48V in a 36v system

[myelectricbike]

A Crystalyte dealer just told me he has no problem running 5,000 watts through the 500 series, but then he lives in Canada.

[Mordaz]

There's no such law here in Brazil.  Do you think I can order such a kit from Phil? 

[mustangman]

  Myelectricbike, I believe that crystalite dealer, if you take 40 amps and 72 to 96 volts, you come up with 2880 to 3840 watts. This is far above the 700 watt "limit" for consumer goods. Thus, Golden should come up with its own "super-duty" hub motor to compete with brand "c" and brand "x". We will call it the "Golden-Olypian" motor in honor of the 2008 Olympic games to be held in China . (Biker shorts optional)

[myelectricbike]

The last kit I ordered for a customer in Brazil was delayed by customs and required Philip's efforts and the Brazilian customer to get involved with customs. I'm surprised the Chinese navy was not involved! There may be no restrictions in Brazil on motor size (yet) but there may be other restrictions which could keep you from receiving a non-standard or "Olympian" kit.

According to my friend in Canada, you can do your own rewind to get higher power, torque and speed. Before I can post instructions here though I'll have to check with Philip. We do want Golden to be able to continue to export standard kits.

[Mordaz]

myelectricbike,

I have ordered a kit from Phil and had no problems (from China do Brazil).  There was indeed a delay, but just the usual.  I paid the due taxes and that was it. 

Now I want to order two more, but it's so difficult to contact Phil.

Roberto

[myelectricbike]

It seems to be a problem that everyone is currently experiencing, due according the Philip his efforts to get a customer service center established. How much did you pay for shipping from China to Brazil?

[Mordaz]

US$ 105 (TNT Air Shipping).  I did not order a full kit, though.  Only the hub motor, the speed control kit and special-sized spokes.

[myelectricbike]

Size box and weight do make a difference.

[pdonahue]

I foresee you having serious problems running 48V through your 36V controller. Both the motor and the controller were warm to the touch after a measly 15kms?

You are going to have a mess of melted wires at some point, pure and simple....
I've worked alot with zener diodes, in defeating the overboost cutoff functions on several turbocharged cars.... It's a nice bandaid...no more.
....you are going to have problems if you continue to abuse your 36V system with 48V.
But to each his own....hammer down

Actually, if the controller and motot being warm to the touch is a problem, then the 36V is an issue as well since it also was warm to the touch after 15km.  FETS passing 10s of amps are going to generate a little heat.  I agree that the wires will melt down eventually, but I'm much more worried about the power leads to the motor rather than controller leads.  When (possibly if) the wires melt down then it'll be a good excuse to take it apart and re-wire it with some heavier duty wires!!    More EE fun!!!

And finally, a question:  What is the problem with using zener diodes as long as you don't overheat them with too much current? 

[myelectricbike]

The regen controller actually uses high volt, high amp zeners to limit input through the mosfets either from applied or from Counter EMF. 1.5KE62A I think.

[pdonahue]

Just an update:

After a week of use (2 x 15km each day plus a 10km trip to my ultimate game) the bike is still running fine at 48V.  The acceleration is a little better, but the real advantage is the higher top speed and higher speed going up hill.  There is slight incline on the road leading to my office.  At 36V the bike would slow to around 25kph, but now it holds 35kph.  My total commute time is down from about 35 minutes to about 25 minutes depending on how many red lights I hit.

Pete

[Electric_Bike_2007]

I bought my KIT direct from China.

and receive it after 10 days here in Brazil.

 (around 105 USD  taxes in mail )

The next test will be add one 6v battery in series with 36v original system.(42v max)

Hope it works...

Regards.
Luciano

[pdonahue]

Just finished the second week of use...  Another 200km of riding and no problems...  I'm beginning to think this may actually work fine!!!!      

[Electric_Bike_2007]

Hi pdonahue.

Good news.. Thank you for your report..

Just to confirm. Did you change something in the controller?
(Are you using 4 x 12v batteries, right?)

I will start adding just 6V more... for preliminary tests(42v)(Enhanced version)

After that, I will move to 48v(Dragster version..)  

Regards

[pdonahue]

Hi pdonahue.

Good news.. Thank you for your report..

Just to confirm. Did you change something in the controller?
(Are you using 4 x 12v batteries, right?)

I will start adding just 6V more... for preliminary tests(42v)(Enhanced version)

After that, I will move to 48v(Dragster version..)  

Regards

Yeah,

The controller should just work with a 42V battery.  To get it to work with 4x12v you have to add a zener diode in line with the 150 ohm resistor that feeds the 15V regulator.

Pete