Mk5 Battery Tray placement

[Pizzman76]

To all my Mk5 people with the remote vac booster option.

I decided to use a 925 series battery to give this area a bit more space for service, which allows me to push the battery tray about 3" further forward. I didn't see anything obvious in the build manual that would prevent me from using that space, but I would like to know if I am missing something before drilling the holes. I planned on adding a couple of L-Brackets off the front crossmember to add back the attachments for the tray.

212775

[Todd Baumann]

This is exactly where we mounted ours in the "Build School" also. We have the same battery your using too.
You should be fine.

Todd

[Pizzman76]

Thanks for confirming Todd!

[Tango]

Thanks for the heads up and confirmation. I am headed in that direction soon.

[edwardb]

If you're going with that battery, you might consider the Artec Industries OY9251 battery mount. Purpose made for the Odyssey PC925, looks better, and (in my opinion) does away with that somewhat janky top battery holder from the kit. Picture from my Coupe build:

https://thefactoryfiveforum.com/attachment.php?attachmentid=97587&d=1542472755

[Jeff Kleiner]

What we learned on the Beta builds is that once the engine is installed the battery will be trapped under the booster and R&R has to be from below which will require removing the tray so don’t make it’s installation permanent.

Jeff

[Pizzman76]

What we learned on the Beta builds is that once the engine is installed the battery will be trapped under the booster and R&R has to be from below which will require removing the tray so don’t make it’s installation permanent.

Jeff

Wow! Without the engine installed, it's hard to imagine you couldn't snake out that small battery from inside the engine bay. That remote booster really closes off the space.

Maybe it makes sense to look at the smaller battery mount Paul posted.

[rich grsc]

To all my Mk5 people with the remote vac booster option.

I decided to use a 925 series battery to give this area a bit more space for service, which allows me to push the battery tray about 3" further forward. I didn't see anything obvious in the build manual that would prevent me from using that space, but I would like to know if I am missing something before drilling the holes. I planned on adding a couple of L-Brackets off the front crossmember to add back the attachments for the tray.

212775
I would be thinking about redoing those brake lines. Remove the lines with unions in them and fix the right side loop, it'll just be a place for an air bubble to set

[MakoGT350]

What we learned on the Beta builds is that once the engine is installed the battery will be trapped under the booster and R&R has to be from below which will require removing the tray so don’t make it’s installation permanent.

Jeff

Jeff - just confirming - are you saying that is the battery used in a beta build and it was able to be snaked out from the bottom once the tray is out of the way? (I am doing an early MKV and trying to figure out battery/tray/etc)

It looks like it could also be snuck out through the passenger side wheel well, as long as the upper liner were put in with rivnuts and easily removable.

[BEAR-AvHistory]

Obligatory dumb *** question. Can't you just mount it in the trunk like a MK-4?

[MakoGT350]

I know that some are doing the battery in the trunk for the MK5, I am trying to leave it up front, if possible.

[edwardb]

Going from a front mounted battery to a rear mounted one is a step backwards IMO. The Breeze front battery mount was one of the most popular mods for a reason. Let me count the ways: The power wiring is simpler and shorter and avoids yet another run through the crowded transmission tunnel. The new Mk5 chassis design, like the Gen 3 Coupe, already has fuel, brake, and wiring harness there. The front mount uses mostly available space and avoids taking space from the already limited trunk. The most recent update to the Mk5 (which mine doesn't have BTW :() allows the battery to be dropped out the bottom which admittedly is easier than the original design where like the Gen 3 Coupe has to come out from the top. Having said that, I've driven my Gen 3 Coupe for five seasons and during that time did have to replace the battery once. Required removing the cold air intake in order to have room to lift it out. But honestly, no big deal. Only about an hour or less work..

Probably one of the main issues here is the addition of a power brake booster above the battery area. Which I'm not installing in my Mk5 build. But that's another discussion. Granted a full size battery and the power brake booster apparently don't coexist. There are options for a lower profile battery. Like the Odyssey PC925T I have in my Coupe and will install in my Mk5 build. Also used one in my truck build. They're not cheap but still a better option IMO than deciding that a rear mounted battery is the only option.

[MakoGT350]

Going from a front mounted battery to a rear mounted one is a step backwards IMO. The Breeze front battery mount was one of the most popular mods for a reason. Let me count the ways: The power wiring is simpler and shorter and avoids yet another run through the crowded transmission tunnel. The new Mk5 chassis design, like the Gen 3 Coupe, already has fuel, brake, and wiring harness there. The front mount uses mostly available space and avoids taking space from the already limited trunk. The most recent update to the Mk5 (which mine doesn't have BTW :() allows the battery to be dropped out the bottom which admittedly is easier than the original design where like the Gen 3 Coupe has to come out from the top. Having said that, I've driven my Gen 3 Coupe for five seasons and during that time did have to replace the battery once. Required removing the cold air intake in order to have room to lift it out. But honestly, no big deal. Only about an hour or less work..

Probably one of the main issues here is the addition of a power brake booster above the battery area. Which I'm not installing in my Mk5 build. But that's another discussion. Granted a full size battery and the power brake booster apparently don't coexist. There are options for a lower profile battery. Like the Odyssey PC925T I have in my Coupe and will install in my Mk5 build. Also used one in my truck build. They're not cheap but still a better option IMO than deciding that a rear mounted battery is the only option.

Thanks for the input and perspective! I am going to keep it upfront, and it looks like the odyssey is the way to do it. Whether it drops out the bottom or it slides out the passenger wheel well - remains to be seen. I just don't want to have to pull the booster out to do it.

[BEAR-AvHistory]

Was just a thought. Have 10 years on my car & only have replaced one battery so it's not an everyday occurance. That said have had no issues with the battery cable run & like the extra battery weight over the driving wheels. The other nice point was putting the kill switch inline mounted on the u-joint cover.

[rickster991]

I can tell you that there is no getting the battery out without removing the brake booster. I hope my battery lasts a long time!

[michael everson]

FFR had updated the frames and battery mount so it can be removed from the bottom. I retrofitted the 3 I have here. Much better solution.
Mike

[rickster991]

So cut the frame to make an opening big enough? I guess that can happen when you need to change the battery for the first time.

[Reddrig]

Here is my mount, I believe if I remove my sway bar it will slip out. Or I can remove the bolts that hold the tray in, I don’t believe it will be an everyday occurrence so not a huge deal for me.

[Jeff Kleiner]

...Granted a full size battery and the power brake booster apparently don't coexist....

Actually they will, but you need to plan ahead for it or be prepared to do some gymnastics for R&R. I was at FFR with the R&D techs while the 30th Anniversary roadster was going together. The full sized was not on hand when the engine and booster were installed so to put it in afterwards required taking the booster loose (but with lines intact) and removing some of the engine front dress. After this is when the new battery tray was designed and went into production ;)

Jeff

[edwardb]

Actually they will, but you need to plan ahead for it or be prepared to do some gymnastics for R&R. I was at FFR with the R&D techs while the 30th Anniversary roadster was going together. The full sized was not on hand when the engine and booster were installed so to put it in afterwards required taking the booster loose (but with lines intact) and removing some of the engine front dress. After this is when the new battery tray was designed and went into production ;)

Jeff

What part of "apparently" isn't clear? I was citing what others have said. Always a danger without personal experience. :p

The update to drop the battery out the bottom is a good change. My earlier Mk5 frame doesn't have it. But since I'm not installing the booster and using a low profile battery, figure I can live with it. Just like the Coupe that's the same way. I might consider modding my frame like Mike mentioned. But for the reasons cited plus the bronze Anniversary PC that I don't want to try to restore since there's custting and welding involved, not going to do it.

[Jeff Kleiner]

What part of "apparently" isn't clear?

I understand "apparently". I was following it up with facts gained by personal experience.

Jeff

[michael everson]

BTW the online manual has been updated to show the new battery mount.
Mike

[rickster991]

I uploaded a video of my battery placement so you can see the obstructions. It’s in the FFR recommended spot. Hope this helps.


https://youtube.com/shorts/aWu9vFMqhpc?si=Zqvun70zLhOldBWP

[Aleinsteingenius]

I have a pretty early (not Beta or 30th Anniversary) MK V complete kit. Sales Order # 0218579. Completion Date 4/26/2025. The new battery box that allows you to drop it out the bottom would require some major surgery. I have the power brake booster. When my engine gets here, I will see how much room there is between the power booster and the Godzilla engine. I am a boat enthusiast and have experience wiring multiple LiFePO4 Lithium batteries to start large diesel engines. I am thinking maybe a couple of lithium motorcycle batteries in a custom box wired in parallel. The newest ones come with built-in BMS (battery management system).

[MakoGT350]

I have a pretty early (not Beta or 30th Anniversary) MK V complete kit. Sales Order # 0218579. Completion Date 4/26/2025. The new battery box that allows you to drop it out the bottom would require some major surgery. I have the power brake booster. When my engine gets here, I will see how much room there is between the power booster and the Godzilla engine. I am a boat enthusiast and have experience wiring multiple LiFePO4 Lithium batteries to start large diesel engines. I am thinking maybe a couple of lithium motorcycle batteries in a custom box wired in parallel. The newest ones come with built-in BMS (battery management system).

I can confirm that the Odyssey PC925 AGM battery will drop out the bottom without mods, even after attaching a battery tray meant just for that battery. turned out nice.

[tonywy]

After reading all, here is what I never could understand is why we mout batteries in the front of the engine or for that matter all the way back in the trunk area. I understand where else. I'm surprised that when the MK5 was designed that they didn't find a better spot like behind the passenger seat area. The originals were there for a reason.