how should i store my lipo battery?
 

i have recently bought the maxamps vxl rtr 5000mAH 11.1 lipo kit with hyperion EO6060i charger and lipo sack. I have read through all the intruction manuals for and have not seen anything about how lipo batteries should be stored (fully charged, 3.0v per cell etc.) I currently do not have a way to use this battery as i am waiting for an rc car to put it in, so i just want t make sure that it doesnt go bad sitting for a bit (pre-ordered slash, so hopefully will be here sometime soon!). As of right now it is fully charged and has been that way for a couple days.

Thanks

Dont leave it plugged in to anything. Just periodically check the voltage and check each cell to make sure it stays above the low voltage (i like 3.2v per cell) and that it stays balanced. If it starts to get low throw it on the charge. My lipo holds charge for weeks with no drop though so it should be fine. Lipos are pretty cool because they dont really go bad sitting like ni-mh do.

you should store them with a full charge. Lipos will hold there charge for a while but I'd check it at least every couple weeks. One downside to your situation is that the slash isn't brushless and comes with an xl-5 I beleive which doesnt have a lvx and I'm not sure that it can handle a 3s lipo, it may wind up being overvoltage and do nothing, 3s fully charged is about 12.6v. I'd recomend that if you don't already have a BL setup to go in this, start looking now! Goodluck

thanks, also, should i balance the pack every time i charge it? the guy ant my LHS says that he as stopped balancing his packs every time he charges, and instead only does so about after 20 cycles or so....He says that he has seen noticeable gains in runtime and power by doing this, but i don't want to risk messing my battery up.

They can go for 6 months+ like that - You can us the hyperion to cycle it in a month or two...

Guys a muppet - ;-) - charge and balance at the same time which is what the hyperion is built for...

already have the vxl system waiting for it!!

I have always read half capacity is best for storage over two weeks- about 3.85v/cell.

my appologies! I'm at work and just browsing on my phone. Didn't see the whole screen, I see your signature now! Now I just wish you luck controlling the thing at 60+MPH! I have a Rustler vxl running 2S and its plenty fast and breaks part easily enough! Crashes happen no matter how good you are! I hope you have $ left for some upgrades. I slid into a curb sideways and it wound up costing a $125 after upgrading everything that broke, stock parts would have cost me about $35. So I still wish you luck!

i fully realize that this will end up costing me more money down the line...speed = broken stuff. i already am planning many durability upgrades for the truck, i actually find it quite cheap to do so (compared to an E-maxx or something else of that size/complexity). an im not too sure if i will even gear it of 60mph...i would like to have allot of low end grunt and perhaps 50ish mph top end, which i think should be possible with some gearing alterations.

Like JRH said, long term storage (over 2 weeks I would say) without use should be done at half charge. Even Maxamps specifies this. And doing so might make any possible warranty claims easier on you. For shorter terms, keeping at full charge is OK.

To charge halfway, just run your vehicle until the LVC kicks in and then charge until about 1/2 the mAh rating is put back in.

Or, depending on the capabilities of your charger; set your CV/CC threshold to 3.7v/cell or 3.8v/cell and charge normally. The lower setting will put about half charge in.

Or, if you already have a fully charged pack, discharge it using the charger (if capable) until 1/2 the mAh rating is taken out. But, it's more fun to use the battery in a vehicle than sitting there watching it discharge. :wink: Not to mention a wasted discharge cycle out of its life.

the charger i am using is a hyperion EO6060i, its the one that comes with the maxamps kit, and since i just got it im sot exactly sure what its capabilities are, guess i ought to go look in the manual.

Might be easier to simply run your vehicle until the LVC kicks in, and then simply charge to 1/2 capacity then...

if i were to use the chargers discharge feature what should i set the discharge rate at? max is 1.00A, but should i do it at a lower setting? Also at the moment i do not have a rc car that is in working order, so that method is kinda out the window.

Max setting is fine, but will take a while. Half-discharging say, a 5Ah pack at 1A will take 2.5 hours. Ugg. If using this method, make sure your pack has a full charge. If it happens to be at half charge already, removing half charge will give you 0 charge...

the pack was charged according to maxamps specification when received, so unless i did something wrong it should be at full charge. will the charger tell me what it is at so i can be sure? I'm sorry for asking so many questions, i just don't want to make an expensive mistake.

Actually, all 4 of my MA packs came at something close to ~60-75% charge. If so, then that's where they should stay and you don't need to do anything.

You can approximate charge level by the pack voltage. But since lipos are fairly flat over the majority of a cycle, there can be errors. To ensure a charge level, I go by the amount of Ah I put into/take out of a pack.

i just started to discharge the pack, according to the charger it is at 12.4v, is it normal for it to be this high (4.13v per cell)? also i will be watching it carefully and pull it when it reads a discharge total of around 2500mAH, is this correct?

and thank you very much BrianG, you have been very helpfull!

Yeah, that's about right. Sounds like it had close to a full charge. Right off the charger, a lipo pack will be at 4.2v/cell, but will drop a bit after a while. You were probably at around 90-95% charge. I would stop the discharge at around 2000mAh. It doesn't need to be exactly half, but somewhere fairly close.

No problem! :smile:

BrianG - You will like this....http://www.batteryuniversity.com/partone-19.htm

Non-recoverable capacity loss on lithium-ion and nickel-based batteries after storage. High charge levels and elevated temperatures hasten the capacity loss.

http://www.batteryuniversity.com/images/partone-19a.gif

does this mean that i should put my packs somewhere cool? thats quite a bit of difference in capacity loss from 0 degrees to 60!!!

http://www.batteryuniversity.com/parttwo-34.htm

If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge.


Let the debate begin!!!

lol, yeah, I read that a while ago. Good stuff there!