Hey Everyone

I have a question about 4200 batteries. How do you know if you have a dead cell without buying a $400.00 charger. I charged my JBR cell 4200mah battery yesterday and it peaked out at 6.14 volts does that sound right.
One side of the pack (last 2 cells) where about 180degrees and the other 2 cells where 110 degrees. Is that a sighn of dead cells or is there a way to find the dead cells. I would like to get a spintec charger but why pay 500.00 for a charger just to race for fun. Any help would be great.

Taylor

A cheapo multimeter from most anywhere will show if any of your batteries are bad. If you charge the pack then check each cell individualy the lower voltage cells probaly have a issue.

Hey Everyone

I have a question about 4200 batteries. How do you know if you have a dead cell without buying a $400.00 charger. I charged my JBR cell 4200mah battery yesterday and it peaked out at 6.14 volts does that sound right.
One side of the pack (last 2 cells) where about 180degrees and the other 2 cells where 110 degrees. Is that a sighn of dead cells or is there a way to find the dead cells. I would like to get a spintec charger but why pay 500.00 for a charger just to race for fun. Any help would be great.

Taylor


Do you equalize your cells before charging?

Get a volt meter and check the voltage in each cell. If your below 1.2 volts on either one of the cells, that cells is on it's way to being dumped in a couple days.

Go to www.tqcells.com there are good tips on battery maintenance and recommended chargers.

If you shop around in the S&S section you can get a good deal on a Stealth charger and an Integy 0-30 or a Trinity DPD.

just throw a voltmeter on the individual cells before charging each week... If one of the cells reads 0.0 or close to it...there is your dead cell..another telltale sign is when running a cycle on a pack at 35 amps you will notice the voltage on the back end take a huge dump..usually average voltage looks OK but your runtime will be waaayyyy short... Ive gotten to the point when cycling batteries I can tell if a pack has a bad cell by just glancing at the discharge graph... Seems like packs with a dead cell 35 amp with 3.60 cutoff...when you get to about ~4.5 volts the pack will almost instantly Fall to the 3.60... where a pack with 4 good cells ramp down gradually to the 3.60 cutoff. the more dead cells in a pack the sooner/faster that happens..

Ive gotten to the point when cycling batteries I can tell if a pack has a bad cell by just glancing at the discharge graph... Seems like packs with a dead cell 35 amp with 3.60 cutoff...when you get to about ~4.5 volts the pack will almost instantly Fall to the 3.60... where a pack with 4 good cells ramp down gradually to the 3.60 cutoff. the more dead cells in a pack the sooner/faster that happens..

If you dead short that is normal behavior.

To me "dead cell" can mean two different things. Some people refer to cells that have self-discharged down to 0 as "dead cells". That is how they are being referred to above. More often than not there is nothing wrong with these cells. Just dead short them and you're in business.

Personally I refer to a "dead cell" as one that just flat out no longer works. How do you know if you have one of these? Your car tops out at about 12mph and when you put the pack back on charge it shows 4.XX volts.

when i was charging my pack one half was at 185 degrees and the other was at 110degrees. I was charging them at 6amps on my Pitbull i had the Peak Detect at .192 I figured that sence the temputers where diffrent there may be a dead cell.

Taylor

How do you dead short????

I just bring my packs down to 0 volts on my 0-30, then charge them.

If you dead short that is normal behavior.

To me "dead cell" can mean two different things. Some people refer to cells that have self-discharged down to 0 as "dead cells". That is how they are being referred to above. More often than not there is nothing wrong with these cells. Just dead short them and you're in business.

Personally I refer to a "dead cell" as one that just flat out no longer works. How do you know if you have one of these? Your car tops out at about 12mph and when you put the pack back on charge it shows 4.XX volts.

My deadshort packs dont fall anywhere near as soon or hard as one with a dead cell...the ones with a dead cell that cell gets HOT and the pack seems to peak late**when the pack is a lot harder...But the cycle has the same effect.. My dead shorted packs go like 370 at 35***packs from last year...***where the ones with a dead cell might go...180-240..

then after sitting for a while when you put the pack on the cdxd2 the bad/hot cell shows 0 volts..which is usually a sign that a cell has self shorted.. Whenever I buy a new pack I put them on the MM unit and check..Ive had a few "NOS" packs that had more self shorted ones than good ones..


However I do understand what you mean by misinterpreting the results... But If you have a pack that only goes 240 at 35 amps all the deadshorting in the world wont bring that back to life..

Sorry Kenwood i dont understand????

BAsically to speak in generalities lets say pack 1 before charging cell1 voltage says 1.3 cell 2 1.2 cell3 1.3 cell 4 1.2... I equalize the pack then cycle it using a GFX 35 amps 3.60 cutoff.. when I get done say the pack says avg voltage of 5.05 and runtime is 410 seconds... Then Pack 2.. same age...Same label numbers... I put them on the meter and I get the following.. cell1 1.2 cell2 0.0 cell3 .05 cell4 1.3.. Allready suspect.. I usually charge the pack for 300 sec.. then let them sit a little while then equalize them.. then cycle on GFX 35 amp 3.60 cutoff... The pack with dead cell usually has the bad ones get waaayy hotter than the good.. and it struggles to peak.. the results end up something like 4.92 av voltage 210 run time... usuallly the I find that disassembling the pack and replacing the 0.0 cell that got hot brings all the numbers back into check.. Then when I try to charge the cell individually the cell acts like its taking charge but doesnt hold it.. the pack when discharged lasts just a few seconds...


a deadshorted pack same scenario I usually have like 360-380 run time...But average voltage is more like 5.10***given the same generic example..

We were messing with old packs at the BRL race during practice...We wound some real winners.. One of them DUMPED in 13.5 practice at about the 3 min mark.Car was off from lap number 1....LOL

I went through this this past week with my batteries.. I have 8 IB 4200 packs. 2 of them had not been run since new years day, and the other 6 had been run one time since new years but sat for 4 months.. I had at least one to two cells in each pack reading 0. I took all of them put them on the tray and dead shorted them.. I charged them up until they false peaked, discharged them then trayed them again. I re dead shorted them, then they all took a full charge the next time.. I ran them all one time.. I cycled them this weekend, and all of the packs averaged 4.90-5.10 voltage at 35 amps when ccled.. They only had about 350 sec of runtime but they should rip.. I was worried i was going to have to buy some new packs. Im on a low budget, and this process worked really well.. All of the cells that read 0 no longer show up as dead..

My deadshort packs dont fall anywhere near as soon or hard as one with a dead cell...the ones with a dead cell that cell gets HOT and the pack seems to peak late**when the pack is a lot harder...But the cycle has the same effect.. My dead shorted packs go like 370 at 35***packs from last year...***where the ones with a dead cell might go...180-240..

then after sitting for a while when you put the pack on the cdxd2 the bad/hot cell shows 0 volts..which is usually a sign that a cell has self shorted.. Whenever I buy a new pack I put them on the MM unit and check..Ive had a few "NOS" packs that had more self shorted ones than good ones..


However I do understand what you mean by misinterpreting the results... But If you have a pack that only goes 240 at 35 amps all the deadshorting in the world wont bring that back to life..

Very true. I misunderstood your description. I have packs that go from 4.50 to done in 5 seconds or so that are fine, so that is the part I didn't get. Yeah 240s is definitely a junk cell that you can do nothing about.

Very true. I misunderstood your description. I have packs that go from 4.50 to done in 5 seconds or so that are fine, so that is the part I didn't get. Yeah 240s is definitely a junk cell that you can do nothing about.

Eh after rereading what I posted I can see where it could be misunderstood..I never liked doing book reports in school...LOL

so what do you think i should do. Discharge them agian and then cycle them.

Thanks Taylor

Here's a question that I haven't seen being asked yet. Is a deadshorted battery any safer sitting there alone than a half or fully charged one? Either way, I suppose the chemicals inside are still churning, right?

Well i got me a volt meter today the cells show the smae as my regular good race packs so i think its good to go.

Taylor