Originally Posted by addicted
No attack at you Charles
I have been reading this thread and no matter what people say you are mind stuck on these Sanyo cells. If you are that happy with them by all means run them . Your way of thinking i am sorry is old school.
Another reason as to why cells these days are matched at 30/35 amps is because this is the AVERAGE current drain on these cells in race conditions.{This could peak and can peak in excess of 100+ Amps(mainly mod and high end stock.)} Sanyos want substain this current drain.
IB cells are one of only a very few that can actually discharge up to 250 amps.Try that from a sanyo.
Do you really think Matchers just pick discharge and charge numbers out of the air with out first consulting Cell manufactures ,Do you also think matchers would be prepared to loose hundreds of dollars haveing cells fail to have to cover this expense themselves.I dont think so..DO YOU..
Sorry Charles Dont take personal offence at this post It isnt my intend
Tony
You are probably correct about my old school attitude. But sometimes the old school methods are better. I am not saying this time. But sometimes.
I think you need to do some maths on your 250 Amp discharge current. Using a realistic Internal resistance value calculate what the cells terminal voltage will be at 250 amps. The car will be almost stalled.
I know they are matching at 30/35 amps. The problem is that during racing the current is not CONSTANT at that value. It goes quite lower and a higher. Which means during the lower periods the cell has time to cool down a bit.
When matching at 35 amps contant current it's just too much for the cells to handle. They get too hot internaly and can be damaged.
As has been said by one of the matchers the IB4200's have a VERY high failure rate during matching. Surly that tells you something about the methods being used to match cells. Their is NO reason at all to match them at that current level. A Cells Capacity is the same at 10 amps, 20 amps and even 30 amps. So even matching at 10 amps will still give you a matched set. And it will not damage the cell at all.
I am sure they dont pick numbers out of the air. The problem is all the "tricks" they use to get those numbers. Any normal person testing the cells after they have recieved them will NEVER get the same results as printed on the paper. And as I have found recently you will be lucky if all the cells are still %100 capacity when you do get them. Cells can weaken in a few hours after being stressed highly.
No offence taken. And I hope none given either
Charles