Newbie questions

[krihol]

Another newbie with questions probably answered a 100 times before, which doesn’t help me a lot since I can’t find the answers…
Basically, I'm just trying to make the right choices for motor/battery.

What is the “difference” between a 500W engine, and a 750W engine? (I can see many choose the 500W model, but the 750W costs just a few dollars more, and as I understand there is 50% more effect? Isn’t bigger better? Are one of them more efficient, heavier, difference between their range, etc.)
I guess both 36V battery-packs Goldenmotor.com are shipping are quite big enough for my relatively short travel, but is there any reason to spend money on the 16Ah in front of the 12Ah? (I really don't think I need a great range, but I guess I will go a lot on "flat pedal" up looong hills.)
As I live in a remote part of Europe, I’m wondering if I order a Pedelec device, is it optional to mount it, or must it then be installed and used? (Or can I simply disconnect it on days when I don’t want to pedal?)

Some background information if you care;
I live in Norway, in a place with quite steep hills and “up and down” terrain. I am hoping to park my car, and convert my bike to a electric one. I live about 2-3 km from my work, but on my way home there is about 350m in altitude to climb, (which have kept me from “normal” biking) and I’m thinking that the “legal” 250W motor is still too small to compete with my car… Speed and time is of course a important matter, and though I am a law abiding person, I really can’t see why I shouldn’t be allowed to put more watts in my bike. (I wear my helmet and is happy with my life, so I’m not looking for hazard, just a convenient and “greener” way of transport.)

[Helgeo]

Hei  
Seems to be quite a few Norwegians around here.

I believe the only reason for choosing 500W over 750W would be to get more range. For your steep hills it makes sense to go with the 750W.
Personally I'm happy with the 250W mini motor, but I live in a flat area and I have about 18 kms to work.

The pedelec sensor can be installed permanently, it is still possible to override it. Actually that is the default setting. You have to press the cruise control button twice to activate the pedelec mode. If you order with pedelec, the controller is still the same. Only difference is that you get the pedal sensor that plugs into the controller.

If you go for the 500W or 750W motor, make sure you get the new controller that has a fix to avoid burning up the controller during regenerative braking. You will probably do a lot of braking going down those hills.

The 16Ah battery pack can provide more current than the 12Ah pack, for this reason it may be better to have the big pack even if you do not plan to ride very far. The 12Ah pack is rated at maximum 20Amps continuosly, and that is not enough to develop 750Watts. If we assume an efficiency of 80% the battery would have to deliver about 26 amps at 36 volts to produce 750W at the output. Most likely the voltage will drop (making the current go up) and the efficiency will also drop when you are going up the steepest hills. So I would say that the 12Ah pack is not up to the task.

Hilsen Helge

[Gregte]

I pretty much agree with Helgeo. I don't understand why a 750 watt motor should give less range though. That should be the same as far as I can see.

I have the 750 watt brushless hub motor from GM and I bought both a 12 abd 16 Ah battery. The 16 is much better. It has much more power. Even though you don't need the range, the larger Ah battery has more power due to less voltage drop and the two batteries weigh the same amount.

The pedelec device is actually quite worthless in my opinion. All it does is provide full throttle whenever you pedal. The power does not change from slow pedaling to fast pedaling. It is full throttle no matter what. But, you do not have to use it. I disconnected  and removed mine. Its only value is in case the law requires it.

[Helgeo]

The 750W motor will drain the pack faster than the 500W motor, so to get the same range you would need to ride at a higher speed with the 750W motor. Higher speed will lead to significantly higher drag, so you need more power to overcome the drag. Thus the 750W motor will have less range. I assume that the 750W motor is less efficient at lower speeds, but I might be wrong

My 250W mini motor has a usable range of about 40 kms with a 10Ah pack, but that is mostly on flat roads and with a fair amount of pedalling.

The pedelec is useless for anything but legal requirements.

Helge

[krihol]

Thanks a lot for answers! (Or 'a thousand thanks' (tusen takk) as we'd say up here)   

I guess I'll go for the 750W motor considering the hills around here, with the 36V 16AH battery pack. The pedelec device will be fitted and used whenever it might be required. (Just in case..)
I am a bit confused about what is inside the package and what is not. Are regenerative brakes included, or is this an additional part? If it's extra, will this part be worth the money?  There is something called "Regenerative Braking Controllers", unit BAC-0200 36V/500W, $85/set.  Possibly dumb question, but is this also good for the 750W motor? The same goes for the cruisecontroll-unit, is it included, extra or included in the campagin "BUY NOW to get FREE UPGRADE to Cruise Speed Controller!
+ Free Extra Throttle (You get both Thumb and Twist Throttle)
You Save $65 -- Promotion extended to 20 August 2009!"

It's a jungle... 

[Helgeo]

The cruise controller also includes the regenerative braking feature. It is a newer model than the "Regenerative Braking Controller", there used to be a standard controller as well, but it seems like it has been replaced by the cruise controller.

The kit comes with a set of brake handles, they have switches to tell the controller that you are breaking. This is primarily used to stop the motor while breaking or to turn off the cruise control speed. However the switch will also activate the regeneration that will charge the battery by pulling power from the motor, this will at the same time act as a brake.

Lately several reports have been written in these forums about regen actually burning up the controller either because the battery was disconnected by the key or because the BMS disconnects the battery to protect it when it is already fully charged. GM has fixed this issue in the latest version of the controller, so if you order now it should be safe.

Just order a standard kit with std. controller and twist throttle, then when you get the confirmation email, respond to it and make GM confirm that you will get the free upgrade. This has worked for me and many others.

I also recommend that you order the rack with mounting plate for the battery, it makes it much easier to mount the battery, and the battery can be locked to the rack.

Lykke til!

Helge

[krihol]

Super!
I'm now awaiting confirmation on the upgrade pack! That means I've put in an order and will hopefully very soon become an e-biker!

Thanks a lot for all advises and help!

[krihol]

Confirmation recived and packing under progress!