Battery (GP3300s) failing... - Page 2 - RC-Monster Forums

10.06.2005, 06:49 PM

The lowest setting i can run is 5mV, my pack just peaked and i got my infra red temp gauge and the temp was 19C. I checked the cells but they are all the same temp. They have been like this since they were new, i got them about a month ago. I have four 7cell packs and none of them ever get really warm. After i play with my maxx the batteries are warm. Should i increase the mV? Thanks for the help :)

Rtsbasic · 10.06.2005, 06:58 PM

No problem :) What temperature are you charging them at? room temp? They're definately not getting a full charge in, do you adjust the mV per cell, or for the whole pack on that charger? With my setup it's 4mV/cell, you could try like 8mV/cell (so 56mV total) and see if that comes off warmer, and how the runtime is.

Another sort of test is, how long (in mins) does it take to fully charge a battery from dead at 4.5 amps? It takes my charger on average 48-52 mins at this charge rate, and that delivers a full charge from a pack thats been discharged and equalised.

Also, make sure there's no fans blowing near the battery, that messes them up. I'm off to bed, will check here in the morning :)

10.07.2005, 02:23 AM

Yeah im charging them at room temperature (16C). I just charged 2 packs and before charging they are 16C, and after charging they are 18C. I charged them at 4.5 amps and 40mV (like i always do), it took about 35 mins to peak (each). Then i put them in my maxx and i got 5mins and 30 seconds run time. Im going full throttle about 60% of the time while my dog chases it. Should i increase the mV ?

Tomorrow i might try charging the packs twice and see how that goes.

Nick · 10.07.2005, 03:43 AM

So is MV the peak sensitivity? The lower the more sensitive? Mine is set to 3! No wonder it peaks incorrectly all the time.

Rtsbasic · 10.07.2005, 04:13 AM

Correct. Although for good cells, you should be able to run it low (on a quality charger). I run 4mV/cell all the time (except when I'm charging NiCD's, then I do 10mV/cell for reverse pulse charging). If the cells aren't warm try raising it a bit, or just put it back on charge again and let it continue until they peak warm.

Cheap chargers aren't very sensitive to this so will false peak, there are 2 ways to tell when a batteries fully charged, when it delta peaks, and when its temperature starts rising more than 1C/min. This is why they generally peak aroudn 40-50C.

Basketti, I don't understand why they're not fully charging, so like you say try putting them back on charge right after it peaks if they're not at least 30C. You are trying to charge just one 7 cell pack at a time right? Or are you hooking 2 up to the 1 output on the 959? Because that would cause this problem.

10.07.2005, 09:57 PM

yep im charging one 7cell pack at a time. I peaked two packs twice and my run time was 9mins and i was going flat out the whole time, thats heaps better than 5 mins. the temp after peaking twice was still the same, the temp doesnt really change during charging lol. i've been waiting for the superbrain 977 to come into stock at towerhobbies since i got my emaxx lol, but it still hasnt come into stock.

coolhandcountry · 10.08.2005, 08:37 AM

Did you try raising your mv? I had a problem with this. I raised the mv up to 10mv on a ice. I guess it was per cell. It made me peak where it supposed to be at.

10.08.2005, 08:45 AM

oh ok, i'll try that, thanks :)

coolhandcountry · 10.08.2005, 08:47 AM

can you adjust how fast it charges to? I seem to get a better charge at lower charge rate.

Rtsbasic · 10.08.2005, 08:50 AM

I normally use 4.5 amps - if I'm re-peaking batteries before a race I do it at 6 amps, but charging a battery at this rate will shorten its life no matter how well you look after it.

10mV/cell is closer to a NiCd's cut off, but will work..if I did that to my cells they'd probably overheat, but as yours aren't getting warm it may well solve your problem.

Let us know how it goes.

coolhandcountry · 10.08.2005, 09:03 AM

If you charging 3300 I like to use 3.5 amp. It is close to the 1c rating. I seem to get a better charge. Less heat to.

Rtsbasic · 10.08.2005, 09:05 AM

Back in the day of old nicd's, wasn't they charged at 3c? How times change..

kulangflow · 10.16.2005, 04:40 PM

Quote:

Originally posted by Basketti
I use a superbrain 959

There's your problem.

In my family, we've owned 6 of those, and every single one of them had problems false peaking no matter what we did with them.

Sell that thing on eBay and get a decent charger like the Duratrax Ice. It'll be worth it. ;)