E bike Q's

[lovemysan]

I picked up 6 good 6v 9 amp hr batteries the other day. They are about 3-4lbs each. I have a source for 20 more. There wet cell lead acid I believe. Would these be good candidates for an electric assist motor for around town. I can mount them on my bag rack. Its a nice topeak aluminum rack.


If so I'm going to look for the simplest motor controller setup possible. Maybe even just a 2 switch on off style that cuts voltage between 18-36 volts.

What size Emotor do I need? Do any of you know good sources for chain,sprockets, etc?

[trebuchet03]

I've had good experiences with TNC Scooters
http://www.tncscooters.com/

I'm not sure if those parts will directly bolt on and such... If you can, you could weld/braze on a scooter sprocket to your wheel hub -- or weld/braze a bike sprocket to your motor

A 36V motor controller is ~$20 - but you'll need a throttle (~$8)

[lovemysan]

Ignorant question but, do 6 6v 9amp hr batteries wired in series make 56 AH 36volt pack. Or is a 36 volt pack @ 9ahs

and was $15 for 6 of them too much money. I actually only wanted one to fix a dumpster found electric 4 wheeler(currently has a stock 4ah batt)

[trebuchet03]

6 in series will make a 36V 9Ahr pack....
6 in parallel will make a 6V 54Ahr pack....


The price is good if they are any good... You have to charge them and do a load test (measure the voltage with a load on it).

[lovemysan]

Okay more questions

1) How much motor do I need? I weigh 225lbs plus the bike,motor,pack weight of 80lbs. I would like to be able to cruise at 15mph on level ground with no pedal assist.

2) Could I have the same amount of range with a 350w or 500+w?(usage depending of course).

3)Is the 9ah pack a waste of time? Should I skip it and go with something better?

I can weld. Whats the highest wattage motor I should run on the stock wheel. I have a 700c bontrager tubeless alloy rim with a shimano freewheel hub.

[MetroMPG]

A 350w motor @ 36v will (just) meet your needs for the weight you'll be moving (level ground).

The 250w motor @ 24v on my mom's electric bike has propelled 220 lbs plus a 65 lb bike at 20 km/h (12 mph) on level ground.

If you get a 500w motor where a 350w would suffice, you'll use it. So your range will be less But you'll probably have more fun.

As for pack size, 9ah @ 36v is comparable to my mom's in total energy: The pack is 2 * 12v @ 12AH, or a 24v 12AH pack of 288 watt hours total capacity. It'll go about 20 km/12 mi on electric only. For comparison, 36v * 9ah = 324 watt hours.

[2TonJellyBean]

on a level surface

150 watts should be able to get you to 15 mph with an 80% trans. effic.
350 watts should be able to get you to 21 mph with an 80% trans. effic.
500 watts should be able to get you to 24 mph with an 80% trans. effic.

on a mild grade of 4%

150 watts should be able to get you to 4 mph with an 80% trans. effic.
350 watts should be able to get you to 10 mph with an 80% trans. effic.
500 watts should be able to get you to 13 mph with an 80% trans. effic.

on a grade of 8%

350 watts should be able to get you to 5 mph with an 80% trans. effic.
500 watts should be able to get you to 8 mph with an 80% trans. effic.

[skewbe]

FYI, on the cheap and easy motor front, I picked up a couple Kollmorgen (built in controller @ 24v, can run 48 with an external controller). I'm thinking of having a luggage cart carrying two trolling batteries and one motor per wheel on the cart(freewheel somehow, still got to do it cheap though) and have that push my bike for 50 miles a day, maybe Just add gears and throttle (5k pots) and tow hitch thingie.

http://cgi.ebay.com/ws/eBayISAPI.dll...m=120165374259

[lovemysan]

Originally Posted by MetroMPG

A 350w motor @ 36v will (just) meet your needs for the weight you'll be moving (level ground).

The 250w motor @ 24v on my mom's electric bike has propelled 220 lbs plus a 65 lb bike at 20 km/h (12 mph) on level ground.

If you get a 500w motor where a 350w would suffice, you'll use it. So your range will be less But you'll probably have more fun.

As for pack size, 9ah @ 36v is comparable to my mom's in total energy: The pack is 2 * 12v @ 12AH, or a 24v 12AH pack of 288 watt hours total capacity. It'll go about 20 km/12 mi on electric only. For comparison, 36v * 9ah = 324 watt hours.

Okay I tested one of the batts tonight, it pulled my daughter around okay. Its obviously not a new bat but they work. Okay my budget so far is

motor $45
controller $28
throttle $8
batts $15
Misc $20

$120ish. Not bad.

Question.

Can I use #10 thhn solid wire? Can I use a crimp based lugs or should I solder them.