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Charged my LiPO for the first time... do I have my facts straight?

NerdDoc

Newbie
Joined
Dec 27, 2014
Messages
26
Location
North Idaho
So my daughters Falken showed up yesterday and after 2 trips to the local RC shop, I finally got her battery charged :)

I ended up getting a Hitec X4 and assumed it had all of the connectors I'd need to charge - I didn't really know what to look for and should have just brought it to the shop with me.

Anyway, after getting some male deans connectors on the ends, I balance charged her battery after doing a little research.

Here's what I *think* I know...
To charge at 1C, I take the mAh, essentially divide by 1000 and that gives me the appropriate amp rate to charge - so for this 5200 mAh 2S battery, I charge at 7.4v, 5.2amps and this equates to 1C and should take about an hour. Is that right?

What about charging slower, is there any benefit other than safety - like prolonged battery life?

What about charging faster? To charge this 5200 mAh battery in 30 minutes, I'd have to run at 10.4 amps (2C?), right? That seems really high. From what I've read, the main concern with charging at higher amps is overheating your battery and catching it on fire?

What else do I need to know related to charging? Does my lipo need to cool for a certain amount of time after draining before I charge it again?

Thanks for any tips!

Oh, and this was my first time ever driving a *real*, non-big-box-store RC car and I'm definitely hooked. Can't wait until my deadbolt gets here on Thursday so we can both head out and tear it up!
 
The battery should have a charge rating on it. Most better batteries are rated at 5c, so about 25 amps on your 5000 battery. Not to many chargers that will put out that much amperage. IMO, the slower charge seems to give my batteries a deeper charge, IE more mah taken during the charge cycle. I would not hesitate to use all the hitec will put out, I know mine only goes to 6 amps. It is when you use the smaller batteries you need to watch amperage. As far as time goes I find about 45 minutes is typical for me on most any battery at 1c charge rate.

As long as the battery is not hot it should be OK to run after charging. I have pulled them hot from the charger and ran them without issue, but it could hurt its lifespan.
 
Fwiw I charge both my Hyperion 2500mah 3s batteries at 6 amps. Have been doing this for about two years now and they still run strong. For a charger I just use a traxxas ez peak and it tops out at 6 amps.
 
You can charge most lipo's at 3C safely with a high quality charger. Will it hurt the battery? NO, unless it gets hot while charging ( over 113*) If you really want to stretch out battery life, have the charger stop at 4.18v/cell.
 
Ok thanks for the comments. As long as I get 2 years or so out of a battery, I think that's asking enough. I don't plan on getting fancy about monitoring my battery temps since I don't mind waiting an hour for a charge, but I'll definitely try some at 2C or higher if my X4 will handle it, and we'll see if they stay cool.
 
Here's what I *think* I know...
To charge at 1C, I take the mAh, essentially divide by 1000 and that gives me the appropriate amp rate to charge - so for this 5200 mAh 2S battery, I charge at 7.4v, 5.2amps and this equates to 1C and should take about an hour. Is that right?

Yup.

What about charging slower, is there any benefit other than safety - like prolonged battery life?

Some say yes, some say no.
I don't believe there's a benefit to charging slow if you're charging through the main leads.
If you are, for some reason, charging through the balance tap, then, yes, I'd say back off on the amps.


What about charging faster? To charge this 5200 mAh battery in 30 minutes, I'd have to run at 10.4 amps (2C?), right? That seems really high. From what I've read, the main concern with charging at higher amps is overheating your battery and catching it on fire?

I checked the instruction manuals for both, and Page 14 says the AC/DC model is restricted from 0.1 to 5.0 amps, and Page 15 says the X4-80 DC model only has available 0.1-6.0 amps. So I don't see you getting anywhere near the 10 amps needed to reach 2C on those batteries.
And I routinely charge my 3S/1300mAh crawler packs at 2C (2.6 Ah) with no malfunctions to date. I've seen no tangible harm from charging faster than 1C on my batteries.


What else do I need to know related to charging?

Just check each time that your charger's set up for charging a 2S Lipo (if that's what you're charging) and you should be okay. NiMh/NiCad charging doesn't use the same CC/CV charge method, but your charger will still start if you're on the wrong mode. And each port on the X4 is independent, so check each port that you're using. Stay present in the room while charging, don't get into the habit of wandering off.
If you're not going to use your LiPos for a couple weeks or more, try and make sure the resting voltage is as close to 3.85 volts per cell as possible.


Does my lipo need to cool for a certain amount of time after draining before I charge it again?

I do, but it's probably just more of a habit learned back in the NiCad days.
 
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