[NCFRC]

Just an Idea to throw out ,,,, we all pretty much agree that heat is the enemy of batteries and when you take todays high capacity cells and cycle them at either 30 or 35 amps , they get some hot !!

To back up ,, I believe the matchers need to cycle at 35 amps to find the stongest cells and discharge to .90 for an accurrate runtime.

This is my thoughts ,, we all want to know the voltage of the pack at a certain time into the race and the IR rating of that pack to tell us the punch factor.

What I've been doing is this ,,, which happens to be with a GFX unit, Set your charge / repeak settings to your favorite amperage ,, Set your discharge setting to 35 amps ,,, but set your voltage cut-off to " 4.60 " volts and with IR on of course and put your GFX on cycle mode and start .

What you'll get is this ,,, a very accurate measurement of a high amperage discharge without overheating the pack " you have to remember that when these cells were cycled at the matcher they were not glued together and they dissipated heat alot better " , any decent pack will still run for almost 400 sec's and will be above 4.80 at the 300 sec. mark.

I measure my packs 300 sec average voltage by manually taking readings off the graph every 30 sec's to give me an average voltage ,,, 5 , 30 , 60 , ect.

The pack will stay much cooler with this shorter discharge cycle and give you all the information you need for any 4 or 5 min race.

If you really need to check runtime for an enduro or something , then use the .90 method but otherwise I feel your just cooking your cells !!

JUST MY OPINION , FEEL FREE TO COMMENT OTHERWISE :thumbsup:

 

[Racin Steve]

Just an Idea to throw out ,,,, we all pretty much agree that heat is the enemy of batteries and when you take todays high capacity cells and cycle them at either 30 or 35 amps , they get some hot !!

To back up ,, I believe the matchers need to cycle at 35 amps to find the stongest cells and discharge to .90 for an accurrate runtime.

This is my thoughts ,, we all want to know the voltage of the pack at a certain time into the race and the IR rating of that pack to tell us the punch factor.

What I've been doing is this ,,, which happens to be with a GFX unit, Set your charge / repeak settings to your favorite amperage ,, Set your discharge setting to 35 amps ,,, but set your voltage cut-off to " 4.60 " volts and with IR on of course and put your GFX on cycle mode and start .

What you'll get is this ,,, a very accurate measurement of a high amperage discharge without overheating the pack " you have to remember that when these cells were cycled at the matcher they were not glued together and they dissipated heat alot better " , any decent pack will still run for almost 400 sec's and will be above 4.80 at the 300 sec. mark.

I measure my packs 300 sec average voltage by manually taking readings off the graph every 30 sec's to give me an average voltage ,,, 5 , 30 , 60 , ect.

The pack will stay much cooler with this shorter discharge cycle and give you all the information you need for any 4 or 5 min race.

If you really need to check runtime for an enduro or something , then use the .90 method but otherwise I feel your just cooking your cells !!

JUST MY OPINION , FEEL FREE TO COMMENT OTHERWISE :thumbsup:

I like the fact that you're trying something different.

But, my experience lead me to beleive that most if not all the cells/packs issues out there are caused during charge not discharge. In my book, too much heat isn't that great of a deal during discharge. What I don't want though is too much heat resulting from overcharging a cell/pack.

I'll be testing 40A on my (soon to be released) TurboMatcher8s and if everything goes as planned all my cells will be matched at 40A come May.

Steve Salvas
TQ Cells

 

[NCFRC]

I really appreciate your reply Steve .

What's the maximum temperature after peak that you'd like to see a cell ? and at what temperature does the performance start decreasing ?

I still here of guys hitting their cells with 8-10 amps , thats got to be building heat and shortening the life.

Is IB back on track with their cells ? or what do you see from them in the future ?

So you don't feel that a full cycle @ 35 amps that produces over 170 degree's is that harmfull .

40 AMPS , WOW !!! I did see that CE unit on their website , pretty impressive.

We'll be back down to 1.20 cells before we know it.

 

[Racin Steve]

I really appreciate your reply Steve .

What's the maximum temperature after peak that you'd like to see a cell ? and at what temperature does the performance start decreasing ?

I still here of guys hitting their cells with 8-10 amps , thats got to be building heat and shortening the life.

Is IB back on track with their cells ? or what do you see from them in the future ?

So you don't feel that a full cycle @ 35 amps that produces over 170 degree's is that harmfull .

40 AMPS , WOW !!! I did see that CE unit on their website , pretty impressive.

We'll be back down to 1.20 cells before we know it.

A good all around cell temp at initial peak is 125F (for 70-75F ambient temp) ... I don't like to see 135F and above ...

Up to the recent IB4200WC date code (for Sept'06-March'07), it was relatively easy to notice if you were overcharging the cells or not because they would start leaking ... actually many cells leaked well before they would actually get overcharged. On the latest IB4200WC date code I worked on, cells wouldn't leak (Intellect finally fixed that) but yet again it was easy see the performance go down as the matchers were set too aggressive on charge settings (like too high peak detect settings) ... average voltage readings would go down as the cells were being overcharged.

The Intellect cells can be charged at a real high amperage without actually getting hurt ... the important fact to understand is that if you decide to "fill up" the battery pack at 12A you oughta make sure not to overcharge it because leaving that 12A for an extra 30 seconds is like overcharging the battery pack a full minute at 6A ... cell temperature (which is the resulting factor of cell getting near full capacity) is rising so fast at the end of the charging cycle it is relatively easy to "overshoot" the charging capacity ...

The new CE TurboMatcher has great features like setting charge amperage up to a certain cell temp then going to a different charge amperage settings for charge completion ...

Steve.
TQ Cells

 

[NCFRC]

Thanks again Steve ,

Can anyone buy matched packs from you ? I know in the past you liked to sell them thru a hobby shop and I do understand and applaud that as I'm in sales myself.

But if we don't have a hobby shop that we can get packs thru , can we get them dirrectly from you ??

I checked out your site and didn't see a section to purchase.

I totally believe in supporting your LHS ,,,, but if the effort isn't given or customer service just doesn't exist then then buy it on line !!

 

[Racin Steve]

Thanks again Steve ,

Can anyone buy matched packs from you ? I know in the past you liked to sell them thru a hobby shop and I do understand and applaud that as I'm in sales myself.

But if we don't have a hobby shop that we can get packs thru , can we get them dirrectly from you ??

I checked out your site and didn't see a section to purchase.

I totally believe in supporting your LHS ,,,, but if the effort isn't given or customer service just doesn't exist then then buy it on line !!

Yes, I will sell direct to anyone under specific circumstances.

You have a PM.

Steve.

 

[TOME57]

As a note, I have a six cell pack of 3800's. When I got them new I cycled them pack and one cell vent fluid on discharge. I disassembled the pack and it has been sitting around for over a year. This week I cycled the remaining 5 cells and a second cell vented fluid on discharge. The other 4 cells are ok. I charge my packs at one charge, 6 amps, .02, and dicharge at 30 to 5.4 volts. Single cells I use the repeak/discharge (this gives one charge and then discharges) 6amps, .01, 30 amp discharge to .90.

I use a Turbo 35 and a Turbomatcher.

 

[Racin Steve]

As a note, I have a six cell pack of 3800's. When I got them new I cycled them pack and one cell vent fluid on discharge. I disassembled the pack and it has been sitting around for over a year. This week I cycled the remaining 5 cells and a second cell vented fluid on discharge. The other 4 cells are ok. I charge my packs at one charge, 6 amps, .02, and dicharge at 30 to 5.4 volts. Single cells I use the repeak/discharge (this gives one charge and then discharges) 6amps, .01, 30 amp discharge to .90.

I use a Turbo 35 and a Turbomatcher.

Can you tell me at what exact time it started leaking during discharge cycle?

Steve.

 

[NCFRC]

Thanks Steve for taking the time to answer our questions :thumbsup:

 

[TOME57]

Steve - it was early in the discharge, I would say before the 100 second mark. As you can see, I don't think they were overheated from the Turbomatcher because I used the repeak/discharge which only charges once and the drop back voltage was .01.

 

[NCFRC]

I think Steve has a very valid point about overcharging is more harmfull than a high discharge ,,,,,, my only point is, how many races do you pull 35 amps for over 6-7 minutes.

I've settled on a 4.70 voltage cutoff on my GFX and still get 370 + sec to that point,,,,, figure your voltage average for 300 sec :thumbsup:

 

[ta_man]

I just ran a cycle on two new EP4200 packs (to establish a baseline). I discharged them all the way to .9V but only at 30A. The temps of the packs at the instant the charge completed was 122F, at the end of the discharge cycle one pack was 148F and the other 154F. That doesn't seem too hot to me considering that some 1500 packs I tested earlier in the day and discharged at 17A got over 160F.

 

[NCFRC]

For some reason the EP cells discharge cooler than the IB's . ???

Most IB cells will be 170 plus degree's at 35 amps.

The High Ir of your 1500's is whats causing heat there.