DIY $60 A123 charger

Put 7.2K ohm 1% 0.5W for 25.2V output.
The white 水泥電阻 5W, 0.1 ohm is current limiting resistor. PUt 3 in parallel for 3A output and 5 in parallel for 6A output.

There is a new version of SUPER car step up adapter rate at 100W.

Original Value:
Parallel Base resistor 7.5k Ohm
Volatge selector resistor: 15V Open circuit, 16V 72k, 18V 22.1k, 19V 18.6k, 20V 14.8k, 22V 10.65k,24V 8.6k?

Modified:
Parallel Base resistor 9.7k Ohm
Voltage selector resistor: Open circuit --> 12.6V, 5.8k --> 25.2V

If not change the prallel base resistor, 7.2 kohm will output 25.2V

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Now I made 4 chargers and take 48A altogether with the car engine & alternator running. Finish charging in 15-20 mins.

My R/C Helicopter Collection

E-Sky FP2
Trex 450
BlackHawk
Lama V2
Compy
Trex 600
Hurricane EP550

$15 1.5A-3A linear charger for lipo

from rcgroups

needs 3V higher voltage input.

upgraded to LDO regulator, but need large heat sink and troublesome. Low efficiency.

Now retired and replaced by cheap switching regulator.