Possible Lipo problem?

I have a Premium Power 4700 20C 7.4v lipo. Ive noticed in the past couple of months, it reaches cut-off, 6v, too soon i believe. When i chuck it on the charger & check its voltage, its not even under 7v, 7.5v is the lowest ive seen it. Im using a mm with vortex 7.5 motor, fan on both motor & esc, TT01 geared mid 7 fdr

I believe under load, its hitting cut-off, voltage spike, or amp rating of pack is not strong enough? Ive also noticed lately the pack is coming off from a run warmer & warmer. I thought it might have been the plugs so i changed them to TRX but problem/issue still persists. Im thinking of buying a higher C rated, higher capacity pack, If you guys know what the problem might be, any info would be great

[crazyjr]

Sounds like the battery is not up to your setup, What is your setup? How many cycles has the battery been through? That might be the problem, Batteries can get old

Edit, nevermid the setup, I see it now, sorry

[What's_nitro?]

It might just be getting old. They do lose capacity over their lifetime which would make the battery work harder to supply power. That could be why it's dumping too soon and getting warm more quickly. Does the car roll smoothly? Any binding would cause excess power consumption which also leads to the problems you are experiencing.

[Tempted]

I would also check bearings and gears. The bearings in the motor could have also gained some friction. More than likely its just your pack aging.

[SpEEdyBL]

Do you use a balancer? The LVC doesn't measure each individual cell, so when your pack is 6 volts under a load, in an exagerated example, one cell could be reading 2.5 volts and the other 3.5 volts.

[tc3_racer_001]

i had 2 of those packs go on me in my 1/10 tourer with a brushed 540 (9 turn) within 20 cycles... wouldnt touch them again personally...

[BrianG]

Originally Posted by Drifted Demon

I have a Premium Power 4700 20C 7.4v lipo. Ive noticed in the past couple of months, it reaches cut-off, 6v, too soon i believe. When i chuck it on the charger & check its voltage, its not even under 7v, 7.5v is the lowest ive seen it. Im using a mm with vortex 7.5 motor, fan on both motor & esc, TT01 geared mid 7 fdr

I believe under load, its hitting cut-off, voltage spike, or amp rating of pack is not strong enough? Ive also noticed lately the pack is coming off from a run warmer & warmer. I thought it might have been the plugs so i changed them to TRX but problem/issue still persists. Im thinking of buying a higher C rated, higher capacity pack, If you guys know what the problem might be, any info would be great

Any battery will measure higher voltage when not loaded at all, but 7.5v is a bit higher "floating" voltage than normal after tripping the LVC. Typically, a floating voltage of ~3.5v/cell is more common. That tells me that the setup is drawing more current than the pack is really capable of and the voltage is dropping too far under the load, which sets off your LVC.

FYI; the connectors themselves would get warm if old/worn because that would be where the voltage loss would occur.

Loss of apparent capacity over time and increasingly warmer cells after a run points to the cells degrading and their internal resistance increasing. Chances are those cells were just barely adequate when new, and now that they've seen a number of cycles, they aren't up to snuff at all. If/when you do get new cells, shoot for a little higher quality, or something with a higher C rate and/or capacity.

I already have an elite 4800 25C 2s lipo, great pack if you ask me, but im also looking at the elite 5000 35C 2s lipo, or maybe even a Neu 5000 25C 2s...

Im also thinking of investing in an eagle tree system, even though i only use my car for drifting, i like to know exactly how the electrics are behaving when being used!

Hey guys, ur right, just flattened the problem lipo, with a load the cut-off kicked in, without a load there was still plenty of juice, i drained the battery with no load til cut-off, chucked it on the charger & it read 6.60v, now that i positively know this lipo is to weak for my setup, i have a funny feeling the elite 4800 25C lipo is starting to do it aswell.

I dont know if buying better packs at the equivelant capacity & C rating will help, or i should just go with a higher C rated lipo...

[tc3_racer_001]

or higher capacity - but a true 20C lipo willl hold its voltage and stay working for a long time i would imagine...