Hello everyone. New subscriber to the forum. I have an issue that I would like some input on.

#1
Hello everyone. New subscriber to the forum. I have an issue that I would appreciate some input on if at all possible.

Before I get to the issue I think it's important to go into detail about what DOES work as well as what doesn't if you are asking for peoples' input.
You get a fuller picture. So please bear with me.

It's not actually my bike but my neighbour's. He has asked me to take a look at it because he's has doubts about it's performance.

I have given it a very thorough inspection hardware wise and everything is fine. Throttle and brake motor inhibitors work, pedal assist sensor gap correct and magnetic
field strength seems good and motor controller no apparent issues. Wiring is clean and robust. Mapped it all out and everything seems to be connected that needs to be.

As an endurance test I ran it on its stand with full throttle for 8 hours beginning with a fully charged battery pack just over 40 volts.

The bike has a 5 LED display for monitoring the battery charge state.

During the test I recorded both the LED count and the wheel RPM on a half hourly basis.

After 8 hours of run time the display showed 3 LEDs lit and RPMs were 120 (down from a 132 at the start of the test).

In travel terms this would be the equivalent of 75 miles. A virtual 75 mile ride if you will. Unladen, of course, but as far as I'm concerned it shows the battery pack, the charger
and the motor are working fine.

The battery pack showed 33.4 volts after the 8 hour test.

So, I put the battery pack on recharge. It took 3.75 hours for the charger to show a green light. The battery pack showed just over 40 volts when fully charged.

With fully charged battery pack on the bike the owner took it for a road test.

The feedback is that it works fine. It goes great when he uses the pedals (ie: deploying the pedal assist) and not so strong when he just uses the throttle.

But his main issue is that the throttle has no effect when he is pedalling.

Now I have looked on a nunber of websites and according to the information about combination drives there are two types. One type you can use both the throttle
and pedal assist simultaneously (let's call that Type 1), the other you can't ie: pedal assist overrides throttle (let's call that Type 2).

At the moment my neighbours bike appears to be a fully functioning Type 2. In which case there is no problem.

However, he tells me that it USED to allow him to use the throttle and pedal assist simultaneously which would make it a Type 1.

So here, at last, is my question.

If it began life as a Type 1 and turned into a Type 2 what could be the cause of this? Have you ever heard of that happening?

What component(s) might be at fault?

Throttle or pedal assist sensor? Both appear to be workig fine independently.

Motor controller? After all, it's the controller that's responsible for handling input and output.

Has anyone else had this experience?

Would appreciate your input.

Pic of the bike attached. It's an obscure make. Kiongying.

Thanks
 

Attachments

indianajo

Active Member
#2
Welcome to the site.
First off your unloaded spin test of the motor proved not much about the battery. Total capacity seems okay since you got 8 hours 30 watts or something, 240 wh. Both my defective batteries were able to spin the tire with it off the ground for longer than I cared to hold it up. 50 watts or less. What the second one could not do was deliver 150 watts for 1 second. As testing that involves pedaling the bike home unpowered, and as I could not tell if the battery was defective or the motor had a shorted turn, I brought the battery to town and load tested it with resistors to 170 watts. As my battery was 48 v I loaded it down with 15 ohm 775 watt resistors, and measured the voltage. Voltage collapsed immediately to 6. That was about 3.3 amps at 52 volts which was full charge. Determine what is the full wattage of the motor, and load the battery down to about a third or half of that with resistors, to determine if the battery is bad. 15 ohms may be too much resistance for a 36 v motor as yours probably is. The resistors I used were 5 ohms 225 watts each. They were dale brand and I got them at apex electronic surplus in Sun Valley. Aparently they've abandoned their website and moved to facebook, which I am not allowed to see since I don't give away the security code to my retirement account.
If the battery voltage is collapsing when the owner uses the throttle, that could explain the lack of increased performance. That could also be determined by watching battery voltage while riding, but I found that too dangerous to do on my bike. I would have had to hold the meter in my hand and that was a bad idea.
Before testing the battery, note that 36 v could stop your heart if it crosses it. Use only one hand at a time to touch metal. Also current through metal could burn your flesh to cinders. Remove all jewelry from hand wrists and neck before fooling with a charged battery. Wear safety glasses, lithium ion batteries can explode into flame especially if defective. Do charging and testing of lithium ion batteries outside where any fire could not hurt anything expensive.

Another idea is that a setup parameter in the controller has changed. One of my bike motors had programmable setup numbers, about 24 of them. I accessed them by pushing both the up and down arrow button with the system off. The you can scroll through the parameters on the display with up and down arrow. WRITE DOWN the original parameters by the parameter number first before changing anything. Then change any parameters below 4, one at a time, to determine what they do. If you don't like the change, put it back for going to another. Yes this is a tedious process. No telling what any parameter actually does without changing it. Unless somebody has experience on this model. Not likely except for the original dealer.
Best of luck.
 
Last edited:
#3
Hi Indianajo. Thanks for your input. Battery pack is new. 6 x 6 volt SLA batteries in series as per original equipment. The neighbour replaced the originals thinking it was the batteries that were responsble for his perceived problem which is that he used to be able to use both throttle and pas simultaneously but now he can't. This is a very basic machine wih no human interface to the controller other than throttle and pas so it's not as if someone could change a config setting to flip it from one to the other. They are logicall opposite too when you think about it so it's not likely to be a programming error. I might just do a load test on the batteries too. Sounds like a fun thing to do although a little, if not a lot, geeky. Motor rating is 350w - 500w. Middle of the road 325w. So I should be looking at about 4 ohms.
 

steve mercier

Well-Known Member
#4
Hello everyone. New subscriber to the forum. I have an issue that I would appreciate some input on if at all possible.

Before I get to the issue I think it's important to go into detail about what DOES work as well as what doesn't if you are asking for peoples' input.
You get a fuller picture. So please bear with me.

It's not actually my bike but my neighbour's. He has asked me to take a look at it because he's has doubts about it's performance.

I have given it a very thorough inspection hardware wise and everything is fine. Throttle and brake motor inhibitors work, pedal assist sensor gap correct and magnetic
field strength seems good and motor controller no apparent issues. Wiring is clean and robust. Mapped it all out and everything seems to be connected that needs to be.

As an endurance test I ran it on its stand with full throttle for 8 hours beginning with a fully charged battery pack just over 40 volts.

The bike has a 5 LED display for monitoring the battery charge state.

During the test I recorded both the LED count and the wheel RPM on a half hourly basis.

After 8 hours of run time the display showed 3 LEDs lit and RPMs were 120 (down from a 132 at the start of the test).

In travel terms this would be the equivalent of 75 miles. A virtual 75 mile ride if you will. Unladen, of course, but as far as I'm concerned it shows the battery pack, the charger
and the motor are working fine.

The battery pack showed 33.4 volts after the 8 hour test.

So, I put the battery pack on recharge. It took 3.75 hours for the charger to show a green light. The battery pack showed just over 40 volts when fully charged.

With fully charged battery pack on the bike the owner took it for a road test.

The feedback is that it works fine. It goes great when he uses the pedals (ie: deploying the pedal assist) and not so strong when he just uses the throttle.

But his main issue is that the throttle has no effect when he is pedalling.

Now I have looked on a nunber of websites and according to the information about combination drives there are two types. One type you can use both the throttle
and pedal assist simultaneously (let's call that Type 1), the other you can't ie: pedal assist overrides throttle (let's call that Type 2).

At the moment my neighbours bike appears to be a fully functioning Type 2. In which case there is no problem.

However, he tells me that it USED to allow him to use the throttle and pedal assist simultaneously which would make it a Type 1.

So here, at last, is my question.

If it began life as a Type 1 and turned into a Type 2 what could be the cause of this? Have you ever heard of that happening?

What component(s) might be at fault?

Throttle or pedal assist sensor? Both appear to be workig fine independently.

Motor controller? After all, it's the controller that's responsible for handling input and output.

Has anyone else had this experience?

Would appreciate your input.

Pic of the bike attached. It's an obscure make. Kiongying.

Thanks
... it looks like a mustang bike had sex with a skateboard .
 

Alex M

Active Member
#5
Must be heavy as hell with those FLA batteries.

I "doubt" there is such thing as using throttle and pedal assist at the same time. Some bikes require you to put it in PAS 4 or 5 for throttle to work fully, some "override" PAS setting, allowing full throttle no matter what PAS is set to. You can run throttle and add a little speed by muscle input, but pedals won't be PAS-powered at that time. It would be dangerous if they were.

If he wants to experiment, tell him to go ahead and replace the controller - shouldn't cost much on Aliexpress.
 

harryS

Well-Known Member
#6
I own and have tried a number of controllers (over ten), but have settled on one type for present and future ebike builds. I've never seen one where throttle could not be feathered in with pedal assist working*. What I have seen though is with lower power ebikes is that the throttle effect can be pretty weak if the bike is at speed.

You did not mention any speeds in your testing. For a 26" wheel, I compute 120-130 rpm to be 9 -10 mph. I haven't thought about lead acid in a while, but shouldn't six new SLA cells in series (@7.2 volts each fully charged) should be over 43 volts? By the way, I don't think 6V SLA batteries can be run much lower than 5.5V, if they are not deep discharge marine type cells. It kills their life fast.

Seems to me the problem could be weak batteries, maybe not fully charged or maybe run too low by owner.

*exception is latest bafang BBS02/BBSHD mid drive kits, Throttle cannot be used with pedal assist. I've only read about this issue. Mine is an earlier model that works fine,
 

Alex M

Active Member
#8
For quick getaways it will be probably quicker to open the throttle to full 1000 watt (or whatever is max motor output), than opening throttle halfway to 500W and then waiting for PAS 5 to kick in for another 300-400W.

OTH, when throttle is fully open, PAS won't add any power - because motor doesn't have any more power :). You would only add meager 30-40W of muscle power then.