RayGT3

Has anyone relocated their battery from the OE firewall location to the floor? Wonder how much work it would be and if there was anything exceptionally nasty to deal with? Any kits available to do this? Suggestions and pics would be a great help. TIA

NJ-GT

I'm thinking about doing that. I want to install two braille batteries in the useless back section inside the trunk. Two of them are lighter than the stock one. Then have one of them with a quick remove mounting bracket, so I can reduce 22# from the stock weight for competition days.

grussell

I bought an Odessey 925 to do the same thing but I haven't got around to it yet.

viperbob

Install is easy. Need a short cable to ground and a longer cable to run to the power distribution box. For a battery holder for the PC925 (good choice BTW) I use a nice CNC'd Billet aluminum hold down from West Coast Batteries... http://www.odysseybatteries.com/accessories.htm They also have a more rigid welded bracket. Either way, simple job to loose weight, and get it down lower...

grussell

Viperbob,

I also purchased the welded tray, it is very well made.

A couple of questions:

1. Did you use the existing ground in the lower trunk that the lights are attached to?

2. when you drilled holes through the lower pan, did you use a plate underneath the car to reinforce the sheet metal.

3. What types of screws did you use? Machine screws going up through the sheet metal and nuts inside the trunk?

Thanks!

RayGT3

Grussell
You may want to mount the bracket on rubber vibration mounts to prevent the vibration from distroying the battery. You can buy them at any industrial supply house. They come in all types of configuration and sizes, about a dollar each.

Anyone have any pics of the battery and wiring layout of the cup car? Would be helpful in getting started.

FixedWing

Why two? I would think one would normally be sufficient. I have had good success so far with my PC680 in an Audi S4.

Stephen

grussell

Great tip! Thanks!

viperbob

PC925 are dry cells and are not prone to issues with vibration. This is one of the benefits.

Sorry, missed your other questions. I connected new cable to the stock attachment points. I did use a somewhat thin plate on the under side of the truck. I did not install the metal bracket that you have to hold the battery. I have usually installed the aluminum one and used allen button heads. Hope that helps.

RayGT3

Odyssey makes a pc925 with and without a metal case, anyone know if the case is a requirement or is their standard offering OK. There is about $15 - $20 difference in pricing between the two. Their reference is to using the battery with the metal case in high temps, don't think this would apply to putting one into the trunk.

karlooz

hey bob,

did you use oem cables? do you cut off the +'ve cable terminal and reattach a new/longer one? if you didn't use oem then what gauge cable do you use?

viperbob

I used a new cable made from 4 guage stranded welding cable (pretty sure it was 4 guage).

RayGT3

I spoke to abput a dozen or so folks, product suppliers, about the PC925 battery, its installation and maintenance. Seems like everyone has a different idea as to how to use these batteries, I couldn't get anyone to agree on most of the questions I had. These are comments from the manufacturers application engineer:

First, vibration...... Vibration is not good for ANY battery and will shorten the life. While these batteries might be vibration resistant (better than most), vibration should be avoided if at all possible.

Cable size...... 4 gauge is OK, 2 is better, any larger is too large.

Maintenance....... Charging any battery shortens the life. He recommended that you simply start and run the car every 2 weeks or so, min. to keep the battery charged in lew of a constant or floating charge. No charger! This applies to locations up north where the car might be in storage as well.

Metal Case...... Needed in high temp applications, above 50 deg C(120 deg F). At higher temps the case plastic gets softer and begins to bulge. Not the end of the world but looks awkward and over time is detrimental. Didn't think we needed the case in our application.

Hope this helps.

viperbob

Ray, I had a PC925 in my car for over 2 years with 75+ track days (high HP turbo, slicks, motons, etc) with no vibration isolation and never had a battery issue. Also did over 7000 miles on the streets during that time.

Started my car every couple of weeks if I was not driving just to keep the battery charged. After 2 weeks, the battery was low. Starting or driving every week would be better.

FixedWing

My understanding is that the life of a battery is measured in charge cycles. Allowing the battery to be drained and then re-charged (through the car's charging system or however) adds a cycle. Keeping it on a crickle charger keeps the battery at one constant state of charge and therefore doesn't add charge cycles to the battery.

I saw a chart once that suggested cables larger than 2 gauge were unnecessary as there was little loss on a 2 gauge cable over the lengths we might use, but other than the weight issue, how can it be too large?

Stephen