over charged lipo

[m1009cucv]

just switched over to lipos.. still learning about them. i have a few sky lipo 7.4 2200 for crawling. been charging them at 2.0 amps. my little cousin charged a 2200 pack at 4.0. never changed the setting. i didint know he was doing it. dont think it was changing to long. the pack swelled up a bit it seems.

is is still ok to use or should it be replaced? thanks

[JohnRobHolmes]

swelling is bad, the gases are flammable. If you have any internal shorts in the pack it is more likely to catch fire. The pack also has a much higher resistance now, with makes more heat during charge and discharge. Get enough localized heat and it will go into thermal runaway.


Use at your own risk, the pack is much more dangerous now. Still usable, but dangerous.

What C rate is that 2200 pack? Charging a decent lipo at less than 2c shouldn't cause swelling. Heck, I shove 5 amps into my 1300 cells and they don't even get warm. The old 25c cells would have a bit of heat, the 35c cells stay at ambient.

[sdtech58]

If it's swelled, I wouldn't mess with it. Not worth the risk on a comprimised battery. A new battery is much cheaper than having it catch fire and burning your RC or garage to the ground.

[m1009cucv]

c rating is 30 i believe. dont have it with me now. yes im cutting the wires off and giving it to the recycling center.. i will buy a new one.. here is the pack im talking about:
Sky Lipo 2200mAh 7.4V 30C

from what i read there a pretty good pack. bit over 1 hour in run time my scx 10.. Im pretty new to lipos. a 2200 7.4 pack should be charged at 2.0 and a 8000 7.4 pack should be charged at 6.0 right? should always be a bit less then what on the pack. one of the guys i run with told me that.. is that correct tho? sure take a long time to charge it seems

thanks for the help

[sdtech58]

I always charge mine at 1C and balance every time. My 5000 mAh's get 5A and my 8000 mAh could take 8A, but only gets 6A due to my charger limitations. Your 2200 should be able to handle 2.2A all day long, even the "budget" LiPo's. Lower charge rates = less heat = better battery longevity.

Think of it like filling up a 5 gallon bucket with water. Using a garden hose (lower charge rate) will take more time than using a firehose (higher charge rate). But with the firehose, it will be out of control and you will most likely "overcharge" your bucket. Same principle. You don't want to overcharge or over discharge your LiPo's.

Since you are new to LiPo, ALWAYS use the low-voltage cutoff on your ESC as well.

[ScaleFreak93]

A good starting point for amps while charging is just taking the MaH and dividing it by 1000. So 2200/1000=2.2 amps or 8000/1000=8.0 amps and so on. That is just a starting point and can be adjusted accordingly. Most lipo will also have a max. charge rate on them.

[m1009cucv]

balance every time? thought that just needed to be now and then. same with my charger. 6a is the highest it goes.. low-voltage cutoff? not even sure what that is. thanks for all the help. learned a few things here

[ScaleFreak93]

Yes, balance every time and you'll keep your lipo in good shape. LVC= low voltage cut-off. What ESC are you running?

[m1009cucv]

ae 2 in 2 scx 10. evx in a emaxx and a xl5 in a rustler thanks

[JohnRobHolmes]

Balance charging is an insurance policy. If you have the plug, might as well use it. The higher the cell count, the more risk to bulk charge without balance wires connected.

[sdtech58]

Originally Posted by m1009cucv

balance every time? thought that just needed to be now and then. same with my charger. 6a is the highest it goes.. low-voltage cutoff? not even sure what that is. thanks for all the help. learned a few things here

For some high quality 2 cell LiPo's, i've heard balancing isn't really necessary every time. But for $12, you aren't getting a high quality LiPo. Anything over 2 cell, I would balance every time. Like JRH said, the plug is there for a reason. Use it!!

Low voltage cut off (LVC) is a setting on your ESC that automatically detects battery voltage and greatly reduces the power of your motor or shuts it off altogether before you go too low on your voltage and damage your battery. I'm not sure on the XL-5, but the other 2 ESC's you mention should have LVC settings built in. Just make sure it is on. Consult your manual from each ESC regarding how to turn it on.

[m1009cucv]

great thanks.. learned a few things.. a friend has a bunch of sky lipos. said they did pretty good by him. so i got a few.. is there something better? i thought they all just came from china or japan and were pretty much all the same.. thanks

[WAM]

Check the labels on your batteries for the really fine print. Most will tell you the max charge in terms of C. Or it may be on paperwork in the box. Those batteries that only allow charging at 2C I consider to be lower quality than batteries allowing 5C charge. I think I've seen 5C on maxamps, gensace, hyperion and thunder power. Note this is separate from the max discharge rate, typically 25C and up. Those get the big print.

If that's not clear, simply multiply your batteries capacity by that charge rate number for a maximum. 2000mah x 5C = 10 amps. Obviously that's just a maximum, not a necessity and many people live by 1C charging. If time is no factor, why not?

I use higher numbers because I like to personally monitor the charging and 1C takes too much time out of my day.

[BigSki]

If nothing else, buy a LiPo sack for charging, it's a cheap insurance policy in case a battery goes into nuclear meltdown it won't set anything else on fire.

[greggreg2011]

you always need to balance your lipos cheap or expensive...i personally for a decent lipo cheap not sky lipo but blue lipo...they are cheap and can handle a higher c charge if it happens.

but yeas charge rate goes something like this

2s
1000-1c
2000-2c
3000-3c
ect.

3s example
5500-3c

thats just the way i go and lipos last me a while and i race so they get alot of non-crawler use

but being new to lipo i wouldnt try and use the puffed pack or your car may end like this http://www.youtube.com/watch?v=773yP...eature=related

[Charlie-III]

Originally Posted by greggreg2011

You always need to balance your lipos cheap or expensive...I personally for a decent lipo cheap not sky lipo but blue lipo...they are cheap and can handle a higher c charge if it happens.

but yes charge rate goes something like this

2s
1000-1c
2000-2c
3000-3c
ect.

3s example
5500-3c

thats just the way I go and lipos last me a while and I race so they get alot of non-crawler use

but being new to lipo I wouldn't try and use the puffed pack or your car may end like this LRP Lipo Brand LRP Lipo Fire im S8 BXe - YouTube

Huh??

The description of "1C" does not match what you listed. A "1C" charge is related to the mah/capacity rating of the pack, basically take the mah rating and move the decimal point to the left 3 places.....thus:

1C charge rate on a 800mah pack is 0.8 amps, on a 1300mah pack is 1.3amps, on a 5000mah pack is 5amps, etc. Frig the cell count (aka 1S, 2S, 3S...etc).
If your packs can handle a 2C charge, take what I listed and double it (thus, a 800mah 2C charge pack can be charged at 1.6amps). PLEASE do not confuse power delivery with charge rate......please......if it's not listed, charge at "1C".

[sheesh, the crap I get from people here for some of my posts will likely mean your inbox will fill up fast......]

[greggreg2011]

Originally Posted by Charlie-III

Huh??

The description of "1C" does not match what you listed. A "1C" charge is related to the mah/capacity rating of the pack, basically take the mah rating and move the decimal point to the left 3 places.....thus:

1C charge rate on a 800mah pack is 0.8 amps, on a 1300mah pack is 1.3amps, on a 5000mah pack is 5amps, etc. Frig the cell count (aka 1S, 2S, 3S...etc).
If your packs can handle a 2C charge, take what I listed and double it (thus, a 800mah 2C charge pack can be charged at 1.6amps). PLEASE do not confuse power delivery with charge rate......please......if it's not listed, charge at "1C".

[sheesh, the crap I get from people here for some of my posts will likely mean your inbox will fill up fast......]

correction...i meant charge amp on the charger not the c charge rate for the battery