Today I tried to reverse enigineer the original C5 charger. The new battery I got must not be charged with a voltage over 14.4 Volts but the original charger goes up to 15.7 before throttling down and that might destroy the battery.
The controller is a potted circuit board with mostly unrecognizable parts. There is a single 100k resistor connected to two pins but changing the value of it does not change the maximum voltage.
Has anyone tried to modify the charger ? Are there any circuit diagrams for the charger ?
If not I could try to make a new 'controller' which re-uses the power parts (the SCR's and such) and will generate the right charging curve for the new battery.