überschnell

Thanks for posting that up, Tony.

FYI, 60 days is our risk free guarantee. The actual warranty lasts two years from the date of purchase. For the L series this is a full warranty. On the C series, it is pro-rated after 6 months. Needless to say, we will take care of you in the unlikely event you have a problem with one of our products. More info on the warranty is available here.

Courtshark

Optimas are made by Interstate, IIRC.

edit: I do RC! http://www.interstatebatteries.com/c...uto_optima.asp

Pcplod

So what does this Battery Management System do that merits paying twice as much for the battery??

überschnell

It provides protection for:

low voltage
over current
short circuit
over temperature
high voltage

Any time one of these conditions is met, the circuit opens, saving the battery, the electronics in your car, or both. Once the offending condition is corrected (could be anything from using an improper charger/booster box/jumper cables to a failed voltage regulator like the older 911s are prone to), the circuit closes again and you can use the battery as normal. Basically, it serves as protection for your investment at a very low weight penalty. Remember, any battery is susceptible to failure by mistreatment. Discharging them too low will often cause permanent damage to the battery, be it AGM, lead-acid, lithium, etc.

Comparing weight vs. power, I think you'll find that our batteries are a great solution for the racer looking for a way to shed a few extra pounds. Due to their efficiency and low internal resistance, you can usually compare a lithium battery to a lead-acid or AGM battery of up to 3x the amp-hour (Ah) rating.

Having said all of this...if you don't mind taking the extra care to make sure you don't leave your lights on, not jump-starting, etc, the C series is more than acceptable. It simply doesn't have the safety factor built in.

Alan

Sorry - but if your battery senses an overvoltage (or over temp) condition from a charger or alternator and goes open circuit - I get that this protects the battery (which at $999 is a big deal) but it also will make the overvoltage condition for the rest of what is in circuit much worse - e.g. the ECU and all the rest of the electronics in the car... so not sure this protection helps anyone much.

If it senses an overvoltage condition and wants to go open circuit - it seems the only option that would protect the other system electronics would be to crowbar the system supply - this is also pretty nasty since it would blow at least the fuse in a charger or the output diodes in the alternator...

So - I think I'd rather have a honking big (cheap) lead acid battery to help soak it up.

Alan

überschnell

I agree with all of your statements. Of course, it is difficult to have any sort of protection built into the battery for an overcharging alternator/failed VR situation.
The avalanche diodes in modern alternators should hedge against the excess current. I don't know how long Porsche has used them, or how many replacement alts for older cars have them.
Well, on a purely objective basis, I agree, but I also think that such thing would progress to the "danger zone" before you would have time to react and turn the car off. Given the rarity of such occurences, I can only speculate! There is no denying that lead acid would give a greater "cushion" in the amount of time you would have. I think that damage to the electronics is a likelihood either way...but you'd more-often-than-not need a new lead acid battery, and my L series would be just fine. *shrug*

Thanks for your post!

77tony

Lucas, If we were to do a group buy on the C680 series battery ($499 retail) what kind of discount could we expect? Thanks in advance. 77Tony

S4ordie

HAs anyone actually test fitted one of the lithium pro batteriers to prove it will work? I listened to all manner of discussion regarding the Optima batteries, was convinced by both the sponsor and others that the yellow top model they were espousing fit with no issues. I ordered two and put them on the shelf at Greg Brown's shop for my two project cars. When the Zyc car was ready for the battery, guess what? it didn't fit. It's too tall. Greg had to fabricate a new baracket to make it all fit and still needed to put a pad of rubber on top of the battery to insulate it. As it had been almost a year since I bought the batteries, I could not return them.

So until I see pics of one of these, very nice sounding Lithium Pro batteries insitu I am not gogin to buy one. When confirmed, I want one.

überschnell

77tony, we had previously ran a 15% group buy (thus $424.15), but that is no longer going on. If there is enough interest, I can see if there is any possibility of starting another one.

S4ordie, the C/L680 is 7.16in x 3.05in x 6.63in. The 680 case size is common, the same as Odyssey and many others. It will certainly fit, but will almost certainly be smaller than the outgoing battery. We don't currently offer any mounting brackets, but there are plenty available out there, and one for us is in the works. You can also mount the battery on it's side (or even upside down) with no problems.

WallyP

For the terminally curious, this site purports to give a complete listing of battery brands and manufacturers worldwide.

http://jgdarden.com/batteryfaq/batbrand.htm

blown 87

I have to say, that what you just wrote makes me want to be a customer.
That was a honest reply to a honest question, no BS, just the way you see it.

JPTL

"Terminally" curious.
Pun intended?

Koenig-Specials 928

I am also one of those folks chasing down a bad drain for 4 years now so I've learned to live with it with the help of a trickle charger and battery disconnect. Someone once mentioned in another post that because of the frequency that some of us experience dead or almost dead batteries it would be prudent to go to a deep cycle type battery. Any merit to this?

JPTL

I went with a deep cycle battery (Yellow Top) in my wife's Suburban - mostly because she's capable of sapping a healthy battery by using wipers/seat warmers, engine off. But interestingly, the Suburban doesn't need nearly the cranking amps that our cars do.
I find that less cranking amps are the tradeoff when considering a deep cycle vs. non-deep cycle.

überschnell

I would say a deep-cycle battery is a band-aid fix. The best option is to find eliminate the parasitic draw entirely, and failing that, perhaps install a cutoff switch so that you can disconnect the battery entirely when you won't be driving it for a while. Of course, this resets your radio presets, trip computer if it has one, etc...which happens anyway if your battery is going dead.

I can tell you that the LiFePO4 cells we use are far superior than even a deep-cycle AGM battery at going to a low SOC (state of charge), but discharging a pack beyond the limit is still very, very bad--this will (in the best case scenario) greatly reduce the capacity of an AGM battery. A lithium pack discharged too low can reverse polarity, and even if it doesn't, it is very likely to not charge back up safely. This is one reason we advocate the BMS in our L series. It also becomes more important to use an appropriate lithium charger when at a low SOC (not low enough to endanger the cells). A proper charger has a "soft start" feature that ramps up the amperage slowly, instead of dumping full current to the pack right off the bat.