New Cell capacity shock.

[andys]

Just thought i'd share this, as I was pretty amazed.

After much dilemer about which cells to get, I plumped for some IB's from Storm Force Racing (a supporter of the forum :) ).

Anyhow, I ran them at the Bury regional, last weekend and I thought i'd discharge them today. I didn't fully charge my set for the final, I took them to 4000 and stopped as frankly the thought of them going 'Bang' scares me...

Today they were finally taken out of the car and discharged at 20amps and to my utter suprise they had 1970 left in them !
Amazing, considering they had being run in my X6 (2wd) and then stood for a week.

I guess most people already know there's loads left in them, but it was quite a suprise for me just how much.

[ashleyb4]

I run neils GP4300 that he had before he did the IB4200. And i can do 4 runs in my b4 with a 19t and 2 runs with a 12x2 in my b4 amazing.

A:p

[Northy]

I regularly only use about 2000mA in a run, but then again I am supposedly 'Mr Smooooooth' :cool: :cool: :cool:

Cheese helps.

G

[super__dan]

Rich Lowe and I ran packs of cells through our cars after the regional on Sunday, it's just brilliant how long you can get with 4200 cells and brushless. 15 mins nearly of full race pace. Motor warm but much cooler than a brushed motor would be after only 5 minutes.

By the time I had gone back to change cells it was cool enough to go again :)

[Northy]

I saw a chicken today.

G

[VONDUTCH]

I saw a chicken today.

G
.....And Barry licked it......said it tasted fowl.

[andys]

Interesting.

So, is there any advantage to 'fully charging' a set of IB's or will you still get the same performance from part charging, or charging to around 4000 as I did ? Will it make the cells last longer, stop any chance of them going 'pop' etc ?

[Northy]

People charge them to the max to get the highest voltage they can. But if you want them to last longer undercharge them a little.

And NEVER re-peak, if they have been charged a while and you feel the need to pep them up a bit, put 200 seconds of charge into them and cut the charge manually. They don't tend to re-peak very well, and that usually when they go bang if they are going to.

All the above is my own personnal opinion, I would rather people do not come back and flame me for it like usually happens on the 'When IB's go bad' threads........ :o :o

G

[super__dan]

I think that's good advice. Personally I have my delta on minimum on pulsar and millenium and don't repeak, my 4200's from last year going well as my practice packs.

[Richard Lowe]

My Demon IB's have stood up amazingly well, they're about 18 months old now, have been abused plenty and still have enough grunt to make my BJ4 wheelie with the LRP brushless :cool:

I had a bit of a bod moment at Bury regional forgetting to change cells (duh) and doing a second run on them no problem :)

I thought IB's were supposed to explode the third time you charged them :D

[neiloliver]

Thanks for the positive feedback Andy. Not peaking the cells will help with overall life as anything which prevents overcharge is a good thing. A lot of HEVs (Hybrid electric vehicles) which use NiMH (Rav 4 etc) get great overall life by never fully charging or fully discharging. You can also promote the cycle life of LiIon polymer by charging at a a lower voltage (4.1V instead of 4.2V)...

One one though on a previous answer, it's not the voltage during charging that is important.. people get too hung up about it saying "oh my battery is peaking, it's at 10V"... A higher voltage cell during charge can be (1) at a lower termperature or (2) towards end of life, both signify an increase in internal resistance which is a bad thing. What counts is voltage during discharge.

N