[frodus]

Originally Posted by Lexus

OK Question .. how do you set up your Brake System on the Bikes ???

Front and Rear ??

just leave it stock... no reason to change it... Its all hydraulic, so you just leave it alone.

[ngrimm]

Thank you for your replies. One more question. Do you think that six 85 ah lead acid batteries could deliver more than 300 amps thus justifying a 400 amp controller? Norm

[frodus]

Yes... Definately. Most batteries that large have CCA (cold cranking amps) ratings. It will deliver that current for <20 seconds, but it will deliver it if needed.

Go for the largest you can afford. Its not going to hurt anything, the controller SHOULD limit the battery side current as well as motor side.

400A on a motorcycle though seems plenty. How big are those 85Ah bats? Whats the weight? Just make sure you're not going to have a 2 wheeled bike that acts like a 3 wheeler (three contact points to the ground.... haha). Seems kinda heavy to me.

What range/speed are you looking to get out of this thing? And how much room do you really have? Where did you come up with the 85Ah battery requirement?

[ngrimm]

I am basing my battery size loosely on this conversion on the Evalbum
http://www.evalbum.com/1414
He claims the performance is decent with gearing set to 50 mph.

He is using six 85 ah lead acid, 300 amp alltrax controller and a permanent mag motor versus my series wound but hopefully my range will be similar to his of 30+ miles. The batteries weigh around 50 lbs each. I chose the battery size based on dimensions of which would fit without hacking the frame. Of course like everyone else I just know I'll have lots of money to buy better/lighter batteries in the future.

[ngrimm]

I had some trouble getting either of my used Curtis controllers to work so I decided to take a few rides just using a contactor and three 12 volt deep cycle batteries in parallel. It was a little sluggish at 12 volts so then I connected them in series for 36 volts. All I can say wow! Even with a rolling start the front end tries to lift up. Then some family and friends showed up and had to try it. Even my son in law who is 6'6' and 300lbs was impressed. Several of the neighbors have been monitoring progress so they dropped by too. I know it's not good on the batteries etc. to run it like that but was just a test and I didn't go under 50% dod.

[kek_63]

I tried the contactor only route for a little while myself - 4 6v GC batts in series for 24v. Took off like a scared rabbit, but cables got VERY warm. I thew an ammeter on it - 650amps. Yikes. Now I have a 275amp controller with 36v of marine deep cycle; everything stays much cooler and except for the first 10 feet or so the acceleration is quite good.

[ngrimm]

I've been running my 36v 400a Curtis with all current limits disabled. I had to bypass much of the circuitry in order to get it to work so basically I have my throttle pot connected to the final comparator before the mosfet drivers and The controller case is fastened to a one inch think aluminum plate to help keep it cool. This is just temporary before enabling my own current limiting scheme. I thought I'd check the amp draw with a cheap clamp meter and so far I haven't been able to get it to pull over 100 amps power braking it etc. The accelleration seems pretty good although I am only running three 12v 85ah deep cycle batteries. I was really worried that I might be over driving it. Does 100 amps sound right? Thanks guys. Norm

[lazzer408]

Originally Posted by ngrimm

I've been running my 36v 400a Curtis with all current limits disabled. I had to bypass much of the circuitry in order to get it to work so basically I have my throttle pot connected to the final comparator before the mosfet drivers and The controller case is fastened to a one inch think aluminum plate to help keep it cool. This is just temporary before enabling my own current limiting scheme. I thought I'd check the amp draw with a cheap clamp meter and so far I haven't been able to get it to pull over 100 amps power braking it etc. The accelleration seems pretty good although I am only running three 12v 85ah deep cycle batteries. I was really worried that I might be over driving it. Does 100 amps sound right? Thanks guys. Norm

The AC clamp meters will not read correctly. They will only read ripple from the pwm signal. Why did you bypass the current limiting? If your that far into the Curtis drive board, why didn't you just change the ref. voltage for the current comparator? Check out my thread about the 3524 pwm. I plan on building my own drive board based on the 3524 for a modded (200v) Curtis 1205 until I get my own controller finished. That chip has a current sense input. Your asking for it not having that on yours. Mosfets like to blow shorted. Hope your manual disconnect is working or your faded brakes are stronger then your motor. =)

[ngrimm]

Thanks for the reply. Actually this one reads ac or dc up to 1000 amps. Here's the one I bought:
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN:IT&ih=015
Incidently, I should have bid on this Triplet meter but I was in a hurry and no one else bid on it either.
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=005

I was just now able to take it out on the open road a little and it read 125 amps briefly when I was accellerating hard. It certainly runs a lot cooler now that it's not 100 degrees out.

[lazzer408]

I still question it's ability to read both at once, or neither of either? I assume it measures DC by applying a freq to it's pickup coil and the magnetic field in the clamp will determine the current based on the amount of disruption of the coil's natural inductive characteristics. AC measurement is simple measuring the voltage induced into the coil and converts that to a current measurement. The battery leads and/or motor leads have both AC and DC present. The frequency of the pwm can even come in and out of phase with the instruments measuring frequency creating more problems.
Take a measurement at different places. Try at the battery, then at the motor. Is it different?

Grab one of those digital meters with a shunt off ebay. Their cheap.