[Biginboca]

I’m wondering what options we have for lighter batteries. My car originally had a 90 a/h ~60lbs battery which I replaced with a H6 70a/h and coded for a couple years ago. That dropped the battery weight down to about 40lbs.

Now my wife’s car needs a battery I’m thinking I could put mine into hers and look for something even lighter for my car.

I found this Odyssey which when I do the *approximate conversion* (CCA divides by 7.25) comes out to 45.5 a/h. I think I remember seeing in Carly that 40 a/h was the lowest capacity coding option so this would still be within the factory battery coding parameters. This battery weighs about 24lbs so saves 16lbs more lbs vs what I have now also.

https://www.odysseybattery.com/Batteries/Model_PC925

There are SAE terminals which thread to fit this battery so terminal type isn’t a reason not to use it as far as I can tell.

Has anyone researched any options for lighter batteries?

[Tr1ppy]

I too would like to know about lighter battery options. I would also like to know if the weight saved helps with the weird issue of having a lower ride height on the battery side for E93s.

[nsjames]

antigravity makes an H6.

https://antigravitybatteries.com/pro...tive/ag-h6-rs/

40AH unit weighs 15lbs.

[Biginboca]

Originally Posted by nsjames

antigravity makes an H6.

https://antigravitybatteries.com/pro...tive/ag-h6-rs/

40AH unit weighs 15lbs.

Dang that is pricey. I decided to try the Odyssey PC680 mentioned in this thread below.

https://www.e90post.com/forums/showthread.php?t=90973

I ordered this one for about $150 delivered with the SAE terminals. It weighs ~16lbs. Will see what happens there are a few reviews of guys running it in e90’s that are positive unless you let the car sit for more than 5 days.

I daily drive my car 5 days a week minimum and about 20k miles a year. It never sits for more than 48 hours and even sitting for the 48hrs is seldom, as in less than once a month. I figure if I ever go out of town I’ll just disconnect the negative terminal or plan on jumping the car when I get back. I have a manual and can push start in a pinch also so figured I would test this one out for a few weeks and see what happens. For only $150 it’s not a huge gamble.

[Soravia]

Don't get PC680. Car draws too much. Barely enough for my Miata with minimal electronics. Your BMWs will go haywire when there's power loss.

If you must, get TWO PC680 and battery tender. You can parallel them and still be lighter.

[Biginboca]

Originally Posted by Soravia

Don't get PC680. Car draws too much. Barely enough for my Miata with minimal electronics. Your BMWs will go haywire when there's power loss.

If you must, get TWO PC680 and battery tender. You can parallel them and still be lighter.

Thanks. I already ordered the PC680 so I might as well try it for a bit. I think I would order the other odyssey battery from my first post if the PC680 is crap, it’s around 20lbs and 2 PC680 would be over 30lbs.

[PhaceN52]

Well that's very interesting, batteries in these cars are heavy as hell (also my 100ah is slowly showing it's age )... After switching on all possibile electronics and with the car running, can we measure the total current draw with a meter from the battery terminals and get an accurate reading?
That PC680 seems great for weight saving, if you mind let us know how it'll perform!

[Soravia]

PC680 can crank. Just no power reserve for big power draw. And don't let it drop to 10v. Permanent damage happens and degrades big time.

[matteblue3er]

Originally Posted by Tr1ppy

I too would like to know about lighter battery options. I would also like to know if the weight saved helps with the weird issue of having a lower ride height on the battery side for E93s.

The suspension is purposely setup this way. It is intended to offset driver weight, hence why the opposite rear corner from the driver is lower.

Personally, unless you are doing time trials, a lightweight battery is pretty useless. You will feel a much more noticeable effect by reducing unsprung weight...aka lighter wheels

[nsjames]

Originally Posted by PhaceN52

Well that's very interesting, batteries in these cars are heavy as hell (also my 100ah is slowly showing it's age )... After switching on all possibile electronics and with the car running, can we measure the total current draw with a meter from the battery terminals and get an accurate reading?
That PC680 seems great for weight saving, if you mind let us know how it'll perform!

I can tell you from using my power supply for programming that just turning on the ignition means about a 15A constant current draw.
that's not running any HVAC or fuel pump things.

when first turned on it spikes to about 30A. so I'd figure that's about the "running" current requirements to just turn on the motor.

but if your charging system is working properly you should not be pulling any current from the battery while the engine is running.

[Tr1ppy]

Originally Posted by matteblue3er

The suspension is purposely setup this way. It is intended to offset driver weight, hence why the opposite rear corner from the driver is lower.

Personally, unless you are doing time trials, a lightweight battery is pretty useless. You will feel a much more noticeable effect by reducing unsprung weight...aka lighter wheels

Yep thats why I'm asking if it will help with that issue as I'm based in UK with a RHD vehicle therefore it makes it worse as we sit on the same side of the battery.

[Biginboca]

So my cheap lightweight battery arrived yesterday. It’s tiny lol



Here’s a pic that really shows the size of it



And it’s probably got enough juice to start a weed whacker and not much more. Actually it’s a motorcycle battery that a lot of guys use in track cars. I’m going to carry my stock battery this week and a set of cables while I test this battery out.



I’m going to figure out a mounting solution and do the install today. I’ll code for the lowest output battery our cars will allow. Will update after...

[freakystyly]

Will the car's positive end hardware still fit on that pop can sized thing? If you're using jumpers from the terminals to the positive / negative plastic hardware make sure it is a heavy enough gauge and won't rattle around.

[Biginboca]

Originally Posted by freakystyly

Will the car's positive end hardware still fit on that pop can sized thing? If you're using jumpers from the terminals to the positive / negative plastic hardware make sure it is a heavy enough gauge and won't rattle around.

Yes the wires reached ok. There really wasn’t anything challenging about the install. Here’s what I ended up doing to mount it:

[Biginboca]

I just made this after running a few errands with the battery...

[matteblue3er]

Originally Posted by Biginboca

So my cheap lightweight battery arrived yesterday. It’s tiny lol


Here’s a pic that really shows the size of it


And it’s probably got enough juice to start a weed whacker and not much more. Actually it’s a motorcycle battery that a lot of guys use in track cars. I’m going to carry my stock battery this week and a set of cables while I test this battery out.


I’m going to figure out a mounting solution and do the install today. I’ll code for the lowest output battery our cars will allow. Will update after...

Wow my battery has 900 CCAs and 130Ah....

Went the opposite way lol

Curious to see if it will start after sitting overnight

[Biginboca]

Originally Posted by matteblue3er

Wow my battery has 900 CCAs and 130Ah....

Went the opposite way lol

Curious to see if it will start after sitting overnight

Started up this morning and didn’t seem to be any weaker cranking than what it was yesterday. I have comfort access so I was wondering how that would affect it sitting overnight.

I’ve done 4 starts total today so far and 3 of them are with the car running less than 2 mins between shutdowns. So it’s working so far.

I’m trying to do a lot of short trips and shutdowns while I’m carrying my old battery and cables. I want to learn the limits of this battery before I feel comfortable not carrying a spare battery and cables lol

[nsjames]

AAA and don't care.

[matthewjmoser]

bimmerworld offers a lightweight battery. i believe its 31 lbs. its the optima red top battery for 200 bucks.