Time to replace the battery: Lightweight options?

[94jedi]

Hey all - so I'm getting the darn "increased battery discharge" warning so I figure it's time to replace the batter and why not do so w/ a lightweight option. I know the Lithium battery technology has come down a bit in price...definitely don't want to pay $800 for a battery. What have you guys done? My car is driven a couple of times per week at most, sometimes once a week. I see the "Antigravity" batteries are still in the $700+ range. Does anyone know what the lowest amp hours is that we can "get away" with? Are there any smaller batteries that fit? My car isn't a "fat spec" but I like to keep her svelte if I can.

[fsmtnbiker]

My car previously had a ETX20L in it. Worked fine as long as the temps were above 40 degrees and the car didn’t sit without a tender for more than a day.

Fried the FRM after getting low one too many times. Fixing that cost more than the antigravity would have in the first place.

Buy the antigravity. Buy once, cry once. I can leave the car sitting for 3 weeks and it starts up perfectly, no tender, no BS. Weighs less than the mini battery did, mounts to stock mounts, and has 1200CA. I couldn’t be happier with that particular spend.

[roastbeef]

lots of discussion here. z4m or mini cooper battery might be a compromise for you.

https://www.m3post.com/forums/showth...1#post19103181

also, sign up for the antigravity email list. they have pretty good sales around the major holidays.

[DRLane]

I ordered the 24Ah, arrived today. We'll see how it fairs. Though It'll live on the charger when sitting for more than a day or so.

[Move Over]

The H6 Diehard from advanced is 34 lbs, down about 27 from the 61 pounder i traded in, and it was 130 bucks, i really wanted a lightweight one but couldn't shell out an extra 600 bucks for 20lbs less weight.

AH is 50, however, I really don't have many electronics. Has not given me any issue since.

[LeveragedTiger]

Don't forget VoltPhreaks.

https://www.voltphreaks.com/products_racing.php

[Richbot]

LiFePo is perfectly suited for long periods sitting. There's virtually no parasitic loss internally, and most of the BMS-equipped batts will shut off if they draw down low enough where tehy might not start thec ar and/or a cell balance issue could be starting

My Voltphreaks has been in the car for almost 4.5 years now. Daily during the not-salty months, can sit for weeks in the garage without being touched and still starts fine.

[///Mobbin]

As someone who charges my battery with a tender once every 6-8 weeks the idea of a battery that doesn't need to be topped up as often alone is appealing, plus the weight loss of course.

[//steve\\]

I know for me when the time comes the right move feels like pay up for the good ones with the extra tech instead of trying to save a few $$s on the cheap options. I owned a tender and have never made it part of regular practice to use it. Seems like an annoyance more than anything so I don't bother with it. This is a non daily driven car that sometimes sits for several weeks at a time without getting driven although rarely more than 3-4 weeks.

[tom @ eas]

Originally Posted by fsmtnbiker

My car previously had a ETX20L in it. Worked fine as long as the temps were above 40 degrees and the car didn’t sit without a tender for more than a day.

Fried the FRM after getting low one too many times. Fixing that cost more than the antigravity would have in the first place.

Buy the antigravity. Buy once, cry once. I can leave the car sitting for 3 weeks and it starts up perfectly, no tender, no BS. Weighs less than the mini battery did, mounts to stock mounts, and has 1200CA. I couldn’t be happier with that particular spend.

Battery didn't fry the module, the FRM2 is notorious for prematurely failing. BMW introduced a campaign for warranty for 10 years/156K mi span to replace dead FRM2s for FRM3. FRM3 modules started appearing in M3s around ~2010.

SI B01 20 16: https://bimmerscan.com/wp-content/up.../B012016-1.pdf

We've been doing a lot of testing for Antigravity throughout the years, the lineup is fantastic for the E9X chassis.

[SYT_Shadow]

Originally Posted by tom @ eas

Battery didn't fry the module, the FRM2 is notorious for prematurely failing. BMW introduced a campaign for warranty for 10 years/156K mi span to replace dead FRM2s for FRM3. FRM3 modules started appearing in M3s around ~2010.

SI B01 20 16: https://bimmerscan.com/wp-content/up.../B012016-1.pdf
.

FRMs have been dying for no good reason for a long time, thanks for clarifying for posterity

[fsmtnbiker]

Originally Posted by tom @ eas

Battery didn't fry the module, the FRM2 is notorious for prematurely failing. BMW introduced a campaign for warranty for 10 years/156K mi span to replace dead FRM2s for FRM3. FRM3 modules started appearing in M3s around ~2010.

SI B01 20 16: https://bimmerscan.com/wp-content/up.../B012016-1.pdf

We've been doing a lot of testing for Antigravity throughout the years, the lineup is fantastic for the E9X chassis.

2 things for clarity:

Mine is a late 2011, had FRM3 from the start.

The FRM failed at the same time that the car was attempted to be started with a too-low battery. Immediately after that a bunch of the body controls did not work. So I correlated the low voltage from the (crap) motorcycle battery with the FRM failing.

[tom @ eas]

Originally Posted by fsmtnbiker

2 things for clarity:

Mine is a late 2011, had FRM3 from the start.

The FRM failed at the same time that the car was attempted to be started with a too-low battery. Immediately after that a bunch of the body controls did not work. So I correlated the low voltage from the (crap) motorcycle battery with the FRM failing.

Yep, the ETX20L is more of a powersports battery. 310CCA doesn't fit the bill.

FRM3s don't usually brick, most likely it can be brought back. E9X is pretty power hungry, until it enters full sleep and needs a battery that can sustain it.

[DRLane]

Originally Posted by tom @ eas

Yep, the ETX20L is more of a powersports battery. 310CCA doesn't fit the bill.

FRM3s don't usually brick, most likely it can be brought back. E9X is pretty power hungry, until it enters full sleep and needs a battery that can sustain it.

Tom, you think the 24Ah (1000cca) antigravity will be problematic for e9x?

[berns]

Originally Posted by DRLane

Tom, you think the 24Ah (1000cca) antigravity will be problematic for e9x?

I've been running the H6-30-RS for a few months. Problem free. Car sits for over a month and still barely drains. Has the re-start feature too, so it'll literally never need a jump. Weighs 13lbs vs stock 60lb battery, fits in the stock location with no modifcations.

Also ran an ATX-30-HD on my 135i. Weighed 8 lbs. Never had an issue.

Can't say enough about Antigravity...

[DRLane]

Originally Posted by berns

I've been running the H6-30-RS for a few months. Problem free. Car sits for over a month and still barely drains. Has the re-start feature too, so it'll literally never need a jump. Weighs 13lbs vs stock 60lb battery, fits in the stock location with no modifcations.

Also ran an ATX-30-HD on my 135i. Weighed 8 lbs. Never had an issue.

Can't say enough about Antigravity...

Thx Berns.

[dogbone]

Not the cheapest option, but VoltPhreaks VPR-P6 weighs 6 lbs and has been awesome. We installed a remote power button on the dash that completely shuts off the battery when the car is going to sit in the trailer for long periods of time.

This year, the car sat in Texas in a trailer for 7 months. It fired right up like no time had passed.

Very impressed with VoltPhreaks.

[Richbot]

Originally Posted by fsmtnbiker

2 things for clarity:

Mine is a late 2011, had FRM3 from the start.

The FRM failed at the same time that the car was attempted to be started with a too-low battery. Immediately after that a bunch of the body controls did not work. So I correlated the low voltage from the (crap) motorcycle battery with the FRM failing.

This was the #1 reason I went to the lifepo for the car's 4th! battery - I got spooked by lead batteries slowly dying and taking a bunch of other small actuators that need to not pull a lot of amps on an undervolt to keep from killing themselves. UV situation killed a driver's door lock and a mirror actuator on our 335i right before the battery finally showed enough canvas to be replaced. Dead driver's door lock actuator is two tons of NOT FUN. The weight loss is a great feature but this is an undervalued benefit of the lifepo on these vampire cars

[m3peat]

Since it’s been over 5 years since the last post and I will likely need a new battery in the coming weeks/months, looking for latest opinions on lightweight battery options.

How my car is used:
- live in SoCal (LA), so moderate to warm weather year round.
- I drive it 2-4x per month for 45 minutes to hours at a time.
- used for mountain drives, autox and occasional track days.
- electricity needs: the car is stock and does not have a lot of options.
- car is an 09’ with 170k miles and runs great.


My current Bosch (not lightweight) battery has lasted over 7 years and cost $180. Great value.

Would like:
- lightweight battery that would not require a battery tender except if it would be sitting for more than 2-3 weeks.
- I would like to keep the cost below $500 unless I am convinced a more expensive lightweight battery will last as long or longer than the current one I have.
- I understand my price point may not offer many lightweight options but even if it’s 20+ lbs lighter, I’m interested.

Any additional details needed or suggestions you have for my situation?

TIA

[bigjae1976]

I use a Deltran lithium iron battery on my E46 M3. It weighs 1 lb, costs $200. It fires up over 60 degrees. 50-60 degrees...it starts to struggle but starts. 40-50 degrees...60/40 it will start, have jumper cables on hand. Below 40...have to jump it. Always starts even in the 30's once the engine is warm. IIRC, I have the 400cca battery. You could wire 2 batteries in parallel to increase the amperage capacity.

Look at lawnmower batteries as well.

Keep in mind that there may be a lithium ion restriction, especially with NASA. Make sure you get a lithium iron battery...like the Deltran.

[amg6975]

You can just get a smaller 'H' size battery. I think the tray has mount points for H6-H8. I made a little extension that bolts to the factory mounts so I can get an H4 in there. With the interior stripped a bit it works just like OEM and is much smaller/lighter without the hassles of a Lithium battery.

[F4rmost]

Originally Posted by amg6975

You can just get a smaller 'H' size battery. I think the tray has mount points for H6-H8. I made a little extension that bolts to the factory mounts so I can get an H4 in there. With the interior stripped a bit it works just like OEM and is much smaller/lighter without the hassles of a Lithium battery.

Does the H4 have any issues starting the v8?

I would like something lighter, but I am not spending $1,000 on a battery (antigrav).