Search found 103 matches

by bobc
Mon Aug 18, 2008 11:10 pm
Forum: General
Topic: Lithium vs lead batteries
Replies: 19
Views: 15799

I appreciate the performance of the lithium cells but the cost is horrific. I think you need to decide whether your needs could be met by lead acid & consider lithium if not. My gut feeling at the moment is a cost ratio of about 20:1 in terms of £/kWh, I'd be interested to hear what others th...
by bobc
Thu Jul 31, 2008 12:01 pm
Forum: Cars,Vans and other road vehicles
Topic: Lightest car to convert?
Replies: 30
Views: 25611

I'm converting a reliant kitten - they were pretty light (650kg ish from memory) & can be picked up reasonably cheap. They were fairly ropey when new mind you, & will not have improved in the 30 odd intervening years..... Doing up seems fairly reasonable though, parts seem easy enough to get.
by bobc
Fri Jul 18, 2008 9:46 pm
Forum: Hot off the press....
Topic: BVS at the Green Power Corporate Challenge
Replies: 21
Views: 14149

'My' greenpower team (Sandbach girls high school) just debut'd their new car at Croft circuit on Wednesday. Fantastic day, great place & we won EVERYTHING. The new car came in 2nd place (was finally put together at the circuit.....) & I'm really pleased with it. It needs a paint job but here...
by bobc
Wed Jul 09, 2008 3:54 pm
Forum: Home Energy Area
Topic: induction motor as generator
Replies: 9
Views: 23011

I know the Nuvinci CVT are being sold into windmill applications - seems like a good idea. Actually the slip principle works in generation too, so to get 50Hz out of the induction motor as a 'generator' you have to put more than 1500/3000 revs in. We use this principle to make cheap regenerating loa...
by bobc
Wed Jul 09, 2008 3:44 pm
Forum: Home Energy Area
Topic: Solar hot water pumps, - PV array sizing & BLDC pump
Replies: 5
Views: 18841

Hi Malcolm The pump runs from a nominal 12V DC - it has internal electronics to do the commutating. It's a cheap 12V pump from ebay intended for automotive use. It is just stuck straight across the PV array. The array output can go up to 17V on load I think, but car stuff is designed for 14.4V conti...
by bobc
Wed Jul 02, 2008 9:49 pm
Forum: Home Energy Area
Topic: Solar hot water pumps, - PV array sizing & BLDC pump
Replies: 5
Views: 18841

BLDC = brush less DC motor
by bobc
Mon Jun 23, 2008 12:29 pm
Forum: Home Energy Area
Topic: Solar hot water pumps, - PV array sizing & BLDC pump
Replies: 5
Views: 18841

Solar hot water pumps, - PV array sizing & BLDC pump

A colleague at work has put a PV powered electric pump on his roof mounted solar heating array. From ebay he got an array of parts including a small BLDC pump and a £50 PV array (12W). It didn't work - the array voltage just collapsed with the pump wired in. He was going to buy a bigger PV array,...
by bobc
Fri Jun 20, 2008 12:30 pm
Forum: General
Topic: Electrical Vehicle Campaign
Replies: 30
Views: 18312

Quite a few interesting points arising. The geek/nerd thing - the ones that use that sort of term as abuse are the ones who still expect you to fix their computer for them. So I reckon it's a reaction to their own feeling of inferiority due to their own stupidity or sloth. At school the term of abus...
by bobc
Fri Jun 13, 2008 12:17 pm
Forum: Cars,Vans and other road vehicles
Topic: AC motor/controller sources
Replies: 9
Views: 9164

Tests on rewound motor, looking at off load power loss and motor current 3rd harmonic, both of these jump up at 60Vrms(line-line) so that gives me 2 independent pointers at a suitable magnetisation current. Windings resistance, per phase, is 37 milliohm (star connection). That should be enough for m...
by bobc
Fri Jun 06, 2008 3:16 pm
Forum: BMS thread
Topic: Old BMS General Thread
Replies: 658
Views: 427639

I'm well into the design of a very similar system, with an overall controlled current source charger & local shunt regulators on each cell. I reckon the components cost per cell will be around £2. I'm using AVR ATtiny44 micros - SO14 package & a fairchild RFP12N10L FET for the shunt reg. ...

Go to advanced search