[longodj]

Hey Guys,
I got my HP Autowerks Battery Mount with Braille B2015 No-Weight Battery in the mail today. The battery is TINY! I was definitely not expecting it to be so small. The mount is absolutely solid and the combination is really lightweight. The stock battery is definitely a fat bitch and I was really taken aback by how heavy the stock one was and how light the aftermarket one was. After install, I started the car up and took it for a drive and everything seemed fine.




Update May 26, 2009:

Every year when I come home from school for the summer, I use my parents garage for a week to detail and maintain my car. This year I just did the basic wash, clay, wash, polish, wax. I also cut some access holes to make rear suspension adjustments, and I'll be rolling my fenders at some point if I can find a spare set of jacks.

I've been home for 4ish days now and the car has basically been in the garage. I left it there for a day, brought it out into the parking lot to wash it, brought it in, brought it out, brought it in, brought it out, moved it, brought it in, etc. etc. So basically for 4 days my car has been not running except to start a few times. Today as I was going to bring it out to wash it before polishing, the car wouldn't start. 4 days...that's all it took...4 days....damnit.

So I just jumped it and then brought it to Sears, where I picked up a massive portable starter that I'll be keeping with me. Of course, someone is going to say "well the weight you lost with the battery is gained right back with the starter." Yes, in day to day driving sure, but I put this in for the track, not daily use so I don't care.

Anywho, just thought I'd let you all know the rough time to which it takes for the battery to discharge. I would strongly suggest a Battery Tender if you run one of these. Unfortunately, I live on campus so don't have that privilege. Oh, also this is the 15 lbs model. I'm sure the 21 pound model would last longer and probably not even need the tender... Someone can chime in though...



Here's my DIY:

Difficulty: 1
Time Required: 30 minutes
Tools Required: 10mm socket, 13mm socket, flat head screwdriver, Phillips head screwdriver

1. Remove the right side trunk liner/tool set combo.



2. Remove the retaining bracket from the top of the battery.



3. Remove the positive cable assembly from battery. There are small metal clips on the sides that you should pull out using the flat head screwdriver while pulling up on the assembly.

4. Disconnect battery terminals.




AT THIS POINT MAKE SURE YOU DON'T CLOSE YOUR TRUNK!!!
If you do, not all is lost. Use your key on the bottom of your fob to get into the passenger compartment. Open the ski hole (assuming you have one), and reach into the trunk compartment with a clothes hanger. Reach for the emergency trunk latch. This should open the trunk.


5. Remove the bolt holding the battery down.



6. Move the positive and negative cables aside and pull the old battery out. It really is a fat, heavy bitch so be careful.

7. Compare and contrast the old porker with the sick new one. Have a beer.




8. Place the new mount and battery in the battery compartment. Replace bolt.

9. Disconnect the positive assembly from the positive cable with 13 mm socket. Connect positive and negative cables to their respective terminals. Make sure the battery terminals are torqued down.



10. Reconnect the positive assembly to the positive cable.



11. Reinstall retaining bracket.



DONE!

I can't speak to any difference in the feeling of the car with less weight since its packed full of stuff right now and I don't have any events for a while. But I'll update this post in the near future with handling characteristics and charge performance. The car started up and ran fine but I'm not sure if it'll last over days or weeks.

Hope this helps someone,
Dave

If anyone sees anything I did wrong please comment!

[JoosyJoos]

Great DIY. I'll be considering this eventually.

[longodj]

Thanks! I was surprised no one even commented...this is a hot kit and I thought I took at least decent pictures Thanks again to Harold @ HP Autowerks for all his help!

[ToadHollow]

Harold mentioned something to me a while back about this setup and I had forgotten all about it. Any idea at all the difference in weight between the batteries?

Thanks for DIY! Definitely worth looking into ........

[Josephkao]

How does this set up work out in daily use????

[scottp999]

Very Nice write up. So did you have to charge the new battery, or did it start right up?

I have this mod sitting in my garage. Gotta get to it soon.

There is also a DIY on this on the M3 forum:

http://www.m3post.com/forums/showthread.php?t=233195

You got the 15, I got the 21. The stock is 58lbs according to the above post:

"Stock - 58lb
Braille -21lb
Weight savings - 37lb"

So with the 15 you are saving 42 lbs.

[PaulBailey@ltbmw]

Great write up!

[longodj]

Originally Posted by Josephkao

How does this set up work out in daily use????

So far so good, I've had it in for roughly a week, and have driven roughly 500 miles on it with no problems.

Originally Posted by scottp999

Very Nice write up. So did you have to charge the new battery, or did it start right up?

Started right up

You know, everything on the M3 is sexier. Even the damn battery is a sexy black instead of the ugly white that our cars come with. Haha!

[scottp999]

Thanks man! I'm typing this with the laptop in the trunk. Just finished the 21lb install and started the car. Putting the tools away now and I'm off for a drive.

Just needed your post for a little motivation to get off the couch from watching the Orioles vs Nationals game. Enjoy Memorial day!

[ToadHollow]

Originally Posted by scottp999

Very Nice write up. So did you have to charge the new battery, or did it start right up?

I have this mod sitting in my garage. Gotta get to it soon.

There is also a DIY on this on the M3 forum:

http://www.m3post.com/forums/showthread.php?t=233195

You got the 15, I got the 21. The stock is 58lbs according to the above post:

"Stock - 58lb
Braille -21lb
Weight savings - 37lb"

So with the 15 you are saving 43lbs.

Awesome. Thanks!

[longodj]

Originally Posted by scottp999

Thanks man! I'm typing this with the laptop in the trunk. Just finished the 21lb install and started the car. Putting the tools away now and I'm off for a drive.

Just needed your post for a little motivation to get off the couch from watching the Orioles vs Nationals game. Enjoy Memorial day!

haha! you too! Congrats on the install!

[scottp999]

At first I didn't notice the little plastic strap handles on the OEM battery. Try getting your hands in there and lifting it out without using the straps. Luckily I noticed them after a couple of attempts...doh!

[longodj]

Originally Posted by scottp999

At first I didn't notice the little plastic strap handles on the OEM battery. Try getting your hands in there and lifting it out without using the straps. Luckily I noticed them after a couple of attempts...doh!

lol, don't worry about it, I shut the trunk after disconnecting the battery Ultimate in stupid.

[longodj]

Car died today. Haven't ran it except to bring it in and out of the garage. It's been...three days. I probably started it about 10 times without really driving it far. See OP for more.

[scottp999]

In a few hours my car will have gone 48 hours without any activity on the 21lb battery. I drove it for about 40 minutes after the battery install and then parked it in the garage. I'll try to wait a couple more days and see if it starts up on Friday (5 days of sitting).

I would guess yours would make it 5 days if it wasn't started without driving it a few times.

[longodj]

Originally Posted by scottp999

I would guess yours would make it 5 days if it wasn't started without driving it a few times.

I agree.

[scottp999]

Started up today with no problems.

[longodj]

Interesting...even today my car warned me "low battery charge" at the track.

I was thinking about it by the way....if someone were to do this mod and remove their rear seat when going to the track (say what I did...), they'd save I'd say upwards of 60 pounds. That's pretty damn good. Add in wheels and you're already talking 100 pounds off stock. I like

[Ramos]

Noob question here: Isn't the whole reason BMW places battery in the truck to achieve better weight distribution... So by doing this mod, while you are reducing weight by 42 Lbs, you are screwing with the weight distribution of the car making it more nose heavy.. aren't you? That is unless you can shed a similar 42 Lbs from the front of the car

[longodj]

Yes...however, how the hell are you going to remove weight from the front? That's not an attitudinal question, that's an honest question because OK, seats are the center, rear seats are...rearish, exhaust is rear, battery is rear....wtf? I really have no idea (besides DPs and maybe the FMIC) how you would remove weight from the front. The hood is maybe what...10-20 lbs weight reduction at most? idk...

[jzchen]

Thanks for the nice write-up and pics! I just walked down to my car and checked. The key hole in the trunk doesn't work with the battery disconnected? Or maybe not all cars have a key hole in the trunk?

About weight saving in the front. This reminds me of something in the movie Cars, (my son's favorite for a while.) I don't know how difficult it is to remove and then put them back, or if they are required on the track but... McQueen says something like "headlights, racecars don't need headlights, because the track is always lit."

[longodj]

Yes, that's right, the key hole in the trunk doesn't work with the battery disconnected. So I would suggest leaving your seats down, or if they don't go down, taping up the latch or something so that the trunk absolutely cannot close. I mean I suppose you could always run cables to the points in the engine bay but whatever.

I'm not running fog lights...but even if you removed your headlights...you're barely saving 10 lbs? So the one battery in the rear adds up to like...everything that you can do in the front.