Controller or Battery problems?

[caykroyd]

I have a WE BL36 wheel and the 50Amp controller that came with it. I hooked this up to 2 series connected 18V ryobi lithium ion battery. got pretty good mileage at cruising speeds, but if I went full throttle the motor would cutoff. I would get a bit of a stuttering or jack hammering effect.

So, I figured the batteries were not sufficient. Switched to 2 parallel Bosch lithium ion since I've read good things about them. Same thing is happening, but recovery seems quicker. I don't know much about controllers, but almost seems like an internal cap is charged by the batteries. Full throttle, discharges cap and batteries can't keep up. But if this was the case, recovery would seem to be seconds to recharge the unloaded cap instead of minutes.

One suggestion given to me is to add another battery in parallel because the 2 batteries cannot supply what the controller demands. I'd almost like to change out controller instead of add more battery. I like the fack of have the two small batteries.

Any suggestions on debugging this problem? Any suggestions on a replacement controller for Wilderness Energy BL36 if the controller is at fault? Or is the clear answer one more battery?

 

[Russell]

I have a WE BL36 wheel and the 50Amp controller that came with it. I hooked this up to 2 series connected 18V ryobi lithium ion battery. got pretty good mileage at cruising speeds, but if I went full throttle the motor would cutoff. I would get a bit of a stuttering or jack hammering effect.

So, I figured the batteries were not sufficient. Switched to 2 parallel Bosch lithium ion since I've read good things about them. Same thing is happening, but recovery seems quicker. I don't know much about controllers, but almost seems like an internal cap is charged by the batteries. Full throttle, discharges cap and batteries can't keep up. But if this was the case, recovery would seem to be seconds to recharge the unloaded cap instead of minutes.

One suggestion given to me is to add another battery in parallel because the 2 batteries cannot supply what the controller demands. I'd almost like to change out controller instead of add more battery. I like the fack of have the two small batteries.

Any suggestions on debugging this problem? Any suggestions on a replacement controller for Wilderness Energy BL36 if the controller is at fault? Or is the clear answer one more battery?

It seems a day doesn't go by where someone isn't having a problem like this so this is going to sound pretty repetitive to most folks here. First of all I really doubt the controller allows 50 amps. I know the re-sellers of the WE kits say it but it doesn't make it so. One retailer who does contribute to this board states the controller is 20A. Controllers usually have rating stickers with such info on them (as well as the LVC, but more on that later) so check for it. Second, GET A METER to check voltages, etc. A Watts-Up meter http://www.rc-electronics-usa.com/ammeters/dc-amp-meter.html which goes in-line between your battery and controller will give you the vital information you need to quickly diagnose a problem like this but at the very least get a cheap multimeter and connect it across your battery so that you can see the battery voltage while taking a short test ride. Watch the meter while you ride and see how much the voltage sags while you apply varying amounts of throttle. Usually 36V controllers will have Low Voltage Cut-offs (LVC) down around 30V (mine are 31.5V on one and 30.5V on the other) and again this is usually on the sticker on the controller. If the voltage of your battery dips to that level while you are applying throttle then you have found your problem.

Two Bosch Fatpacks in parallel can not supply 50A of current without severely sagging so if your controller is truly capable of outputting that kind of current then you don’t have anywhere near enough capacity and need to get a bigger battery right away (I use three Fatpacks with a little 15A controller and have no complaints). My bet is your controller puts out significantly less than 50A and two Fatpacks should handle 20-25 amps while accelerating and a 10A cruise for miles before they drop too much however you should get 2 (or 3) more if you want greater range and battery life with loads like that. One thing you should be mindful of is how you connected the batteries. If you simply stuffed a couple of skinny wires into the batteries then your connections and wiring will be relatively high resistance and could drop significant voltage before the controller. I use 14 gauge wire (good for ~30A tops), solder connections and use quality high current connectors, however if you are pulling high currents then you should be using even thicker wire. Oh yeah and make sure you are charging the batteries properly. Use the Bosch charger or charge to 41.0V (+/- a few tenths).

This should be enough to get you started.

-R

 

[dogman dan]

Still not enough battery in my opinion, at least for this particular kit. Love the way marketing people hype stuff. Cut most vendors claims in half, cut WE claims by half and then cut that in half. On an uphill start, or if you stall the motor, the controller may produce a 50 amp spike before it shuts down. Mine averages around 15-18 amps at full cruising speed. It's not impossible that you do have an issue with the controller, like a high lvc that trips when you get voltage sag. My controller runs fine with 28v nicads, by the way. You might have a bit too much solder on the shunt, and have a true 50 amp controller, or more. Hard to test that without some kind of no bms battery around. Sla's are good doorstops, but when you need to test a controller, it's nice to have some around. Any other ebikes in your town? A test with a set of sla's or nimh would be priceless right now. Another option, though pricy, would be to get another controller and see if the same thing happens.

You may have told us before, but what size wheel, and are you over 200 pounds? The stuttering you describe is what mine does if I put more power through the motor than it can handle at the speed it is running. So I get that noise if I am stalling the motor. It could be something as simple as something wierd with your throttle for all we know. Will it run full throttle with no load?

 

[caykroyd]

I may have access to an sla. I'll check. It's a 24" trike. I'm 180, so I'm sure myself and the trike are over 200lbs. The stuttering happens from dead stop or slow roll. It never seems to cutout during any sustained throttle.

Actually last night I ran up and down my block going dead stop to quick full throttle. I only had one problem where the motor stuttered but then started going. Never had that happen before. Usually when I get a stutter, I have to wait minutes.

It does run full throttle no load without issues.

I'll keep testing. thanks for the insight. I may pull the trigger on a watt's up or cycle analyst to help me debug.

 

[dogman dan]

What you describe does sound a bit like what I experience when I run my 36v aotema motor on 24v. It will run, but I have to really ease into the throttle and pedal to help it get going. If I try to push too hard, the stuttering indicates I'm stalling the motor. Once rolling I can gradually advance the throtte to full and the motor will run fine. The fact that it runs fine no load seems to me to indicate it's not a wonky throttle, or controller, but just a matter of not enough watts to make the motor run well.

This stuttering I described can happen at 36v too, if I am staring out on too steep a hill, and try to floor it too soon. When I ride steep trails in mountains, I have to downshift real low, and then use less throttle. As an assist it still works good, but beyond a certain incline, the motor will stall If I try to just motor up it. So less throttle and more pedaling works best in that situation. I don't know the tech reasons for it all, but It seems like the WE-aotema controller needs a certain relationship between the power going in and the rotation to happen for it to work. Get outside of the "power band" and you get stutter. With a 24" wheel on the hub and you only 180 pounds, the problem is not the bike or the motor. There is still a possiblity that the controller is not 100% though, so a test with another 36v battery would be very interesting. I don't know of any features in the controller that reset with time, so I suspect the waiting a few minuites is something in the batteries bms.

 

[Russell]

I don't know of any features in the controller that reset with time, so I suspect the waiting a few minuites is something in the batteries bms.

FYI, Bosch Fatpacks don't use a BMS. I think what circuitry they do have is simply for monitoring the charging process but I don't believe it has any effect when discharging. I removed the circuit boards completely when I put together my 3-pack.







-R

 

[caykroyd]

Well, after a no fault ride last night, I don't get any power to the motor today. At load, I get the stuttering all the time now. And at no load, I get no stutter or spinning. I get four quick blinks on the controller light. I'm sure this is some fault condition, but the manual doesn't state anything about it.

The battery voltage doesn't drop when throttling either (40.5V). The stuttering while pedaling changes frequency as I change speed. Not sure what this means, but thought I'd point out all my symptoms.

Thanks for all your inputs. I appreciate it.

 

[dogman dan]

Well, now that does sound like a controller problem. The only fix this dummy knows is buy a new one. There is allways the possibility of a bad connection somewhere. If it were me, I'd be buying a new throttle and a new controller from high tech bikes. We are asuming that you have the newer aotema with no hall sensors.

 

[caykroyd]

I have a new motor only 3-wires. Called up my supplier (BernsonEV) and he agrees that's it's likely the controller. He's sending me a new one. He's definitely good with customer service. Hopefully, new controller works out for me.

Thanks for the help.

 

[dogman dan]

Cool! Some of those ebay vendors would do the same thing for you, this year, or next, after 6 months of haggling with pay pal. Who you buy from sure can make a difference!

 

[icecube57]

Hmmm stuttering... sounds like my situation. Mines gets better or worse with speed changes. But he is running a sensorless controller im running one with hall sensor... prob as eveyone else suspected a controller problem

 

[caykroyd]

Received new controller. Bike worked great for one day. Came back next day to try it....no success. Unplugged then replugged all cables and it worked fine again. Tried a couple hours later and no success. The unplug/replug trick didn't work either.

If I lift the wheel, spin it with my hands, and apply throttle, the wheel stops. If I'm riding, this is how my stuttering problems happens.

I'm sure all ideas are exhausted at this point. Not sure there's much debug left. Maybe it's the motor.