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Costco carries the Interstate Battery for our car

17 November 2002
Santa Barbara, CA, USA
I have been looking at battery options for the car. On the one hand getting a Lithium based battery like the Shorai is a possibility. While not cheap it is very light weight. I had one in my 2001 NSX-T that was supercharged. I never had a problem in the two to three years that I had it. I used the Shorai trickle charger when ever the car was not being driven. that battery was the LFX36L3 which is still being sold. Best price is around $240 then another $75+ for the tender. What I don't know is what voltage the current NSX outputs to the battery during normal operation. It has to be above 13.1 volts and not exceed 15 volts. The upper end is probably not an issue. Then there is a light weight version of what we have a Pb based battery that just happens to be smaller and lighter at around 9 lbs. It can be had from a number of vendors. Amazon sells it for around $140 and is the Yuasa YUAM72Z14 YTZ14S Battery. I just found out that Interstate who supplies Costco does in fact have a battery for the 2017-2020 NSX. It is a H5 designation which refers to mat based plates inside the battery. Costco does not show it on their web site but in the store can order it for around $145. It comes with a 3 year 100% replacement. My current battery is still functional though I noticed after installing the wire harness for the NSX charger that it always blinks when I finish driving and have returned home. The light blinks when the voltage has dropped below 12.4 volts, indicating that it no longer is behaving as new. I could just wait till it gets to be bad enough to change it out on warranty. But I hate waiting on stuff like that. I think I would rather pay and replace it with a new battery then try and get it done through warranty. So it is a dilemma, do I wait for my current battery to degrade enough for a warranty replacement or do I change it out now? Should I go with a light weight version, and if so which one the Lithium based or the Pb based? You can tell I have way too much time on my hands....
Knowing how sensitive to voltage the NC1 is, and how the car can become disabled, it’s great that you can get one from Costco. However if something goes wrong will Acura decide to void your warranty because you decided to DIY with the battery?
Knowing how sensitive to voltage the NC1 is, and how the car can become disabled, it’s great that you can get one from Costco. However if something goes wrong will Acura decide to void your warranty because you decided to DIY with the battery?
Interesting point made. With respect to the Magnuson Moss Warranty Law, I might be treading water a bit. Generally speaking you are protected in using an aftermarket product if the manufacturer does not offer it for free. Acura would have to prove that the battery I used caused a specific failure and therefore they will not cover the repair under warranty. In truth, what happens is that you must sue Acura in Court if they deny warranty coverage and demonstrate that they have no specific proof that what you did was the root cause of the failure. As I mentioned it gets tricky when you are talking about a part that Acura would provide. So in my case, my car is still in warranty and the OEM battery is still covered. Even if they did void the warranty they would do so only on the part of the car affected by the aftermarket part. So I would still have the general warranty. Having said all this, I am not in the least worried about the battery say from Costco, or the Pb (Lead based) light weight battery from Yuasa. Both of these are basic Pb based and 12 volt as well as Glass Mat versus the old Lead based plates. In fact the Yuasa was the light weight battery that was originally offered as a option for the NSX. Acura later discontinued the offering. They probably did not see the numbers necessary to keep stocking the parts for the next 10 or 15 years. I did some consulting work for GNB before they became Exide. As a chemist I am very comfortable with battery technology. What might be questionable is the Lithium based battery as it is not designed for a car but rather a Motorcycle, ATM, and/or non automotive applications. So yes the voltage and its behavior might be different than a traditional Pb based battery. Lithium batteries have been know to ignite, recall some of the cheap imports coming in for battery scoters and other applications. I would first do some investigative work on how the NSX charges the battery and what it is looking for etcetera. I find this stuff really exciting.
I ended up taking my car in to my local Acura Dealership. They tested the battery thoroughly. They can only warranty if it fails one of the tests. It is getting weaker, evidenced by when I drive into the garage the headlights come on and the battery voltage drops below 12.4 volts. That is indicated by the red light flashing associated with the trickle charger. Once the headlight go off then it stops flashing. I ended up ordering a battery through Costco (Interstate). It was special order and took three weeks to arrive. I went in yesterday and decided to take it. With tax and no core the price was $177. That was the cheapest I could find the H5 battery from any supplier. Got home and installed it into the car. When it fired up the Navigation said that I needed to hold on the power button for 2 seconds or longer. I thought initially it meant to hold on to the start button. That did not work and it asked for the Navigation code. I retried later and this time held down the audio power button and it completly reset, so now it is working correctly. With the headlights on the trickle charger light is staying off indicating that the battery is above 12.4 volts even under load. So at least that is done. I prefer spending the money now, rather than having to go through the hassel of returning to the dealer when the battery actually fails in the near future. With Costco you only have to take the battery back before 36 months and tell them that it is not behaving and they will refund the full purchase price no questions asked. By the way the Interstate was the exact dimensions of the OEM battery. Everything fit easily. One nice thing when you reconnect the battery you do not have the alarm going off as was the case in my 2001 NSX-T. Inside the battery box you can see that there is a electric fan on the back as well as a vent input on the bottom. There are aircirculating fines to insure that the incoming air properly cools the battery. Clever
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I replaced mine a couple days ago with an Interstate H5(47) AGM from Costco. They had it in stock for $179.

I first got a battery for our 2013 Volt to replace the original battery. Figured it was 9-10 years old and probably way past due, yet everything seemed to work fine. I didn’t have it tested. Then I had him look up the NSX battery and said you may have to order it. He said they can’t order - only get what they send us. He looked it up and confirmed year, etc, then said it’s the same battery as the Volt… H5(47). Easy, grabbed a second one.

Easy job. Getting the battery cover off and back on took some fiddling but wasn’t hard. The tough part was the rear j-bolt that holds the battery down. Getting that j part in its hole took time. I ended up using a borescope to see back there.

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