I own a LOT of chargers. 13...
From the starting days of the 50W/5A "4 button" chargers, to the next levels of 150W/10A... 200W/7A... (still "4 button" type)... and then onto the LEMON Radiolink CP620 750W/30A (and has 6A balancing!!!) capable!!
50W chargers can't charge many battery capacities very fast at all....
Some Charger Info:
The Watts rating sets the MAXIMUM POWER the charger can pass. But it also has a Voltage maximum and a Current (Amps) maximum.
So they will most often list Voltage as "2S to 6S" etc (2S to 8S). So then you know how many cells it can charge at most.
And they will list the maximum Current it can pass. eg say 5 Amps.
"Up to 6S at 50W/5A"
Then for any given cell count, thus Voltage, you can derive what it could charge that battery at the most.
So let's use 6S to make it tough for the charger (because it is the highest Voltage it can do).... 6S peak voltage is 6 x 4.2v = 25.2v
To see what maximum Current is POSSIBLE at that Voltage, divide the POWER by the Voltage. 50W / 25.2v = 1.98 Amps
This is because no matter what, the POWER is the top limit of the charger.
There are the THREE limits - Voltage, Current and Power... and NONE can be exceeded. (eg not even just one). The charger itself will stop at its limits.
So the MOST you could feed into a 6S battery with a 50W charger is 1.98Amps....
If it was a 2200mAH battery then that 1.98A max is almost 1C (0.9C). If it was a 5000mAH battery then it is 0.4 C
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