Cells venting on discharge

[minichamps11]

Anyone else experienced this?

Was discharging a pack of new 4600EP's on an Eagle CDC @20amps when the negative end cell started loudly venting. Now I've had old cells vent during charging, but these cells are only 3 charges old & were discharging.....are they screwed?

I take them down to 7.2v on the CDC before using my Novak equaliser to go down to 0.9v per cell.

[Rich D]

20A ?

My LRP Pulsar 3 can only discharge @ 10A max

Could this be anything to do with it ?

[Thomas P]

I Disc on 22A..no went on my cells at all..20A discharge aint much if you compare to what a TC can draw on 5 min..

New cells can do that, wenting..( my SMC IB manual, there was about 200 sec of charging, then tray down to 0.9 per cell..then charge about 5-6A...if the cells starting to went, abort, disch , tray and then reedo it..)

have ya read the manual for the pack?

[Jonathan]

Measure the voltage across each cell when the venting occurs. Could be that one cell has a problem ?

[neiloliver]

venting during discharge is not good. check to see if that cell still has a positive voltage during discharge; it may be that it has been driven negative and is now generating hydrogen gas. I would suggest swapping this cell out.

Neil

[dan_kitty]

i was discharging (10a) a new pack the other day, then one of the cells (end negative cell) made a loud pop noise followed by a fizzing sound. i took it off the charger and the cell continued to fizz for a good few minutes. extenally cell looks ok, checked the voltage on each cell, which was fine apart from the fizzing one. briefly popped the whole pack on charge to regain the voltage., then took it off.


is it safe for me to try and charge the pack up, or should i not risk it?

this was one of my 2008 legal packs so i want to rescue it, or im down to 2 packs for oswestry

ta

[Chris Harte]

After the battery was used did you take it straight out the RC and straight onto the discharger? If so that might be where your problem lies. Wait a little bit for the particles inside to cool down because a warm cell to the touch equals a hot core of the cell. It might just be the heat and pressure that has caused it.

The key thing with charging and discharging is supervision of the cells all the time.

[super__dan]

Sounds like bad news to me, I'd send it back.

[dan_kitty]

the cells had been sitting for about a week with partial charge left in them, and the popping happened about 2 minutes into discharge, think im gonna have to send the cells back

cheers guys

[minichamps11]

That's exactly the same thing that happened to me. The cells had been left partially charged for 3 days so were cold when I started discharging.

My packs aren't matched - could this be why one cell vented? If they're really badly out I guess one cell could go flat well before the others and get reverse charged. If so, even if I replace the faulty cells, I guess there's nothing to stop it happening again

[Chris Harte]

You did charge slightly before you discharged didn't you?
If not, then you should know the cells would of discharged them selves because they were sat around for a few days so you discharged them even more. If that makes sense.
Failing that explanation send them back and try your best to get a refund or replacement.

[Snakesonaplayne6]

EP cells are the only ones I use, so I'm used too "how they act". They vent A LOT. I balance my packs once a week, because they vent so easily. One of the cells was probably below voltage.