What do you think about this one?

Before connecting the cells to the charger the max charging voltage has
to be set by adjusting P1 (2k potentiometer).
The max charging voltage must not exceed 4.2V per cell (Kokam), e.g. 8.4V for
two serial connected cells. It is recommended using a digital voltmeter.
The max charging current is set by choosing the value of Rx.
Rx = 0.6 / max charging current

For example, for a max charging current of 600mA, Rx should be 0.6 / 0.6 = 1ohm,
while for a max charging current of 1.2A it should be 0.6 / 1.2 = 0.5ohm.
The dissipated power on Rx at a charging current of 1.2A is:
P = V x I = 0.6 x 1.2 = 0.72W

The dissipated power on the LM317 IC is:
(Vin - Vout) x Charging Current.
It's advisable to use a heatsink to prevent the IC from getting too hot.
Notice that the IC's metal package or tab also carries the Vout, so it's necessary
to use isolating washers in case you attach the heatsink to a metal case.