I picked up an ETX16L 17lb battery as I wanted a little more power than the 11.5 lb ETX14L used in this diy:

http://www.planet-9.com/reviews/caym...the-track.html

With inspiration from that thread, I knocked out a pretty clean install. Here are the parts I used and their approximate cost:

ETX16L battery ($75)
Universal battery mount kit ($5)
Odyssey SAE terminals ($15)

Total cost <$100
Total weight including factory battery tray: 19.4 lbs
Total weight lost: ~30 lbs


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Good work

What's the battery rated at?

 

325 CCA, it starts up just fine but I'll have to report back with updates. I only drive the car on the weekends and I presume it will hold a charge fine for most of the year. If it's a cold week then I may need to put the tender on it. Fortunately I live in Texas so that isn't much of an issue.

 

HI,Actually those are standard AGM motorcycle batteries with some kind of modified posts....I dont think for cold climates they will supply enough CCA to start our cars plus the recovery time is not that great as compared to a rated car battery......IMO

 

all of this is pretty accurate and I obviously don't think this setup is right for the masses. If you live in a warm climate, own a battery tender, and weight reduction is important, it may be fine. I will report back honestly with my experience. I ran the 21 lb version of this battery for over 3 years and the current owner of the car says it still starts just fine...and it's NEVER been on a tender or recharged.

gotta love Texas!

 

You mean that you would rather have warm and sunny weather over cold and snowy winters???....lol...I guess you would so then your battery would work for you....lol........

 

Awesome write-up, awesome pictures, and thanks particularly for documenting the weight reduction. Reps to you good man!

 

thanks for the kind words! I'll be installing a roll bar, carbon fiber seats, and harnesses over the next few weeks and I'll try to snap a few pics along the way and post up some threads similar to this one.

 

Great Install!

The standby current on the 911 is quite high, I'd be more concerned with Ah capacity than self drain. If the car is standing unused for long periods I would use a float charger.

 

well, I let it sit untouched for 3 days and it started right up, no hesitation. I keep the car locked as I've heard it uses less power that way?

 

After 5 minutes or so, around 50 - 60mA with the doors locked, 100 - 130 mA with the doors unlocked. After 5 days of being locked the remote key system switches itself off, not sure what the current is at that point.

 

well I've been running this setup for 3.5 years and figured it's time for an update.

for a little while the battery wasn't holding a charge so I kept it on the tender all the time even with driving the car once a week. Tried replacing the battery and that didn't seem to help.

as it turns out, my alternator was gradually failing. After replacing the alternator it fires right up even if sitting for up to 2 weeks with no tender on it.

My long term assessment of this setup is if you don't live in a cold climate and your alternator is functioning properly, it is "A OK"

 

I did a similar setup a few months ago. No complaints here and I tend to drive my car once a week.

 

I foresee another alternator replacement in your future.....

 

Nice, I was just searching for a way to safely install my Braille 21 this weekend & you just simplified things.
Thanks