What battery should I use for my e30

[moatilliatta]

Another one here for Duralast gold... If it craps out, there are a lot of Autozones!.

Alternatively I sell mostly interstate.

[Sledgehammer_01]

So I've got a euopean market 320i touring with an S52, the previous owner did a battery relocation to the trunk and I'm struggling to figure out what group size battery to put back there. Group 48 doesn't sit low enough to clear the plastic cover panel and searching the intergoogs hasn't really turned anything up. I guess the next step is to get out my tape measure and go to the battery store... Thoughts?

[ForcedFirebird]

Group 48 is 192mm tall (306L x 175W), the e30 calls for group 91, which is 175mm (280L x 175W).

Link: https://www.batteryequivalents.com/b...ize-chart.html

[ForcedFirebird]

I had a Napa branded battery that lasted OK - maybe 5 years. but it was only like $100, so not too bad. Maybe I'll try Deka next - you'd think for $300, you'd get at least a year out of a battery, lol. I don't mind paying more if I can get one that doesn't die in a couple years..

I can't even blame letting it sit this time, as I was driving the E30 regularly. It maybe didn't get driven for 2-3 days, which shouldn't be enough for the battery to go flat, much less as dead as it was (4-5v IIRC). At first I thought maybe I had a drain, but the battery drains itself even disconnected from the car, and I can still charge it to 12v. So I'm pretty sure it's just crap.

Missed this post, but you probably have/had a dead cell. Batteries should charge closer to 12.8v. They are easily repaired. I have batteries that were sitting in the shop for years with ~3v on them. Before recycling, decided to try a reconditioner, and most of them came back. It's been a long time, but I used to replace the acid in them.

[reelizmpro]

So I've got a euopean market 320i touring with an S52, the previous owner did a battery relocation to the trunk and I'm struggling to figure out what group size battery to put back there. Group 48 doesn't sit low enough to clear the plastic cover panel and searching the intergoogs hasn't really turned anything up. I guess the next step is to get out my tape measure and go to the battery store... Thoughts?

You should be aware that the person who did that relocation used the "wrong" battery with the poles reversed and did so with non OEM wiring.

[nando]

Missed this post, but you probably have/had a dead cell. Batteries should charge closer to 12.8v. They are easily repaired. I have batteries that were sitting in the shop for years with ~3v on them. Before recycling, decided to try a reconditioner, and most of them came back. It's been a long time, but I used to replace the acid in them.

I tried reconditioning, no dice. Ended up getting a different battery from Costco. so at least I can return it if it goes to shit before it should, lol.

[Sledgehammer_01]

You should be aware that the person who did that relocation used the "wrong" battery with the poles reversed and did so with non OEM wiring.

I'm aware. The battery he had in it was an x2 power D925, but it had dropped a cell. The relocation was never completed and the wire was just slightly short so I added in a battery disconnect switch instead of pulling a whole new wire, I know the jumper from the disconnect to the battery is garbage, it's just temporary. Since I needed a battery I looked to the forums and saw group 48's were called out but apparently only for the USD sedans and coupes so that doesn't fit. A group 91 or T5 doesn't fit, the box is very shallow. I'm trying to recondition one of the D925's that he left me with the car to see if I can get it to work, so far it's holding voltage.

[ForcedFirebird]

I'm aware. The battery he had in it was an x2 power D925, but it had dropped a cell. The relocation was never completed and the wire was just slightly short so I added in a battery disconnect switch instead of pulling a whole new wire, I know the jumper from the disconnect to the battery is garbage, it's just temporary. Since I needed a battery I looked to the forums and saw group 48's were called out but apparently only for the USD sedans and coupes so that doesn't fit. A group 91 or T5 doesn't fit, the box is very shallow. I'm trying to recondition one of the D925's that he left me with the car to see if I can get it to work, so far it's holding voltage.

The link I posted in post M10 has all the dimensions for all the different groups.

[Sledgehammer_01]

yep and all of them are too tall, the dimensions of the box is something like (LxWxH) 13" x 6.75" x 5". So I'm going to go back to the D925, the one I reconditioned yesterday was sitting at 12.6v this morning after 4 hours of resting so hopefully it's good to go, it did start up the car this morning just fine. My only concern is that it sat for an unknown amount of time in a very very low state of charge, so even though it rested at 12.6v I'm sure there's some level of sulfation damage within the battery. Probably just a good idea to get a new D925 and not worry about it leaving me stranded.

[ForcedFirebird]

You might want to change over to the tray, holder and cover. Fortunately there's an early grey market import here. Went and checked - you'd just need to pull the plastic box out and add the late model stuff.

Tray and hold down (#9&10): https://www.realoem.com/bmw/enUS/sho...diagId=61_0675
Beauty cover (#10): https://www.realoem.com/bmw/enUS/sho...diagId=51_1754

That way you can use any late model battery that belongs in the e30.

[digger]

i bought a genuine battery from BMW it was only $205 for a 90AH p/n 61217604822. It is bigger than the e30 one as i wanted to fill the tray a bit better.

[reelizmpro]

My thoughts about batteries in 2024.

Battery Warranties:

For years I always recommended Costco but apparently Costco changed their warranty on car batteries. Instead of offering a free replacement before 3-4 years like before, they are now 36 month prorated. So after 18 months, you'd only get about a 50% refund. This means, Walmart, who still has the 3 year free replacement warranty is the new local go to place for inexpensive batteries and you don't need a membership.

All battery warranties have seem to lessen over the years. Nowadays, 3 years is the cutoff so what incentive do they have to produce a quality long lasting battery? A lot of things aren't what they used to be, same with batteries.

H6 vs H8:

Another thing I wanted to mention is that for years I have used H6/group 48 batteries on my E30's but as we know...rear battery E30's can accept the larger H8/group 49 battery. I remember these batteries were more expensive but that seems to not be the case anymore. Costco and Walmart both list their AGM H6 and H8 at the same price. My guess is that H8 has become a more common battery as it's used on many newer cars with a lot of electronics. If it's the same price, mind as well get the bigger battery. It will certainly help with cars that have a lot of accessories and sit for long periods without being driven. The only downside is that it weighs a little more but that's not a big deal on a street car.

H7:

This battery can also be used as it's length is in between the H6 and H8 batteries. I have seen someone stuff one in the engine bay but it's a very tight fit. The rear battery tray tie down only seems to accommodate H6 and H8 so you would need a spacer or something to fill in the gap.

T6/group 91 vs H6/Group 48

I've had 2 made in germany Duralast gold T6 batteries that didn't last long in my vert (lots of accessories and driven once a week). It's shorter than the H6 and has less CCA's. I went to H6 AGM and haven't any issue with the car sitting. The H6 fits front and rear battery E30's just fine, so not sure why people are saying the battery cover doesn't fit.

[strickland]

Bump for good info!