrical componets. The surge will go to the battery which can handle it. Also if the alternator wire is cut the Megafuse should blow which is why you want it close to the battery.
3. Turning off the cutoff switch kills power to the main harness. Because the alternator wire is cutoff from the main harness it can't backfeed and keep the engine running.
4. The one problem that could occur is if the starter solenoid malfunctioned and was always "on". The only way to stop that would be a second cutoff switch.

[ponyboy88]

This is on my f350, with a 460. Weight distribution is more of a by-product, and I reckon my truck is significantly more nose heavy then a bronco. And the battery is mounted fine as is now, but thought it might see less abuse/shock mounted mid-ship.. Plan is a turbo down the road, or two, either mounted under hood(where the battery is) or remote mount, thought it might also be good to move the battery away from high engine temps, but agree with what's being said here about over complicating things and adding more strain on the electrical system.

[Steve83]

Originally Posted by ponyboy88

This is on my f350...

So then this thread should never have been posted in the Bronco Discussions > Noobie Bronco Tech Questions forum. And regardless where it's posted, if you're NOT asking about the vehicle in your profile/avatar, MENTION THAT IN THE FIRST POST!

[DNBELOWBRONCO]

Originally Posted by ponyboy88

This is on my f350, with a 460. Weight distribution is more of a by-product, and I reckon my truck is significantly more nose heavy then a bronco. And the battery is mounted fine as is now, but thought it might see less abuse/shock mounted mid-ship.. Plan is a turbo down the road, or two, either mounted under hood(where the battery is) or remote mount, thought it might also be good to move the battery away from high engine temps, but agree with what's being said here about over complicating things and adding more strain on the electrical system.

I thought you were talking about the Bronco too. Where would you put them on the truck that would be safer than the engine compartment? Plus, if in the bed you deal with sun etc. I would never want them behind the seat or inside my truck, any kind, because of safety reasons and because I've seen one blow up and man you don't ever want that to happen. The clean-up is ridiculous and that is OUTSIDE of the truck, inside I would just sell it......lol. RuffStuff and other companies make dual battery brackets or can make you one if you ask them to quote you. That way you can bolt it in solidly and still increase the wire gauge which is always good for cold weather, but I guess that doesn't help much as far as installing a turbo or two.... -Kevin-

[war1ock]

hahaha this all makes so much more sense now. I agree with the others though, probably be best to just leave it in the engine compartment. Ford designed it there, no reason to move it. Maybe you can relocate something else under the hood in room for a turbo? Washer bottle maybe?

[JBfab]

I made all kinds of room under my hood by going to an aftermarket rad catch can and an import car washer bottle. It only holds half a gallon but if i recall the stock one did too. Could posibly move the battery down further esp if its an optima or oddesy as they are smaller in size.

[bluebolt]

Originally Posted by DNBELOWBRONCO

I thought you were talking about the Bronco too. Where would you put them on the truck that would be safer than the engine compartment? Plus, if in the bed you deal with sun etc. I would never want them behind the seat or inside my truck, any kind, because of safety reasons and because I've seen one blow up and man you don't ever want that to happen. The clean-up is ridiculous and that is OUTSIDE of the truck, inside I would just sell it......lol. RuffStuff and other companies make dual battery brackets or can make you one if you ask them to quote you. That way you can bolt it in solidly and still increase the wire gauge which is always good for cold weather, but I guess that doesn't help much as far as installing a turbo or two.... -Kevin-

I am not a Corvette guy but even I felt sad when a freshly restored early 1960's Corvette at a car show had an electrical mafunction, the battery blew up and the engine caught on fire. The mess from the powder fire extinguisher was almost as bads as all the battery acid all over the freshly restored engine.

[psychlopath]

Originally Posted by bluebolt

The mess from the powder fire extinguisher was almost as bads as all the battery acid...

Y'know, that's funny. Depending on the agent in the fire bottle, that stuff can REALLY do a number on wiring, non coated metal and just about anything else that makes things do what they do...

[Alvin in AZ]

Get the lead out. :)

Melt it down... pour it into homemade molds and bolt it into your bumper... :)

133" wheel base = 322# in the bumper = 120# off the front tires and
effectively 442# added pounds to the rear tires for traction.

What's you wheel base and how much wight you willing to add? ;)
Since that picture I took the two inner weights out they were 66# each
including hardware...

66# x2 = 132# lighter in the rear and 48# heavier in the front and 180#
lighter over the axle.

It helped with steep dirt "road" traction but mostly it was done for making
it behave better on a high speed dirt roads. YMMV

Alvin in AZ

[Steve83]

That explains a lot...

[ponyboy88]

Honestly I don't want to add a pound. Watching the trucks girlish figure and all (in all honesty the truck sees some time on sand, and the weight already causes problems there).

My apologies for not mentioning it was the f350, but thought this would be more universal to the full size ford, and well, this is the best place to come to for info in that area. I have had vehicles designed from the factory to have the battery in the passenger area which I agree is less then ideal, but in my case the truck will be getting a wood flatbed with storage underneath, planed on mounting battery underneath that and on level with frame (in theory helping marginally with c.o.g too, keeping out of elements, away from exhaust heat or shielded)

[Alvin in AZ]

Originally Posted by ponyboy88

Honestly I don't want to add a pound. Watching the trucks girlish figure and
all (in all honesty the truck sees some time on sand, and the weight already
causes problems there).

That tells me one thing for sure, you haven't been experimenting you've just
been using your superior powers of logic. ;)

Alvin in AZ is dumber than dirt

[4DI2D]

If you want to relocate a battery go to your local industrial supply company and purchase the necessary length of WELDING cable. Very flexible and 2Ga. will be more than sufficient.
If your starter is drawing "over 200 amps" then you have serious issues with the starter. Newer high speed starters are more efficient electrically and the actual amperage consumed during the brief start cycle is way less than it ever was with a carbed engine.

[reptillikus]

Its more than the starter though, you need to be make sure the cables dont overheat when the alternator is charging the barrery(s). Plus think of the load on those cables while running a winch.



That said:





Thats two batteries secured underneath my toolbox, behind grating to keep em safe. Ran 2/0 gauge welding cable to them, and have had zero issues with them ever since.
The dead space to the left now houses an 11 gal tank for my OBA.