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View Full Version : How do I test cells.


referjohn
2014.12.04, 02:34 PM
Well I want to know how to test cells. I have 3 multi meters.
Whats a good way to know your resistance?
I set my meter to OHM right?
Do I test it full charged, or half charged, or discharged?

Is there a certain reading ( OHM VALUE or Resistance) # that's within
Specs that I should be looking for?

And what is the Bad reading ( OHM VALUE or Resistance) # that falls
Out of spec and the cell needs to be discarded.
Thanks in advance
John

imxlr8ed
2014.12.04, 11:37 PM
Measuring Battery Internal Resistance: http://youtu.be/HZUDFcOSe48

Best answer I could find.

Honestly, I treat my cells like dirt. I used to be a bit obsessive about my sets (though not nearly as much as some in the hobby) but then I just kinda got lazy with it. New cells are always better than ones that are 2 or 3 years old, try to keep sets together as much as possible but if they start to feel weak, I feel it doesn't really hurt to just mix them up a bit. Usually I'll just keep an eye on my charger and wait to see which one out of a set takes longer to charge, I'll pull that one out of that set and put it with the other weak ones. Then I'll take the ones that charged the quickest and keep those in a pile. Then I just make new sets from those piles, weak sets and strong sets.

I know, not very scientific and probably wrong way to go about it but I have run fresh bought matched sets in the past and any advantage they may have given me was easily erased by one or two driving errors. Some of my cells sets are more than 2 years old but I did just give in and get around 8 new sets just to spruce up the battery box.

I'm sure others will be along soon with much better methodologies for you to utilize.:D

referjohn
2014.12.05, 10:19 AM
Thanks for your input, let me also say....I forgot to mention
I am running over the counter Duracell 800s or 900s, so nothing fancy there. I love the real world truth about driver errors negated top batteries.
Agree.

And my charger is also a doozy...... a OTHC,Duracell 30 +\- charger
I have had since my mr01 .
I don't race.

Thanks again

arch2b
2014.12.05, 02:33 PM
i'm with ed. lucky to get my cells charged before the next race day... if i'm feeling really ambitious, i cycle them before the next race day. other than that, i just charge and go. i know proper care and sorting can make a difference but in the end, i just don't have the patience, energy or desire to cater to cell management with my valuable free time. my priority is to keep my car moving on the track vs. making sure my cells are matched, cycled, etc.

imxlr8ed
2014.12.05, 03:49 PM
I linear charge 4 cells at 1.2 amps on my PN chargers, and then I have Duracell 30* min chargers to charge cells individually at 1.7 amps. I have the 1 amp discharge function in the PN chargers and I also have the PN discharge trays.

My favorite discharger is the three automotive taillight bulbs soldered together and a Radioshack AAA tray for 4 cells. I used to have a Reedy cutoff on it but now I just watch the bulbs until they are just about completely dim. Dumps the set at around 3 amps.

Now if I was running twice a week and my cells were constantly being cycled like in the old days, I'd be paying more attention to my battery scenario but for now, it's not totally necessary.