Safety First

[Bruce S]

Wanted to share a big reason why it's always pays to play safe.

Here is a side view of the NiCd pack that I believe I had posted before.

Nothing special. 12Vdc 26Ahr setup.

This was the first try at building the packs for our daughter's E-Bike (48Vdc 550watter). This pack has been in service since late last year. Just to the very left of the screen you can see the connectors.

However during routine charge, I heard a "hissing" sound, checked internal temps, all was okay. Checked the watt meter coming in from the HF panels, all was okay, then POP!! then came the magic smoke and lots of it. None of the fuses blew, none of the Thermistors opened nada. Exhaust fan and debounced disconnect switches room was cleared in short order. I always wear safety glasses and some kind of gloves when working with these, glad I did.

For anyone getting into RE using which ever charging method you chose, PLEASE BE SAFE ALWAYS!!

Cheers

Bruce S

[BigBreaker]

Cadmium is quite toxic.  Please carefully inspect the damaged cell and clean up any bits that were ejected.  Frankly there could be cadmium dust all over that room...  Take precautions!

[Bruce S]

Hello BigBreaker;

 Yup; I work with these types day in and day out. ALWAYS try to be careful. No dust fallout, I use old hepa filters and an ION room cleaner to clear out these problems. Gloves are mandatory for anyone around my stuff.

Batteries are good to have but even the most experienced person can get a surprise now and then.

Of the 1000s I worked with, this is only the 2nd set I've had blow, first was stupid user error during charging.

Cheers

Bruce S

[RogerAS]

Wow,

I had my mustang blow a battery at the shop when the guy put a load on it with the engine running (internal short). All batteries can fail in unpleasing ways. That's why I'm on the side of the fence where the battery bank is in one place and my house is in another. With a pile of batteries I'd rather lose all of them than even a little bit of my house.

I know, not really probable with this example, but it doesn't make the issue go away either.

I pray every summer not to have a thermal run away, even with a probe.

I'll shut up now.

:-)

__

[ghurd]

Any idea how hot they got?

That shrink-wrap stuff seems pretty heavy-duty.  Looks like it melted into goo.

Jeeze Bruce.  Buy her a car.

Kids these days can't be bothered with pedaling or recharging!

LOL

G-

[Bruce S]

Roger AS;

 I hear ya. I like the NO batteries in the house rule, at least none setup like these. Woofer's setup is a very good way to go for most too.

I'd much rather watch the shed melt than my house.

Keep talking, knowledge is good :-)

Bruce S

[Bruce S]

G-

Honestly I have no idea. I put the thermal probe on the ones right next to them and other side, nothing out of ordinary.

That shrink wrap in the high-temp stuff and you are correct it melted, not just it but a couple banks directly next to it.

This being the 1st large bank was a test unit, so I did abuse it on purpose, meaning put it through tests such as charging with full solar setup and making coffee with it :-). Several rests in between.

I will be doing a complete dissection to hopefully find the problem.

I'm thinking that it was not a thermal run away, but a single Sub-C that failed, the hissing leads me to this.

No car!, at least not until Mother-E-News finishes MAXX and I can find ALL the parts for free. Plus she likes the scooter :-> BUT The Harley riders like her on it too ;-/

Cheers

Bruce S

 

[ghurd]

I always wanted a Harley.

Buy her a car.  Quick!

G-

[independent]

The cell failed looks like it was in the dead centre in the middle of the pack. Could it be a balancing issue? Many nicads in series..