Intellect Bang

[P_B]

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]

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]

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]

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]

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]

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

[losixxx]

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]

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

[strobe]

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.

[mark christopher]

how many do number 1 then?

(A) Guidelines on handling Intellect Sub-C NiMH pack :

1. Charge the battery with quality charger, and max. current 3~4A.
   
2. Charging cut-off setting : Peak voltage = 5mV per cell, Temperature <55ºC,
   and best with timer.
   [Example on Peak voltage calculation : 6-cell pack = 5mV x 6 = 0.03V]
   
3. The battery can offer high current discharge, and be good for the level of
   10A+ (with Tamiya plug).
   
4. If you expect to leave the battery idle for >2 weeks, charge it for 1/3 capacity
   (say, 3A for 20 minutes)
   
5. Avoid to store the battery in hot & humid environment. Best temperature
   would be around 20~25ºC.

[Kopite]

i've followed all those rules, and still had loads of cells die on me. Not many other options at the moment is there though, unless anyone can recommend me an alternative?

[Southwell]

You charge at 4 amps all the time? What cells and charger do you use?

[millzy]

i do 4.3maps on ib smc 4200 at 0.3vpc on my charger .. thet have bene ok, but i have to equalise them befor uses as they have whats left in the pack after a run stroed in them...normaly 1500mh max

[Kopite]

yeah, charge at 4 amps, cos i already heard of them being dodgy. I use the robitronik overloader charger. I've never come close to overcharging them either, it's really weird cos i've heard people have a couple of cells die here and there, but not this many!!

[Southwell]

overloader charger , not the best name haha....anyway, i have had two cells go in two years, this was in just one pack. Apart from that they have been fine. This is with charging, using, leaving in car for a month, charging, using, sometimes discharging and equalising, but normally just charge them again They are in their second year and are still awesome, maybe treating them like crap helps?

[mark christopher]

i know i bang on about lipo, but the dont explode like a metal case cell such as above, i know what id rather be sat next to, tho i do have 4200