Virgin ebike wanna be seeks advice for first time build

[bikeskirun]

Hi all,

I’ve been lurking here for a while and done some RC flying with lipo’s, so I’ve got just enough knowledge to be dangerous. I’d like to convert my commuter bike, a 700c Specialized Tricross with the following from EM3ev:

6 Fet 25A (36-52V, IRFB3077) controller
Upgraded vers. MAC 255 rpm loaded 10T motor on 700c wheel
10S, 6P, 29E cells 36V, 16.5Ah Samsung frame mounted pack
PAS Controller/Display with Sensor
3 speed Switch for EM3ev Infineon Controller

I’m not looking to be a speed demon, but a ~20 mph cruiser would be great, plus we have some significant climbs in the area. I’m also considering pulling a trailer with my 75 lb dog and I’m 160 lb, so we might need some torque for the load. Mostly I want the ebike for short trips, generally less than 15 miles so range is not a big issue. With a 700c wheel, does at 12T motor make more sense? What benefit, if any, would a 48V battery give me?

This is the part where my ignorance really starts showing :? . I’d like to keep my drop bars and integrated shifter/brake levers and I really don’t see the need for a throttle. I would rather just have a PAS system, that is just pedal assist – I don’t mind pedaling all the time. How well do these cheap PAS controllers work?? I’ve seen the bottom bracket torque sensors, but they’re rather spendy. Also, I’ve seen some in-line brake sensors (http://us.itselectric.ca/In_line_e_brake_sensor_p/e-brake-3pin.htm) that seem like they’d work with my existing wired cantilever brakes, for motor cut-off. Again, does anyone know how well these things work?

Thanks for any advice/feedback!

 

[Ypedal]

I have yet to try a pedal sensor/throttle setup that i like, they all seem to " pulse " or provide power at the end of a pedal stroke when you dont really want it right then ....

3 speed switches are rarely used, with a MAC motor and 48v, get a hand throttle and ride happily ever after imo !

 

[arkmundi]

I’ve been lurking here for a while and ....
This is the part where my ignorance really starts showing :? . I’d like to keep my drop bars and integrated shifter/brake levers and I really don’t see the need for a throttle. I would rather just have a PAS system..

Awesome that you're going to do a build. Agree, get a throttle. Mine is an index finger grip that fit on the handlebars without my having to mettle with the brakes or shifter. These throttles are made with that in mind.

 

[teklektik]

You might consider getting a Cycle Analyst V3 from Em3EV - Paul pre-configures these - otherwise you can get it directly from ebikes.ca and configure it yourself. A simple out-of-the way thumb or 1/2 twist throttle (for backup up use - walking bike up inclines, etc) will come with your package anyway. The CA will provide PAS support with or without a throttle. Not sure, but you may need to upgrade to a 9FET controller to get the CA-DP plug - Paul will fill in the blanks there - just a few bucks extra if necessary.

You can get a plug and play PAS wheel and eZee potentiometer from ebikes.ca - these will hook to the CA and give you RPM-scaled assist with an adjustable limit. I use this setup and the pedaling operation is smooth and predictable. This isn't an inexpensive solution, but it will certainly do what you wish and give you monitoring as well. If you are a fair DIYer, you can fab the adjustment pot from a 5K pot and mount it up yourself. Details of the V3 are available here.

You will not need the controller 3-position switch with the CA PAS assist-level adjustment. If you wish different operating modes, the CA allows three selectable configurations or presets.

 

[heavymetalthunder]

I built a small trailer for my 48v 1000w bike as a test and I can tell you just with the drag of the trailer my power usage really went up with speeds above 15 mph especially climbing even small hills. The trailer idea of mine worked but power draw made it usable.

 

[Joppo]

Em3ev is a good kit, I have it on my bike now and I'm using a 9 feet controller, bike 20km every day with my kid to kindergarten and I got two hills that are so steep you can only do them in first gear when your 16 years old. I'm just rolling up them, not fast. But I'll get on the top whitout any problem. so impressed of the power. But I use a 48v lipo tho..
I like the tumb throttle. Didn't get the half twist in the buy.

 

[bikeskirun]

Thanks all for the advice. I'm rethinking the idea of using my 700c Tricross because of the hassle of the drop bars. Instead I may pick up a cheap hard tail like this: http://www.bikesdirect.com/products/dawes/hay1500xi.htm. It simplifies things regarding throttle, ebrakes, etc, and would probably be more fun to ride. Baby steps.....

 

[dogman dan]

That looks like a good bike choice to me. In 26" wheel, lots more bikes to choose from. You might like a more upright stance on the bike too, since you won't have to crouch to lessen the wind anymore. That particular bike has a nice looking rear dropout for installing torque arms. Nice and flat and wide. You will definitely need at least one torque arm with an alloy frame.

I do like a multi speed switch on a bike, even if 99% of the time you use it in high mode. When you do want to ride slow to stretch range, you can hold full throttle on a slow setting easier for 3-4 hours than you can hold a throttle half open. I do the poor mans cruise control, and jam the grip against the half throttle barrel.