opperpanter
100 W
In the mean time, why is it better to replace the resistor instead of the regulator?
Help me identify and upgrade 36V controller to 48V
- Thread starter opperpanter
- Start date
dnmun
1 PW
the regulator is there to make 12V but it needs to have the input voltage low enuff that it can drop the voltage down to 12V so that is why you may have to increase the resistor to make a larger voltage drop to the input of the regulator.
opperpanter
100 W
Thanks, I understand that. But replacing the regulator with one that can handle the higher input voltage could work as well? Why is replacing the resistor beter?dnmun said:
dnmun
1 PW
there is no other regulator which handles higher input voltage.
dnmun
1 PW
with 14S lipo charged to 58.8V your input voltage to the 317 is about 50V.
if you find a 200 ohm 2W then you could put it in series with the 150R that is there by unsoldering the end and sticking the extra resistor into the hole and tie the lead together and solder them on top.
that might work but it will be hot. about .6W of heat in the 200R so 2W is ok. and you would have 350R total, 19-20V drop from 58.8=39V is ok for the regulator imo.
if you find a 200 ohm 2W then you could put it in series with the 150R that is there by unsoldering the end and sticking the extra resistor into the hole and tie the lead together and solder them on top.
that might work but it will be hot. about .6W of heat in the 200R so 2W is ok. and you would have 350R total, 19-20V drop from 58.8=39V is ok for the regulator imo.
opperpanter
100 W
What about lm317ahvt ?dnmun said:
https://www.fairchildsemi.com/datasheets/LM/LM317AHV.pdf&ved=0CCYQFjAB&usg=AFQjCNGBeTNyRCjHDEwlI_I1tXU7FuEcIQ&sig2=W_Pr4d8C0TmfA6cP1Awb2g
Just thinking out loud here. The lm317(ahv)t has a little heatsink so might handle the heat better?
Maybe i first need to measure, might be current resistor already is good enough.
dnmun
1 PW
your controller is made to work with a 36V SLA so the LVC is 30V and the voltage drop is 9V across the 150R resistor. so the input to the regulator normally would be 21V at the end of discharge. which is the critical point. you are starting with 14S and LVC will be 42V so with 350R the voltage drop is 19V and the input to the regulator is about 23V so it should work best with 350R and you will catch on eventually when you measure.
opperpanter
100 W
opperpanter
100 W
I can now confirm that the resistor is 150R, as expected by dnmun.
Can I just connect my 48V now to see what voltages goes to the lm317, or will I burn it that way.
In other words, do I need the extra resistor to be in place before testing the lm317 input voltage with a 48V battery?
Can I just connect my 48V now to see what voltages goes to the lm317, or will I burn it that way.
In other words, do I need the extra resistor to be in place before testing the lm317 input voltage with a 48V battery?
dnmun
1 PW
did you measure the voltage on the input to the 12V regulator? it is clear it is 150R from your picture. if you measure the voltage across that resistor you will know the circuit current so you can then estimate what to use for the extra power resistor.
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