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Anyone running a lightweight battery like a Deka 11 lb? Our cars have very little accessories
and it makes sense to shed 20+lbs of weight. That's a lot of weight for $150 or so.

Mine is in the back now but I could move the battery to the front down low if it was
small. On second thought The wiring is already there.... for rear mount.

Lots of BMW guys run these in their 2002s

http://www.aircraftspruce.com/catalog/e ... seydry.php

The PC680 is pretty popular and will start just about any I4 for these cars.

Here's the PC680 installed in a Caterham SV with a turbo Miata 1.8 crammed in it.

Those are very good batteries. They used to be sold by Gates and others for race cars and cost something like $300 in the 70's. That was real money back then.

They hold charges for a long time. They don't leak. The plates are wrapped in fiberglass, so good for vibration and accidents. I used the one I bought in the eighties last year and it still worked fine...

Race car use is not the same as daily driver though, so your mileage may vary. It's a good choice for a light battery that could be in an accident next to your feet and for parking in the garage months or years at a time.

Go with the Odyssey PC680. They also have a vibration-resistent version available, and either cost around $100 on-line.

Odyssey suggests a trickle charger for the battery at times when the car is in storage. I have a fused line in which I plug in the charger when I'm not driving the car.

Deka has a large line of batteries, so I'n not sure exactly which one you are referring to:

http://www.dekabatteries.com/assets/base/0083.pdf

A miata battery is minimal at 320cca and 25 lbs.
A replacement battery for a Volvo 240 is 600cca extra 7 lbs.
Deka suggests that using a battery with less than the minimum cca will shorten the life of the battery.
More cca is always better as long as the cables are adequately sized.
The charging system keeps your accessories going.
The battery is for starting and to keep you moving when the charging system fails (reserve capacity).
Fewer cca also means less rc so while a 240 may only need 450cca, the amount of accessories in a volvo push the rc requirement up and the cca with it. A 5.0L mustang needs only 580cca.

The Odyssey 680 is around 220 cca apples to apples (i.e. 30 seconds at zero F):

http://www.odysseybatteries.com/odyssey101.htm

A PC925 is appropriate for a miata 1.8l.
A PC1200 is appropriate for a stripped down volvo 240 2.3l.

Check out the specs at the bottom of the page:

http://www.odysseybatteries.com/batteries.htm

You need a lot less battery to run an engine with a carb. The Odyssey 680 I think is what's in my racecar and there is no charging system. It will start several times in a day an gets used for an hour or two on a busy day. If your car isn't being used on the track an extra 5-7 lbs. here might make sense. Especially if your running fuel injection. I do carry jumper cables and a charger with the racecar, but the battery is also 25 years old. I don't always use them though.

I think weight towards the rear is a good thing for these cars, so moving the battery back is good.

I stole the battery from my lawn mower for autocross this summer with good success. Starting a 3.0 v6 about 8 or 10 times each autocross with no charging system and no problems. I could do several events without charging the battery. Battery is I think 340 cca. With properly sized cables in the car, this battery has a harder time starting the 15hp lawnmower then the car.
Kristian

Braille also makes some lightweight batteries with competitive prices. Their lithium batteries are ultra light weight.....all the way down to 2 lbs, but they also cost a lot more than what most Locosters would like to shell out. Their "no-weight" battery line makes a bit more sense to me though. The B106 for example, weighs just shy of 7 lbs and delivers 500 something cranking amps for under $150. http://www.braillebattery.com/index.php ... ies/b106/#

BTW no I'm not advertising. Long time lurker, First time poster.