Charging lipo and temperatures?
 

Prob. a newbie question, I DID search and did not fint what I was wanting. Anyway, I have a couple Lipo's ordered (sky 1300mah 2s 25C) and a thunder ac6 charger and a fire proof charging bag. My question is this, even with the fire bag I still have some concerns about charging these things in my house where my wife and children are. Will charging these things in my unheated/uncooled garage be ok?? Im in NC and the temps right now at night are in the mid 30's but 20's F is not uncommon and summer can easily reach 100*F Anyone have any thoughts?

Re: Charging lipo and temperatures?
 

You probably don't want to store the batteries in the garage at 100 degrees during the summer because that will reduce their life. In the winter you should have no problem. My LiPO's rarely get over room temp when charging. I also charge at 1c though. The cells I have say they can be charged at up to 5c, but I've only got about 6-10 cycles through them and I'm not sure if they really "break in" like people say.

Re: Charging lipo and temperatures?
 

While charging them out in the garage isn't a horrible idea, I don't know that I personally would store them at below 40°. Perhaps 1/2 hour to an hour after they're charged, if they haven't puffed up, I'd bring 'em inside. Mine reside (and get charged) on a countertop in the basement. For storage, they're just like any other batteries, any place you have away from intense heat scources, cool & dry if at all possible. Some poeple store them in the fridge, allow an hour to get them back to room temp before using or charging them.

While I am still a bit of a worry-wart with LiPos, they're not that bad. So long as you choose a (in your case) 2S program you should be fine. There's going to be those who will say, (and I fully agree with them) that all those videos of LiPo fires are staged, they're either shorted out or over-charged on purpose. True. But if someone who just doesn't know what they're doing throws a 2S on charge and figures "I'm gonna charge at 3S and it'll get done really fast!", aren't they going to overvolt these things? Hence the warnings. Charging a LiPo on a NiMh program is just as bad. Just follow the directions, charge a 2S battery on a 2S program, and life will be good.

If your charger doesn't automatically set it, charge at 1.3 amps, and you'll be fine. Amps aren't AS critical as volts, you can probably fudge these a little and get away with it. If you ever want to get into 2C or 3C charging, you'd adjust the amps, never the voltage. (probably wait a year or so until you try stuff like mutiple pack charging) And it is normal for your LiPos to start at whatever amps you selected, and the amps will (should) get lower and lower, and it'll keep on charging. The charger you ordered is a peak charger and shuts off at the end of charge. Let it do it's thing. Charging your batteries at 1C should take about 60-72 minutes, balancing adds time onto that, so if it sits "for like 5 minutes without doin' nuthin' ", don't freak out. If you want to reduce the charging time, set your ESC's cutoff at a higher voltage (ie, 3.5-3.7 volts per cell), and this'll cut you off with your LiPos only half drained, they'll charge quicker. (kinda like filling the gas tank on a car when it's only half empty, it's cheaper to fill up.) If I have the ability to set my cutoff, I'll usually go 3.4 per, but even as low as 3.0 should be okay. Set it higher if you don't ever plan on balancing.

LiPos arent like NiXx batts, in that they shouldn't get at all warm durring charge. They should stay pretty much at ambient temperature. Careful if you're using your hot little hands to repeatedly check battery temp, as your body heat could heat up the pack and make you think something's wrong. If it does get 'rather warm' and puffs, then yeah, get it disconnected immediately, but if you're in the right program, you're more than likely good.

Balancing is up to you. I find it's not that hard to hook up, so I see no reason to ever skip it. Some say they never balance. Do what you feel you gotta do, man.

It may take a couple of charge cycles for you to get used to them, but I think if you keep a sensible head on your shoulders and follow directions, you'll really enjoy life with LiPos.

Re: Charging lipo and temperatures?
 

You actually want to charge them where You can keep an eye on them!!! Too many fires have been started by over amping the batteries ( hurry, negligence ) while in a garage, out of sight.

I know of one guy at a scaler-forum that actually lost his house while charging some NiMh cells unattended. Didn't notice them gassing, came back from a walk, house gone.

Batteries are not to be toyed with, nicad, nimh, lipo, whatever. They all hold the capacity to go " boom" or set their environment ablaze. You wouldn't store the 2gallon of nitro next to Your fireplace, or in the cellar next to the heater-furnace ey? Common sense, dilligence and keeping an eye on charging.

Carefully follow the instructions on the packs and with the charger. Manuals are to be read! ( unlike what most people seem to think)

For storage: charge them 50% and store them in a fridge. They will, indeed, take some time to "thaw". But they also keep their charge for, like, forever.

Re: Charging lipo and temperatures?
 

Thanks guys, that is some great input. I guess my biggest fear is I just dont totally know what I'm doing and have twin 1 year old girls at home so its VERY easy to get side tracked. Just trying to do this as fool proof as possible. I always like to plan for the worst, which in this case would be batteries catching on fire. In one of my earlier searches I read about charging and storing them in a metal tool box or ammo box, I like that idea, especially the heavy gauge ammo box. I guess I will place them in the fire bag and in a ammo box for storage and while charging, atleast until I get familiar with them and feel comfortable. I know I sound like a worry wart.

Re: Charging lipo and temperatures?
 

i used to worry a lot about lipos, but to be honest i have probably had more hassle with nicad and nimh batteries. as long as you set the charger up correctly you should be ok. my charger will beep like crazy if i connect to balance lead in the wrong slot or set a 2s as a 3s.

as for temperature i would keep them warm while charging and before use, but if just storing i wouldn't worry as long as its now intensely cold or hot

Re: Charging lipo and temperatures?
 

For the past ten years I have been working at a small alternative energy research company and one of our main focuses is developing thin film lithium batteries. In those ten years we only had one small fire due to rapid and high current charge rate. If you charge your batteries to the battery and charger manufactures specs, you should be fine. But, it's always a good idea to have a fire extinguisher on hand. No water, lithium reacts with H20.

Re: Charging lipo and temperatures?
 

Frikkin "F You":flipoff::flipoff:

Re: Charging lipo and temperatures?
 

For the past ten years I have been working at a small alternative energy research company and one of our main focuses is developing thin film lithium batteries. In those ten years we only had one small fire due to rapid and high current charge rate. If you charge your batteries to the battery and charger manufactures specs, you should be fine. But, it's always a good idea to have a fire extinguisher on hand. No water, lithium reacts with H20.

Re: Charging lipo and temperatures?
 

how do you charge them to 50%? cut the mah in half?

Re: Storage charge
 

I did exactly that, and my batt still charged all the way, just at a reduced amp rate. But that was on my Onyx 230. The AC6 that the OP has coming may have a 'storage charge' feature on it, dunno.

In my case, I just put mine on the discharger until the LVA flashed blue. Of course, this requires one to have an LVA and buy/build a discharger.

Re: Charging lipo and temperatures?
 

For pretty much ANY battery chemistry, charge at "1C".....basically, the mah rating move the decimal point.

Thus a 1300mah charges at 1.3amps.....

A 850mah charges at 0.85amps.....

Re: Charging lipo and temperatures?
 

Chargers charge to a voltage peak, has nothing to do with mah/capacity.

This is set by chemistry (NiCD/NiMH, LiPO, etc), the charge RATE is set by the capacity/mah.

Most packs charge at ~1C, thus all packs charge (from "empty" to full) in ~1 hour.