Electric Bikes - Scanning interest.

[yorkie_chris]

Originally Posted by thefallenangel

i guess. It's why for a 180w motor i'm looking at a 600w inverter to try and not get the heat to affect it too much. I'm looking for a massive amp hour battery to run it.

0.9bhp

Bear in mind the bare basic, your-grandad-can lift-into-the-car model mobility scooters we sell have a 350W motor.

Originally Posted by yorkie_chris

0.9bhp

Bear in mind the bare basic, your-grandad-can lift-into-the-car model mobility scooters we sell have a 350W motor.

Sure about that? I make it around 0.25bhp. Either way, it's scary power.

For comparison, my vacuum cleaner has a 2000 watt motor. What sort of speeds is the OP hoping to obtain? I'd be surprised if a 180 watt motor could move a bike at all.

[yorkie_chris]

Nope for some reason I used a completely different number to what he said :P

Still, basic shopping scoot allowed to do 4mph has more power. You need bigger motor!

yes it was just a motor i knew that was kicking around our workshop because it got taken out for damaged feet which is fine as it will be mounted differently onto the frame. Looking at a website there's a 1500 watt motor to go 30mph for 40 miles but again this is DC voltage. I don't want to use DC.

[Sid Squid]

Originally Posted by thefallenangel

I don't want to use DC.

Can you explain your antipathy for DC motors, don't take this wrong but I find your desire to use an AC system bizarre.
Now as you are unquestionably well aware you can't carry AC with you, so you're going to require an inverter, (as you said). As a number of people have pointed out, any inverter system will incur losses, some are more efficient than others but it will with absolute certainty involve a loss of your carried charge.
Seeing as the central factor of all electric vehicle problems are related to range, anything that will lose you charge capacity available to drive the motor is to be avoided. Thus any inverter is a short route to less useability.

[yorkie_chris]

The only advantage of AC is no brushes, but the brushes in the DC motors I'm familiar with on the powerchairs and scooters aren't a serious reliability issue. Fair enough the dinks keep sending us gorgonzola rather than graphite... but that's a supply issue. Get decent brushes on a clean comm and they last AGES.

Also remember to recharge your battery from regen which is a massive aid to braking you will need to rectify and regulate it again which is horrendously inefficient.


If you are determined to go AC then rather than an invertor then IMO you need a seperate control system with variable frequency to get the driveability. AC motors don't throttle well.
I don't see why a low voltage, pulse type control could not work well, though it may not be suited to your windings.

[tigersaw]

If you are going to use AC motors then look into going 3 or 6 phase with star / delta configuration and controller. At least that will allow you to choose between torque and power

180W is about what is allowed in some states in Oz for an assisted bicycle. It'd need pedals.

For a home project, I'd want to be keeping it simple using proven gear (in electric vehicles) such as Etek motors and Alltrax controller.

Originally Posted by tigersaw

If you are going to use AC motors then look into going 3 or 6 phase with star / delta configuration and controller. At least that will allow you to choose between torque and power

Nah i'm going for a drive. Eliminates all the hard work and programming is easy as i can program one with my eyes closed. 10K pot throttle and were away.

The only reason i'm going AC is the bits will be free to try it with all i need is a rolling frame. I'm happy to go to DC but i'm, just as experienced on DC as i am on AC as the only things i've ever dealt with being DC were a fan motor at 35v and a Shunt buggy from Port Talbot steelworks at 55v. I think it maybe a case of me being scared.

If you don't know a drive with a 240v input will put out 110v or 240v out in a 3 phase simulation.

I've spotted this http://www.electricmotorsport.com/st...roller_kit.php

I am now thinking this could become a serious consideration. If i pick up the kit for £750 then this could become a more viable option.

Oh a motorcycle SVA test is £70 too which isn't too bad.