4s 2200mah 70C with a 4.2V?????

[beng]

I just got the FT mig-3 kit it comes with a battery that gets me......"G5 70C max 4s 2200mah 4.2V." I have seen something about each cell will charge to 4.2V. Is this what they are saying and how do I re-charge? My charger when put on 4s will say 14.8V. I tried to contact them, nothing yet...This is what THEY say to use for the E-max 2215/09 1200KV motor. In the video, they were putting in a 4s 1600amh 14.8V 70C Can I use a 2200 4s battery? Thanks

[rustygunns]

Hi Beng,
Only a student pilot myself but I've been doing alot of research into Lipo battery and such. The whole line of "G5" battery's they sell are all labeled that way(4.2v) which I'm assuming they do because they have a "G7" line of battery's they label as 4.35v. As you have read 4.2v is the standard fully charged voltage of a single lipo cell(1s) where as 3.7v would be the standard voltage to discharge a single lipo cell down to. From what I've read if you discharge a lipo battery much below 3.7v per cell you risk damaging the battery. They advise that you could charge that battery at 5c-6c maximum but personally I'd only charge it at 1c meaning a 2200 mah would charge at 2.2 amps. the 5c charge rating would mean you'd charge it at 11 amps. From what I've read althou they claim you could charge at that higher rate you'd only be shortening the life of your battery. As far as using the 2200mah battery instead of the 1600mah battery you should be fine, the mah rating of a battery is the capacity of the battery so the 2200mah would give you longer run times over a 1600mah battery. The important thing is the voltage, a 4s or 4 cell battery should'nt be used in place of a 3s or 3 cell battery unless the esc is capable of handling the extra voltage. As far as your battery I'd charge it at the 4s setting(14.8v) using 2.2 amps charge current, once fully charged you'll probably see a total voltage reading somewhere around 16.8v. Try not to discharge that pack lower than 14.8v, there's several small devices you can put on the battery that give a warning sound when you reach the recommended discharge voltage. Hopefully I didnt overwhelm you with figures, I'd recommend spending some time on youtube, there's several good video's explaining all the ins and outs of lipo's, If you need anymore help just let me know

[WintrSol]

Limiting the charge rate to 1C to extend the life of a lipo is old school, and no longer required. There are many battery testers who have charged at many times that rate, with no measurable decrease in life of the batteries, some up to 10C with batteries made in the last few years.

Charging a standard lipo cell above 4.23V, or discharging to a resting Voltage of less than about 3.3V, will quickly degrade it; the low number is kind of fuzzy. But, leaving one below about 3.7V or above 3.9V for any length of time will also degrade it, but more slowly, which is why storage charging is recommended. For the HV type, 4.35V is the limit, while the lower limit doesn't change; storage charge also still applies.

Note I said 'resting Voltage'; under load, the Voltage will be less because of IR, and cause a false alarm with a small monitor. I will often see an in-flight Voltage of 3.5V per cell and, after landing, the battery will be between 3.7 and 3.8V, but it depends on the battery and current drawn. My Admiral 4S 4Ah batteries behave this way in the Sabre, which cruises around 25-30A, which is only a 6-7C load; if I flew it at higher power levels, I could see as low as 3.4V per cell at the same state of charge. This is why those cheap monitors, assuming you can hear them under load, can be misleading. I always fly with a timer, adjusted until the resting Voltage, after a typical flight, is above 3.7V; on windy days, or days I get more sporty in the air, I land before the timer expires.

I agree that the markings are to distinguish the standard line from the HV line - charging a standard lipo with a charger in HV mode could start a fire; it will certainly waste a battery.