Search found 103 matches

by bobc
Mon Sep 15, 2008 12:07 pm
Forum: Cars,Vans and other road vehicles
Topic: Electric Vehicles and the Law...
Replies: 20
Views: 24830

DISAPPOINTED!!!!



never mind - lets try the suggestion scheme - might get a charging point and a £10 award.......
by bobc
Mon Sep 15, 2008 11:58 am
Forum: General
Topic: Transmission losses
Replies: 17
Views: 12322

Researching for the greenpower racers, I found a "human powered vehicle" report on transmission losses. The interesting fact from this was a massive increase in losses if any sprocket has less than 12 teeth (i.e.start to see a 2-3% increase in losses c.f. 13/14 teeth)
by bobc
Mon Sep 08, 2008 11:34 am
Forum: Cars,Vans and other road vehicles
Topic: Electric Vehicles and the Law...
Replies: 20
Views: 24830

On the subject of EVs & the law....... Years ago I read or was told that, under european law, any commercial concern that you do business with is obliged to charge your car while you're there. In principle this is pretty cool - it means I get my own parking bay with a socket in the works car par...
by bobc
Wed Sep 03, 2008 7:45 pm
Forum: All things battery related
Topic: Lead Acid - the choices
Replies: 11
Views: 9526

Car batteries are designed to provide high currents for a short time for starting cars - as a power source for an EV they ain't so good because they can't take the deep cycling. However there are UPS, caravan and golf cart lead acids around which are much better, you just can't get 'em from Halfords...
by bobc
Fri Aug 29, 2008 8:22 am
Forum: General
Topic: Multiple motor & controller approach?
Replies: 87
Views: 62961

Hi Jeremy, unfortunately I'm an inductoin motor man... I've never really done anything with BLDC. So what follows is surmise & prejudice ;^) Hall sensors - there's nothing magic about hall sensors. For BLDC control you need position & the hall sensor is a convenient way of getting that consi...
by bobc
Thu Aug 28, 2008 8:24 am
Forum: General
Topic: Multiple motor & controller approach?
Replies: 87
Views: 62961

Just thought I'd make a few observations. 1) I presume these are 3 phase motors - as part of the voltage discussion there is also the issue of star-delta connections which may or may not be possible with the wires supplied on your motor. But this could let you get full power at lower voltage. 2) Mul...
by bobc
Wed Aug 27, 2008 8:39 pm
Forum: All things battery related
Topic: Yet another battery management/monitoring system....
Replies: 4
Views: 3733

No load resistor - all the dissipation is in the MOSFET. In the final assembly there will be an approx 1.5inch cube heatsink on each one with a single fan blowing through all of 'em. I'm calculating on about 30W max for each board (though they will transiently sink up to 120W) Basically if any one b...
by bobc
Sun Aug 24, 2008 12:58 pm
Forum: All things battery related
Topic: Yet another battery management/monitoring system....
Replies: 4
Views: 3733

Hi Peter, I'm not worried about electrical noise, it's a small board with a complete ground plane on the back, a big C on all the analog inputs & local V regulator - it will be just fine ;^) Those single chip micros are pretty bombproof actually, give 'em 3.3V & they don't have much option e...
by bobc
Sat Aug 23, 2008 11:01 pm
Forum: All things battery related
Topic: Yet another battery management/monitoring system....
Replies: 4
Views: 3733

Yet another battery management/monitoring system....

Thought I'd post a picture of the battery charging/ monitoring system I'm putting together for the kitten project. These little boards are installed across each 12V lead acid battery in the car. Each communicates with the next lower cell in the string, which appends its own data to the message and p...
by bobc
Fri Aug 22, 2008 9:24 am
Forum: Cars,Vans and other road vehicles
Topic: Advice and comments please on design spec 400kg car and 4d
Replies: 6
Views: 6443

We used to use small 4QD controllers on our greenpower car & they were pretty good. They were a simple 'buck' regulator in voltage mode with synchronous switching & we measured 99% efficient(!). Anyway, reason for post - we did DIY controllers in the end using a current mode switcher, result...

Go to advanced search