I've read many guidelines on battery prep for races, and am getting very confused. Do I charge at 5 amps? 8 amps? or will 8 amps short their lifespan?

Is it more important to fully discharge them than the rate of charge, should you deadshort the batts? I think deadshorting is a very heated issue right now. Are theRE any official rules from the lead battery makers on ni-mh batts.

Is their a diiference in battery care for 4 cell, 6 cell. For modified or stock? OH MY ALL THE QUESTIONS>>>>>..lets start some info rolling and get ourselves a defining thread on total battery care.

Try this older thread for some battery info.

http://www.hobbytalk.com/bbs1/showthread.php?t=85846&page=1&pp=15&highlight=xipp

That's a good thread... Although, from what I have seen in review of that thread and from talking with lots of folks about charging batteries... There are as many 'ideal' ways to charge a pack as there are people who try to find the ideal way...

I have packs that set around for about 8 months, that I recently started using again, and they perform as good or better then they did last year when I ran them. THey even out proform some new packs I have.... so there goes one theory that you can't let packs sit for that long...

Anyway, I'll spare you all my 'secrets', since they really are just my own personal ideas and methods... I did recently come up with what I think is the best way to evalute a pack on a T35 or simmilar discharger/cycling device... Charge all packs the same way while evaluating, wait the same amount of time before discharge, etc... Document how many seconds it takes before your voltage drops 1/10th of a volt for the pack... Then look at the voltage curves for the amount of time you typicaly race...

Say you have the following packs...

NAME - AIR ADV -seconds to volts- 5 4.9 4.8 4.7 4.6 4.5 4.4
P1 - 11.2 4.72 ------------------ 35 60 160 235 285 315 335
P2 - 11.7 4.68 ------------------ 25 45 _90 200 285 335 365


P1 is a year old pack, the total discharge time is under 400 seconds, P2 is new this year and has a total discharge time of like 430 seconds... P1 has voltage above 4.8 volts for the first 160 seconds, while P2 drops below 4.8 volts after just 90 seconds. Or said anotheer way... P1 has a voltage of atleast 4.8 seconds for nearly twice as long as P2 does. At 285 seconds both packs have the same voltage, after that P2 has bette voltage. For four minute oval racing, I suggest that P1 is a much better pack then P2 is. Now even based on the Actual Internal Resistance (AIR) and Average Discharg Voltage (ADV) P1 is beter then P2... but not by all that much... To me the voltage level at number of seconds is a much clearer picture of which pack is better...

Many people perticularly matchers are now saying... "don't cycle your packs", you just waste the good runs, etc... however you have to do it now and then to know what you've got. Just make sure you get as much documentation as you can when you do it. I personaly save the ASCII/TEXT graphs that the T35 can spit out, they tell you alot of valuable information... Not sure what the GFX can do, since I don't have one.

can o worms opened up now,lol.

can o worms opened up now,lol.
http://www.promatchracing.com/batteryins.htm

Not sure how they came to their conclusion about storing them with a charge... more charge for longer storage... as I showed above.... that P1 was/is a pack that I purchased early in last year's winter season, I used it the whole year, probably like once or maybe sometimes twice a week. It sat from say last April to this February, I started using it once a week untill two weeks ago when I cycled it to get the numbers posted above. P2 was a new pack buit two weeks ago...

I will say that I pretty much used the method ProMatch explains with P1. That is I would discharge it to 3.6 volts after each use, then put it back in the box. Then the day of the race I would discharge each cell using a Trinity Realtime tray... I'd just leave them on there for anywhere from 5 to 60 minutes before I'd charge them. I did this because I was skeptical and/or worried about dead shorting and thought this was a reasonable compromise.

I'm dead shorting my newest packs, simply because they have WAY more runtime then I'll ever need, and the voltage is not very good by todays standards, so I figured I had little to loose.

Having said all that... I do belive that your matcher should be the one telling you how to treat your packs. They suposedly are the ones that have done the research, and should know what's best for the packs... but then, well you'd better trust your matcher is doing a good job testing and evaluating various techniques...

Good point dyno

http://www.smc-racing.com/ Goto SMC charging.

http://www.hobbytalk.com/bbs1/showthread.php?t=97825
look at post #11 and #12.

I personally feel that dead-shorting, charge rate, and storage is a personal choice. Its your money so do it how you want. Whichever way you choice to do it, the only true good advise comes from your car. The method that you used when you ran your best race will be the method you'll tend to stay with. Every person and matcher has their own opinion. So I don't think there is a right or wrong way. As long as sparks and flames aren't coming out of the cells, then you're doing ok.

SPC (www.specpointbatteries.com) has some battery care info on his site also.

Pro match has some real good ideas

Qual_shen - As OvalmanPA suggested, please check out my article on Battery Care (http://www.specpointbatteries.com) . If you have any battery related questions please don't hesitate to contact me.

Tom

I have ran Tom's packs for awhile now and you will not be disappointed in them. First they are REAL NUMBERS AND THIS IS VERY HARD TO COME BY NOW. I would run a pack of his 1.17s before i would ever think about putting at 1.19 from all these other companies. Cycle your packs and see if they come out to what the numbers say. Whats printed doesnt mean S#*t if they dont cycle to that!!!!!!!!!!!!!!!!!!!!!!!! Give him a try you will not be disappointed.
Matt Erich

Qual_shen - As OvalmanPA suggested, please check out my article on Battery Care (http://www.specpointbatteries.com) . If you have any battery related questions please don't hesitate to contact me.

Tom I lloked at the battery care section and it confirmed most of my thoughts. Just wondering what discharger to use. Looks to me like the best one for me s the novak smart tray as I do like to walk away, and tend lapse into other projects. any thoughts?

Qual shen. I personally have the smart tray.and like it alot.Since you can set it for where you want the cuttoff voltage to be. as well as dead short batts. :thumbsup:

Slider , Be carful of the NOVAK Smart tray when in DS mode it does not take the cells all the way down to ZERO ......Check it before you deadshort....


ROCKET

any thoughts on dead shorting the GP3700's ???

NIP No idea///Did here something about 3300gp being deleted very soon .....I will call Terry Brownm and se what he says....

ROCKET

the only way you will get a cell to identically match the label is to cycle each cell individually?? your numbers are never going to match labels as a pack! but they should be close, once you add bars and solder you add resistance! there is just no way around it !!! that is a fact, i worked for a local company when it was here in st louis i have assembled hundreds of packs and no matter what methods we used your numbers are always gonna be off!!!!!hope this helps??