C5Alive General Category => C5 Chatroom => Topic started by: alexbromo on 28, September, 2010 - 16:06:35

Title: PWM regulator
Post by: alexbromo on 28, September, 2010 - 16:06:35
I've found a cheap 30A PWM regulator (350W calculated) that seems to be a very simple and fine solution to efficently manage the power of C5 motor from 0 - 100%.

http://cgi.ebay.co.uk/12V-30A-DC-Motor-Speed-Control-PWM-HHO-RC-Controller_W0QQitemZ220664664733QQcategoryZ42899QQcmdZViewItemQQ_trksidZp5197.m263QQ_trkparmsZalgo%3DSIC%26itu%3DUCI%252BIA%252BUA%252BIEW%252BFICS%252BUFI%26otn%3D20%26pmod%3D170400933060%26po%3DLVI%26ps%3D63%26clkid%3D5364199445045854670 (http://cgi.ebay.co.uk/12V-30A-DC-Motor-Speed-Control-PWM-HHO-RC-Controller_W0QQitemZ220664664733QQcategoryZ42899QQcmdZViewItemQQ_trksidZp5197.m263QQ_trkparmsZalgo%3DSIC%26itu%3DUCI%252BIA%252BUA%252BIEW%252BFICS%252BUFI%26otn%3D20%26pmod%3D170400933060%26po%3DLVI%26ps%3D63%26clkid%3D5364199445045854670)

The potentiometer can be replaced by a standard throttle 'drive-by-wire' component, like this:


I believe that C5 should be more driveable, and all the motor/drivetrain components (gearbox/belt/gears) should be happy tho have a smoother torque applied (and less prone to crack).


Alex Bromo
Title: Re: PWM regulator
Post by: C5 ENTHUSIAST + RESTORER on 28, September, 2010 - 17:16:01
Hi there Alex I don't think a 30 amp pwm will be powerful enough ....
Title: Re: PWM regulator
Post by: alexbromo on 28, September, 2010 - 18:38:16
Theorically a 250W motor @ 12V drain (A=W/V=250/12 -> 20.8A), so 30A controller should be sufficent ... 

Or are there some other variables to compute ? ???

Alex Bromo
Title: Re: PWM regulator
Post by: techytype on 28, September, 2010 - 20:50:51
under heavy loading say up a slight hill or near stall it can draw a lot more current.

one school of thought suggests the 'push on/release off' control actually has an advantage, while 'off' and coasting the motor and drive train is cooling and also saving some juice, on a variable control system your likely to be constantly applying power over longer periods.

great thing about C5's is they lend themselves to experimentation, so i'm not trying in any way to dissuade your enthusiasm. earlier this year i bought the yellow C5 in the main picture. it is fitted with an early 24 volt variable control, i'm told by Karls it;s simular to one he has.

i've only just got it going, mainly due to time constraints, no major faults just some basic attention to detail and wiring skills needed, early days as to prove theories either way ;).

Title: Re: PWM regulator
Post by: alexbromo on 29, September, 2010 - 07:27:07
Yes it's true ... near stall condition the motor can draw a lot of current: the total internal resistence is 0.1 ohm, so virtually it can absorb near 120 A, a value that can kill the regulator.  :-\

However i believe that, if the regulator has a decent efficiency, it can help to save the battery, especially in the city running when is normal to have to frequently reduce/increase speed.

Obviously that considerations are totally theoretic, as i've not yet put my C5's wheels on the road.


Alex Bromo
Title: Re: PWM regulator
Post by: techytype on 29, September, 2010 - 09:18:28
tbh i think we all get a big buzz from plotting our next move, don't matter if its the satisfaction of restoring a sick or neglected machine back to health, or pottering about in the garage trying out ideas, it's half the enjoyment of owning what is the unique Sinclair C5.