Intellect Bang

P_B · #1 16-07-2007

Okay, so excuse the jovial pic treatment, but it happened again this weekend - a set of IB's going pop. Luckily the tent in question was empty at the time and no lasting damage was done.

I know we're enjoying more voltage and runtime than ever before, but has the performance/reliability threshold been breached or are we simply using these cells too far outside of manufacturers' spec?

I've seen this happen a handful of times now (though only with IB's) and know of a fair few people with packs where a cell has gone down quite early in the expected lifespan. Whilst the percentage of failures is very small and catastrophic failures smaller still, it seems like it's only luck which has prevented anything serious happening so far.

Any informed opinions/cell experts?

Southwell · #2 16-07-2007

Yeh, it was mental. Thats why i charge my cells in the box with the lid facing away from me. (and pointing towards paul

)

Lee · #3 16-07-2007

Its good to hear your using protection.

These cells are tempermental if treated a little aggressively, try a very low delta peak so they dont get warm and try not to charge above 5.5 amps.

P_B · #4 16-07-2007

The chap whose cells they were was charging at 5.0A and the cells were also in the shade. No idea about the rest of his cell care regime, but the end result was a more than a little violent! Just wondering if had happened to anything other than IB's lately?

Lee · #5 16-07-2007

I have seen a GP3700 do it a while ago, i saw one go in a touring car once also, there was very little left

We do everything we shouldnt do to these cells, things are bound to happen. Its just the way it is, there is nothing we can do really to maintain peoples safety, as the manufactures will insist they are being abused. Its down to the user to bear safety in mind, ie point it at a mate

But on a serious note charging them in a box is probably the best way as long as there is sufficient airflow. But not enough to cool the cell as it charges.

mark christopher · #6 16-07-2007

hmm wonder what dcm will say, these cells are available to jo public without and saftey warning!!!

neiloliver · #7 16-07-2007

I have doubts about the effectivess and reliability of the vents on these cells. Most Cs cells now have a rubber slug type vent backed with a metal disc. When the cell is in overcharge, gas is developed which is combined internally, however higher charge rates produce more gas, more than be combined. When this happens the pressure builds up inside the cell and the rubber disc should move to release the gas. Soldering to cells can damage this vent mechanism, or sometimes the vent holes can become blocked by the internal cell components (electrode or seperator).

I should imagine that the cell in question had 'issues' (low capacity) and this caused it to be in overcharge while the others were still charging.. so the charger was not aware... its all not very good. I doubt these cells could pass the safety tests insisted upon by the power tool manufacturers.

As with all batteries, they should be treated with extreme caution whilst being charged. they shoudl be soldered very carefully and not charged >4A. They shoudl be matched as often as possible and dead cells should be substituted.

Neil

OldTimer · #8 16-07-2007

I wish they made the A123 cells in a sub C size, seem to answer all of our needs, fast charge, no memory effect, don't flame like lipo's. Currently used in the 36v battery packs for Dewalt. Info - http://www.a123racing.com/index.html

And the drag bike they have powered by the A123 cells is awesome a electric bike doing burnouts

PaulRotheram · #9 16-07-2007

It was abit of a scary moment, i heard the loud bang, saw some crazy black mesh thing on the ground then heard hissing and saw the cells pissing some mad stuff out.

Just lucky no one was in the tent, i believe the family was there for the weekend too? Put the lottery on fella!

strobe · #10 16-07-2007

Those are the remains of my cells.
Very lucky my missus and two young kids were out of the tent at the time. Glad in a way it happened on saturday and not yesterday as they would of been in the tent for sure as the weather was crap yesterday.
If anyone has some more photo's of the remains can you PM me please.
Had to dispose of cells as some were leaking.
Have found a contact e-mail for intellect cells and want to send them some photo's so they can see what can happen to there cells.
Found the end of one of the cells 20 foot away.
I am releived that no body got hurt and an innicent member of the public did not get hurt.
Bought these cells of Dr Voodoo. Won't be buying any more Intellect cells.
Any recomendations for future cells.

Would like to thank all involved and to those who bravely entered the tent while some of the cells were venting to disconnect power supply.

Mark

losixxx · #11 16-07-2007

Quote:

Originally Posted by P_B

The chap whose cells they were was charging at 5.0A and the cells were also in the shade. No idea about the rest of his cell care regime, but the end result was a more than a little violent! Just wondering if had happened to anything other than IB's lately?

no he wasnt, 6amps (too high) and 15mv per pack as he change his charge rate to 5amps when i was looking at the scorch marks in his tent

Southwell · #12 16-07-2007

Im pretty sure i have mine at 3mv per pack lol.

strobe · #13 16-07-2007

Losixxx. You are correct about the settings. Did ask Dr Voodoo when i purchased cells what to charge at and other settings and he gave me those charge rates.

Southwell · #14 16-07-2007

No sorry, 3mv per cell 18mv per pack, thats the lowest my charger would go.

OldTimer · #15 16-07-2007

In the past i have seen cells go bang, but this is only due to them being over charged, sorted out etc. I didn't realise they can go bang under normal changing conditions

.

Northy · #16 16-07-2007

I replaced a dead cell in one of my packs at the weekend with a brand new IB worlds version cell and it vented on first discharge

and took the paint straight off of my discharge board, its proper nasty shit that comes out!

G

Kopite · #17 16-07-2007

i've replaced 7 cells from 5 packs so far, and 2 more cells went at the weekend, costing me two rounds of qualifying. So pissed off!!!

Southwell · #18 16-07-2007

Ive had 2 cells go in one pack when they first came out, apart from that ive had no worries, all my packs have worked fine since.

mark christopher · #19 17-07-2007

Quote:

Originally Posted by Northy

I replaced a dead cell in one of my packs at the weekend with a brand new IB worlds version cell and it vented on first discharge

and took the paint straight off of my discharge board, its proper nasty shit that comes out!

G

done that too then realized why, the pack was charged the new cell was not so all the power was going through a flat cell

Northy · #20 17-07-2007

Nope, the cell was replaced, the pack equalised, charged, raced then discharged.

1 run cells..... nice!

G