Battery Relocation Suggestions

[Doc76]

Hey all
Looking for suggestions, hoping I am missing an option, to relocating my battery which is currently located per the build book between the two roll bars up inside the trunk.
I want to convert that space to the cubby mod.

Seems like the drop truck mod only nets 5" in depth. given the battery is 8" high, it doesn't really present as a great solution.
Tucked over to the right ends up covering the fuel tank access. (maybe my only option however)
I am aware of the battery relocation similar to Breeze up under the hood. Not a fan of cramming it in there due to space and elements.

Is there an option I am missing......hopefully?

Kindly

[65 Cobra Dude]

Have you looked at the ffmetal option? That drops the battery under the upper part of the trunk.

Henry

[Rebostar]

Not sure where your at in your build but if you have the body off and have a drop trunk and want to do some major surgery you can mount the battery to the left of the drop trunk.

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[Doc76]

Have you looked at the ffmetal option? That drops the battery under the upper part of the trunk.

Henry

I measured the space yes, forgot to mention that. That would be my first choice but not sure if it’s due to being a setup with an 8.8 solid axle but there isn’t enough space to fit my Optima Red Top there.
Not sure why.
Maybe the guys dropping it there are on IRS?

[Doc76]

Not sure where your at in your build but if you have the body off and have a drop trunk and want to do some major surgery you can mount the battery to the left of the drop trunk.

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Now that is probably the coolest relocation I’ve seen to-date.
Nice work!!

Unfortunately my body is on. I’ll have a look at that option thanks.

Can I ask about your drop trunk?
Did you cut out the lateral brace 1x1” tube?
For me that’s the Achilles of that mode. I don’t like a drop trunk with the tube running across it.

[Jeff Kleiner]

I put the battery in front behind the X member on most of the cars I build.

https://thefactoryfiveforum.com/attachment.php?attachmentid=206472&d=1731762162

I make my own but if you're more of a buy rather than build sort of guy Breeze has you covered.

https://breezeautomotive.com/shop/engine-compartment-battery-mounting-kit-mk3-3-1-4-roadster/

Shorter cables, easy access and puts the weight in a better location.

Jeff

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[rich grsc]

The battery behind the driver side rear wheel is bad location as far as weight distribution goes. Like Jeff notes, the front is a better location

[Jeff_J.]

x2 on the relocation to the front, I purchased the Breeze kit personally. The Drop trunk probably adds about 20% to the storage area of the trunk, gives perspective on how little area there is in there. I've read if you fit a soft top in the trunk there isn't much room for anything else so whatever space you can get is a bonus. The cross members are in the way but benefit outweighs the hindrance. These are pictures of the RT Drop trunk I purchased, I added the trim to clean up the carpet edges.
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[Jim1855]

I like Rebostar's battery location, it uses normally unused space. FYI, it is where Superformance places the battery although Rebostar's is a much easier to access installation.

I do agree that it skews weight balance, putting a +/- 40#s behind the left side rear wheel makes a huge difference especially in a corner that is already heavy. I tested this with a previous car by moving the battery forward and improving corner weight imbalance. A battery is a great chunk of ballast IF you can move it around.

Corner weight matters but more so on a track focused car.

Jim

[rich grsc]

I have 20 yrs with these cars. Corner weight ALWAYS matters with these cars. I never checked or set the corner weights on my first car, it would always lockup the right front on a hard stop. Corrected the corner weights and that went away. With a 40# battery behind the left rear wheel, I would expect that issue. Just something to think about and be aware of.

[Jeff Kleiner]

Google "moment of inertia." Adding weight high and behind the rear axle on the corner of the car that is already heavy will have a negative effect on the vehicle's handling. Remember how 911s had a reputation for being tail happy with a propensity for nasty snap oversteer?

Jeff

[Cobradavid]

x2 on the relocation to the front, I purchased the Breeze kit personally.


+1 on the Breeze battery kit. It's a very nice kit and it's nice getting that mass low and in the front.

David

[Doc76]

I put the battery in front behind the X member on most of the cars I build.

https://thefactoryfiveforum.com/attachment.php?attachmentid=206472&d=1731762162

I make my own but if you're more of a buy rather than build sort of guy Breeze has you covered.

https://breezeautomotive.com/shop/engine-compartment-battery-mounting-kit-mk3-3-1-4-roadster/

Shorter cables, easy access and puts the weight in a better location.

Jeff

206472

Yes and Marks a real solid guy to work with.
I do have a couple sheets of SS in the shop and Tig/Mig so definitely fabricate it myself if I go that route. Recently did the pulley mod with my own spin. Didn’t want to drill any holes in the frame in the event I wanted to change it down the road so ended up making a bracket to hold the pulleys coming off that secondary e-brake bracket beside the tranny that’s unused and also replaced the donor clevis that was hanging up with a fabricated aluminum-bronze lock block for the cables.
E-brake didn’t work at all before…works perfect now. I much prefer the fab work :)

[cv2065]

Big fan of the Breeze battery relocation kit as well.

[Norm B]

Doc, I am in agreement with most of the people that have replied and recommend the front battery placement. I also did my own trunk drop mod during the build and added a little tool box to the front of the drop section. Room for the Whitby top on the top shelf, regular size carryon bag for my wife and a duffel bag for me for overnight trips.

Norm

[Doc76]

Doc, I am in agreement with most of the people that have replied and recommend the front battery placement. I also did my own trunk drop mod during the build and added a little tool box to the front of the drop section. Room for the Whitby top on the top shelf, regular size carryon bag for my wife and a duffel bag for me for overnight trips.

Norm

Thanks Norm
I’ll need to relocate my remote oil filter if I go that route up front. Builder mounted it right in the middle. No biggie I guess.
Looks great in that trunk. I see you choose to cut out the lateral bracing in that drop trunk area. No structural issues taking those out?
I see some builders leave them in. Certainly makes more send taking them out.

[Rebostar]

Now that is probably the coolest relocation I’ve seen to-date.
Nice work!!

Unfortunately my body is on. I’ll have a look at that option thanks.

Can I ask about your drop trunk?
Did you cut out the lateral brace 1x1” tube?
For me that’s the Achilles of that mode. I don’t like a drop trunk with the tube running across it.

Yes I did cut out the diagonal tube on the left and added a new tube on the right to loose the rear part of the right diagonal. I wanted the drop trunk completly open.
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[Rebostar]

The battery behind the driver side rear wheel is bad location as far as weight distribution goes. Like Jeff notes, the front is a better location

Drag racers and hot rodders been puting them there for 50 years!

As for me I dont plan on racing this car on a road track. In addition having 30 lbs over the rear axle will help a bit with traction. Also I wanted to be able to use a common g-34 battery, not that skinny one that fits in front of the engine. Though, if there was room for a g-34 there I would have saved a lot of work.

Having been in general aviation for 45 years I'm very familiar with wieght, moment and arm calculations. The numbers are tolerable. Here are my last two builds with a trunk mounted battery.

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[Doc76]

Has anyone heard of an install in the upper trunk space where the battery was laid on its side to sink it into the floor?
I have an optima red top AGM and really wanted to sink it into that space but it’s too deep. According to Optima it that battery can be located in any position except upside down.
I may be able to lay it on its back though. Will have to check tonight

[Rdone585]

I changed to a lithium battery (much smaller, lighter, and pricey) and made a bracket to mount it behind the passenger. This removed almost 40 lbs from driver side to 7 lbs on passenger side. Really helped in my case to balance out the car. I wanted to put the battery in the engine bay, but could not with my setup. As you state, not sure you can fit the AGM there without dropping the floor of the shelf area. But beware, if you put it there in a dropped floor, make sure you can get it back out. It must also be firmly mounted.

[Doc76]

I changed to a lithium battery (much smaller, lighter, and pricey) and made a bracket to mount it behind the passenger. This removed almost 40 lbs from driver side to 7 lbs on passenger side. Really helped in my case to balance out the car. I wanted to put the battery in the engine bay, but could not with my setup. As you state, not sure you can fit the AGM there without dropping the floor of the shelf area. But beware, if you put it there in a dropped floor, make sure you can get it back out. It must also be firmly mounted.

For sure thanks
What did you do for a lithium battery brand and size?
I guess that’s something I hadn’t considered (bummer my Red top is only 4 months old, but hey, if it solves my relocation issue.)

[rich grsc]

Odyssey battery
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[tonywy]

You know, Shelby put the batteries behind the passenger seat probably for a reason.

[Jimmy B]

Odyssey battery
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What part number is that one?

[rich grsc]

it's a PC680

[CraigS]

I moved my battery up front in my old MkII. I don't remember sizes anymore but remember I stepped down one from the old standard size and used a standard lead acid battery. Maybe 2ft cable run to the starter, 1.5ft to the engine block for the ground. If I were you I'd dump all that remote filter plumbing and screw your filter onto the block.

[Doc76]

I moved my battery up front in my old MkII. I don't remember sizes anymore but remember I stepped down one from the old standard size and used a standard lead acid battery. Maybe 2ft cable run to the starter, 1.5ft to the engine block for the ground. If I were you I'd dump all that remote filter plumbing and screw your filter onto the block.

Thanks for the feedback
I actually looked at that last night.
Is there a heat shield available for between the oil filter and header that you’re aware of?
There’s really no way for me to burry the battery in the back easily. I looked for a lithium battery but all the specs on CCA and HCA’s on the manufacturer sites list significantly below recommended requirements for even a stock 5.0, 302 so I think that’s out.

[kgkeys]

Has anyone heard of an install in the upper trunk space where the battery was laid on its side to sink it into the floor?
I have an optima red top AGM and really wanted to sink it into that space but it’s too deep. According to Optima it that battery can be located in any position except upside down.
I may be able to lay it on its back though. Will have to check tonight

I didn't try to sink mine into the floor, but I originally used a battery similar to Rich's PC680, called a "Dyna-Batt", in the upper passenger corner. I used as much of what came with the kit as I could, including the cable and the battery hold-down. I used some all-thread in the 3/4" tube on the passenger side to make the hold-down captive. I used a sheet of 3M rubber underneath to give it some shock absorption.


https://zeys.zapto.org/Battery3.jpg
https://zeys.zapto.org/trunkfloor.jpg

The battery was sometimes under-powered for cranking with that #4 cable all the way to the back, So I went to an Odyssey PC925.

https://zeys.zapto.org/Graduation/20241028_142354.jpg

This is a fairly inaccessible area of the trunk, anyway. It might be a little tricky if you have a passenger roll-bar downtube going through there, but I think it could still work. The front mount options are probably better, but this solution has been good for me.

-Kyle

Edit: I forgot to mention that I riveted in a piece of thin steel underneath the trunk aluminum to support the weight of the battery...

[Rdone585]

Here is the battery I put in about two years ago.
https://shopbraille.com/collections/green-lite-lithium/products/braille-g30-greenlite-lithium-battery
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[Doc76]

Here is the battery I put in about two years ago.
https://shopbraille.com/collections/green-lite-lithium/products/braille-g30-greenlite-lithium-battery
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Hey now I could make that fit below my floor. Thanks

[rich grsc]

Thanks for the feedback
I actually looked at that last night.
Is there a heat shield available for between the oil filter and header that you’re aware of?
There’s really no way for me to burry the battery in the back easily. I looked for a lithium battery but all the specs on CCA and HCA’s on the manufacturer sites list significantly below recommended requirements for even a stock 5.0, 302 so I think that’s out.

I guess you have a thought process issue?? There is NO need for a heat shield on the oil filter, :( it circulates hot engine oil by design. I've been using a PC 680 battery for over 4yrs, never an issue. There isn't a need for a huge battery has these cars don't have a large electrical load.

[D Stand]

For those that have installed lithium batteries, did you alter the charging systems any? Just curious as there are different chargers out there for lithium.

[Rdone585]

The one I put in is designed to replace a standard battery. It will work with standard alternators. But you should use a lithium charger instead of another type. If the "head" voltage is too high it can damage the battery. Also some are really not suppose to be jumped with another battery. There are tutorials out there about how to deal with jumping a lithium battery. https://msxxfast.wordpress.com/2018/02/22/how-to-safely-jumpstart-a-lithium-motorcycle-battery/

[D Stand]

The one I put in is designed to replace a standard battery. It will work with standard alternators. But you should use a lithium charger instead of another type. If the "head" voltage is too high it can damage the battery. Also some are really not suppose to be jumped with another battery. There are tutorials out there about how to deal with jumping a lithium battery. https://msxxfast.wordpress.com/2018/02/22/how-to-safely-jumpstart-a-lithium-motorcycle-battery/

Copy. Thanks

[MikeD]

Agree with the front location. Phil and I did it on our cars, and we made a video of the process:

https://youtu.be/mUXRIsNmBc4?si=kqgi_hbZ-IzQXE6t

[Doc76]

What is the battery of choice for the up-front location?
I have an Optima Red Top which looks bigger than what most guys are using and I thought it wouldn't fit there however after watching Mikes video its tight but I could make that work.

[Doc76]

Agree with the front location. Phil and I did it on our cars, and we made a video of the process:

https://youtu.be/mUXRIsNmBc4?si=kqgi_hbZ-IzQXE6t

Thanks for taking the time to make the video and share!

[Mike.Bray]

What is the battery of choice for the up-front location?
I have an Optima Red Top but it wont fit there.

The Breeze kit uses a group size 51 battery.

[Flip Smiley]

I used the stock 1990 battery, size 58 I believe. Shown on Mikes video. Note it isn’t mounted exact center but slightly to the passenger side. No fit issues. I also agree with Craig S above as usual, ditch the remote oil filter location and mount the filter on the block where it belongs.
Flip

[Doc76]

I used the stock 1990 battery, size 58 I believe. Shown on Mikes video. Note it isn’t mounted exact center but slightly to the passenger side. No fit issues. I also agree with Craig S above as usual, ditch the remote oil filter location and mount the filter on the block where it belongs.
Flip

Ok thanks
Ya filters been in the way a few times now.
Back it goes.

[Bill_VA]

As the current owner of FFmetal.com, the source of battery boxes for the trunk area, I would like to add my two cents to this conversation. I built my car 18 years ago, and when I did so I found FFmetal.com and ordered just about everything he had for my car, including a trunk mounted battery box. I learned that the owner, Linwood, had designed the box to either fit in the center of the car for IRS suspension or the far left (driver's side) for 3-link builds. He did this because the drivetrain is actually shifted over in the chassis about an inch to add a bit of balance to make up for the weight of the driver. That's why the headers are a bit shorter on the passenger side. I had my car corner-scaled a couple times and was able to get the left-right balance almost perfect and the front-rear balance about 51/49%.

FYI, I acquired FFmetal.com from Linwood about 7 years ago.

Some will argue that the battery is too difficult to remove, but honestly, if you only have to do it every 6-8 years, why is that such a concern? BTW, the box has a large hole in the bottom that allows you to push the battery out with an extra hand. I just left the carrying handle on the battery and was able to lift it right up and out. The whole removal/replacement took me 15 minutes. In 18 years I only did this three times.

A neater, less cluttered engine bay is a plus too.

[Doc76]

As the current owner of FFmetal.com, the source of battery boxes for the trunk area, I would like to add my two cents to this conversation. I built my car 18 years ago, and when I did so I found FFmetal.com and ordered just about everything he had for my car, including a trunk mounted battery box. I learned that the owner, Linwood, had designed the box to either fit in the center of the car for IRS suspension or the far left (driver's side) for 3-link builds. He did this because the drivetrain is actually shifted over in the chassis about an inch to add a bit of balance to make up for the weight of the driver. That's why the headers are a bit shorter on the passenger side. I had my car corner-scaled a couple times and was able to get the left-right balance almost perfect and the front-rear balance about 51/49%.

FYI, I acquired FFmetal.com from Linwood about 7 years ago.

Some will argue that the battery is too difficult to remove, but honestly, if you only have to do it every 6-8 years, why is that such a concern? BTW, the box has a large hole in the bottom that allows you to push the battery out with an extra hand. I just left the carrying handle on the battery and was able to lift it right up and out. The whole removal/replacement took my 15 minutes. In 18 years I only did this three times.

A neater, less cluttered engine bay is a plus too.

Interesting
I'll check it out. I agree and am not a fan of placing the battery in the engine bay.

[Bill_VA]

It's designed for an Optima RedTop battery, group 34, not a 34/78 with top and side terminals. The last thing you want is the side terminals to come in contact with an aluminum box side. See here: www.ffmetal.com (https://www.ffmetal.com/#bb)

[Doc76]

Noted Thanks Bill
I sent you an email via your website link. Please have a read at your convenience and let me know.

[Doc76]

Well it’s back to the drawing board For anyone wanting to use the FF Metals battery box, if you have a 3-link, mk4 with a GT500 finned cover, this box will not fit.
I tried to make it work but under compression, this cover will hit the box corner.

I will add this is a super nice piece and Id like to find a smaller battery that may allow me to notch the box and still use it. Very well made.

Any suggestions on battery options would be appreciated.

[Valkster]

I wanted to use the Breeze kit, but it would not fit for my particular engine. It would have interfered with the engine pulleys. I bought a generic battery tray from eBay and added some tabs and bars to set it on top of the X member and stabilized by the top radiator mount. This was a big, wasted area for me and I thought it fit well there. I had read a lot of posts about the battery "needing" to be in the back and low due to weight distribution :confused:. I'm not building a race car, and I am currently pudgy (or more) so I more than offset the battery move, lol. I have a Group 34 battery in mine. That battery size seemed readily available and cost effective here. I plan for it to be on a maintainer so I should get 7+ years out of it based upon the other old cars I have.

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[Doc76]

Hoping for advice on this one.
I finally got around to cutting the fins off the diff cover to try to make this FFMetals box work. Looks like I am near flush with the face of the cover and about 1.125” away.
It appears I have ~2.5” of Koni shock travel.
I know these boxes are tight but for those of you that have fit this box, what are your thoughts?
Too close for comfort?212176212175212177

[Doc76]

Just an fyi for anyone running this configuration, I ended up trimming back the fins on the diff cover and installed the box. I ran it for a few hundred miles at the FFR recommended ride height and had no contact with the cover and the battery box.
I’ll now confidently move the battery into the box and be able to install the Breeze trunk cubby!
Talk to you soon Mark ;)

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[Nigel Allen]

Just an fyi for anyone running this configuration, I ended up trimming back the fins on the diff cover and installed the box. I ran it for a few hundred miles at the FFR recommended ride height and had no contact with the cover and the battery box.
I’ll now confidently move the battery into the box and be able to install the Breeze trunk cubby!
Talk to you soon Mark ;)

221497
221498

Nice job on making the battery box fit. Super clean under there.

Cheers,

Nige

[Bill_VA]

I measured the space yes, forgot to mention that. That would be my first choice but not sure if it’s due to being a setup with an 8.8 solid axle but there isn’t enough space to fit my Optima Red Top there.
Not sure why.
Maybe the guys dropping it there are on IRS?

If you have a MK4 with a 3-link, the FFmetal battery box fits very nicely. Order with confidence.

[Doc76]

If you have a MK4 with a 3-link, the FFmetal battery box fits very nicely. Order with confidence.
It did however I did have to modify my diff cover. The cooling fins would have almost certainly contacted. If I had a simple stock style cover, I’m sure it would have been no issues. None the less I would 100% use this mod again!

[BornWestUSA]

https://www.odysseybattery.com/products/ods-agm28l-battery-pc925/

shorter, more than enough power.

[Wizbangdoodle]

For what it's worth, I mounted my battery behind the passenger seat just under the passenger rollbar. It's an Optima red top and fits well. Added a brace under the sheetmetal and made sure I could access the hold down from underneath.

[MikeHolt]

I put the battery in front behind the X member on most of the cars I build.

https://thefactoryfiveforum.com/attachment.php?attachmentid=206472&d=1731762162

I make my own but if you're more of a buy rather than build sort of guy Breeze has you covered.

https://breezeautomotive.com/shop/engine-compartment-battery-mounting-kit-mk3-3-1-4-roadster/

Shorter cables, easy access and puts the weight in a better location.

Jeff

206472

That is exactly what I did! Helped with the codes I was throwing, too!