Trouble shooting a broken bike

[Hugh]

The title of this thread is beginning to annoy me.

If the OP has trouble shooting his broken bike, he should take better aim.

Elvis shot his car - maybe he could provide a bit of ghostly assistance........

 

[Gdread]

If you overdo it, you can get battery cut-outs when going up hills. If your battery is bigger than 10aH, you can go quite high, but some of the 8 or 9aH bottle batteries are already struggling as standard.

Don't forget that your range will be a probably be bit less as well.

Cheers only got a 9ah so will leave it alone now, commute is 6 miles round trip and uphill on the way home so range isn't a worry.

Thanks again

 

[electrickery]

please could someone explain why soldering 1/3 of the shunt increases amps. would have thought we would have to solder whole shunt ( like increasing diameter of wire? ) obviously missing something ??

 

[Nealh]

Whole shunt solder will double the resistance in general most only want 3 - 5 amps more so only part solder needed, also got to think about battery rating.

 

[Alan Quay]

please could someone explain why soldering 1/3 of the shunt increases amps. would have thought we would have to solder whole shunt ( like increasing diameter of wire? ) obviously missing something ??

The shunt is basically a resistor. It has a very low value, but is of a known resistance. Because it's a resistor, a voltage exists across it, and this is proportional to current. The controller uses this voltage to infer current.

If you solder some of it you reduce the resistance, and the voltage across it. The controller is fooled into thinking it's putting out less current than it actually is, and increases it accordingly.

 

[Alan Quay]

Whole shunt solder will double the resistance in general most only want 3 - 5 amps more so only part solder needed, also got to think about battery rating.

Sorry to disagree, but soldering the shunt reduces its resistance.

 

[electrickery]

so its resisting voltage.. ok..i had the impression current was flowing through it. makes a little more sense now.. I really should look out those o grade physics books. Thanks for the input guys

 

[Alan Quay]

so its resisting voltage.. ok..i had the impression current was flowing through it. makes a little more sense now.. I really should look out those o grade physics books. Thanks for the input guys

Current is flowing through it. Lots of it. But a small voltage is developed across it, because it has a small resistance. This small voltage is proportional to the large current.

Imagine a hose pipe, with two pressure gauges two foot apart, and the tap turned on. The two pressure gauges start off about the same. Now put your foot on the hose half way between them, creating a partial restriction (like the shunt resistor). The pressure closer to tap will rise, the other will fall.