ToothDoc

That's a pretty good deal. I think with the balancer and stuff it's close to 300 anyways and these cells are VERY difficult to solder cuz the can is all aluminum so they dissipate the heat very quickly. Plus, you don't want to overheat and vent them either.

CCA is kind of different for LiFePO4s vs. Lead acid. Lead acids have max amps cold while lithiums get stronger and stronger the warmer they are. I've found that 5 in parallel is strong enough for even ZERO degrees for our F - but it did take a couple of cranks to do it.

ilv1004s

iTrader: (8)

doest any1 wanna sell me this set up?
looks to hard for me to do DIY

High PSI

iTrader: (1)

Since I really only drive my car in the spring/summer/fall I'm not too worried about CCA, just PCA, but I couldn't figure out how to calculate what estimated PCA I would have based on the battery stats (which just give mAh). Since I just have a fairly low-compression 2JZ I'm confident that if I copied your exact design I would have no issues, but since I'm not overly confident in my soldering skills I was looking to pick up those packs you referenced earlier - I just don't know what I'm looking for, however.

Kramer

iTrader: (15)

I love seeing the use of Deans connectors and technology "coming up" from the R/C industry with the use of these batteries. I used to be a hobby shop owner and talking about this 5 years ago, with no one believing me it could happen!!! Nice work, awesome job guys!!

ToothDoc

I was going to do it years ago - but LiPoly's voltage isn't quite correct for alternators (and they might burn up). Still, it's been over 3 years. Too bad A123 is bankrupt. I'm sure some Chinese company is going to sell low resistance LiFePO4s. I bet one day they're just going to have a 15-20 amp hour LiFePO4 so you don't have to do all this soldering. They can make it really cool if they could simply package it in one container so the electrolyte could move freely from one cell to another so we wouldn't even have to balance it! But that's beyond my abilities. I do have BMC 10 amp hour LiFePO4s in my electric scooter but they're only rated at 100amps cont, 200 amps peak so no go for starter duty.

megomaniac

I've had my battery installed in my is300 for about a week.
I went a little over board on the wiring, 6awg. I plan to change that later when I get more deans bars. I still need to install my astro blinky, just got the right plug for it.

So far my car fires up quickly every time. Even one morning at -7C.
I weighed it with my bathroom scale, roughly 7lbs. Stock battery was roughly 39lbs.

I just need to come up with a better mounting solution then a cardboard box and foam.



Found another a123 cell being used for starter battery. I think the C rate would be too low for a 3.0L. still really cool though. maybe 4s2p would do it.
here: http://endless-sphere.com/forums/vie...0c15&start=600

ToothDoc

LOL, look at those wires! Hahahaha Remember that you can go 1/2 wire size if you got 1/2 wire length with the same internal resistance.

If I had to do it over again, I would've just gotten some simple LiFePO4 12 volt packs and just put them in parallel instead of doing all this soldering and wiring. LOL

Technology is catching up... But at least the project was fun.

megomaniac

tweaked my setup a bit, got the balancer in there. i like blinking led's

I did some more reading, some people us 4awg for battery relocation, so I figured it would be good for battery leads.
Got the 4awg welding cable from princess auto. fairly cheap.

I screwed up about 8 cells rearranging the setup.

the cells have a thin piece of nickel I believe that allows soldering, if this this piece is removed from the positive terminal, it is next to impossible
for me to solder on the aluminum under it.

cranks a little slower when its cold out, still working fine though.
my is300 started just fine this morn, -4C.
I do drive my car everyday, so it doesn't get a chance to sit for very long.


considering a polycarbonate box with a clear lid for in, look a bit more finished. http://www.digikey.ca/product-detail...41-C-ND/439778

ToothDoc

Hahaha Good Job Megomaniac! I just finally found the limitations of my setup (5 parallel). Went on a 2 week vacation and the battery was DEAD! So if you plan on leaving for a couple of weeks, disconnect the battery. I was lucky and able to charge it back up - but LiFePO4 cells don't like to be down to 0 volts.

megomaniac

Hey ToothDoc, hows your battery holding up?
Mines still going strong. Had it installed all winter. 4s6p and it still started my car when is was like -27C outside. Recently shrink wrapped it. My car doesn't sit for more then a day or two. Driving back and forth to school...
Astro blinky seems to be keeping the cells in balance. I have never charged my battery with balance charger. Went to the drive-In for Fast furious 6, put the stocker back in cause I didn't want the lightweight to drain. I just need an accurate volt gauge to keep tabs on it, probably would have been fine.
Estimated weight is 5lb.

jleonard71

That is a very nice looking finished product, job well done! Any chance you have a parts list for what would be needed to make one of these? I have been following this thread since it started and it's definitely on my to-do list. If you could put together a DIY guide for this I'm sure a lot of forum members would love to give it a shot.

ToothDoc

Mine is holding on fine too. The first version lasted over 2 years until the car wash guys left the doors open while detailing it. Caused some of the cells to die and caused all sorts of imbalance.

V2 with the balancer is PERFECT except doesn't last 2 weeks in storage so you have to make sure you dd it. Fortunately, it didn't kill the cells so it's working fine. Mine is only 4s5p and has always started the car. It's 3.5 pounds.

It's a 200-250 dollar mod that saves 40 pounds. Cheapest weight savings IMO.

But you don't have to make them anymore. Some guy makes them online in a plastic case so we no longer have to make them. LOL I forgot the link - he specifically uses A123 cells also.

jkeifer3

Isn't A123 the company that the gov't heavily invested in, went belly-up, and the assets of which were sold to a firm in China? I assume they are still producing cells however.

ToothDoc: Disregard as you mention this in an earlier post.

jleonard71

Is this the guy you're talking about, who someone else linked to on the previous page about a year ago? http://www.lithiumaviationbattery.com/

PSJ

I recently picked this up from a buddy, I think it's 15lbs vs the 45 lb stock one in my 2010 Camaro.

We haven't seen any of you Lexus guys out, we've been going Tuesdays but I might try some other days.

I'm sitting at 12.20 so far this year.

2010 Camaro