Curious lipo behavior - RC-Monster Forums

Gustav · **Curious lipo behavior -** 04.05.2007, 12:30 PM

just wondering if anyone else has come across this before.yesterday i ran an evo20 3300 3s pack that's been stored for the last 6 months,stored at the recommended voltage.Charged it up and ran it (xxxt with a basic4200),basically it wouldn't hold voltage underload,Li-saver was kicking in from about 3/4 throttle with the pack fully charged,tried 2 different Li-savers both said the same thing.tried replugging in loads of times,sometimes it will read a fully charged pack as 4s until i run it for a minute and then replug in the pack,couldn't have been that though since i ended up drawing 2400Mah from it.

anyway charged it and ran it again today,exact same setup,and it ran like a champ,ran it for about 25mins and the li-saver still hasn't kicked in yet.So what gives? it's slightly warmer today but not hugely so.do lipos need to be cycled after storage to wake them up?

Serum · 04.05.2007, 12:41 PM

Did you balanced them during charging?

Gustav · 04.05.2007, 12:47 PM

yeah,i always use a balancer.It just seems like it needed to be cylced that one time,didn't think lipo behaved like that though.it's slightly warmer outside today but it wasn't cold at all yesterday,doesn't seem to be enough of a temperature difference,the pack was still at 95F yesterday.

Serum · 04.05.2007, 12:50 PM

Very weird. i never experienced it like you discribed.

BrianG · 04.05.2007, 12:56 PM

That IS weird. What kind of charger are you using? Sounds like you really didn't get a good charge when you "topped it off". Your typical CC/CV charger shouldn't have errored like that, but some chargers use a pulse charging system which may have "false peaked" (I know lipos don't use peak-detection, but it's the closest term I could think of).

Gustav · 04.05.2007, 01:09 PM

It's a schulze 330-d,it's really a trustworthy charger,i did take it off a couple of minutes early now you mention it,but it was down to below 50ma which normally means it's just about done,it'd been at 12.6 volts for a long time.also i kepted coming back inside and checking the resting voltage and it's lower now than it was then,still without the lvc kicking in,it's showing 11.4volts now.i'm going to go run it untill the LVC kicks in then charge it and see how much capacity it takes.

edit;no,charger settings were definately right.

MetalMan · 04.05.2007, 01:01 PM

Never heard or seen that before from a Lipo. I know NiMh does it all the time.

BrianG · 04.05.2007, 01:02 PM

Maybe a stupid question (and not trying to insult your skills), but did you have the charger in NiMH mode?

Serum · 04.05.2007, 01:11 PM

Perhaps the charger read some stupid value or something like that.. Any balancer lights blinking like crazy on the first charge?

BrianG · 04.05.2007, 01:14 PM

I figured you hooked it up right and selected the right charge profile; it's just that this problem is so weird that I was grasping at straws. At least your pack is running right now, although it would be nice to know what happened...

Gustav · 04.05.2007, 01:25 PM

Serum,no there wasn't really much imbalance before or during the first charge at all since i'd been checking it was balanced and at a nice voltage periodically whilst it was stored.

Brian,yeah it just seems wierd,would be nice to figure out what happened there.