Apparently NiMH can be dangerous too!

[DrGoatboy 132]

Managed to do this today. 

Thankfully no harm to me and on a heatproof mat so only minor damage to my kitchen worktop. House stank for a while though 😂

Moral of this story is even though they are only NiMH if you don't read the manual you can still do stupid things....

 

[ChrisHGTV 37]

Wow, what happened?!

I only use NiMH's and even though I charge them on a granite kitchen worktop i'm still quite wary.

 

[ChrisRx718 4470]

In my younger years I used to throw everything into a single box and chuck it under my bed. All my spares, the screws, tools, parts and of course batteries.

I once had a go at building my own 'matched pack' by soldering tabs onto cells. This also went in the box.

Then one day I was rummaging through said box and must've shorted out the battery, as it lit up like a sparkler 

Gave me and my girlfriend of the time a bit of a surprise  

Sparks / fire quickly went out and I chucked it in the garden never to be used again! 

[No Slack 454]

Please can you tell how this happened? I charge my NiMH's on a safety mat and store them in an old ammo box (a bit overkill but better safe than sorry).

[Gazzalene 171]

You should say how this happened OR if you do not know give some info on what you did and someone will tell you what you did wrong.

This might help you or others.

[Wooders28 4723]

Impressive!!

All batteries have the potential to be dangerous,  just lipos are more ,headline grabbing...

[DrGoatboy 132]

Thanks all. I believe the source of the problem is my own ineptitude. I have 2 chargers. 1 a very basic one I have always used for my NiMH with tamiya connectors. Another I have used for my lipo which is an all singing and dancing number that chargers everything. 

I recently purchased a 2nd hand car and it came with a NiMH pack but an Xt60 connector. So I got my fancy charger put, switched it to NiMH auto mode. Plugged the battery in. Checked it was charging and went off round the house to do other things. 10 mins later Cue alarm from charger smoke and a smouldering quartz worktop.

Basically I didn't realise there was a setting for amps and I charged the 3000mah battery at 20amps. 😫 Lesson learned...

[Problemchild 2149]

[runs out to check his LiPo and nimh charging in the shed]
 

JJ

[Juls1 1661]

Lol, yes NIMH are ideally 1C charging only!!!

[TwistedxSlayer 1290]

20 amps. That's impressive. Lol.

 

 

[DrGoatboy 132]

Ah yes. Feeling slightly daft now but on a safety note the charger (turnigy reaktor) didn't come with instructions. The manual online is obviously translated from another language and doesn't give any guidance on good charging practise and comes set with everything on its highest setting.

I took the time to make sure I worked out how to use it for lipo. I guessed for NiMH. 

Yes I am a numpty 

[Mad Ax 9313]

I've found that in some RC circles saying, "Yes, but NiMH can explode too" is a bit like saying "Yes, but people die of flu as well" during a Covid conversation...

[Howards 456]

I find it a bit bonkers that you can buy a consumer charger that will do 20A without a temperature sensor present. 

[No Slack 454]

That was a brave attempt of quick charging! 

[waterbok 1282]

13 hours ago, Howards said:

I find it a bit bonkers that you can buy a consumer charger that will do 20A without a temperature sensor present. 

And at least 200watt power supply.👍

[berman 5315]

Most half reasonable NiMh chargers come with temperature sensor that you rest under the pack. I am also suprised you have the option of feeding the battery 20amps. I believe there is still more record of NiMh that LiPo fires/explosions, although NiMh has still been around longer.

As with any battery chemistry, take care.

 

[Nicadraus 6198]

Any battery can be dangerous if mishandled. Even small button cells can ignite fire.

[hedge 314]

I raced at the point between brushed and brushless, NiMh and Lipo. During the end of the nimh era at every event someone would blow up a NiMh pack - every event. Mostly just a pop as the ends blew off, but sometimes a little more damage was caused. Nothing compared to a LiPo fire, but it could take your eye out.

[Ferruz 11702]

Oh, wow. I knew that every battery is potentially dangerous, but thought NiMh were safer than Lipo by a long shot. I didn't know that many used to blow up.

I have a basic (I feel many would say unpresentable) wall charger, with no switch or led whatsoever. One of those that get bashed hard in every battery/charger discussion. Its output is very low (300 mA) so it takes me 10 hours to charge a 3000 mAh battery, the wait is long but I read that a slow charge has its good sides, one being that it is safer. Dunno if it's true, but I can say the charger never gets more than barely warm even after 10 hrs, and the batteries warm up just the usual, towards the end of the charge. Forgetting to unplug did happen, quite a few times, but apparently one or two extra hours of charge didn't seem to affect the battery (and it sure didn't blow up, fortunately). Does anybody confirm that a slow charge is safer? Or am I risking even more with my China wall thing? 

My charger is too slow anyway, I have to invest in a decent one, but I have to say I've been going over 3 years like this with no problem.

One thing I will do, though: figure out some sort of safety undertray, like some of you pointed out above. It's a good and quite obvious idea, can't believe I didn't think about it, thanks!

[Biz73 603]

5 hours ago, hedge said:

I raced at the point between brushed and brushless, NiMh and Lipo. During the end of the nimh era at every event someone would blow up a NiMh pack - every event. Mostly just a pop as the ends blew off, but sometimes a little more damage was caused. Nothing compared to a LiPo fire, but it could take your eye out.

Just out of curiosity, how many of these were home made?

[hedge 314]

31 minutes ago, Biz73 said:

Just out of curiosity, how many of these were home made?

It would have been a mix but mostly it was down to NiMh cells trying to compete with LiPo and just getting right up to the edge. They got banned from a couple of countries at the time, if memory serves it was a particular batch of IB batts. 

[Biz73 603]

2 hours ago, hedge said:

It would have been a mix but mostly it was down to NiMh cells trying to compete with LiPo and just getting right up to the edge. They got banned from a couple of countries at the time, if memory serves it was a particular batch of IB batts. 

Thanks. I was just curious because I've read so much about people building their own batteries.

I only charge my Nimh's at 1C so hopefully I can avoid flying cells! I'm glad the OP didn't get injured.

[•Axle 145]

I’ve bought this Overlander D100v2 charger, as the last one had a winding mechanism on the front. I have x3 4000mAh and it tells you to input 4A, I’m charging them at 3.5A, discharging them every time and even re-peaked two of them, heat wise the one that concerns me is re-peaking, they get soooo hot, I’m standing right next to them waiting for something to go bang hot.

I was presuming this charger was sophisticated enough not to wreck the batteries if everything was input correctly, is this right?

[Howards 456]

10 hours ago, •Axle said:

I’ve bought this Overlander D100v2 charger, as the last one had a winding mechanism on the front. I have x3 4000mAh and it tells you to input 4A, I’m charging them at 3.5A, discharging them every time and even re-peaked two of them, heat wise the one that concerns me is re-peaking, they get soooo hot, I’m standing right next to them waiting for something to go bang hot.

I was presuming this charger was sophisticated enough not to wreck the batteries if everything was input correctly, is this right?

Re-peaking NiMH isn't the safest thing to do. Why bother unless you are trying to eek out every last bit of punch. 

[•Axle 145]

7 minutes ago, Howards said:

Re-peaking NiMH isn't the safest thing to do. Why bother unless you are trying to eek out every last bit of punch. 

Perhaps I’ll give re-peaking a miss from now on then, having what I feel is a pretty decent charger might be lulling me into a false sense of security.