Battery or Pyro

[Sci Fi Steve]

So I was fast Charging one of my Intellect 8.4v 1200mAh NiMH Stick batteries, on a Pro-Peak varipulse at 1.5A when It started to sizzle. I rapidly pulled it for the charger by the wire a threw it out my bedroom window an a minute or two later BOOM (akin to a pyro going off at least).

Has anyone had this happen ?

Is Intellect considered a "cheap" brand ?

Any ideas to why it happened

Can this happen or anything else happen to a fully or partially charged battery, or is it only something that can occur while charging, as I am now concerned about keeping the batteries in the house. ?

[SAS Scott]

Re: Battery or Pyro

My one went after positive and negative touched , charged it on the same charger than you and it went boom.

IMO Intellect is no better than cheap rc batteries infact my rc batteries out lived my Intellect one .

Also omg your not a mod anymore ?

EDIT: if your concerned buy a lipo safe bag there only £5 and will save your home if the worst happens.

[thekonassure]

Re: Battery or Pyro

when fast charging a bit too hard some bat`s end up venting hydrogen

If it was very hot then that could be what was happening then the cell blew ?

I think its also why damaged lipo`s can then explode when being drained hard as they leaky hydrogen too when used or charged incorrectly and being damaged makes the leak worse

I had some firefox bats that would get rather hot when fast charging and I could hear a hissing sound so I put them in water to see the bubbles just the cells not the wires and the used a lighter on the bubbles and go small pop`s.

So I assumed the popping was hydrogen

[Sci Fi Steve]

Re: Battery or Pyro

dont think it was a short as it was comming close to ending its charge and had not be moved from where it was charging

[JOE90]

Re: Battery or Pyro

I had this happen to a nimh while it was plugged into my gun. the fet went bang first.then the beattery swelled up. i unplugged it and slung it out frontn

[mcdon2401]

Re: Battery or Pyro

Had one go pop in a hire gun a while back, and I know one of our regulars had one go bang on charge.

That's why it's never a good idea to leave batteries unattended while charging.

Having said that, as a test, I took the cheapy LiPo that came with my Sten, and put it through some serious punishment (started off with some basic whacking it off a tree and blasting it with a gun, left it exposed to the weather for a fortnight, drove over it with the truck, then stepped up to smacking it with an axe) and it was only at the end that it started to leak Hydrogen, so I dropped it into a burn and lit the bubbles. Childish but fun. But it does show that they can take a fair bit of punishment if needs be.

[S3V3R]

Re: Battery or Pyro

What current where you charging at? We've blown a NiMH in the lab because it was charging at a high current. Was also a fairly old used battery.

[Sci Fi Steve]

Re: Battery or Pyro

Heh I did say in the OP 1.5A, battery was brought In May and this was its second charge. I have since charged 2 other identical batteries (at 1A) without issue so I am guessing some sort of cell failure..... Will be purchasing a fire bag soon

[KaRcop]

If it was bought in May then stored without a reasonable charge then it could have discharged slowly to an unsafe voltage. Then when you recharge it, it swells up and boom!

This happens to LiPo if you store them at 3.7V per cell or lower... Could have been a similar case?

[HunterAndy]

Re: Battery or Pyro

Don't confuse NiMh with LiPo, completely different system of cells- no such thing as an "unsfafely low voltage" with NiMh, you can run them flat.

Edit: What's likely to happen is that the charge capacity reduces if you leave it flat for ages, and then when you charged it, the battery, in lemens terms thinks it's fully charged, and overcharges in effect.- if it doesn't have a safety valve cap (i'm assuming because it blew up it didn't) then the gas builds up inside until catastrophic failure.