40YRW8

I can't post attachments so if anyone would like a roster, send me an e-mail address.
Gary

40YRW8

Nearly three weeks into the test and so far, the best evaluation I can post is that you can't tell any difference between the Shorai and a stock battery. If there is any chance that I might drive the car within the next couple of days, I don't even put it on the tender. I have decided that if the car sits for more than 2 consecutive nights, I will put it on the tender just to keep it from seeing a deep discharge.
Gary

mcar00

Just received mine yesterday. Once again, great find!!

abstruse1

Is there a reason specific to the Shorai that you use the battery tender for such a short down time? I'd think that with the stock battery you could go for a month or more w/o trouble. Are the Shorais not as good in this regard?

mcar00

It's a five pound motorcycle battery.

abstruse1

Well...

5 lb. or not, I'd expect that the total energy contained in a battery would be roughly proportional to the battery's CA or CCA, which in this case is pretty good (~550 CCA, as I remember), and in any case orders of magnitude greater than the background drain of the electrical system.

So it doesn't seem likely that these batteries would require tenders when not in use for just a few days. Months? Maybe.

Why doesn't someone experiment. As soon as I get mine installed, I'm going to.

db2xpert

My '07 Z06.... two weeks is OK, three is maybe, four weeks is dead,
around 6-7 volts, and won't recognize a key fob.

Vette5.5

Actually, the drain down time is the batteries AH(amp/hour) rating, with the factory Delco 90 at 54AH and the smaller Shorai 36 at an amazing 36AH. Theoretically the Shorai should be down about 35%, but different battery designs have different run down characteristics. Some run down quite linear, with others running pretty strong through most of the cycle, then suddenly drop to near nothing. Not sure of the Shorai design characteristics, but probably good information to know.

40YRW8

Don't forget that the main problem with reserve capacity is the fact that our TPMS and security systems run 24/7 whether the car is running or not and they will show a constant drain on your battery any time the car is idle. That drain will deplete your stock battery as well. The Shorai doesn't have as much reserve capacity as the AGM stocker but it will provide more starting power at a lower charge. With lead acid, as the charge goes down, the available amperage for starting goes down also in roughly the same amounts. A lithium battery will supply more starting amperage as the charge goes down then, when the charge gets too low, it will just cut off. That is the main characteristic that I was looking for as it allows a lithium battery to start your car when you have much less available charge or, in my case, a much smaller and lighter package. Everything is a compromise. I am willing to work around the characteristics of the Shorai for the 30 pound weight savings and the relative affordability.
Gary

FNBADAZ06

Excellent info, Gary

You may have just supplied a solution to a friend who has a LS2 powered RX-7 that had a Braille go out on him. I'm going to check into this battery solution as well....30 lbs is a TON of weight (metaphorically speaking ) to shed

40YRW8

Victor,
Be careful. You are pulling some very impressive times in your nearly stock Z and you might want to try the battery in a back-to-back test at the track to see if the loss of weight affects your 60' times. And since this is my thread, I gues I can go off topic if I want to. If we break the tires loose too much, the cars tend to yaw quite a bit. Since there was an earlier discussion about the fuel system and that it was set up to drain the passenger side tank first, we all probably run our cars with not only the weight of the gas being on the driver side of the car but also the driver and steering gear along with the seat motors as well. A little of that weight is offset by the battery and dry sump tank but it seems to me that our cars are heavily loaded to the drivers side of the car. I would think that this asymmetrical loading would be the main culprit in causing the cars to yaw under wheel spin as the left side tire should provide more grip than the right. Maybe if there was a way to have the fuel system drain the driver side tank first and have you race with the available fuel in the passenger side tank, the shift in lateral weight would mitigate the yaw tendencies. Any thoughts?
Gary

FNBADAZ06

Many excellent points
Wouldn't corner weight balancing the car fix any weight bias the battery would introduce ?

Katech_Zach

The Braille 2015 that I'm using is 21 Ah so the Shorai should be much better at 36 Ah.

40YRW8

Corner weighting can balance the suspension loadings but it can't affect static weight bias. With a car that is biased either to the front or to one side, corner weighting can even out the cross weights but you will have a situation where even though the cross weights are the same, one cross will have more weight on the front corner and less on the rear corner. The other cross will have the opposite and the cross weights can stay equal. The major reason for corner weighting the car is to insure that the car handles the same (understeer vs oversteer) in both right and left turns. If the car is weight biased toward,say, the left side, the car will generate a little more g loading in left turns than right turns even though it can be dead neutral. In accelleration, the left rear tire will tend to bite a little harder than the right tire. You could increase the left front and right rear corner weights (we used to do this with cars that didn't have a posi rear) but at our accelleration rates, so much weight is transferred from the front to the rear that I think you would lose most of the advantage you get from the left front pre-load. However, a little experimentation wouldn't hurt just to find out where and how much it makes a difference in a pass. My best guess is that pre-loading would help most on a 1-2 shift when the rear normally would want to kick out but wouldn't have enough time to lift the front much.
Gary

40YRW8

Well, I have the bad news today. I killed my Shorai battery because I got a little careless. I let the battery get pretty low on charge because I lost track of how many days it had been since I had driven it. It had been working so well that when I felt that I would be driving the car the next day or so I didn't bother to hook up the charger. I had a local tuner come to my house to read some codes that popped up on my first emission test. He plugged into the port and spent about 30-40 minutes reading and making adjustments. When we tried to start the car, it wouldn't turn over and it showed only 8 volts. After he left I hooked up the charger and all I could get was the light signal for battery damage. No indication of charging at all. I let it sit over night and tried again and the charger indicated a charge so I let it run for a while but when I returned, it was showing the damage fault again. I went to my local Chevy dealer and bought a stock AC Delco battery and installed it. Since I already have the $75.00 charger, I am going to buy another battery and keep it on the shelf for "Special" occaisions and keep the Delco in the car for daily driver use and for long trips. I knew all along that LiPO batteries were sensitive to severe draining and it was totally my fault that it failed. One of the advantages of the really expensive lithium batteries is the low voltage protection system that is built in. I am not giving up on the Shorai yet since it served me well until I killed it. And a word to Jim and Jason, "Yes, putting the 35 pound Delco battery back in my car was very painful".
Gary
P.S. As a side note, I took the car to my friendly neighborhood test road to see how much more traction I would get with the additional 30 pounds of weight in the right corner of the car. I have been having some substantial traction problems the last couple of years, most noticeably since I installed my first Braille 11.5 pounder. About the only place that I seemed to feel the difference was on a rolling start in 3rd gear. Before, I always got wheel spin at around 3500 rpm. With the Delco in the car, 3rd gear wheel spin was negligeable. The wheel spin from first and second gear roll-ons were substantial to scary. My 345x19 PS 2's are right at 4 years old and have 45,000 miles on them with about 1/3 the original tread left but they are hard as rocks. I tried heating them but it didn't help. I even tried a big, first gear burn-out and they wouldn't even lay down any apparent black marks. I think my next experiment is to try the Cup tires on the rear for a year to see how they react to aging and see how much forward bite they give and how they behave with my 295x18 fronts that are practically new.

Halltech

Thanks for Pioneering this R&D. The Lithium Ion battery from Braille purchased almost 4 years ago is still going strong. I has an autoshutoff switch (manual as well) which turns the battery off at around 11.5V.

The battery unattended starts out at 13.2V static and stays there when off during normal driving (non winter). 14.7V during driving.

If the car sits not started for a week, it drops to around 12V, still starts. After two weeks it is on auto off. I have jumpers to turn the switch back on, which makes no sense since the switch should turn it on, but does not. Once I turn it on with the B&D portable jumper, the on light stays on, but the 11.5V is not enough to crank 13:1 in the cold, so I use the B&D charger for 30 minutes to bring back to 13.2V.

The battery is then like brand new again and never disappoints me.

For $1,799 it should make me bacon and eggs each morning, but 9.2lbs and now $450/year cost it gets better every year. At some point, if the battery lasts 10 years, it will have paid for itself in my opinion. The other Braille batteries I have tried are junk. I could never count on starting the car, even after two days of sitting. Winter time forget it.

I am going to put these back on my site. They are for those that want 26lbs off the rear and reliable starting, where cost is no object.

This battery is almost the exact model used on the GT2 and CTS-V I saw at Pratt and Miller last year.

rynobull

I know we all like to mod our cars for performance sake... but I'm guessing many of us can stand to lose 20-30 pounds and some possibly even more.

Not trying to start a pissing match, but these batteries are pricey and don't seem to last. It seems like you could gain more by dropping bodyfat and spending the extra money on lighter/ better brake rotors or something.

Ryan.

Halltech

I am already 168 down from 190. That area was already seen to years ago.

This thread is for the hard core race weight nuts like Gary, Jim and Jason types. Others need not apply.

MTIRC6Z

[QUOTE=40YRW8;1579813096] My 345x19 PS 2's are right at 4 years old and have 45,000 miles on them with about 1/3 the original tread left but they are hard as rocks. QUOTE]

To say I can't comprehend this mileage would be the understatement of the century...are you sure you didn't mean 4,500 miles? My first pair of 345x19 PS2s were virtually bald at 6,000 miles and that was with no burnouts or track time. Of course I don't mean to imply that they were never spun, they were, lots, and usually at relatively high speed, but still, how the h*ll did you get 45,000 miles.

Cheers, Paul.

40YRW8

Ryno,
I don't think you really got our message. We have already done all those things. It is what you have to do to take the car to the next level.
Gary