Dead Shorting, a Discussion
05-13-2004, 08:01 AM
#47
I have dead shorted it for 3 days already (more then 72 hours).
I read in some Jap mag that you could dead short the cells till the next time you plan on using it.
Don flame me for this.
I read in some Jap mag that you could dead short the cells till the next time you plan on using it.
Don flame me for this.
05-13-2004, 09:59 AM
#48
You can dead short till the next time you race if not more than a week or two. I've also noticed that with some cells they take a little to kicj start again. Some chargers show a reverse vlotage error or will false peak in the beginning, so you have tyo keep restarting it to make it work. Once it gets going, it deos give a little extra punch.
05-13-2004, 12:42 PM
#49
Actually, NASA deadshort for long term storage purpose. But that's with NiCd's and NASA also might have different performance needs, than we do.
05-13-2004, 04:21 PM
#51
NiCads and Nmh react differently to deadshorting.
05-14-2004, 05:27 AM
#52
Tech Apprentice
Do you dead short them as a pack or as individual cells ?
05-14-2004, 11:59 AM
#54
Originally posted by Cain
I dead short as a pack. Never tried as individual cells.
I dead short as a pack. Never tried as individual cells.
05-14-2004, 12:06 PM
#55
Originally posted by ratter
Do you dead short them as a pack or as individual cells ?
Do you dead short them as a pack or as individual cells ?
Then dead short as a pack.
05-14-2004, 04:52 PM
#57
Does your pack have to go RIGHT down to 0.00v? Just curious cause my Trinity 2.5 trays can't take them down to all 0's on my volt metre no matter how long I leave them on there. The closest I can get the packs is 0.06 :/ and I've been dead shorting that way for months now.
Sooooo, I'm THINKING it's okay, since my older pack numbers have been constantly improving or holding steady. Hope I'm right
Haven't shorted my Fukuyama's though, don't need to.
Sooooo, I'm THINKING it's okay, since my older pack numbers have been constantly improving or holding steady. Hope I'm right
Haven't shorted my Fukuyama's though, don't need to.
05-14-2004, 06:20 PM
#58
i got a pair of yok gp3300 packs awhile back, and since i really didn't know if dead shorting was better/worse, i dead shorted one (deans bulbs with cutoff, then integy tray, the 1157 light bulb across whole pack for storage), but not the other.
using this great little volt meter from radio shack that came with software to record voltage levels at settable intervals (1 second in this case), i "dynoed" my battery packs as new, then after 3 months (7 race days at 2 runs a day). i had lost fairly significant runtime on my shorted pack, about 43 seconds vs. my non-shorted pack (21 seconds). i did however have a very slight gain in avg voltage on the shorted pack, while the non-shorted pack lost a very small amount.
BUT...... after taking the output of the discharge curves, and plugging them into an excel spreadsheet, i found something really interesting. the shorted packs only had their voltage advantage for about the first 450mah of the discharge cycle, then the non-shorted pack was better. this leads me to believe (in this grantedly small test pool) that the dead shorting produces higher initial charge output as well as a stronger intial discharge voltage. also, i think the earlier cutoff time masks the shorted cell as having a higher discharge voltage since the discharge curve at the end is steeper.
using this great little volt meter from radio shack that came with software to record voltage levels at settable intervals (1 second in this case), i "dynoed" my battery packs as new, then after 3 months (7 race days at 2 runs a day). i had lost fairly significant runtime on my shorted pack, about 43 seconds vs. my non-shorted pack (21 seconds). i did however have a very slight gain in avg voltage on the shorted pack, while the non-shorted pack lost a very small amount.
BUT...... after taking the output of the discharge curves, and plugging them into an excel spreadsheet, i found something really interesting. the shorted packs only had their voltage advantage for about the first 450mah of the discharge cycle, then the non-shorted pack was better. this leads me to believe (in this grantedly small test pool) that the dead shorting produces higher initial charge output as well as a stronger intial discharge voltage. also, i think the earlier cutoff time masks the shorted cell as having a higher discharge voltage since the discharge curve at the end is steeper.
05-14-2004, 08:54 PM
#59
Ok, this is what I'm thinking of doing. I've got 3 old reedy sanyo 3000s, the old ones, pre-HV cells. And they are shot, no run time or punch, so I'll try dead shorting them. So first I'll put them on my Trinity real time 2, then once the LEDS go out, without removing the pack I'll plug in my 16A discharger, then remove the pack from the real time 2, and for an hour have them connected to the 16A discharger, then charge them. Is this the way to do it? I've never dead shorted any of my packs before, so even though these cells suck now if I can make them work that'd be good.
05-15-2004, 03:42 AM
#60
Tech Addict
Wheelnut
I would do it like you said except leave them shorted at least over night or a day or two. I doube it will help those packs, but let us know what you find. I understand, nothing to loose.
David Root
David Root