MP3 - Controller died or what ? ... NOPE! A DEAN plug was the culprit. It Works!

[Aliasssss]

Hello. I'm Daniel from Romania and I bought myself a Magic Pie III electric bicycle conversion kit form an EU reseller of MP III kits. I do not post the link to the website as I do not want it to be considered SPAM or advertising. If someone from European Union needs to know more just PM me. Nice to meet you all.

It seems I do have the new MP III controller as it can supply continuous about 31.92 amps for about 5 seconds at startup. I do use my MP III at 48V so my trusted Turnigy Watt meter it's showing almost 1600W during start up and on full throttle, after about 5 seconds of almost 1600W it drops down steadily while accelerating, until it stabilizes to about 900W when reaching the top speed of about 42.6 kilometers per hour, that's about 26.6 MPH. I'm a heavy rider weighing 124 kilograms or 273.3 pounds and my bike is an 26" mountain bike, Leader Force. MP III is rear mounted. Also wanted to mention that my settings are: 48v, 100 speed, 100 acceleration, 30A continuous and 70A peak. During takeoff the motor really pulls hard (those 1600 watts) if it's set at 100 acceleration. Now if you pedal also during takeoff you really can outrun just about every car normally found in a city and they wont catch up until you reach about 30KPH. If you don't wanna feel the thrills better set the acceleration down a notch to around 70%. Now about the battery I use, it's a modular one made from 16 Headway 40152S cells. Each cell gives around 3.2v nominal and 15Ah, but when fully loaded the pack open circuit voltage is around 54.6v. I don't use a BMS, but I did bottom balanced the cells to 2.75v each before making the pack and after about 20 cycles all cells are within 0.01 volts when discharged or charged. I try to use the cells fully as that still gives me 1500 until they reach 80% of the original capacity and that is plenty for me. The pack weights 8.1 kilograms.

I only installed one of the brakes supplied because my front brake is hydraulic disk brake and could not use the lever, but although I have regenerative breaking set to 50% if I squeeze the lever nothing at all happens, no breaking, except mechanical. The lever cuts the power to the motor and that's it, no regen breaking at all. I'll try to set the regen breaking at 70%, but I'm afraid to go any higher than that. I'll also try to connect the lever to the other socket ( from 1 to 4), I'll even try the other lever, maybe the one I'm using now it's faulty...  Any ideas guys?

Thank you.

[Aliasssss]

Hey guys. I tried setting the regen breaking to 70% and when coasting at 35km/h and I squeeze the break lever after about 1 second I do feel a very tiny feeling of slowing down, but using only that I should be stopping in about ... 300m I guess ... if at all, I'm not even sure if by cutting the power only I'm not taking the same distance to stop... but I do get a stopish feeling... Next I plan to disconnect the rear breaking cable from the break lever to see if the stopping is not from the actual rear disk brake. I'll return with my findings.

Something is very wrong with my regen break. Anyone any thoughts?

[Bikemad]

I'll try to set the regen breaking at 70%, but I'm afraid to go any higher than that.

What are you afraid of? Set it to maximum (116% if you have the MiroMax setting program) and see if it works any better.

I have my regen set to max on all my controllers and have never had any problems with it, apart from the occasional partial-skid on wet grass. The regenerative braking is a bit like anti-lock braking as it always allows the wheel to rotate and can not lock it up 100%

Alan
 

[Aliasssss]

I might be wrong with this, but I was under the impression that MiroMax controller software allows up to 120% regen breaking setup. I'll check that as soon as possible.

I'm afraid not to burn up the internal controller because it seems it is a good one as it allows me to draw almost 32 Amps during takeoff. I read on the forums about some guys that burned their FETs because of a too greater speed downhill combined with high percentage regen settings...

[Juggler]

I might be wrong with this, but I was under the impression that MiroMax controller software allows up to 120% regen breaking setup. I'll check that as soon as possible.

I'm afraid not to burn up the internal controller because it seems it is a good one as it allows me to draw almost 32 Amps during takeoff. I read on the forums about some guys that burned their FETs because of a too greater speed downhill combined with high percentage regen settings...

I'm worried about it too!

[Aliasssss]

Guys I've set the regen breaking on my MP III to the max, which is 116% (you were right there Bikemad).

 Now about 0.4-0.5 seconds after I squeeze the lever the regen breaking kicks in.

I did some testing and:
- if I try to slow down when cruising at 16km/h or more the regen break kicks at first slowly (I will call this stage I), then at around 12km/h another regen breaking stage kicks in (I will call this stage II), when the energy regenerated drops down a bit, but the breaking effect is more powerful than in stage I, then at around 7km/h the regen breaking is disconnected and the slowing down is done by shorting out the phases of the motor (I think), because the regenerated energy drops to 0W but the breaking effect is the same as in stage II.
- interestingly enough if the speed before breaking is less than 16km/h the stage II never kicks in, there is no feeling that the break effect increases and at about 7km/h the regen is out and the phases are just shorted.
- is the speed is slower than 9-10km/h you do feel the break effect but I never managed to regenerate any energy at all. In fact the threshold seem to be at around 11-12km/h, but that probably is due to the lag in refresh rate of the GT Power Watt Meter I use to do the measurements, because if the speed before breaking was higher I see energy regenerated right up to the point when the phases are shorted out. This is why some guys out there are saying that they only regenerate energy for a short period of time.

I only had little time to test the regenerated energy, but under normal conditions of city driving, with stops at the stoplights in the little time I had I managed to use 1.473A. On the second lap I swap the input and output on the watt meter (yeah, I know I need 2 watt meters, the second one will come soon) and after the same distance, same stops and same accelerations (I think) I regenerated 0.171A (minus the energy consumed by the watt meter, but as the watt meter consumed energy both ways I will ignore that, probably is insignificant anyway). Now I do realize that the 2 test laps were surely no where near the same, but  if I do the math it seems I managed to regenerate 11.6% of the consumed energy, which in a strange way is resembling the 116% percent set on the regenerative breaking.... weird one!

I can say that the test lap (starting point was the same as the finish point) was almost flat (I think). Anyway the elevation drop surely was under 1m. Possibly under 0.5m.

At (almost) the top speed 41.2km/h (1568W at startup)when I squeezed the lever I saw a max of 808W regenerated power that dropped steadily as the bike slowed down. Anyway I ran out of street and I had to use the front hydraulic break combined with the rear mechanical disk break, but as frustrated as I was before when the regen was at 70% and there was no break effect, I must say now that  I'm amazed about the amount of regenerated energy on a bike achieved by the MP III, at least mine. I may be a heavy rider, but still - is a bike. Nice one there Golden Motor

I will do more testing and be back with more feedback. Cheers guys!

[Aliasssss]

Hey guys.

About 2 months ago I accidentally dropped one of my Headway 40152s cells onto the floor. It was dented a bit but because of no voltage drop right after the accident, nor observing any capacity loss after 3 cycles and 3 days later, I forgot about it, just like that without any worries. After around 40 cycles that cell is dead, just 0,281v and never could get it to hold any higher voltage. It spikes out around 1.7v but after a few minutes of rest it drops down dead.

So now using only 15 cells my top speed dropped a bit to around 40.8km/h, that's on flat and no wind, but I got a problem, a weird one and I don't quite know if it can be solved until I replace my dead cell.

Now I know that the way that internal MP III controller works is that it resets if the motor is spinning while the battery is disconnected. Well with 15 LiFePO4 cells, that is 50.02v, it turns out that if I do about 10-12 breakings from a high enough speed, let's say more than 35km/h, the regenerative breaking setting slowly drops in percentage... Weird I know.

Got my regen to max 116% setting and that was on Sunday. Monday went to work and I cand confirm that in the morning the regen was set to 116% because I reconnected it to recheck the unimmediate setting of the reverse. I don't have the reverse wired it yet but I do set it to unimmediate just to be on the safe side if a short occurs on the 2 reverse wires. While riding after breaking a few times I could feel the regen setting dropping in percentage. I was afraid I burned some FETs, but the symptomes were missing. Anyway the regen breaking power slowly died after breaking a few times more. Once at home I connected to the PC and my regen setting was down to 50%. About 2 months ago I played with regen setting and I know that while it was set to 50% or 70% there is no noticeable breaking effect! Weird one huh?

Soon (I hope, because my seller does not have 40152S cells on stock right now) I will replace my dead cell and hopefully this behavior will be long gone and forgotten.

Cheers!

[Aliasssss]

Hey guys.

Back again with not so good news and I think this time my controller is DONE for!

The thing is that in Romania this time of the year, this year in particular, the temp at noon goes hi above 38 Celsius (or 100 Fahrenheit) and for about 1 week now, while returning home from work I had to travel about 6.5 Km ( ~ 4 miles) in busy city traffic (that involves alot of full stop an take-offs in a relatively short period of time), I started getting some cutt-offs. The throttle response goes nimb, battery lights die completely, not even red is lit. Now if I unplug the main connection between the battery and the motor, It was all OK and I could continue my ride. As I said I am a heavy rider +120Kgs and combined with the how weather I assumed it was overheating. Now after reconnecting the main feed from the battery I was limping home at about 20 Km/h and with very little acceleration of my choosing, as the MP 3 would take off like normal, with full force if I chose so.

About 2 days ago my MP 3 cut off again under full throttle for about 45 seconds while taking off at a traffic light and since then I think is dead. If I disconnect and reconnect the main feed from battery the battery light sometimes come on (other times not) and if they do, when I try to pinch the throttle , even when the bike is unloaded ( me not riding it, so only bike weight, about 37Kg load), no matter how slow I push the throttle it cuts out, no more throttle and no more battery gauge lights, and trust me I had a light thumb so I could start up very very slow and I could maintain a steady 3Km/h while riding the bike.

I plan to test it again and see what happens if I don't try to accelerate, but instead try to regenerative breaking while running beside the bike at about 15Km/h.

Don't know what to think other than that the controller is fried.

Any thoughts on this matter or anyone else got the same problem and managed to solve it?

Thank you.

PS - As I already said I'm not using a BMS and my battery pack is very Healthy so count it out from the possible culprits.

[Bikemad]

The battery gauge LEDs should not be affected by the temperature of the controller (or even a "fried" controller, unless it had completely shorted out) as the gauge unit is fed direct from the battery feed wires before they enter the controller.

I suggest you check the output voltage of your battery (on the controller side of the connector) while the fault is there to make sure there are no poor connections on the main battery connectors.

Make sure that the ends of the unused wires for the horn, lights, pedelec sensor and reverse are not exposed and touching together.
If possible, check the lighting feed voltage with the switch pressed in and also the +5V supply for the pedelec and see what voltage readings you get.

As you don't have a BMS it sounds like it could be a poor connection somewhere on the battery or one of its connectors, or possibly the fuse or switch contacts (assuming a fuse and switch are fitted).

If you don't have a fuse already, I strongly advise you to fit one so as it can protect your battery and wiring in case a short circuit occurs, as those Headway cells can deliver a huge amount of current if you don't have a BMS or fuse to limit it.

Alan

PS - As I already said I'm not using a BMS and my battery pack is very Healthy so count it out from the possible culprits.

P.S. Even a healthy battery can suffer from poor connections or contacts, so don't rule out the battery until it has been checked thoroughly.
 

[Aliasssss]

Hey Bikemad. Prompt as usual.

No switch involved yet, though I plan to use an ignition key switch sometime in the future, the kind they use on e-scooters. I had a fuse mounted inline on battery harness near the positive right of the battery, but I had to replace the battery harness terminal connectors so when I made the new one I haven't mounted a fuse inline this time, though I will use one as it can save a whole lot of troubles at times.

What I call the battery harness is a double wire silicone insulated (don't know the gauge, but as it is for RC and rated for 80 Amps and 200 degrees C I am pretty sure it's OK) which connect the battery terminals to a DEAN plug (rated for 50 Amps). Evidently on the motor side of things I also connected a Deans Plug(male) on the main feed wire.

There are more DEAN plugs with the 2 interconnected Turnigy RC Wattmeters, one for current consumption, and one for regenerated ( http://www.himodel.com/img_sub/rc_img/09/09/6610.jpg ), but the connectors are very firm.

When I get home I will recheck all the unconnected wires and see if by any chance some of them are touching together and if so isolate them and retest.

It would be nice to be something as simple as this, but I'm afraid it might be the controller...

Thank you.

[Aliasssss]

Got it to work again. The culprit was one of the DEAN pulgs in between the second Watt meter and the controller. Did a 10 Km test ride and it did overheated after about 9Km, but then again I was riding like mad full throttle with maximum take off acceleration and speed and outside were about 38 degrees C.

Thank you Bikemad for suggesting me to check the wires.

Cheers guys.

PS - Another MP III get's to live on... for now...