damselfly

Hi Guys,

I've got a Turnigy 4A 30-40C battery here that's done somewhere between 70-100 cycles with a Vxl3s esc and velineon 3500Kv motor in a Rustler geared high at 28/83. I mainly do speed runs btw.
Not sure if i'm just used to the speed of the car but it seems a fair bit slower compared to what it used to be.
I'm now using this Lipo with a Sidewinder sct with 3800Kv motor geared 27/78 in a Firestorm and i'm still unhappy with the top speed.
Anyone noticed a fair decrease in performance after a similar number of cycles, or am I unlucky?
How many cycles are you all seeing before performance drops?
Cheers.

racer1812

iTrader: (31)

How many of those 70-100 cycles was the pack run down to the LVC? This will affect a batteries life span. Your motor could be the problem as well but that's hard to tell...from here Lipo care and storage also play a part in lipo life as well. If you've run it down to LVC a lot it could very well be at the end of it's life with that many cycles on it.

damselfly

I've accidentally ran it down to 3v per cell (7v) twice in the 3 1/2 months that i've owned it. It's never dropped lower than that though, and I often stop using it when the voltage drops to 3.7v per cell.
I also often top up to a storage charge of 3.85v per cell if i'm not going to be using it for a couple of days.
Btw my motors are in good condition and have never exceeded about 120F so that rules out demagnetisation, ETC..

bigben1165

iTrader: (9)

here is another wrench in the equation.
when i was using flightpower batteries i got 135 charges out of 2 different 10s packs for my helicopter. when i was at IRCHA, i talked to FP about what i thought was a premature failure of the packs. i treat all my lipos like gold. he asked me how old the packs were, i told him about 3 years. he said that was very good for the lifespan of a battery. he said unless you mistreat a battery, the lifeTIME is about 2.5-3 years. he said i could have charged it 300 times in those same 3 years and it still would have died at about the same time that it did.

so i guess that how old the pack is also limits it lifespan.

still learning i guess...

Duster_360

iTrader: (21)

Refrigerated storage (37 - 40F) is supposed to suspend that. I'm getting ready to find out....

youbleed

iTrader: (36)

75-100 runs for under $30 is still a heck of a deal (about the turnigy)

bds81175

iTrader: (20)

I had read that you could see some degradation at that level. I've also heard that under the right circumstance you can get the things to run well up to 1000 cycles. Seems a bit far fetched. You guys have any recommendations for a good balance charger with power supply for the money?

bigben1165

iTrader: (9)

i dont think 1000 cycles for lipo, life maybe, but not lipo...yet

merx9

iTrader: (2)

Does storage voltage make a big deal in performance? I like to keep my batteries fully charged because there may be that day where I just decide to take the truck out and dont want to wait to recharge batteries, but they may be sitting for a few days fully charged... I have heard this can have a negative affect on performance and life what do you all say?

rcgod

iTrader: (33)

In my experience full charge for a few days is fine. Not a good idea for months though. How close to lvc u run them, how hard u discharge them, how many amps u charge them, and the quality of the cell all are factors. I have a thunderpower that I bought used over a year ago that's still one of my best packs. Probably has hundreds of cycles. I also have a venom pack that is basically crap after running to lvc once. Best advice I can give is charge at 1c and try not to run to lvc for long life.

nytryder

iTrader: (7)

I have a turnigy 2s 40c 4000mah pack that is starting to be a little off balance at full charge after about a hundred or so charges. It is maxing out at 4.17v on one cell and4.2v on the other. this has been the case for the last 4 charges. How far off can they be before it is time to throw it away?

bigben1165

iTrader: (9)

as long as the cells are within 0.05 volts of each other the pack is till safe to run it. prolly not a good sign tho since it is still present after several charges

nytryder

iTrader: (7)

Thanks, glad it's just a $20.00 battery. I feel like I got my moneys worth out of it so it looks like it's time to ditch it for a new one.

rcgod

iTrader: (33)

Best batteries for the money I have found are the gens ace 40 or 50c from hobbypartz. Around $30-35 shipped.

nytryder

iTrader: (7)

Yes, i just so happened to order 2 of those(gens ace 2s40c5000), and can't wait to try them out.