LIPO Cycling Questions

[jdbauman]

I'm sure this has probably been covered on this forum ad nauseum, however I cannot seem to find any real conclusive information on the subject. My question is, is it necessary to cycle your LIPO batteries on a monthly basis? I was watching some videos on the Maxamps website, and the guy in the videos was saying that it is important to cycle your LiPo batteries at least every 30 days. I am wondering if anybody on this forum has opinions as to whether this is necessary or not. In addition, he recommends discharging the cells down to 3.2 V, and charging them up to 4.2 V.

I am wondering if this is really necessary to help maintain the health of your cells. There seems to be a lot of opinions out there, and I'm just not really sure what I should be doing in order to maintain the health of my LiPo packs. Any help would be appreciated!

Jerry

[mvly]

Here is my experience from Lipo:

1) I left one of my RC lipo pack near fully discharge and left it there. After a year, I notice the pack was really puffed. I ended up recycling it at RadioShack. I didn't want to risk a fire in my house.

2) I had other Lipo I kept at storage capacity (40%, ~3.7-3.85V per cell). I never had any problems with those. It has been 2 years since I used them. I rebalance charge them to storage twice in the 2 years just in case.

3) I balance charge my Lipo ALL the time. I go to work and come home late, so there is no need to bulk charge for me.

4) Currently I am using Lipo on my ebike. I charge to 4.1V and discharge to 3.6V at the lowest. Most of the time I discharge to only 3.75V. So far, after 135 cycles and pushing 1357Ah through the batteries, and no problems. I did leave my pack at 3.85V for about a month and after a the initial few cycles charging from storage, one of the cells was resisting balancing when it was near full charge. i.e. all the other cells were at 4.1V and one cell would be at 4.06V. It would take a long time to get it to balance. But after a 4-5 cycles everything was back to normal. Now they all end charging at nearly the same voltage.

SO there is no need to cycle them every month. Though just know Lipo do degrade even if you don't use it.

So most people would give you these recommendations if not already:

1) Charge to 4.1V or 4.15V
2) Discharge to 3.6V or 3.65V
3) If storing for a long time, keep them at 3.8V to 3.85V. Store in cool area if possible. Check on them once in a while to see if any cells are discharging faster than others
4) Never store at low or high capacity. Low capacity = puffing, high capacity = faster degradation of the cells.

If you follow the general above rule, I have a feeling your lipo will give you long years of service.

Best of luck!

[wesnewell]

In addition, he recommends discharging the cells down to 3.2 V, and charging them up to 4.2 V.

In a high discharge environment, setting LVC to 3.2V is pretty common, but in the ebike world, it's going to kill your pack pretty quick. Unless the guys a complete idiot, he had to be talking about high discharge RC applications that draw constant max amps from a single battery, and not the resting voltage after use. RC lipo is completely drained at ~3.5V. That's a good lvc setting for ebike use unless you have a large ah pack with less sag, where an even higher lVC should be used. Minimum resting voltage should be kept above 3.60V.

[dogman]

Well, I don't know about the battery. But I'll be in the loony bin pretty quick if I didn't get out on the bike and cycle my adrenaline junky battery at least monthly!

Since I've been sick for about a year, I have been carefull not to let my pingbattery bms kill my pingbattery. So I put it back on the charger long enough to completely balance it at least every two weeks. I'd rather store it full charged than worry about the bms draining down on cell. I wanted it to still be ready to ride because I do try to get at least a weekly short ride in, despite the illness. My lipo I have been storing at about 3.8v. Some of it not cycled since I raced last, more than a year. When I pulled it out to run a 24v ebike I got last winter, It seemed as good as when I stored it. It spent the winter stored in an old, not running refrigerator in the backyard. Who knows if it did something to my cycle life, but it didn't ruin em so far.

For those interested, I'm back! Feeling much better, and hoping to resume bike commuting soon.

[docnjoj]

Good to hear you talking healthy again, dogman! I can't wait to see you on the track doing stuff we can only dream about!
otherDoc