Giant MTB to be converted with MP III - advice needed

[pszilard]

Greetings, y'all,

Just joined the forums, and I have a whole bunch of questions:

'Bout me: I am mid 50's and have a Giant MTB and a Specialised full carbon flat bar. Wife also has a Giant MTB. I would like to eventually have e-converted bike for both me and the missus. I have read about 8hrs of internet from various places and concluded that the best option is using MP III motors with Lithium Iron Phosphate batteries and using the Cycle Computer controller. I live in a hilly terrain and am more interested in range and hill climbing, rather than top speed (for that, I can always jump on my 1200cc BMW motorbike!).

Now for some questions:

1) For a single motor e-bike, how does one decide between front or rear conversion? - I suspect that front conversion gives greater flexibility regarding the gearset used, so why would someone fit rear only conversions? Also I guess that front conversion may give more optimum weight distribution? No?

2) I would like to have pedal assisted control, as well as electric "throttle" control. Is this what is referred to as Pedelec? Can they to co-exist on the same installation?

3) Our MTB's have front suspension forks, and mine is aluminium framed and the wife's steel framed. Both have hard tail at the back. Would this also lead me to use front motors?

4) If I had a Cycle Analyst, could I use the higher power battery (48V 20Ah) to give torque and range, but limit max speed to satisfy local regulations and safety (for wife, in particular)? Or should I stick to the 24V 20Ah battery?

5) Would the Cycle Analyst allow changing parameters for off-road use, or do I still need USB + Notebook to do this?

6) I want to have regen braking, should I convert my existing V-brakes to disc at the front?

7) Is there a battery holder for mounting inside the triangle, for better weight distribution?

8) What wired LED lights should I use that are powered by the main battery?

9) Can you ship batteries to Australia?

Well, that should cover my first thoughts. LOL. Look forward to replies. Bye 4 now...

[Bikemad]

Hi Paul andto the forum.

Here are some answers:

1) If the front forks are not steel, I would not recommend the use of a front motor because of the amount of torque on the axle while under power or during regenerative braking. Some riders prefer to use front wheel drive for weight distribution reasons, but I much prefer rear wheel drive (and the rear wheel regenerative braking too). With a front mounted motor you need to be extra careful when braking on poor surfaces if the regen is set too high, because the braking force might be too much when the grip is marginal. Front wheel drive is not ideal for pulling away on steep inclines when all the weight is transferred to the rear wheel. I like my driven wheel to be located where all the weight is for better traction.

2) It is possible to use either Pedelec or throttle if a switch is wired into the pedelec sensor. I removed my pedelec sensor because I didn't like the way it operated. It is not torque sensitive, and can enable too much power from the motor when you don't always want it.

3) If the forks have cast aluminium dropouts, I would not recommend a front motor, but if they are nice strong steel dropouts, then a front motor is an option. Front suspension is more likely to cause problems with the motor wiring as there will be a lot of movement from the suspension and steering, which can result in metal fatigue within the wires.

4) The Cycle Analyst can be used to limit both the power and the speed if required, but you may need to carry out a modification to the CA's circuit board for this to work successfully.

5) I think the parameters can be changed by using the buttons on the display unit, hopefully Gary can confirm this.

6) If you have cable operated brakes there should be no problem with the regen, but hydraulic disc brakes can be a bit more awkward to adapt.

7) GM don't supply anything for mounting the pack within the triangle, you would have to fabricate something suitable yourself if you want to relocate the battery within the frame triangle.

8 ) The GM LED lights are designed to run directly from the battery voltage, but they are not the brightest of lights. A suitable DC/DC converter can be fitted to allow higher lumen LED lights to run off the main battery voltage.

9) Gary should be able to tell you if he can ship batteries to Australia.

Alan
 

[GM Canada]

Greetings, y'all,

Just joined the forums, and I have a whole bunch of questions:

'Bout me: I am mid 50's and have a Giant MTB and a Specialised full carbon flat bar. Wife also has a Giant MTB. I would like to eventually have e-converted bike for both me and the missus. I have read about 8hrs of internet from various places and concluded that the best option is using MP III motors with Lithium Iron Phosphate batteries and using the Cycle Computer controller. I live in a hilly terrain and am more interested in range and hill climbing, rather than top speed (for that, I can always jump on my 1200cc BMW motorbike!).

Now for some questions:

1) For a single motor e-bike, how does one decide between front or rear conversion? - I suspect that front conversion gives greater flexibility regarding the gearset used, so why would someone fit rear only conversions? Also I guess that front conversion may give more optimum weight distribution? No?

The rear of any bike is usually stronger the the front. That's the main reason for selecting rear drive. Most people are worried about losing gears but it on takes a short time to realize you only use one two gears, top speed and bottom.

2) I would like to have pedal assisted control, as well as electric "throttle" control. Is this what is referred to as Pedelec? Can they to co-exist on the same installation?

Pedal assist is not what you imagine. With a true pedelec system the harder you push on the pedals the more throttle applied by the pedelec. You can actually slow down to a slower speed while peddling by only applying slight pressure. A true pedelec system is usually quite expensive

The GM pedelec is like most other low cost systems. The pedelec only determines you are peddling when you spin the pedals. It gives full throttle every time you rotate the pedals whether you are applying pressure or not. Actually you can go full speed by just turning the pedal crank very slowly. Most commercially sold prebuilt Ebikes that have pedelec place a switch that can be set to give high, medium and low assist by modifying the voltage sent to the controller. Not sure if this can be done with our pedelec.

3) Our MTB's have front suspension forks, and mine is aluminium framed and the wife's steel framed. Both have hard tail at the back. Would this also lead me to use front motors?

A hard tail doesn't really make any difference in the choice of front of rear motor. A hard tail is certainly good for a standard Rack which is my preference as the seat post rack is not as secure.

4) If I had a Cycle Analyst, could I use the higher power battery (48V 20Ah) to give torque and range, but limit max speed to satisfy local regulations and safety (for wife, in particular)? Or should I stick to the 24V 20Ah battery?

5) Would the Cycle Analyst allow changing parameters for off-road use, or do I still need USB + Notebook to do this?

A cycle analyst is purely for reading live and post trip statistical data. The best thing about it is you always know exactly how much power you have consumed, how much you are currently using and how much power you have left. The lights on the throttle do little in helping with this.

To control speed watts etc, the USB cable is good for this and the cycle analyst is good for seeing the results of any changes.

To have the cycle analyst control the bike you need to do an advanced hookup requiring a diode a resistor and some soldering. There is a thread in the forum somewhere on this, maybe someone can help track it down.

6) I want to have regen braking, should I convert my existing V-brakes to disc at the front?

Regen is enabled by default and no additional parts are required. When you pull the brakes even a slight amount the motor is cut and regen is activated. It doesn't matter if you have disk or v brakes.

7) Is there a battery holder for mounting inside the triangle, for better weight distribution?

We just have the racks for the batteries but people have come up with different mounts on their own.

What wired LED lights should I use that are powered by the main battery?

We have simple LED front and rear light that are fairly inexpensive. They suit most people's needs. For those wanting much brighter lights there are other third party options but be prepared for the price. My front lights cost 280 dollars. But I never regret the price when I turn them on.

9) Can you ship batteries to Australia?

Of course, I ship anything anywhere. I am sure GM China does too.

[/quote]

Well, that should cover my first thoughts. LOL. Look forward to replies. Bye 4 now...
[/quote]

Enjoy the Ride!
Gary

PS while I was writing this it seems there was another response. I may as well post this anyway.

[pszilard]

First of all, a big THANKS to both Gary and Alan for the informative replies. I really appreciate them.

When I get home from my trip, next week, I will check to see if the forks are aluminium or steel.

I understand now that the GM Pedelec is rather basic. Is there a realistic alternative at higher cost, from another manufacturer, or is it not worth the effort? I am quite happy to give this one away.

I understand the explanation of front versus rear. Thanks for that, very useful.

Is there any control on the regen braking strength, or is it just like an on/off switch? What happens if I want to gently brake the bike to slow down gradually?

If someone can point me to the way to use the Cycle Analyst to change the settings, that would be great. I am quite comfortable using a soldering iron and frequently built PC so not afraid of some mods, as long as the instructions are there.

Should I go with 24V 20Ah or the 48V 20Ah battery. Our &^*&^ laws limit ebike power to 250W, but I weight a slender 110kg and we have some significant inclines around here, so perhaps the higher voltage is required for getting the torque.

I know that GM motors are hub mounted gearless, but any thoughts on centrally mounted alternatives, that drive the pedal crank set? This arrangement makes the motor's assistance take advantage of the rear gears, so might be better for hill climbing. Any comments on this?

As I am a motorcyclist from way back, I lean towards twist grip speed control, but would you recommend thumb type, for whatever reason?

Would I save a heap on shipping, if I had the wheel built up locally, and just ordered the rest of the kit? I figured that doing this would greatly reduce the size of the shipping package. Any thoughts on that one?

Lastly, I am a bit confused about the battery description. From what I read, there are at least two type of Lithium bateries: (a) Lithium Cobalt has a life expectancy of 800 charge cycles and requires a more sophisticated charger, and (b) Lithium Iron Phosphate, which is dearer, but has a life expectancy of 2000 charges and is able to use a simpler charger. The GM sites indicate that the slab batteries are Li Iron (LiFePhos), but then say they have a life of 800 not 2000 charges. Which is it?

I gather that MP III is now shipping. Gary, do you have stock, so you could put together a shipment for me in the next 2 to 3 weeks? Any indication on shipping costs to central Sydney, Australia, would be very helpful.

One more thing - just saw the thread about burnt out controller on an MP3. Would it be safer/more reliable to buy the external controller, or was that guy just unlucky and the internal controller is usually fine?

Thanks guys...

[Bikemad]

Check out Ginge's thread regarding a variable voltage pedelec unit.

The fixed level of regen can be set with the usb interface lead but unfortunately it is not variable during use.

Here is an updated diagram for the Cycle Analyst wiring details:


The switch is optional, but it enables the Cycle Analyst throttle override to be connected or disconnected to quickly swap between restricted speed/power and unrestricted speed/power.

The original solution to the Cycle Analyst problem can be seen here.

The 24V battery will give a top speed of around 15mph and the 48V battery will be around 25mph.
The motor's power with a 48V pack would be at least double that of the 24V. If you're using the Cycle Analyst to limit your speed and power, either voltage can be used for a road legal bike. Higher voltage is much more fun off road, but it will also drain the battery far quicker as you will be drawing more power from the pack with faster acceleration and higher speed.

I haven't tried chain drive motors, but I seem to recall that they are considerably noisier than a direct drive hubmotor.

A twist throttle will be far more natural to use and the installation looks neater too, but it can be a problem to install if you also have a twist type gear-change mechanism. One disadvantage with the twist throttle is the chrome end caps that stick out on each side actually increase the width of the handlebars by about 2 inches, which can be a pain when negotiating narrow openings, or squeezing between two lanes of traffic waiting for the lights to change.

I have a twist throttle with lever operated gears on my main bike:


I had to install a thumb throttle on my MPIII powered chopper style bike:

although I really would have preferred to use a twist throttle, but unfortunately it has the original twist type gear-changers .

I'll let Gary answer your question regarding the shipping costs.

GM no longer supply the LiMnO₂ packs, so now they only sell the LiFePO₄ packs, and I would expect the the LiFePO₄ packs top be nearer 2000 charges than 800. I'm guessing GM have not fully updated the website yet.

Check out Gary's Website to see what he currently has in stock.

"When you look at the page for each item if the option for "add to cart" is there then it is in stock. I do my best to ship everything with 1 or 2 days"

There have been a lot more external controllers fail than the newer internal MPIII controllers, and a lot of MPIIIs have been sold since they were launched last year, but Gary is in a much better position to comment on this than I am.

Alan
 

[pszilard]

Thank you again Alan. My MTB is lever operated gears, but I have bar ends. Wife's MTB is twist change, so I guess Thumb Throttle is the way to go for us.

[GM Canada]

I gather that MP III is now shipping. Gary, do you have stock, so you could put together a shipment for me in the next 2 to 3 weeks? Any indication on shipping costs to central Sydney, Australia, would be very helpful.

One more thing - just saw the thread about burnt out controller on an MP3. Would it be safer/more reliable to buy the external controller, or was that guy just unlucky and the internal controller is usually fine?

Thanks guys...

Yes the MP3 has been shipping by the "boatload" for a while now.

Anything you can add to your cart is in stock or it will tell you the expected shipping date. You can not buy anything that is not in stock or does not have an expected shipping date clearly declared on the individual items page. Anything that is not in stock will also be clearly stated on that individual items page. 

Once you add what you desire to your cart then view it and click "get shipping estimate" for the final price. You only need to enter your country and postal code to get a quote on anything that is in stock.

As for MP III failures, they are out there. But no where near as many as when the MP2 internal was released. If there is any Issue I take care of it pretty quick.

I think Alan answered the rest of your questions, so far

Enjoy the Ride!
Gary

[truly_bent]

Hi Paul.
Turns out we weigh about the same, but nobody's callin' me slender.

I just wanted to point out that the MP II/III is unlikely to be seen as street legal anywhere in Oz, under any configuration. Well not any. You could make it street legal if you ran it at 8.3V (250W / 30A = 8.3V), but I suspect the acceleration would be seriously underwhelming and top speed would keep your pet Koala comfortable.

Here in the Great White we have a similar problem, but at least we're allowed 500W. The MPs are rated at 500W for 24V, but I suspect the Chinese fellow who worked that out was using a broken abacus since 500W by 30A is only 16.6V. Suffice to say, i'm not running at 16.6V either.

Just so you know, I once (yeah right) put it to the mat and found out my bike will cruise between 45 and 50 kph (Americans get out your calculators) on the flat. I would never do that again of course (smirk), because it violates our 32 kph limit ("...there were no cars around officer"). I mention this to give you some empirical measure of what to expect. Running at 24V will effectively halve your top end.

As for hills, i've posted a pic of my friend pushing his non-electrified RANS up the hill behind me (he gets the better work out). I haven't yet been stopped by any of the hills in our area - close, but not quite. Since efficiency drops off at lower speeds on a non-geared hub motor (any electric motor actually), the price paid to reach the top of the hill is in higher current consumption than might otherwise be used by a mid-drive unit.

I spent a lot of the time pedaling on this run, instead of just letting the motor do the work, and used up about 5 amp hours (AH) over about 37km (23 miles). If I hadn't pedaled at all, I would have expected to use around 10AH. You can do better, but I got lazy toward the end.

Happy trails...