Hey Guys,

I noticed my battery was on the way out in recent months. I had planned on replacing this winter but it didn't make it. Died today and I need a replacement.

I noticed that battery is a beast. Bigger than my Toyota Tundra's battery lol. I pulled it and weighed it. 48 lbs. dang lol.

When I pulled it I noticed the bracket that secures it in the tray has multiple threaded holes it can go into so you can use smaller batteries. Awesome. The stock battery measures 12" long and 6 1/2" wide. I noticed when I move the bracket to the smallest hole it would only need a 9" long battery.

As luck would have it my kid's Fox body Mustang has a 9" x 6 1/2" battery so I weighed it. It's 27 lbs I would save 21 lbs just going that route. Not bad although I'd need to figure out an exact battery. Like terminals in the correct spot etc.

So I did more searching and found these Odyssey AGM batteries.

http://www.batterymart.com/p-odyssey-pc925-battery.html

That's the size they recommend for street cars but they spec at 26 lbs. Only 1 lb lighter than the 9 x 6.5 battery that I could get for less than half the price when considering the custom bracket needed to mount the Odyssey ($135 just for the bracket from rennlist.com).

I figure a lot of you have been down this path. What batteries do you run? Has anyone already figured a part # or something for the 9 x 6.5 battery needed?

Thanks
Malcolm

 

yellow top in mine when i got it. voltphreaks vph900 now 7 lbs auto shut off

 

H5, H6, H7 batteries all fit the stock tray. H5 can weigh up to ~20lbs less then a H7 and should have more then enough capacity for an enthusiast owner

 

Your car is pretty much a track car these days though right? You can get away with a super small battery that sits on a tender between track days
I daily my car when weather permits but then there'll be times I only drive it once or twice a week if the weather sucks, or even once every couple weeks. IT varies like crazy. Obviously when winter hits I'll throw a trickle charger on because then it just sits for a few months. Curse midwest weather lol

Ah I was reading HX ratings last night when looking up specs. I plan to take my battery in to the parts store today as a sample and I'll see if they can match up an H5 or similar smaller one. Thanks.

 

I took my stock battery up to a local Sears (after trying a local auto parts store and failing). I found a 9" version of my battery that seemed to be identical in every way. They didn't call it H5 though. At Sears it's group 47. I got the AGM version because of all the good things I read about AGM batteries.

When I got home I was a little disappointed that despite the size it weighs 38 lbs. So I only saved 10 lbs. Really odd, I wonder if it's because it's an AGM? My kid's battery of almost identical proportions is only 27 lbs. Oh well not a big deal. I have a decent battery in there now and saved 10 lbs

Here's my stock vs the new. I know the shorter one looks wider in the pic but its only because its closer to the camera. They are identical width and height. Only length is 9" instead of 12".




My kid's 27 lb battery vs my 38 lb.




In case anyone else is looking for a smaller battery for their car here's what I got.

 

goodstuff! for the record, H5=47 groupsize so you got exactly what you needed.
All batteries end up weighing different, despite same size
H6 is a group 48
H7 is a group 94R

 

I think my 3yr old Odyssey 925 is done. It’s not holding a charge. Car was at the shop for a while and was not on a charger. I heard AGM batteries have a hard time recovering from lengthy discharges.Think it’s time for a replacement. Not sure if I will get the same or maybe try the DieHard AGM, since I can pick one up at Sears. Plus it has a bit more CCA then the 925. Don’t use the car often, so I keep it on a trickle charger when not in use.

 

Talking about batteries , what is the lightest battery in the market ?

 

Volt phreak would be the lightest 7 lbs

 

The battery came out of Randy's car and was his 800 Hp daily. It works flawlessly and should it ever drain down below 12 volts it shuts off. There's a button to push which reenergizes the battery enough to start it

Street legal drag car no rain driving

 

One good thing I noticed is my starter motor has never sounded so alive since I've owned the car. I guess my old battery was always performing at subpar levels.

 

Oh and yes the AGM batteries are definitely heavier than the non AGM. I went back to the Sears store and picked up one of each and although I didn't have a scale with me for exact numbers you could feel a day and night difference. Had I realized that earlier I probably would have opted for the regular battery and saved some 20 lbs instead of just 10 lbs. Oh well, no biggie. Next time.

 

these cars love to go through batteries. I had numerous receipts for new batteries in the record book when I got my car, same with a good friend of mine and his 996 turbo. I went and bought a CTEK Multi US 3300 charger (same as Porsche branded charger) and I installed a quick-connect with M8 eyelets to my stock battery terminals so I can quickly pop the hood and hook up my charger in the garage. I've started doing that any time I know the car will sit for 3 days or more and it's completely cured all my issues.

 

I put one of those Sears batteries in a couple years ago. Still going strong. These cars are hard on batteries though.

https://www.6speedonline.com/forums/...-gold-agm.html

 

I'll find out soon enough how it does. All my cars, boat, bikes etc. end up on battery tenders in the winter. During the summer there's enough frequent use.