Riding without the Battery - damage to the MP ?

[DirtyGinge]

Hi All

if I wanted to ride the bike, but without the weight of the battery, will the volts generated by the regen / motor spin damage the controller / motor as the volts have nowhere to go...
( not sure, think I read this on a forum....)

maybe there is a way to burn the volts off, use a lightbulb ?

Regards

[Leslie]

I cant answer for sure.  I am in the position with a MC I am trying to repair to hook up a volt meter over the phase wire and give you some results in the morning.  But will the multi meter register the voltage spikes?  I think not.

But to say that a motor will generate electricity current flow with no load is true to a multimeter, however the multimeter creates a small load over phase wires and orders up some volts to the voltimeter.

That said there is always leakages in the fets and the controller, so there is alway a little resistance to bridge the motor into a circuit.

Voltage is determined by R (resistance).  Meaning that every source has the potential to be omega (endless volts).

If it wasnt for resistance everything would be destroyed by infinite energy. 

The motor has low resistances and so voltages can be very high on the ouputs at high RPM and tiny high voltage spikes are common when changing states to a large current source with capacitors around. So if you do ride it do not switch controller on and off..

Honestly youre best to switch it on and ride it and switch it off when you dont.  This way there is no if's or maybe's.

[DirtyGinge]

Thats the safe method at the moment...however large hills, Magic Pie, and the occasional willingness to actually cycle instead of throttle.....

It seems at the moment, the only safe option is either to try and attampt to use the bike as a bike with both battery and wheel, or take both off for leisure cycles...and cycling withe the Magic Pie non throttled isnt funny at all

It would be nice to only drop the battery, to save stressing the forks with taking the Magic Pie off

regards

[Leslie]

Really the ebike should be able to run out of power and be able to use pedals.  It maybe just me but when I have to pedal any bike and pack home the memory tied with this experience is normally a bad memory.

Riding around with no pack seems to scare me for some reason..

Maybe riding around a cant hurt, going down a big hill you would still be lucky to get the RPM high enough.

The worse thing you could do is switch the controller on or off while the wheel is spinning at higher RPM.  It is a temptation and even with akll the em protection IMO your controller will come to an end.

I think I would pedal the Pie if I had to but not by choice.  One way is to set the motor speed, max current and constant current very low so the motor only assists your pedaling power only to the point it takes away the motor resistance and weight of the pack from your pedals.

This style of ebike would get some serious range per each charge to the point your ass would be so sore from sitting and pedaling on a bike..

The longest lived controllers Ive owned.  One was a GM factory second regen controller, after it was modded, it was installed. Switch on ride, switfch off when finished.  Nothing more. 

The other long lived controller was an ecrazy sensorless controller that ran for about a year. I changed my switch location.  And oops bumped the switch off with my leg when pedaled during a take off.  Switch it back on whilst still rolling. The motor kicked in and I could feel one phase channel dying.  The motor started to exhibit little jolts untill it stopped noisily and abruptly. No regen either.

Bad battery connections can take your controller out.  Any sparky spark in your rides should be fixed ASAP. 

[DirtyGinge]

I second that

My daily commute is 2 x 20 Miles through hilly countryside...I can do this on a normal bike, but only 2-3 times a week, not 4-5...

So I think, hey , lets cycle the Magic Pie, will build nice strong legs....It will be good for the weight loss

5-6 miles of constant resistance im sure will break many men, I snapped like a twig.....

[Leslie]

While youre still here.

Honestly thinking youre missing something about ebiking.  Youre wanting the cycle experience back and like the exercise.  Not a bad thing, just maybe look at the bike differently.

What ever what you like, make it so.  This is a new thing and what people do and get up to with ebikes is being defined as we speak.  

Slow it down in Forward speed scale.  Take time to enjoy the fresh air and the view.

Slow it down and use your pedals.  People are saying the ebike can make people fat.  Really? I guess it could, if getting out and about is worse than eating junk food watching TV all day the ebike seat is better than the couch.

I know I lost weight with riding ebike.  Instead of driving a car into town or catching a taxi..  Pedals are good for getting you in front of the cars at the lights on take offs.

The other day my front wheel left the ground using pedals and motor assist together.  Awesome.


Think! I can pedal 10km a day, phew exhasted  .  With this motor I can pedal 50km per day   but still exhasted  .

[Leslie]

I second that

My daily commute is 2 x 20 Miles through hilly countryside...I can do this on a normal bike, but only 2-3 times a week, not 4-5...

So I think, hey , lets cycle the Magic Pie, will build nice strong legs....It will be good for the weight loss

5-6 miles of constant resistance im sure will break many men, I snapped like a twig.....

See you are comming up with your own definition of what the MP is for you.

Sometimes I think posting things to members on the same wave length is just a formaility.


Here!

One could suggest the best way to mount a pack easier and better than the rest, but at the end of the day, "everyone" does it differently almost everytime.

All we seem to do is share and utilise the smaller parts of a larger thing and incorporate what works for best for the individuals needs and wants.

You can throw thousands of dollars at it and get a rolls royce ebike that you ride once a week or something you ride all week.  Sometimes the short cuts are the right way sometimes you pay.

I think regen is bad on the MC and others are finding it fine for their uses.  Some people ride hardcore and others ride more relaxed.  Some have bad roads and other smooth roads.

I really torture my ebikes, I do a lot high loads towing trailers and transporting passengers.   The rodas are terrible here and I rely on my ebikes as a primary means of transport for everything from taking the children to the doctors to getting cheap deal night pick up Pizza's. 

[DirtyGinge]

thanks 317537..

to be honest I get loads of excercise....getting the ebike was really all about saving fuel.( £1.25 per litre this morning)
still the plan was maybe cycle 2 days, ebike 2 days ( and then the other sports, running kickboxing etc.....)

I really didnt expect though, the Magic Pie to be so resistant.....still wouldnt trade it in though, its been a great experience,

thanks all

[Dummy Dave]

thanks 317537..

to be honest I get loads of excercise....getting the ebike was really all about saving fuel.( £1.25 per litre this morning)
still the plan was maybe cycle 2 days, ebike 2 days ( and then the other sports, running kickboxing etc.....)

I really didnt expect though, the Magic Pie to be so resistant.....still wouldnt trade it in though, its been a great experience,

thanks all

When I want exercise with my transportation, I press the cruise button at a slower speed than I want to go, then pedal to speed up.  The slower the cruise, the more I have to pedal... to the point of punishment for a while, as you found out.  The higher the cruise, the more I can relax.
It's easy to find a balance that makes the bike feel almost like it did before the Magic Pie.
It doesn't take much power for the motor to carry its own weight.
The more I pedal, the longer the range, but I take my battery with me to help get up the killer hills.

...But that's just a dummy talking.

[MonkeyMagic]

Hey G'day

I would be surprised if not having a battery connected did cause any problem. After all, there would not be any load going through the motor and not having the controller powered up, it won't be able to switch to regenerate.

Without a battery connected, a single wheel can power a LED (40 led) headlight at full power, so I am also curious what power it generates!

[Bikemad]

After all, there would not be any load going through the motor and not having the controller powered up, it won't be able to switch to regenerate.

Without a battery connected, a single wheel can power a LED (40 led) headlight at full power, so I am also curious what power it generates!

The voltage generated by the wheel at speed would still power up the controller, even with the battery switched off (or removed).
 
If you disconnect the battery and pedal fast enough (with the brake lever pulled in enough so that the regen is on) the voltage being output does not go above ~60V which is fine, but if you do not apply the brakes, the voltage continues to rise with the wheel speed and can go well above this level.
I once tried this out by hanging my bike up so the wheels were off the ground and then I wound the pedals as fast as I could by hand, and I had a voltage reading on the battery connector of ~77V with no battery connected!

I would still be concerned about damaging the controller with such a high voltage going through it, how long would the 63V capacitors in the controller be able to cope with this excessive voltage before they finally failed?

I'm not sure if it would be OK to leave the regen permanently switched on to prevent the voltage in the controller from going too high while riding without the battery, because I don't know what the controller actually does in order to prevent the generated voltage from exceeding 60V at speed.

My maximum measured regen current was 23.35 Amps (681.5 Watts) using a 7 cell LiPo pack (25.9V 10Ah) and 9.65 Amps (525.8 Watts) using 14 cell LiPo pack (51.8V 5Ah), and these readings which were obtained at approximately the same speed. So at the 60V limit I reckon at least 8 Amps (480 Watts) would be available if a load was put on the controller while using regen at a similar speed.

Alan
 

 

[DirtyGinge]

Hi All
Many thanks for the feedback all....GM should really warn people about this...in big bright letters

Ive resolved my issues.....the best thing, when I want to occasionally go back to real cycling as opposed to assist, I went on ebay and bought another bike for £30...needs a little work but thats life ...15 Kg biek as opposed to 39.9 ( yup, 40kg is legal limit in uk)

Not that there is anything wrong with the Magic Pie...its great great great ( but lets face it, you really do need to be at least handy with a soldering iron, the connectors are bad, the anderson SBM50 connector ( chinese) melted, and ive made so many modifications and bypasses to make it appear legal, that it would really fail with a ground level user without good LBS support)

But oooooh, it makes me smile, and ive now found a source of lithium batteries, hacking my own batteries for nice long range ( but damn, no easy source of BMS systems, unless anyone can suggest where I can get cheap 13 serial Battery management systems in the uk)

I cannot wait until spring....its a shame that I waited this long...Tomorrow morning to work -7 degrees centigrade...i look like the michelin man dressed up

regards to all

[MonkeyMagic]

Wow Alan yes that is a worry as the caps are not rated for that lol
Those are some good figures...cheers

And you would have done this on your MP I assume, but it had me thinking because I thought the FETS would have needed power somehow to complete the circuit. Anyways I won't be going anywhere far or fast

There is a ton of room in the hub casing let alone the PCB for something to sort this but seriously, this would and should have been addressed in testing... Big surprise huh lol

[MonkeyMagic]

Hey Alan I was thinking

If I just switch off one of the phase wires to the controller, do you think this would stop any voltage?

I'm currently building a brush motor into my frame to obtain higher top speed, so this is something I should address now while the topic is out

cheers

[Bikemad]

Many thanks for the feedback all....GM should really warn people about this...in big bright letters

This particular problem was discussed last year and has supposedly been rectified:

We have recently enhanced the cruise controller to detect if the battery pack is in place. If the battery is switched off, or is not connected at all, the controller will check the back EMF voltage, if it exceeds the preset limit, the controller will disable the regenerative braking to protect controller from being damaged.

As of today, 22/7/2009, the day of the eclipse, all GoldenMotor controllers have a new function to deal with the issue of regen braking burning out the controller while battery is off.

Although they appear to have dealt with the regen problem, I can't help thinking that the voltage produced at speed without activating the regen function might still cause damage to the controller.

If I just switch off one of the phase wires to the controller, do you think this would stop any voltage?

Disconnecting just one of the phase wires would change it from a three phase generator to a single phase generator, but this might not reduce the voltage as much as you might think. Disconnecting two of the phase wires would produce an open circuit, and this should definitely prevent any damage to the controller.

Alan