difference WF-138 and WF-139

[gravityz]

can anybody tell me the difference in charghing circuit of these
in another thread the wf-139 is discussed but i can not see anything about the WF-138

the charging circuit is about the same
if anybody has an opened wf-138 and can tell me the value of the resistors i can check with my wf-139
only take the resistors which have a normal size. the smd types are top small and are probably not interesting

 

[matrixshaman]

You know the 138 does both 3.6 and 3.0 volt? Any differences are related to that I'm sure. Are you trying to convert a 139 to do 3.0 also?

 

[gravityz]

no it seems that chargingcurrents are different so i try to match the current of the WF-138 with the wf-139(for the 10440)

i allready tested that 1ohm in series with the 10440 will give me roughly 300ma
i tested this last night by replacing the 0.22 restistor with a 1.22 ohm resistor

well probably did not look right at the flowchart because this results in a 60ma current.
i think this is because the r5/r6 voltage is divided by other resistors and then feed back to the LM393

i calculated r5/r6 and indeed if you make this 0.33 ohm(same as wf-138) you will get 250ma so that is what i will do
moify one bay for 10440 and leave the other standard.

 

[gravityz]

i checked on the wf-139
R24/R24(not R25/R26)=10K
R31/R32=220K
D11/D12=330 ohm (why the hell is this low resistor in series with a high one)

if anybody can give me the same resistors on the WF-138 that would be nice. those i need are R14/R28, R21/R15,

thanks

can anybody tell me the difference in charghing circuit of these
in another thread the wf-139 is discussed but i can not see anything about the WF-138

the charging circuit is about the same
if anybody has an opened wf-138 and can tell me the value of the resistors i can check with my wf-139
only take the resistors which have a normal size. the smd types are top small and are probably not interesting