N-19 NIMH batteries

[phillip1]

Ok so here is a weird one I cannot figure out, I burn tested the batteries of our 3 N-19's for some reason two battery packs went "bad" and would not go past 10 mins but the third one went all the way past 1.5hrs and still had juice.
I tried everything, charging then turn off charger then on again, left the bad ones on charge for 3 days etc.. still they both would not go beyond 10mins but the good one was still burning past 1.5 hrs easy.

I took one of the "bad" packs today stuck it in one of the scooters and did an UW pool test tied to a rope UW. The "bad" pack that would not burn for more than 10mins on the tester did 1hr 20mins at setting 8 full throttle the entire time in the pool and still had plenty of juice.

Why would 2 fare so badly on the tester and do very well in the pool? I also have the prop pitch set to "more power" so the battery was really being used full on.

Any input would be appreciated

[DA Aquamaster]

How many amps are you pulling on the burn tester?

[FW]

There is a guy on this forum that has a procedure for reviving NiMH batteries. I don't remember the exact numbers, but he discharges them past the motor cut-off voltage, then re-charges them. You have to use the burn tester, and an accurate voltmeter to get to the right discharge voltage.

[JamesK]

I would love to know his procedure on that. I have a NiMH that has sat for a over a year and want to revive it. Here is what I have done so far and it seemeed to help. I placed it on the charger and it only charged for 25 minutes before the charger said it was charged. I then let it burn for 5 minutes and it was drained (light changing colors). I let it sit for 5 minutes and turned it on again until it was drained. After that I placed it back on the charger where it took the standard 2.5 hours to charge. I let it sit on maintenance charge over night. I took it out the next day and it burned for 30 minutes and shut down. After 5 minutes of it off I turned it back on and it burned the next half hour of the dive without problem. Weird.

I am not sure if the dive shop has a burn tester or not, but they have told me whatever they have, I have. So I am going to see what they have!

[phillip1]

I am getting 15.68amps on the burn tester and it will still drain the battery in less than 10 mins, the very same battery that in the pool test lasted 1.20mins

[phillip1]

The N-19 is the best though IMO a perfect balance of size/range and it is a super tough little scooter, like a scooter equivalent of an LED light so to speak, they get banged up a lot here, no problemo so far.

[FW]

The N-19 is the best though IMO a perfect balance of size/range and it is a super tough little scooter, like a scooter equivalent of an LED light so to speak, they get banged up a lot here, no problemo so far.

They make a battery conversion for the N-19. http://www.silent-submersion.com/Pro...per/Viper.html

[FW]

I managed to find the screen name of the guy with the method of reviving NiMH batteries. He hasn't been on here is a couple of months, but I just sent him an email. I will post the method, when I hear back from him.

[phillip1]

great thanks a lot

[JamesK]

Thanks Forrest! I have been searching threads with NiMH in them, and now my brain hurts! LOL