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Old 02-15-2005, 01:06 PM   #16
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Quote:
Originally posted by primusblowsgoat
theres just too much you can do to batterys, who really knows whats good and whats not, you just try stuff and see what happens right? if it works for you and your happy with it who cares right?

...

theres too much knowlege in this and not enough time or money to absorb and use it all
You're so right.... It would take a lot of money and time to get some excat facts...

I've been wondering, why so many people with different methods seems to get good results? Maybe these GP-cells are much more tolerant, than we usually think they are...

Anyway, about cut off voltages: When discharging a PACK, it's important to not go too low, because of the risk of cell reversal.

But at higher discharge rates (20A+, maybe even 10A), there's quite a huge voltage drop due to interbal resistance in the cells. So after a discharge at lets say 20A, there's actually quite some juice left in them. So I dont believe it matter much, whichever the cutoff voltage is 0,9 or 0,8 volt per cell - in both cases there's juice left in them.

I've been using 20A discharge with 0,8 volt cut off for around a year now, and I havent experienced problems yet, my packs still performs great. And no, I'm not sponsored, and my budget aint excatly unlimited

But at low discharge rates, a few amps or less, the cut off voltage should be higher than 0,8 to avoid cell reversal.

About equalizers; It's important to note, that the discharge rate matter here; A high amp (5 amp or so) in conjunction with a relay cut off, and a 0,9 volt cut off, will result in there's still some juice left in them.

While a slower EQ (less than one amp) and 0,9 volt cut off, will draw more juice out of the packs, especially if the cut off aint implemented with a relay like type.
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Old 02-15-2005, 01:07 PM   #17
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Quote:
Originally posted by picco007
What I can tell you is that getting your cells hot while charging will deteriorate them faster. I usually lower the delta volts to keep the cells from getting hot. If they are not getting warm then you will have to raise your delta volts. After your done with them for the day discharge them to .9 per cell and leave them alone. That is what I have done....tray them to equalize to .9 per cell right before you charge next race day......
I'll second this.
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Old 02-15-2005, 01:07 PM   #18
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Yes you have to equalise to get best performance. The studies have been done, you definitely get more run time (~30 seconds) if you equalise all the way and leave it there. I personally don't dead short, I just don't like the idea of it and I do know that equalising works very well indeed. I don't run cells more than once in a day, I think performance goes down quite a lot and I think it is not good for the cells.

I do not know what the long term effects on the cell is with equlising, I don't knwo that it is too bad if there is an issue, there has been no studies that I know of so far.

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Old 02-15-2005, 01:08 PM   #19
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Quote:
Originally posted by RCNitroDude999
Im still new to electric as well, and i recently bought a couple of 3300 matched packs, and when i charged them they only peaked at around 3300-3400 mah, but after putting them on a Integy Indi Zero-Equalizer and leaving them on there untill the lights went out, the packs peaked at close to 3800mah. I also use a 20amp discharge with 0.9 volt cutoff.
This is quite common. I tend to say the capasity difference while discharged, will be much less...
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Old 02-15-2005, 01:11 PM   #20
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Quote:
Originally posted by crimson eagle
I do not know what the long term effects on the cell is with equlising, I don't knwo that it is too bad if there is an issue, there has been no studies that I know of so far.
I'm quite sure the pack will last longer, while equalized, because you ynchronising the cells, and thus prevent that one cell will differ more and more over time. Of course, at some point, the weakst cell will die first anyway, but by equalizing, you prevent that that particular cell will be overcharged (or overdischarged) again, and again, and again....
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Old 02-15-2005, 01:12 PM   #21
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Quote:
Originally posted by crimson eagle
I don't run cells more than once in a day, I think performance goes down quite a lot and I think it is not good for the cells.
Usually, I also only runs my packs once a day. But if I run the same pack twice, it'll be much more punchy the second time. I believe at the cost of run time
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Old 02-15-2005, 01:20 PM   #22
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what is cell reversal?
what is dead shorting?

i hear these terms all the time but dont understand the fully

why, when a battery is discharged down to say .9 does it rebound back to 1.25 or whatever?

whats the relation between volts and Mah, the mah gives us the runtime right? and the volts are the punchiness?

whats the differnce between a non rechargable alkaline and a nimh for example?

anyone got a website with indepth descriptions of whats in side these 80 dollar battery packs we are buying?
so i can understand more what im doing when im doing it, when im charging a pack whats really going on?
when im discharing a pack whats going on there?

this intrigues me, i want to know more, cause at the moment im just doing this stuff cause its working and because someone told me to do it, i dont know why or whats really going on inside this little battery
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Old 02-15-2005, 02:11 PM   #23
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I deadshort my batteries with great results you don't have to worry about cycling or equalizing before next charge the equalizing is done before deadshorting

I let them on the tray (indi ocatane-2) for over four hours before installing the jumper from (+) to (-) store them until next race day just get the jumper off and they will be hungry for voltage keep in mind I run 7T to 9T motors although it is not recommended when you run mod they still go the distance (5min) and show great punch. that's my personal experience with smc batteries.
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Old 02-15-2005, 02:51 PM   #24
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Mr. Shookie,

How do you like your Integy discharge tray's you mentioned at the beginning of the thread? I'm interested in buying some for myself and would like to know more.....How long does it take to get down to zero volts? and so on.

thanks
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Old 02-16-2005, 10:10 PM   #25
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Old 02-16-2005, 10:24 PM   #26
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i have sumthing to add to this discussion,

i have a tray here but each globe is only rated @ 2.2amps i think... its an integy tray with a black top and a green base.. called an INDI activator

is this of much use??? one of my chargers Yokomo BMS discharges @ 20amps, but is it really worth equalising on this tray or not???

is there anyway to modify this tray to discharge @ more amps??? i dont really wanna go spending another $50-60AUD on a tray if not more

please give me any advice you can

thanx

robbie
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Old 02-16-2005, 11:21 PM   #27
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Quote:
Originally posted by picco007
Mr. Shookie,

How do you like your Integy discharge tray's you mentioned at the beginning of the thread? I'm interested in buying some for myself and would like to know more.....How long does it take to get down to zero volts? and so on.

thanks
Hey picco-
I actually have the INDI Zero 6S and I like it ALOT better than my Novak ST. With this I don't have to worry about polarity, it's bi-polar (of course), it's small, 6A discharge rate, no chance for cell reversal and it's stackable. After the bulbs go out, leave it on the tray or take it off. If you choose to leave it on the tray, just be aware of the increased chance of false peaking when you charge the next time. I think you have to worry about this with any 0.0v discharger though. You're going to definitely get more cap. into your cells this way if that's what you're after. I figure the only time I'll use .9v is when I'm storing my packs; otherwise it's 0.0v before I charge and race. Oh, to get by the false peak issue just set-up your charger using temp. charge and or higher del.V. I'm learning all this myself so any and all confirmation on this is appreciated ...

- JB
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Old 02-17-2005, 06:06 AM   #28
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I have a question about a pack. Its about a year and a half old and bought it off of a racer last year that was quitting. It started getting pretty hot when charging and so I stopped the charge and let it cool. Didn't run it and then discharged it that night. Put it on a tray till the lights went out then tried to charge it again after it was cool.

On my LRP when I first put a pack on I think it says around 5.~ some odd volts and then climbs from there.
This pack started at 10 volts and kept climbing till the charger shutdown at 13. I havent even thought about using the pack because I assume its toast.

Just wondered what exactly it was so I will know in the future.
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Old 02-17-2005, 06:44 AM   #29
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new92,

It sounds to me like that pack is toast. You may want to try equalising and charging it on a very low amp rate but it really sounds like it's gone to me.

Chris.
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Old 02-17-2005, 08:43 AM   #30
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Quote:
Originally posted by picco007
Mr. Shookie,

How do you like your Integy discharge tray's you mentioned at the beginning of the thread? I'm interested in buying some for myself and would like to know more.....How long does it take to get down to zero volts? and so on.

thanks
This tray/s are awsome, I have four. Because Hot Rods runs three quals and a main so you need four packs as I won't run a pack twice in a day. I did that once with a $80 fusion pack and the runtime went in the toilet. As for the trays they lights go out at .09v as with most trays and you can leave them like all the rest, but with them they pull 6v's per cell so it really gets the juice out. I really don't use the trays as dischargers because I have the Integy Zero thirty to do my dirty work.....Then I store them and put them on the trays the night or day before then race day then I charge them with my APS or GM Commander with a temp probe because when you use the night before technique most chargers will false peak so. I hope I answered your question.
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