feep

Can anyone tell me how to determine the correct " charge status" on a Skyrc e4 charger ? I bought it to charge a 4 cell Lipo battery. It 3700 mAh, 45C, 14.8 v. The charger has a switch for 1A, 2A, or 3A but the directions don't indicate how to determine the setting.
And will the charger even be enough on 3A for a 3700 mAh battery?

trax de max

battery capacity / 1000
3.7A but your charger can max a 3A which would just take longer.
But your charger has only a 20Watt output power which would take even longer, much longer expect a time of 4 hours from low voltage to charge.

chuckk2

Any of the charger's current settings are OK for the voltage and capacity of a 4S3700mah Lipo.
But, a 20W charger will not deliver 3A charge current to a 4S Lipo.
So, the real question is how much current can the charger provide, and how long will it take to charge.
This is a bit messy, since the battery voltage increases as it's charged, and also
increases with the charge current (Up to a limit of 4.2 per cell, which causes the charger to voltage limit.)

Picking a voltage of 3.7v per cell as the initial battery voltage
3.7x4=14.8v
20W/14.8v=1.35A

Lets look at 4.0v
20W/16v=1.25A
And finally 4.2v
20W/16.8v=1.19A


Lets use 1.2A as a charge current to approximate the charge time.
3700mah Lipo
80% of 3700 =2960
(Round to 3000)
3000mah/1.2A=2.5hours (Plus any balance time)

So, the 2A or 3A settings will result in the shortest charge time. (That was rather obvious to begin with)
If the charger gets warmer than you like at the higher settings, try using the 1A setting and accept the longer charge time.