What do you do with your batteries?

[TC3-MikeB]

I am curious to see what people do with their batteries. How do you prepare them for a race day, do you charge them the night before then peak them at the race? Do you charge them all the way at the track and time it so they peak and then you race? What...? And when the race is over what do you do with them then? I know for nicads you drain them totally and then they are safe to store, but what of the NiMH's? After a race what do you do with them? Basically run me through what you do to/with your batteries for a weekend of racing.

Thanks, Mike

[KTRTS]

I charge mine before I go to the track (last one is charged about 30mins before I leave) :) I discharge mine (ni-cds, but just got a new set of ni-mh :cool: ) with a home-made bulb discharger.

[Pro3/nmt105]

I charge them at the track because the batteries perform best when they are still warm/hot after peaking. I discharge them after a race before I charge them again. I dont bother discharging durning practice because I run them until they dump anyway. After a day of practice or racing I discharge all of my packs and leave them until next week.

[Sparkey_STi]

I charge them at the track because the batteries perform best when they are still warm/hot after peaking. I discharge them after a race before I charge them again. I dont bother discharging durning practice because I run them until they dump anyway. After a day of practice or racing I discharge all of my packs and leave them until next week.

Hope your talking NiCd... as if you do that with NiMH... say goodbye to your batts!

[TC3-MikeB]

So pretty much with my nickel metals just drop them to .90v/cell and I can store them till next week? And if I plan on storing them longer just put a little juice in them first, right?
And as far as charging just charge them up that day? Will peaking them prior to the race be a good step if I charge before I go to the track?

[Sparkey_STi]

No. When your done with NiMH, eather leave them at what they are (unless they are low on vlts) if your going to use them within the next 2/3 days, or charge to 50%. NiMH SHOULD NEVER BE DISCHARGED! Except to cycle them.

[Exterminator]

If you are using GP 3300's at least once a week then discharging them to .90 and letting them sit until next week is fine. The current GP's are handled much like NiCd's of old. Also some people are even discharging them all the way down and dead shorting them for a few hrs to increase voltage output but lower runtime. This will shorten their life but give you more punch for stock racing.
Tim W.
Team BrOOd

[nitrofun]

No. When your done with NiMH, eather leave them at what they are (unless they are low on vlts) if your going to use them within the next 2/3 days, or charge to 50%. NiMH SHOULD NEVER BE DISCHARGED! Except to cycle them.

Contrary to this statement, many top level drivers dead short their cells. This increases voltage but decreases runtime. I personally have dead shorted cells, and have had no ill effects. This is all preference, and the rule with dead shorting NiMH died once the 2nd gen eration of NiMH cells arrived, they are now supposed to be treated almost exactly the same way as NiCD.

[Pro3/nmt105]

"At the end of the race day, discharge the pack down to .90 volts per cell. This equals to 5.40 for a 6 cell pack or 3.60 for a 4 cell pack. Let the pack rest until the next time you plan on using them. You do not need to place them on the tray. You can store it without any charge on these newer GP 3300. WARNING!: MAKE SURE YOUR CELLS HAVE COOLED COMPLETELY BEFORE STORING THEM IN A CASE OR BOX." -Fukuyama Racing

I have actually tried leaving them partially charged and discharging the night before. But they perform noticeably better when I leave them discharged, and I havent had any negative effects so far.

[TC3-MikeB]

So what constitutes a 2nd gen NiMH cell, and how can I tell if I have them? I have GP's with the rainbow wrapper. So now its ok to discharge NiMH's, and leave them as long as I plan on charging them back up within a week or so? And if Im going to store them for a while get them back to at least .90v/cell?

[Cain]

I have done the discharging techniques on both the rainbow and flat top shorty GPs. they work quite well, especially if you tray them for about 10 to 20 minutes before charging them.

A good example of this is yesterday I got a 12V battery that I wanted to test so I hooked up my charger and put my cheap 3300s from promatch on to charger before traying them. I used to use promatch's old instructions on maintaining the cells but I lovst alot of runtime because of this. since doing the discharge method, my packs came back up some and the voltage was better. Anyway, when I charged the pack It peaked out at only 2300mah. Before I was getting up to 2900mah or even 3000mah on these old packs. Plus the cells were hot. never had that issue when I trayed them.

So in short, make sure you tray them to equalize the voltage when you charge them up.

As for dead shorting, I run 19 turn spec class, so voltage here is more important than all the extra runtime. I have deadshorted my best packs and they put out better power than I ever had. they still even charge up to 3900mah.

[Sparkey_STi]

Ok, so whats "dead shorting"? Im going to be running 19t spec, and it sounds like thats the way to go.

[Rog]

Deadshorting is when you connect the pos to the neg after all the cells have been brought down to 0.00V. I don't know all the technical stuff about doing it but I do know that it has worked for me.

[Sparkey_STi]

can someone tell me how to dead short properly and what not and how to maintaine the batts after i dead short them?

[Cain]

SMC has some good info on this, i believe there site is here:

www.smc-racing.com

Basically what has been working for me as I race everyweek is that after I am done with racing, I put my batteries in a tray discharger like the Octane 2, bring them down to 0 Volts ( usually leave them for about 10 to 20 minutes AFTER the lights go out ) and then since I use powerpole connectors I have a jumper set rigged to go between the two, if you use powerpoles and have the wire long enough, just hook them together, make sure you leave them in the discharger while you do this. Once that is done, you can take it out. Since I run once a week, I leave them site like this till I need to race.

Some people cycle them mid-way through the week and that works great for them too.

You can also use a piece of solder between the positive and negative ends.

[Cain]

another thing you can do if you run deans is take an extra set of male connectors, run some solder between the two ends and then plug it in, that should work too. I believe the advantage of using solder is if there is a problem the solder will burn up first, breaking the connection.

[TC3-MikeB]

What again are the positive and negative aspects of dead shorting again? And do you have to have a tray to do this?

[TC3-MikeB]

And yes I meant to say again again.....I wasnt paying attention to the first again:)

[Spoon37]

only diff for me with NiMH is I dont discharge them before charging. I am using GP 3300's tho.....

you are supposed to store them part charged as previosuly stated, but I dont bother once they dump for two reasons: #1. they get cycled regularly(so dont see this as storage), #2. their voltage never seems to get all that low after running....

I'm told sanyo and panasonic NiMH's are more sensitive to the way they are treated.......

[junior081]

i usaully charge my batterys at the track at 5 amps and they usaully get done about 10 minutes before the race so i put them on the fan to cool them. then hit them at 7 amps for about 1-1 /2 minutes right b4 race.When done using them i discharge to 5.4 until next weekend. usaully charge then discharge once about 3 hours b4 race day.I usually tray my batts. once a weekend.

(gp3300 yellow top)

[cardboard]

No. When your done with NiMH, eather leave them at what they are (unless they are low on vlts) if your going to use them within the next 2/3 days, or charge to 50%. NiMH SHOULD NEVER BE DISCHARGED! Except to cycle them.
wrong! several sources tell me that leaving gp3300s on an equalizing tray with a 0.0v cutoff per cell yields great results.
leave them with a 50% charge, and you will lose plenty of runtime within the next few months.

[junior081]

wrong? everyone has their way of doing it. i have heard of problably 50 ways to treat your 3300's. i tray mine and then recharge for a few minutes and then discharge back down to 5.4 to sit for the week.thats just the way i like doing it.some ppl even leave there cells on the tray all week.

[cardboard]

it isn't neccessarily wrong, but by leaving them at 50% charge and letting them sit for a week you are killing your runtime and not gaining anything.
i just get alittle irritated when someone gives advice while having no knowledge of the topic. never discharge nimh batts! what garbage!

[Sparkey_STi]

i just get alittle irritated when someone gives advice while having no knowledge of the topic. never discharge nimh batts! what garbage!

Sorry bud... sounds like you dont know what your talking about... You discharge them to cycle and condision them. And (i didnt know this, but do now) you discharge to dead short to gain more punch for 19t spec racing. So sounds like your irritated at yourself, and when your irritated you shouldnt type. :p

[cardboard]

idiot. you discharge nimhs just like nicds. maybe down to around 0.3v per cell.
sounds like i don't know what i'm talking about?!?think before you type!

[TC3-MikeB]

Calm down children there's no need to get fiesty. Cardboard, what sources are you getting your facts from? And why would leaving 3300's with some charge in them be "killing" their run time???? Dude...there's no reason to call names, ok.

[gizmoguy303]

Actually discharging the GP3300's to store them is a good thing to do. I just started doing this and my packs seem to be working better, and longer. Other trustworthy sources suggest this method of storage as well:

SMC Racing:
"After the race discharge the pack down to .90 volts per cell. This equals to 5.40 ( 6 cell ) or 3.60 ( 4 cell ). Let the pack rest until the next time you plan on using them. Don't put them on a tray."
Link (http://www.rctech.net/forum/showthread.php?threadid=31010)

Fukuyama Racing:
"At the end of the race day, discharge the pack down to .90 volts per cell. This equals to 5.40 for a 6 cell pack or 3.60 for a 4 cell pack. Let the pack rest until the next time you plan on using them. You do not need to place them on the tray. You can store it without any charge on these newer GP 3300. WARNING!: MAKE SURE YOUR CELLS HAVE COOLED COMPLETELY BEFORE STORING THEM IN A CASE OR BOX. "
Link (http://www.fukuyamaracing.com/page3.html)


It seems to me that when you store the cells discharged it takes less time for them to "wake up", whereas, when stored charged, they need a few cycles before they start performing well again. Just my take on it. Hope this was informative. :D

[cardboard]

Calm down children there's no need to get fiesty. Cardboard, what sources are you getting your facts from? And why would leaving 3300's with some charge in them be "killing" their run time???? Dude...there's no reason to call names, ok.
if you visit a more racing oriented forum(not a knock on this one), then you will see that many racers there have complained about runtime loss with GP3300s. NiMHs suffer from the memory effect also, although it's nothing close to nicd cells. the runtime loss problem was solved by discharging a bit lower voltage. NiMH should be discharged after a run, just like NiCDs, but not to the extent of nicds. i would say discharge them on a tray to around 0.3v per cell.
many pro and sponsered racers do this. it increases voltage, but you will lose runtime just from discharging it that low. however, your runtime loss will be about 1/3 of what it would be without discharging them.

[TC3-MikeB]

So you are saying that by discharging to 0.3v/c I will keep a higer runtime longer than if I discharged to 0.9v?

[TC3-MikeB]

And how would I judge these voltages with a bulb discharger?

[cardboard]

yup, on the runtime.
you can't judge this on a bulb discharger, i guess if you really wanted too, you could buy a voltmeter and watch it till it gets to 1.8v pack=roughly 0.3v per cell.
buy an integy booster2 discharge tray, it has a 0.0v cutoff, but it also has a row of led status lights so you can see the per cell voltage, it also equalizes, overall much better for your batts then a bulb discharger. will lengthen your batts life in the long run.

[gizmoguy303]

If you want to use your bulb discharger to discharge your packs to 5.40v, go to your LHS and pick up an auto cut-off unit. You wire it inbetween your battery and the load (bulbs). When it senses that the voltage is 5.40v, it cuts the power. They cost $10 to $20 I believe.

[Cain]

If you only have a tray that doesn't let you measure the voltage level or set it to cutoff, I was advised that you can bring them down till just as the light goes out, disconnect that cell and it will be fine.

Personally, I discharge my non shorted packs to 5.4V and leave them sit. When race time comes, I then go ahead and tray them for about 20 minutes or so, then charge. as I said before, these packs suck, as they were only doing about 2300mah at one time, now they get close to 3000 again.

[junior081]

you can discharge all you want.. it wont hurt them.

Mike boylan who races pan cars and also does the race "mike boylans" snowbird nats. leaves his gp3300 on the DISCHARGE tray all week.

there are many opinions on this subject.
do what you think is right and i will do what i think is right..

[viper2002]

Quick question - I know for maximum performance cells should be fresh off the charger - does this hurt them at all? By logic it seems like the cells wouldn't be able to "rest" like it is recommended after a discharge. Wouldn't the chemical reaction still be going on if you took them off the charger?