What Aftermarket Batteries Are Recommended?

Black Panther

[KJ] First, the choice of the unit. I read the info at and was convinced that the Black Panther was a better choice than the  Optima. Specifically:


"Black Panther has the capability to withstand more than 400 cycles at 100% deep discharge! Optima is not a deep-cycle battery. Using it in that kind of application will void its warranty. It will only take one deep discharge cycle to prove this information."

I had been having a problem with the battery discharging when I parked the car for several days at a time. It turned out I had a loose wire at the starter, but I’ve heard that others do have trouble with dead batteries after a week or more parked.

I figured that a BP battery would extend the battery life for someone who occasionally discharges the battery nearly completely, *plus* it would never ever leak acid on my car. (I’m replacing the battery hold-down bracket because a bit of acid got inside its vinyl covering.)

The choice was then the BP1000 (32 pounds, 1.5 hours reserve at 25A, $190 after discount) versus the BP800 (23 pounds, 1 hour at 25A, $170). I paid the extra $20 to get 50% more reserve for extended parking, but the BP800 really should be more than adequate. My car drains 40 mA when parked, meaning that I have about 1000 hours of reserve.

Since I try to avoid driving the NSX in the rain, I can survive a biblical flood of 40 days and 40 nights. 🙂 Harry Somerfield chose the BP800, and I might have done the same had I known that my biggest problem was a loose wire, rather than battery drain.

Either battery is smaller than a standard lead-acid unit. As Brian Cooper noted in the FAQ, you can put a VHS box under the BP1000 to raise it enough to engage the hold-down clamp. I cut a piece of 4×4 wood to fill the passenger side of the box, and a piece of foam to hold that in place and keep it from rattling.

The BP800 is smaller, and I think Harry mounted his sideways. The BP batteries can be mounted in any orientation.

The dealer told me never to trickle-charge this battery, by which I think he meant continually charge it when it’s already fully charged. He said that will kill the battery.

Here are some BP contacts, which I followed in this order:

       HQ: 800-44CRANK in Colorado
  • Norcal distribution: 888-777-1898
  • SF bay area lead dealer: 650-349-3820
  • Oakland dealer: 510-452-4025

[LL] The NSX was my first high parasitic loss vehicle, and I’ve been a little frustrated with having to attend the battery through the winter. I’ve had toy vehicles for close to 30 years and have never had batteries go so quickly. I’ve personally been on premises when charged batteries blew, so I’m not at all keen on the maintenance chargers. Any device hooked to a battery has the potential to short that battery, so I’ve been thinking about better batteries for some time.

The true deep cycle batteries such as the Optima or the Black Panther look like just the ticket for toy vehicles, so I set out to find the negatives of this battery. Fortunately I wasn’t successfull. I’m not going to go into a lot of engineering detail, I suggest anyone interested call Hawker and get their marketing brochure, it’s quite informative.

First, our problem is that standard lead-acid batteries can loose up to a third of their ability to be recharged every time they are fully discharged. After the second total discharge, you’re well into risky territory. The battery may take a charge, but it’s capacity is probably down a good 40% plus and may fail without warning. I personally get nervous after the first

 deep discharge. I don't like to gamble on a car that is potentially hard to get home when  disabled. So in the best case scenario, assuming your discharges are not quite complete,  you'll get 2, maybe three discharges. Enter the dry cell battery. According the the MFGR,  it's good for 400 total discharges with a 95% recharge ability. 

Hawker Energy has produced a battery that is considerably more effient by using the latest technology and the best available materials. Their battery delivers more power per unit of weight and size and uses very little electrolite(acid), which degrades with age. One of the significant efficiency gains comes from the dry cells ability to deliver it’s current much faster than the lead-acid batteries. This means more available cranking amps to the starter. The typical numbers quoted are that a typical lead acid battery needs 70% of it’s charge to reliably start an auto, the dry cell technology batteries can start a vehicle with only 30% of their charge left. The dry cell also holds it’s voltage tighter to the optimum range. Standard batteries voltage drops quite a bit when they get low putting a strain on the starter components and potentially keeping the engine from turning fast enough to start. The Black Panther’s ability to maintain this closer voltage range is also important to maintain optimum electronic component performance. In the old days this was a big deal that often cost HP, many systems today just flat shut down the engine when voltage drops below a set point.

The Black Panter is a non-spillable, mount in any plane unit. It is currently used in many government aircraft and land vehicles. It’s also favored by Police and emergency vehicles where idling with high wattage lighting is a big problem for conventional batteries.

The NSX uses a group 35 battery. Hawker recommends one of two batteries for our application. They are the BP-1000MJ or the BP-800MJ. There are many rating methods, but here are the few that you may recognize:

Standard group 35: 310-500CCA, HCA

450-725, RC

80-110min, usable reserve=24-33min

 BP-800MJ: 400CCA, 450HCA, RC

45min, usable reserve

 BP-1000MJ: 600CCA, 930HCA, RC

90min, usable reserve


Note: Standard numbers vary depending on quality of the OEM type unit. CCA

cold cranking amps, HCA

hot cranking amps and RC=reserve capacity.

As you can see the BP-1000MJ provides roughly 50% more starting power and 100% more usable reserve than OEM. The BP-800MJ requires a closer look. The"usable" reserve capacity is calculated from the efficiency differences and

 is good for evaluating starting power including the ability to start the car after sitting  idle. What it does not apply to though is the reserve capacity available to run the engine  if the charging system fails, the RC numbers apply in this case. The 800 does cut the OEM  RC time in half. One will have roughly 45 minutes to get home or to a service center  running headlights and considerably longer without headlights.

Hawker recommends the BP-800MJ for performance cars where weight is a factor. This battery should be fine for those with relatively known disuse periods, especially if a disconnect switch will be used.

The larger BP-1000MJ is recommended for cars with higher than OE current draws such as vehicles equipped with monster audio systems. This batteries high reserve capacity may be better for those that do not put their cars through defined sleep cycles, yet do have disuse periods, and do not wish to use a disconnect switch.

The OE Honda battery weighs 32#. Hawker’s claimed weights are: BP-1000MJ

34.6#, BP-800MJ


Due to the low quantity of electrolight, the batteries longevity should be considerably longer than the lead-acid units. While the literature claims 5 years for medium to heavy useage, distributors tell me it’s not uncommon to see a life in excess of 8 years. The shelf life of a standard lead-acid battery is around 7 months. The dry cell Panther holds 50% of it’s charge for 2 1/2 years.

The bottom line for me is that with this battery and a terminal on-off switch, I won’t have to charge the vehicle during periods of disuse. There is absolutely no reason to charge this battery after a winter sleep. The battery can stay in the car with nothing plugged into it. It’s a no brainer for me.

Hawker Energy designed this battery, as well as the popular Optima in their past, and Crischell Automotive Products builds them. Their battery design is also known as the "Predator". Names of Distributors in your area can be obtained by calling 800-44-CRANK. Ask for Bruce Essig for tech info. Their URL is  I was quoted some excellent prices from Mid-West Battery in Indiana 317-841-7900 of $114.95 for the 800 and 145.95 for the 1000. Mention the NSX Club if they quote you higher prices. Happy starting!

[BZ] Factory OEM – 440 cold cranking hours $ 69.70 34lbs.

 Optima 800 cch $139.99 39lbs.
 Panther 1000 cch $214.95 34lbs.
 Panther 800 cch $169.95 23lbs.

[BB] (12 Jul 1998) FWIW, my BP800 purchased in 2/98 has failed. I have started the car up every few weeks, and driven it around a bit. About a month ago, the car turned very slowly. I pulled the battery, charged it, and reinstalled it. Immediately, it started fine. 2 days later, I tried to start it, and again barely turned it over. If the engine warmed up, it wouldn’t turn it over. Anyway, the long and the short of it, they are sending me a new one under warranty. I just have to pay for shipping each way.

[BZ] One other person on the tech list also reported a failed Black Panther battery. I tested two of Mark Johnson’s BP500 batteries and one of them was DOA. It would not hold a charge. I hope this in not an indication of Black Panther’s overall quality.

[KS] The first Black Panther battery I received (new battery, unopened box) was dead. It had been manufactured a year earlier. They promptly replaced it, no questions asked. But this makes me doubt those who have claimed that there is virtually no drain on this battery if it sits. So I have once again installed my battery charger with this battery. It is the kind that monitors the voltage and only charges the battery when voltage drops below a certain level. I plan to keep it plugged in whenever the car sits for an extended period, just as I was doing with my previous stock battery.

[HS – 99/1/16] As noted back in November or December, my Black Panther 800 battery failed. Today I replaced it with a new one — but now the battery is called a "Hawker Energy – Odyssey PC-925." The specs are slightly better, the unit looks identical except for the label on its top. It was a 100-percent warranty deal. Let’s see how long this one lasts.

[KJ – 99/1/16] About 2 months ago my father’s BP1000 ran down due to an open door. He found that the charger would not re-charge it using the normal setting, but in the "activate" (high-current) mode the charger managed to wake up the BP1000, after which it could be charged normally. I haven’t called Black Panther, but I speculate that this battery has a different internal resistance than standard car batteries, and thus behaves differently under charging.

Dali Racing BP 800 Battery Mount Bar

[DNG] Dali Racing has a great aluminum battery mount for the BP800. Looks clean.

[KS] The Black Panther is WAY smaller than the stock battery. I am not using the battery box. Instead, I got the aftermarket battery bolt-down bracket that’s available from Dali Racing. This holds down the battery very nicely and keeps it in place. It sits directly on the battery tray (the flat metal piece that the battery box normally sits on). The flat bar goes over the top of the battery and the two posts go vertically down alongside the battery (left and right side). At the bottom of each of the two posts, you drill a hole through the pan that the battery sits on.