Potential problem with throttle on an R-20

I don't know about the throttle voltage, but it sounds suspiciously like a controller problem.

When I started riding my Z-20, there were times when the bike would start to move and then just quit. Most of the time, recycling the throttle (going back to 0 and starting again) would get the bike going, sometimes I would turn the ignition off and back on and it would go. It didn't happen very often but did make me hesitant when entering traffic.

Then one day after about 4 miles on the first 90 degree day of the year, I was accelerating and the motor just quit after hitting about 20mph. I stopped, tried turning the ignition off and on, and waited to make sure the controller wasn't overheated, but all I could get was a little lurch and then nothing. After a number of attempts it wouldn't even lurch anymore. There was no smell from the controller, and even after I opened it (which Andy scolded me for) it did not appear to be burnt out.

After about 3 months of frustration with EVT, I finally got what Andy called a "4th" generation controller, installed it, and it has been working since. However, we have had a cool spring and are just now hitting the 90 degree mark again in Chicago. I've been hesitant to ride any distance in these temperatures.

I did purchase a KEB72601 replacement that I have not installed yet. I sent several email to Andy months ago trying to get a pre-wired Kelly and have never gotten a reply. But after emailing Kelly directly, I had my new controller 3 days later.

There is no question the Kelly is a better controller that should serve for the life of the bike, but I'm not really looking forward to figuring out the wiring. Kelly included a prewired "J2" cable that helps greatly, but is not plug and play.

So, it is possible you have lost a couple of MOSFETs in your controller and it is still working but at a reduced output. It is also still possible it could be batteries. One disadvantage of charging batteries in series is if batteries reach full charge at different rates, it is possible for one or two to get overcharge and damaged, which could then pull the whole pack voltage down.

I had added battery balancers to my bike and they are now standard on the 30 models. From what I read they seemed to be worth the roughly $180 I paid for them if they actually end up increasing pack life 2-3 times. The disadvantage I have found, is they are contantly balancing the batteries, so they are always pulling a small amount of power. If the bike sits without the charger for more than a few days, the pack will not be fully charged. They need to be disconnected for storage. Some people have also wired their bikes so they can use 5 separate 12 volt chagers, one for each battery. That also eliminates the imbalance problem.

Hope that helps.

Scott...

I would also suspect a controller problem. I had similar lurching behavior with the original EVTA controller. The Kelly controller does not have that problem. My throttle was returning 4.4 volts at full throttle, so your's may be a little on the low side, but I don't think it's your fundamental problem.

Looking at the Kelly Controller manual, I don't see an adjustment for the voltage range. The manual shows a 0-5v range for the throttle. However, the controller does provide a 5v supply input. So, if the throttle is a variable resistor, the top end of the range is normally shorted. In other words, full throttle is the equivalent of putting the 5v supply directly into the throttle input.

The controller is programable using software that can be downloaded from their web site, so I wouldn't rule out being able to control the throttle voltage range.

As far as a "dampener", I'm thinking you are saying exactly what the Kelly controller does that the OEM does not, that is protect itself. If the controller detects an over current or over temperature condition, it will reduce output or shut itself off to prevent controller damage.

Scott...

Looking at the Kelly Controller manual, I don't see an adjustment for the voltage range. The manual shows a 0-5v range for the throttle. However, the controller does provide a 5v supply input. So, if the throttle is a variable resistor, the top end of the range is normally shorted.

Hi Scott,

in the configuration software, you can change the "0" lower voltage limit and the "full" upper voltage limit for the throttle.
they dont label it in volts, they label it as percentage.
for lower limit you can choose between 0, 10%, 20%, 30%, and upper you can choose between 80%, 90%, 100%.

you can use eitehr a variable resistor, or a hall effect device.
If you have the option, *always* use the hall effect device. They are more reliable and last *forever* (failure mode on a hall effect is not working, failure mode on a resistive throttle is dead spots of full throttle)

Matt

Electrolex, Hi I just installed a kelly keb72601 in my xm3500li. It was fairly easy. If you have any questions post them here and maybe I can help. I live in Lindenhurst so we're In the same general area. You'll love the kelly controller and you should hook up the regen braking. You can set it to work through the throttle as is but I recommend getting a 0-5v thumb throttle and using that to get full variable regen. I'll post the link to some other info on regen.
http://visforvoltage.org/forum/6520-activating-regen-braking
If you look at the other thread that says kelly controller much smoother I left some info on installation. I could have done a better job. I might install one in a friends scooter. If I do I'll take some pictures and describe the process better. Hope this helps.
PS I know it's frustrating but the quiet electric ride is pretty cool you have to admit