48 Volt mod details?

[kickabear]

Is anyone who has done the 48V mod willing to post the details of what they did and their results?

Thanks!

[myelectricbike]

To start off with I would not use the 36 volt controller but rather buy the 48 volts controller. From there all your need is a 48 volt battery pack and charger. It is likely, however, that you may need to improve the power wiring from the motor to the controller to make it more heat resistant. I suggest replacing all the motor power leads with Teflon insulated 16AWG silver. From there be aware that if you take it on the street in the US you will need to have it tagged. On a freshly charged battery pack I had to back off the throttle at 28 MPH because my old MTB was designed for 10 MPH over rocks and holes in off road terrain and not 30 MPH on a closed but somewhat paved street. Also I had 18 AH batteries strapped to the back - 48 lbs worth.

[pdonahue]

Did you get the 48V conversion working?

[johnbear]

I have tried up to 42, I would like to try 48, but I am concerned about blowing the controller.

[pdonahue]

I've been running 48V for some time now.  There are details on the previous 48V thread.  I had to add a zener diode in line with the resistor feeding power to the 15V regulator on the board.  Other than that, everything worked fine.  I was planning to order the 48V controller, but I didn't get a response from Golden Motors when I e-mailed.  Now I'm convinced that the FETs and other components in the 36V controller are fine operating at 48V. 

One note:  MEB said that his wires melted when he tried passing too much current through it.  It is possible that having the wire zip tied to the bike allows it to dissapate any heat before it builds up enough to cause damage so I'd recommend that you tie the cable tightly to the side of the fork. 


Pete

[myelectricbike]

I have a bunch of melted cables but in all cases, whether it is a single phase power lead tied to an internal spoke or tied to another lead or the whole cable is tied to something perhaps other than the forks, the points at which the tie is tightened is where the short occurs. The low temp insulation melts and the ties force the conductors together.

As for the forks there may be somewhat less pressure from the ties and some of the heat may be dissipated by the forks but even the cables that have not shorted are dented from the pressure of the ties on the forks.

In cases where I did not tie the cable to overcome the problem the jacket provided enough pressure to compress the melted insulation so that the leads could not be pulled apart.

My overall impression is that this was intentional on the part of the designer to keep the motor rating under 750 watts. 

If your insulation has not yet melted perhaps you have an earlier motor where the insulation temperature rating was not degraded and can handle 1000 watts.