Fully charged Lipos...

[Checkmateguy01]

Simple question, how long is it safe to leave Lipos fully charged with out using them? I charged both sets of my lipos this weekend but never got the opportunity to run my boats, so I'll have to wait till next weekend to get a couple runs in. I ask because I've heard that lipos will puff if left fully charged for any length of time, I'm still pretty new to lipo so I don't know. Thanks!

[MR2NR]

How old are your batts? If they are fairly new I'd say you will be fine letting them sit for a week. They really don't puff as much just being fully charged that usually comes from letting them get too low voltage and charging them right after a hard pull. Letting them sit fully charged just degrades capacity. If you don't plan on running it for more than a week or two discharge them to the 3.8-3.6V per cell storage rate.

[iamandrew]

Ive got some 5S 5000MAH Flightmax packs, i left them sit there for 3 weeks fully charged, when i went to charge them again i got about 30mah back into the pack before it cut off.

I havent really had lipos fully charged sitting there for a year doing nothing yet though, but none of my Digital cameras that have lipo batteries have needed their batteries replaced in 3 years

[Fluid]

...If you don't plan on running it for more than a week or two discharge them to half there full voltage per cell.

I am sorry but this is very wrong and dangerous advice! You DO NOT discharge LiPo cells to half their voltage (2.1 volts) as this will ruin them. Never discharge a LiPo cell below 3 volts. Storing voltage for a LiPo cell is between 3.8 and 3.9 volts.

It is not a good idea to keep LiPos at full charge longer than one week. It isn't dangerous to store them longer, but as was mentioned above their capacity will diminish with time. Most chargers have a discharge function, but I prefer to discharge a pack by running it in the boat.



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[Jersey Crewmax]

The manufacturer of my batteries (SPC) say they can stay charged for 2 days. They might advise on the conservative side though.

[Checkmateguy01]

Ok, thanks for all the advice! My old Superbrain charger has a discharge function, I'll drop the voltage back down, it only has one channel so it's gonna take a while. I know I won't make it to the pond this week so the boats won't get run, and when I'm at the lake house I'm at the mercy of the wind and boating traffic, which is why I never got to make a run.

[Checkmateguy01]

It is not a good idea to keep LiPos at full charge longer than one week. It isn't dangerous to store them longer, but as was mentioned above their capacity will diminish with time. Most chargers have a discharge function, but I prefer to discharge a pack by running it in the boat.
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So what do mean by the capacity of the batteries will diminish with time? By that do you mean they may/will stop taking a full charge?? Or just that the voltage/charge will drop off a little bit giving a shorter run time the next time i run the packs? I guess i'm a little confused here. Also my packs are fairly new with just a hand full of runs on them, they are Turnigy 5000MAH 2S 40-50C's.

[MR2NR]

I am sorry but this is very wrong and dangerous advice! You DO NOT discharge LiPo cells to half their voltage (2.1 volts) as this will ruin them. Never discharge a LiPo cell below 3 volts. Storing voltage for a LiPo cell is between 3.8 and 3.9 volts.

It is not a good idea to keep LiPos at full charge longer than one week. It isn't dangerous to store them longer, but as was mentioned above their capacity will diminish with time. Most chargers have a discharge function, but I prefer to discharge a pack by running it in the boat.



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Sorry but I was wrong. If you have a 7.2V 2s pack run it down to 3.8v per cell. So I meant to say 3.6-3.8V per cell. Sorry about the confusion. Ive got 4s on the brain.

But yeah leaving them full charged for long periods will diminish mah as the batt looses it's chemical potency. NiMh are supposed to be better at non memory feature but really it's not much of an advantage in the long run.

I don't use the discharge feature on the charger also. Using the same rate of discharge for your batts is better for them anyways.

What is really good practice though is not too charge your packs right after a run. Letting them rest a couple hours lets the batteries balance better and prevents puffing. So having enough mah/batts on hand too run as long as you want without charging the same battery in between runs helps battery life. Also letting it rest an hour or two after charging is good practice also.