Lightweight battery installation: -20 lbs from the front

This weekend I finally did the best weight reduction mod ever - installed lightweight battery. If you have to ask "why?" - I guess you can safely skip this post But if you do care about performance of you car - acceleration, braking and especially cornering - read on.

I run Odyssey PC545 on my 350z (except winters) for 5 years with no problem. It you consider $/lbs ratio - it's THE most efficient mod ever. As it costs about $100 to shave 20 lbs - nothing else come even close to that. As PC545 is completely sealed - it will also always look clean and nice and terminals will never corrode (the stock battery looks disgusting after less than 2 years of use).

http://trusevich.com/album/other/Subaru%20Legacy%20GT%20type%20B/odyssey%20pc545/odyssey_pc545_1.jpg

So I looked around and find the best deal at PortablePowers. They had the best price for battery and shipping with some instant saving deal they offer. For some reason battery comes without terminals, so if you don't have them (I did) you'll have to add those to your order.

http://trusevich.com/album/other/Subaru%20Legacy%20GT%20type%20B/odyssey%20pc545/odyssey_pc545_2.jpg

http://trusevich.com/album/other/Subaru%20Legacy%20GT%20type%20B/odyssey%20pc545/odyssey_pc545_3.jpg

While waiting for the battery to arrive (less than a week) I visited best auto performance shop - Home Depot - and bought 10x32-12" zinc plated threaded rod, nut and washer for it, about $1.50 (?) worth + spray can of Plasti Dip, the liquid vinyl paint. That's all installation hardware you'll need!

The installation was a snap. If takes about two hours (including drying time) to clean and paint/insulate the bracket - as it was in bad shape. And put some layers of Plasti Dip on the bottom of battery - for grip. After that installation itself takes about 5 to 10 minutes.

Here's what you do

1. Unscrew terminals (10 mm wrench) and mounting nuts (also 10mm) and take the old battery out. Mine was visually in bad shape, as you can see in the pictures.

http://trusevich.com/album/other/Subaru%20Legacy%20GT%20type%20B/odyssey%20pc545/odyssey_pc545_5.jpg

2. The mounting hardware consists of two rods and a braket that goes across the top of the battery. Set aside/store the longest rod. We'll reuse the short rod and braket.

3. Sand, clean with spirit and paint the braket with PlastiDip. PlastiDip will also insulate it, as it will be very close to terminals of PC 545. If yours is not in bad shape, or you don't care how it looks - you can just wrap some electric tape around where it will be close to terminals.

http://trusevich.com/album/other/Subaru%20Legacy%20GT%20type%20B/odyssey%20pc545/odyssey_pc545_4.jpg

4. Mask the sides of the battery and put few thick layers of PlastiDip on the bottom of the battery - for grip. I guess you can also prevent sliding using some piece of rubber or some non-sliding material. Remember it should be heat resistant to some degree.

5. Measure, bend and cut the Home Depot threaded rod, to make a very short part you see on picture. Bend in few steps, gripping few threads further every time, to make a radius. If you try to bend all the way in one place - it'll break. But you have long rod to practice as we need only 3 or 4 inches out of 12.

Heating the rod with torch will help big time.

6. Install PC545 across the space where the OEM battery was. Use the original short rod in front, and new rod you just made - at the back. Leave some space

7. You'll have to play with harness a little to make the (+) side reach. I bent 90 degree plate to almoust straignt, and also inverted that thing upside down, as it was the only way to secure connect it to the (+) terminal without touching the bracket. Even if we insulated the bracket - why risk it.

http://trusevich.com/album/other/Subaru%20Legacy%20GT%20type%20B/odyssey%20pc545/odyssey_pc545_6.jpg

8. Tape the red plactic cover to the harness as it's made for 90 deg angle and won't stay by itself now.

9. You are done. The PC545 came fully(?) charged, so car will start, even if little hesitant. After you drive it for 30 minutes - it'll be in top shape. It starts the car reliably and strong every time.

*10. I'm thinking about some lightweight insulation around sides of the battery, as it gets pretty hot in the engine compartment... Few layers of some kind of aluminum bubble wrap type insulation will do. But it needs to be heat resistand up to 200F at least, and most house insulation materials/radiant barriers and rated to 180F only...

NOTES:

- Obviously with a battery that small you can't do things you could with OEM monster: listen to the loud radio/cd or leave ligts on with engine off. Also remember about small things - I imagine even trunk light will kill the battery if left on for long time.

- I once had a problem starting 350z in very cold weather (Michigan mid-winter). So I swap back to OEM battery when temperature is consistently below freezing (December - March). It takes about 5 minutes to swap.

Interesting mod. I guess I don't need to save 20lbs that badly...

A few notes: Plastidip is a good start to insulating the bracket, but I'd be concerned with it chafing-through. Shorting terminals on a battery would be very bad for fire reasons, much less being left stranded.

Also, for bending the threaded rod, you you could heat up the rod in the bend area to keep it from breaking... if you have a basic torch or gas flame to work with.

I stripped around 60 or 70 pounds from the rear of the car (need to weight it all again and make a post) by just taking out things not needed and not visible - everything out of the trunk, trunk and trunk lid liners, rear middle seatbelt, etc. It's very difficult to shave anything in front to balance that. Hood liner + engine cover is about 5 lbs, fog lights 4 lbs, and now with battery it's 29 lbs. Not bad... With lightweight wheels being 6 to 8 lbs lighter each - I'm sure i'm about 120-130 lbs lighter than stock.

The bracket is not touching any terminals it has about 2mm gap to both terminals. To shorten it'll need to close the gap and go through the plastidip on both sides... As there are no moving parts there, I'm not too concerned. I'll monitor it for some time though.

Too late with the heating idea for me, but I updated the DIY.

I'm amazed that you never state exacly how much your lightweight battery weighs! I'm running an 11.5 lb Braille.

BTW, I've got my 2005 Legacy down to 2999 lbs.

I'm amazed that you never state exacly how much your lightweight battery weighs! I'm running an 11.5 lb Braille.

 

BTW, I've got my 2005 Legacy down to 2999 lbs.

What do you mean??? The first picture has weights for both batteries. PC5454 is 11.5 lbs.

What did you do to strip the weight? I should be about 120-130 lbs down now, but don't know where to find scales for the car I hope it's at least 3395 lbs now. I know how to shave another say 60 lbs, with carbon seats and titanium exhaust. But 395 seems impossible.

Duh!! I was looking at the text, but not the pictures (I've seen batteries before)

I cut weight as follows:

Removed F/R bumper beams

Replaced exhaust Y-pipe and mufflers with a 3" straight pipe

Removed trunk floor heat shields

Coilovers

Installed aftermarket seats

Removed rear seat and back

Removed stock seat belts and velocity reels

LW battery

FW flywheel

LW pulleys

Stripped trunk of everything including stupid inside child latch

Removed AC pump

Removed fogs

Removed glove compartment door

Other stuff I can't remember

NOTES:

- I once had a problem starting 350z in very cold weather (Michigan mid-winter). So I swap back to OEM battery when temperature is consistently below freezing (December - March). It takes about 5 minutes to swap.

That's to be expected when you use a battery rated at 185 CCA's, not really sufficient for starting even small car engines. Even the stock battery is just adequate in cold temperatures (at least in my opinion) at more than twice the output (430 CCA's). While there are many factors to consider with CCA ratings, its still a bit small for a car.

You know that the battery spec'd for a Honda CBR1000 motorcycle has more CCA's than the the battery you just put in your car, right? Heck, most of the weight crazed Miata guys don't even go that small..

NOTES:

- Obviously with a battery that small you can't do things you could with OEM monster: listen to the loud radio/cd or leave ligts on with engine off. Also remember about small things - I imagine even trunk light will kill the battery if left on for long time.

That's an understatement. And I wouldn't exactly call the OEM battery a monster. It doesn't have a reserve capacity on its label, but a stock replacement interstate is rated at 85 minutes, to the PC535's 18 minutes. That's about than 1/5th of the capacity, and is a huge deal if you happen to leave a map light on, or listen to the radio for more than a couple of minutes with the engine off.

It seems like a bad trade off to me. Track car, looking for every pound (especially those in front of or behind the axle) I can maybe understand the reasoning, but for a street car, I'm sorry I can't. I'd much rather get more battery capacity for my street car.

The bracket is not touching any terminals it has about 2mm gap to both terminals. To shorten it'll need to close the gap and go through the plastidip on both sides... As there are no moving parts there, I'm not too concerned. I'll monitor it for some time though.

And I'd be worried about that mount as well Things tend to shift around under the adverse conditions of street driving, and the bracket is positioned too close to the terminals, and has no mechanical means to keep it from moving (like a lip over the side of the battery) when used in that orientation. You'd be better of making a new bracket all together to complete your custom install..

...

 

You know that the battery spec'd for a Honda CBR1000 motorcycle has more CCA's than the the battery you just put in your car, right? Heck, most of the weight crazed Miata guys don't even go that small..

 

...

It seems like a bad trade off to me. Track car, looking for every pound (especially those in front of or behind the axle) I can maybe understand the reasoning, but for a street car, I'm sorry I can't. I'd much rather get more battery capacity for my street car.

I know it looks crazy when you see battery this small on a car, and it seems like there should be a catch for stripping 20 lbs so easily... But there isn't any. If all you use your battery for is to start a car - than it's a safe and well tested mod.

A lot of people run 350z's on this battery (stripping weight is a big thing in 350z community). I personally ran my 350z on it for 5 years (except winter) and it never died.

As I don't listen to the radio with engine off - it's not a trade off for me. You just have to remember to not leave any lights on and that's it. Taking 30 to 35 pounds off of front (with hood liner, engine cover and fogs) is very noticeable when turning.

I used to run a Miata battery with a Civic hold down in my WRX. Probably about half way in weight savings to your PC545,but you have about 370 CCA to work with.

Since the PC545 is in,i would suggest at least grinding off some material on the bracket for more post clearance. Then re-plasticote.

I wrapped two mm of electric tape around a (+) pole where bracket would *theoretically* contact the terminal. Only because you all guys are so concerned. So no the bracket has to move, grind through thick plastidip, and than grind through 2mm of electric tape on (+) pole. And it's not a moving part. It didn't move anywhere during two weeks of spirited driving since installation.

I'll probably buy the plastic bracket or machined something from aluminum in future... but for now there is really isn't a chance of a problem.