Lowest voltage PER CELL of a Lipo?
 

Hi guys, i'm confused. I googled this, and i found videos on youtube with different info.

I have a 1s, 2s, and 3s lipos. What is the lowest PER CELL that the voltage can go?

When i google it, i get:
3.7V is the average voltage; LiPo can be charged up to 4.20V and discharged down to 3.0V per cell, any lower or higher in voltage and the cell will almost certainly be damaged and will become unstable which can be very dangerous.

But when i search on forums, some people say 3.7V, some say 3.8V, but here we are with 3.0V...

:confused:

Below 3.7V per cell you'll start to notice a large drop off in performance and the voltage will start to sag quickly under load.

I would say 3.0V is the absolute limit before you start damaging things.
If you are asking about a voltage cutoff for a pack whilst in use, I would say 3.4V per cell should cover you.

3.2 is the lowest I ever take them

Don't confuse minimum voltage with minimum storage voltage. All LiPo batteries should be kept at a 60% storage voltage when not in use. If you use a proper charger, the end voltage should already be set. It is true that you do not want to run your batteries lower than 3.0v per cell as that will induce damage to the cell. That's why balancing is so important with LiPo batteries. One cell could be at 3.2v and the other at 2.8v and you wouldn't know it till one of the cells totally craps out.
It's best to never run you batteries down below 3.2 volts per cell. In racing, we rarely run them down below 3.5v.

my low voltage cut off on my ESC is 3.3V. I tend to never actually go that low unless i'm just checking that the cut-off function actually works as designed. I have a friend who's cut-off on the ESC was set to 3.85v but the actual voltage measured from packs was 3.3v. So its good to at least test the cut-off.

You might be reading about 2 different Voltages.

1) Voltage under load. While running, the Voltage is pulled down under the load of the motor. The lowest anyone recommends is 3V per cell. Like several others have mentioned I also prefer to use a slightly higher cutoff in the 3.2-3.4V range and rarely even hit it. And have great pack life with no noticeable puffing.

2) Resting Voltage. After the pack has sat for awhile. The Voltage will recover or bounce back up a bit. Usually back up to near 3.7V per cell. There isn't much capacity/run time left below that resting Voltage.

A typical resting Voltage vs capacity table for a lipo cell discharged to 3V/cell cutoff (under load):

4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%

Most recommend limiting discharge to about 80% (20% left) for best lipo life.

Not a percent of Voltage, rather capacity. 60% of Voltage would be well below 3V. Best I can tell the exact value is not critical, anywhere in the 40 to 60% range of capacity is far better than left fully charged for any length of time. Since getting serious about following storage guidelines my packs hold up much better, both for capacity and performance (low IR).

Fortunately for racing, many classes & heats will leave a pack within a safe storage level. 4x4 SCT might be the main exception.

Cadman1981, The info in the article coincides with everything that I have read. However it could have been written a little bit easier to understand.
3.7 "average voltage", perhaps should have read "storage voltage". My findings have been 7.2 to 7.4 for a 2s pack. "can be charged up to" might have been better explained with words like "peaked to" or "balanced". And, from what I have read, below 3.0 will hurt them. Check out rogershobbycenter.com-lipoguide- Sorry it's not a direct link.

This actually is very helpful. I often think of ESC cutoff voltage as a resting state but when the motor is actually pulling a load from the batteries, the instantaneous voltage is lower than it would be in a resting state. I guess the question is why my resting voltage after a run where the ESC low voltage cut-off kicks in (let's say 3.3V per cell), is similar if not the same as my ESC cut-off. Shouldn't the battery after pulling off the track be higher than cut-off voltage since I'm assuming the ESC is getting an instantaneous average voltage from the two cells?

Thanks guys!