4600nimh exploded
 

My new 4600nimh exploded on its first charge ,one middle cell on a 6cell flat pack . I used a astroflight 115D charger , any idea what could have happened ?

RE: 4600nimh exploded
 

Did a cell pop and leak out? Did it burn?

I had a poorly soldered pack that had some rubbing for the + tab to the side. The plasctic wore away and it shorted and the pastic caught on fire..

RE: 4600nimh exploded
 

i would send it back.

RE: 4600nimh exploded
 

send it back for sure

RE: 4600nimh exploded
 

Woah wait, what cell brand was it? (i'm assuming it's venom lol)

RE: 4600nimh exploded
 

What charge rate did you use?

RE: 4600nimh exploded
 

Hi Glenn,

New cells should receive an equalizing charge of 1/10C ( 400-500 mA in this case) or less for 20-24 h prior to charging them with whatever you think appropriate.
Not all chargers will detect the Delta peak at this low charging current, just let it charge untill the pack feels warm.

Failing to do this, the individual cells all have a different charge level, meaning one or more will be 'full' before the other cells are, these cell will overheat and vent hydrogen gas, or as you've experienced, go with a bang (which is an indication you charged it with more than 1/10 C...).

As you have no idea how long the pack has been shelved, it's always wise to give it an equalizing charge.
The same goes if a pack hasn't been used for a number of weeks, the charging level of the individual cells will have drifted apart.

As high Ah NiMH cells are notorious for theirs self discharge, it's odd, most suppliers don't offer this information with each pack.

Regards, Jan.

RE: 4600nimh exploded
 

The bat. was a trinity match pack ,the cell exploded ,shrapnel all over work bench(wasn't there at the time).The solider was good bat was brand new, charging for the first time at about 4.5 amp ,was going to use it for the first time that eave.Have to fined instruction sheet to see what they say about equalizing ,I do know they said the bat. is ready to go from new

RE: 4600nimh exploded
 

Oh my[X(], that's a preeetty high charge rate. It's really pushing the charge limit if you use the C charge formula.

Multiply the mah by 1C for the max.
1C x 4600mah = 4.6 amps

That's the absolute MAX you should go, no higher. The charge rates should never be near the max for the first charge time cuz it's really pushing the cells when they haven't been "trained" enough.
(personally I would stay away from the highest charge rate)

The charge rate you should have used is this:
0.1C x 4600mah = .46 amps.

While charging nimhs you should do a charge rate between 0.1C–1C.

And just to add on to what pompeled mentioned, when you charge nimhs for the first time and use a low charge rate it's known as balancing/matching.

RE: 4600nimh exploded
 

Yeah, right....

If there's one lesson I've learned from all stuff I've wrecked over the years, there's usually always someone who has done it before, so always check the forum before trying something that's new to you, to avoid this kind of situations.

If the store, you bought the battery from, is half decent, 'they' should give you a refund or a new battery to compensate for their incompetence.

Regards, Jan.

RE: 4600nimh exploded
 

4.5 amps is pretty high. I have match cell 4300 GP packs and even they get warm above about 3.5 amps. I have tried charging them at 4.3 amps and they got too hot for my liking. Basically the lower the charge rate (to a point) the better it is for the life of the battery.

RE: 4600nimh exploded
 

I have to agree with you Grant.
I have IB4200 side by side six packs and a few other 4000 packs.
I generally charge them in the evening at 2A then let them sit on 500mA for 1/2 an hour to help balance the cells.
In the morning before going to the pond I give them a burst of 4A max, this gets them warm and ready for some speed.
None of my setups will make the packs hot after a run, warm is good, hot is bad.

To me warm is like the outside of a coffee mug, hot is like the inside !!
Note. This comparison is based on a normal ceramic or glass mug not my big thermal ones, the mug must be full and the coffee fresh.
Actually I am off to have one now.;)