Norwegian federation closes down all electric races and training

[neiloliver]

I was also told there were lots shipped to Europe. It is strange that we are not seeing them. I have also asked in Japan and China and the answer has been "not available". odd.

[mole2k]

I got some GP4300's last summer and my LHS says he hasnt been able to get GP's in since.

[DaveG28]

Would the GP4300's be any better than IB's? The reason I switched to IB's was that my GP4300's seemed to lose punch very quickly which I asumed was cells deteriorating?

If its just a little performance difference but they are safer, I may try and switch back!

In general though, would 4A charging and using the equaliser make a good difference anyway? Should I worry about the batterys which are popping/fizzing a lot?

Dave

[Ole C]

We have tried a few 4300's and they have all been bad (ie. low capacity and no punch). 3700's and 3900's performed much better. But they are hard to find now, since IB4200 has been dominant for so long.

[Spencer Mulcahy]

This is starting to worry me a little. For the first time I have a full compliment of batteries after just running on three sets for years, all of them IB 4200. If we have to change I dont know where I will get the money from to replace them all. Will the companys compencate financialy if they are banned (I am not talking about model shops as they operate on slim profit margines as it is). Has anybody E mailed anybody from the brca about this to see what they think about all this.

[neiloliver]

I know the BRCA are working hard on this. I am sure they will communicate something once all the facts are known, we should not panic, just follow best practise and use some common sense.

[super__dan]

I've held out on this thread. I firmly believe the problems are caused by the enormous variation rates of self discharge on modern cells. I think equalising before charge is vital and with this your chances of problems are enormously reduced.

I always equalise cells before use on their first charge of the day. If I'm using a pack of cells twice, I most likely won't bother for the 2nd charge though.

For racers this is fine, but it's the kids with stick packs etc I get most worried for.

[Spencer Mulcahy]

OK Neil cheers for the reply I have re-set my novak millenium to all the setting that you posted earlyer in this thread.

[neiloliver]

Originally Posted by super__dan

I firmly believe the problems are caused by the enormous variation rates of self discharge on modern cells. I think equalising before charge is vital and with this your chances of problems are enormously reduced.

I agree. If a cell does develop a small internal short (called a 'soft' short) then the Self Discharge will be worse for that cell. this means that guy has a lower state of charge and will be discharged first when you are discharging the pack, it also stands a higher chance of being forced to zero or being driven negative. This can lead to development of hydrogen gas which cannot be recombined. When the pack is then charged again this guy lags behind the others in the pack and never reaches top of charge.. it is then forced lower on the next cycle.. it is a downward spiral... Yes, equalisation is good.

Ideally your discharger should have a 0.9V-1.0V per cell cutoff but if it doesnt then you are still better using it and maybe suffering some irrecoverable capacity loss than never equalising. I will confess that my equaliser does not have a low voltage cutoff (shock horror!) but I dont leave it connected for long after all the lights have gone out. It is keeping NiMH cells shorted down that kills them, not doing it for a few minutes.

Im off to rebuild buy bx now... Need to beat Mike, Jeff and Ash and Kidi tomorrow..

Neil

[DaveG28]

Yep, think I am definitely going down to 4 Amp charging, and using the equaliser the night before each meeting too!

[showtime]

so if you had a discharger that took the cells down to zero that would be a bad thing right?

i'm new to the leccy side of things as i usually run nitro

[neiloliver]

I know that my saying you can discharge below 0.9V is going to get a lot of 'stick' because this goes against everything we have been told for NiMH. I am not saying that it is ideal, i am just saying that if your only option to equalise is to use a discharger without a cut-off then it is better to use that than to not equalise at all. Dont leave the battery pack connected for ages. For example I did mine last night, I put the pack on the hearth and kept an eye on it while i watched TV*. Once the six lights went out i measured each cell (still on load) and the voltage of each was ~0.2V. I removed the pack and measured each cell again.. they were all back up at >1.2V. (because they instalntly recover when taken off load) I let the pack cool and then charged it.. it worked fine.

*Rocky II DVD, but any other program or film works just as well.

[Spencer Mulcahy]

If you put packs on the hearth to discharge make sure the fire is not on.

[SlowOne]

I can't think of any cell we've ever used since 1976 where there hasn't been the odd problem. From venting to disintegration, every type of cell has been misused to the point of failure. Recently it appears that one make of cell has had more of these issues than any other.

Appreciating that this is a guess (so please put your own numbers in if you like) there are 2000 people racing every week. Say they charge 3 times on average, and they do that 30 times a year. That's 180,000 cycles. I can count about 20 incidents quoted of a cell failure that might cause injury, or 0.01%. Any incident that hurts someone is horrific, and that's a very, very small number from which to trace a root cause.

To make things more difficult, there doesn't seem to be any common situation surrounding the incidents that have occured. We need to be patient, let the BRCA/EFRA and their contacts do their work, and hope that there is a resolution that reduces the possibility of an incident. Please also remember that someone has suffered an injury from a pack fitted into a Nitro car (receiver pack), so any action affects almost all RC, not just Electric RC.

I use the same regime as Neil Oliver, and I have not had the problems suffered by others using IBs.

[telboy]

just a couple of things, not realy on topic, but sort of, is....if that makes sense.

I've use IB's for years and never really had a 'serious' problem with them (like exploding cells).
Of course I've just bought some new ones, which look like they are going to be useless soon. But I've got a couple of things to ask.

Is it common for them to vent?
I've had a pack that has vented for ages probably the whole of this year, yet it doesn't seem to lose any perfomance...infact its probably one of my best packs.

the other thing is discharging. I have a nosram equaliser board. but there is one cell in the middle of the pack that ALWAYS takes longer than the other cells to discharge. This is on every pack. Why is this?

I'm looking forward to the saddle pack li-po's.

[SlowOne]

Terry, I don't have the venting problem, though my older cells do what yours do on discharge.

I think that when the pack is discharged, there is always one cell that had more capacity than the rest, and it takes the longest to discharge to the minimum voltage. Add to that the low discharge rates of my (Novak) tray, and it seems to take ages for the light to go out. It's just a co-incidence that it is always a middle cell, as mine can be anywhere in the packs I have. HTH

[SlowOne]

This was posted on (ahem!) another forum

"The Swedish federation has now banned the IB4200 cells with batch code "AZCWT". They have also specified that EP4600, EP4200 (with the black ring) and also Team Orion 4200 SHO is allowed in Sweden dispite not being EFRA legal.

As far as I can see of the info released they don't say anything about banning other batches of IB so I would guess all other IB4200 are allowed.

http://forum.radiostyrdbilsport.nu/p....php?f=2&t=749 "

Tried the link, but we didn't do Swedish at school...

[b4rs]

it may sound stupid, but if you cant use solder to join batterys what do you use?

[b4rs]

i have used a Venom Racing 3600 battery, and i have had this almost a year now, it still give sharp and ace performance, i love it and it still lasts till the end of the race as long as i dont break owt!

[DaHomie]

Originally Posted by b4rs

it may sound stupid, but if you cant use solder to join batterys what do you use?

First of all I think they are talking about the terminating cells. This means that everyone will have to use plugs from now on, instead of directly soldering the wires to the cells or to the L shaped battery bars.

Secondly, you could avoid the heat of soldering the cells together, just take your battery to a professional shop that can cold solder them together for you. Takes them about 5 minutes and most often the cost is very low.