Using two controllers?

Post by **jbuttenshaw** » Thu, 04 Jun 2009, 01:23

Excuse my noobness, while i am very interested in this topic i don't know that i am very knowledgable. I'm looking at making an electric motorbike, but doing it very cheaply. Bet thats a new idea... So the question is could you use two lower voltage controllers, which are often cheaper instead of one high voltage one? wire them in paralel or something? thanks for your patience.

James

Post by **acmotor** » Thu, 04 Jun 2009, 03:14

Hi James, welcome.

Series or parallel controllers ?
Well not really a viable idea.

Motorbike ? What power (hp or kW) did you have in mind ?
Wnat voltage battery pack ?
What type of motor AC,DC brushless DC
What type of drive ... gearbox, shaft, chain, belt or a hub motor ?

Maybe this sort of thing ?http://e-motor-cn.com/product/product_id/53

Post by **jbuttenshaw** » Thu, 04 Jun 2009, 12:33

Well from what i've read it seems the etek style motor is the easiest and cheapest, 48v from 4 lead cells and just a chain drive with different sprockets to acheive hopefully 100km/h That sound feasable? whats the unviable part about the controller idea? has it been done? thanks alot for the reply, much appreciated. What are those hub motors worth?

Post by **woody** » Thu, 04 Jun 2009, 13:35

A DC controller is usually a buck converter
This is one or more fast electronic switches (MOSFET or igbt) which turn on and off together to do PWM. If they don't turn on at the same time then it won't work. Also the motor windings form part of the circuit. If you have two switches in series then it's only on when both are on, if you have two controllers in parallel they will switch at different times and fight each other.
If you build your own very simple controller (contactor controller) this attached your batteries to the motor directly in various combinations of series and parallel, e.g. 4 batteries as 1S4P , 2S2P, 4S1P - only 3 throttle positions like a fork lift truck. I don't think this would me usable on a motorbike though...

Post by **jbuttenshaw** » Thu, 04 Jun 2009, 18:17

Yeah i was wondering if that was an issue, thanks.

Post by **Bluefang** » Thu, 11 Jun 2009, 03:51

How does the brushless motor from http://www.goldenmotor.com/ compare to the etek one? Cause to me there is a huge difference in price, ie Etek is double the cost while only having 8 vrs 7kw and weighing like 7kg more.

Post by **antiscab** » Thu, 11 Jun 2009, 04:57

the golden motor rating could be a peak power rating?
the etek motor rating is continuous (with peak being whatever your controller can throw at it)

btw, is anyone here on the PSB forums?
theres a guy there making an EV scooter and motorbike (or at least planning to)

Matt