Discharged down to 3.5v/cell -- now what?

[jhamel]

After 4 years of not making a single LiPo mistake, I flew a brand new pack 2 flights back to back, and discharged down to 3.52-3.54v/cell. This is a Pulse Ultra 6S 45C 1.8Ah pack. The pack came back warmer than the other packs, and that's what tip me off that I did not change packs in between flights. The pack looks brand new without puffing. It took 1,856mah to fully charge this 1,800mah capacity pack. IR is very similar before and after the mistake.

IR after first full charge: 2.8/2.6/2.4/2.3/2.5/2.4 (full charge)
IR after mistake discharge: 3.0/2.8/2.5/2.7/2.4/2.6 (full charge)

I flew the pack today, and it performed similarly to its sibling packs.

I understand that I should keep an eye out on this pack. Are there any special concerns or considerations that I should look for?

[B.R.C.]

It will be fine. Doing that once or twice won't hurt it to bad. I've done it as well.

[Slyster]

That's not too low

[iscripter]

Yeah that should be fine. You are in the danger zone if you go below 3.0v per cell.

[jhamel]

Prior to this incident, I've never ever discharged a pack below 3.77v/cell. Although it seems that I have not caused a significant permanent damage to the pack, this incident made me reevaluate my vulnerability to outside distraction(s). I checked the pack voltage prior to installing it on the heli, but then I picked up and installed a used pack. Of course, I was having conversations with other pilots at the field during this process. From now on, I will check pack voltage after the pack is installed in the heli.

[KSHeli]

you can place rubber bands on charged packs and then remove them and stick into your pockets as you place them in the heli, I use to do that when I was first starting out.

[Xrayted]

These are cool and work well at keeping the flown packs sorted from the others if you get distracted.

http://www.hobbyking.com/hobbyking/s...0pcs_bag_.html

[CrashNburn420]

Best way to check for a charged battery imo. Takes 2 seconds.

[jhamel]

I checked the pack voltage, but I got distracted and picked up and installed a used pack. I now changed my routine; I check the pack voltage AFTER I install the pack in the heli.

[Gregor99]

Originally Posted by Xrayted

These are cool and work well at keeping the flown packs sorted from the others if you get distracted.

http://www.hobbyking.com/hobbyking/s...0pcs_bag_.html

I'm using these as well. They work well to supplement cell checking. I also use pack voltage telemetry. Check it at the start of the flight and there's an alarm if the pack gets to low.

[Smoggie]

As the others have already said, 3.5V per pack is no problem at all, nothing to even be the slightest bit concerned about, and no need to 'keep an eye on it'.

The change in IR you noted will no doubt just be down to other factors such as temperature of the battery when you did the measurements, certainly nothing to do with the fact that it was discharged to 3.5V.

If you did it every single flight then you would shorten the life of the battery but as a one off event it's irrelevant.