Hey guys, I found some old LiPo batteries I’ve stored for like four years. They have about 40 charge cycles and were stored at the right voltage in an ammo box. Just wondering if they’re safe to use or if I should get rid of them. Any advice on testing them before I charge them up?
Honestly, after 4 years, they’re probably okay to use if you stored them right, but don’t expect top performance. I’d suggest doing a slow balance charge to be safe.
Dacey said:
Honestly, after 4 years, they’re probably okay to use if you stored them right, but don’t expect top performance. I’d suggest doing a slow balance charge to be safe.
Good to know! Do you mean a balance charge on a regular LiPo charger?
@Mai
Yep, most standard LiPo chargers should let you do that. Just make sure to monitor it, especially if it’s been sitting a while.
I read that LiPos can last a couple of years without much drop if stored at around 50% charge (like 3.7v per cell). Four years might be pushing it, but they could still work.
Joss said:
I read that LiPos can last a couple of years without much drop if stored at around 50% charge (like 3.7v per cell). Four years might be pushing it, but they could still work.
Yeah, I heard the same. Room temp and storage voltage help keep them from going bad too soon.
Joss said:
I read that LiPos can last a couple of years without much drop if stored at around 50% charge (like 3.7v per cell). Four years might be pushing it, but they could still work.
So if they’re around 3.7v per cell now, they’re good to go?
@Vince
Pretty much! Just avoid charging it to 100% right off the bat. Balance charge and monitor like @XYZ said.
You might want to check the internal resistance too. If it’s over 20mΩ, I’d think twice about using it. High resistance usually means lower performance.
Wendell said:
You might want to check the internal resistance too. If it’s over 20mΩ, I’d think twice about using it. High resistance usually means lower performance.
How do I measure internal resistance? Is that with a regular charger?
@Mai
Yeah, most LiPo chargers have a feature for that. Look for ‘IR’ or ‘internal resistance’ in the settings.
@Mai
If it’s under 10mΩ, it’s in great shape! Over 20mΩ, maybe time to retire it.
Watch out for any swelling or puffing on those batteries. If you see that, it’s best to dispose of them safely. Swelling means they’ve degraded inside.
Rowen said:
Watch out for any swelling or puffing on those batteries. If you see that, it’s best to dispose of them safely. Swelling means they’ve degraded inside.
Swelling is a big no-no for sure. They can be dangerous if you keep using them.
Rowen said:
Watch out for any swelling or puffing on those batteries. If you see that, it’s best to dispose of them safely. Swelling means they’ve degraded inside.
Got it. I didn’t notice any swelling, so they might be okay. Thanks for the heads-up!
Just FYI, LiPos can last up to 300 cycles if they’re high quality, but most don’t make it that far. Four years stored might reduce their capacity, but they’ll probably still work fine for light use.
Emory said:
Just FYI, LiPos can last up to 300 cycles if they’re high quality, but most don’t make it that far. Four years stored might reduce their capacity, but they’ll probably still work fine for light use.
Yeah, quality definitely matters. Lower-end LiPos don’t last nearly as long.
Emory said:
Just FYI, LiPos can last up to 300 cycles if they’re high quality, but most don’t make it that far. Four years stored might reduce their capacity, but they’ll probably still work fine for light use.
I’ve had some last around 2 years with regular use. Four years in storage could go either way.
Just remember to store them at 3.8v per cell next time if you’re going to put them away for a long time. That’s the ‘storage charge’ level to keep them safe.
Micah said:
Just remember to store them at 3.8v per cell next time if you’re going to put them away for a long time. That’s the ‘storage charge’ level to keep them safe.
Thanks for the reminder! I stored them around that, so they might be okay.