gravityz
Enlightened
got my order from dx today so i tested my idea
WF-139 charger
8x 8mm magnets from DX to extend negative charging pole
ultrafire 10440 unprotected 3.7 volt battery
1.5 ohm resistor
first i extended the negative pole with the magnets so the 10440 battery makes contact with both + and -
i put a 1.5 ohm resistor in series with the battery.
you can do this by seperating the resistor threads with a thin piece of plastic/carton.(+pole--resistor thread--carton---resistor thread---+pole battery)
late i am planning to do this permanent on the magnets for easy removal
Charging current is 250ma and declines to 160 ma when the battery is nearly full
Charger goes slowly up to 4.28 volts and then the protection kicks in
after protection kicked in the voltag of the battey is 4.18 volts
sounds like the way to go for charging 10440's
please note that the resistor is only used to lower the carging current from the standard 400ma to 250ma
the voltage can not be adjusted and terminates depending on how accurate your charger is.
i was told 4.25 volt +/- 0.05 volts is the setting for protection circuits on batteries so the charger protection fits nicely in this range.
i will place photo's as soon as i have a permanent solution(i need to mount the sesistor somehow to the magnets to create 1 unit i can easilly attach/remove in case i need to charge other types of batteries
WF-139 charger
8x 8mm magnets from DX to extend negative charging pole
ultrafire 10440 unprotected 3.7 volt battery
1.5 ohm resistor
first i extended the negative pole with the magnets so the 10440 battery makes contact with both + and -
i put a 1.5 ohm resistor in series with the battery.
you can do this by seperating the resistor threads with a thin piece of plastic/carton.(+pole--resistor thread--carton---resistor thread---+pole battery)
late i am planning to do this permanent on the magnets for easy removal
Charging current is 250ma and declines to 160 ma when the battery is nearly full
Charger goes slowly up to 4.28 volts and then the protection kicks in
after protection kicked in the voltag of the battey is 4.18 volts
sounds like the way to go for charging 10440's
please note that the resistor is only used to lower the carging current from the standard 400ma to 250ma
the voltage can not be adjusted and terminates depending on how accurate your charger is.
i was told 4.25 volt +/- 0.05 volts is the setting for protection circuits on batteries so the charger protection fits nicely in this range.
i will place photo's as soon as i have a permanent solution(i need to mount the sesistor somehow to the magnets to create 1 unit i can easilly attach/remove in case i need to charge other types of batteries
