Search found 79 matches

by andylaurence
Wed Jun 24, 2009 1:39 pm
Forum: All things battery related
Topic: Battery Life
Replies: 20
Views: 45201

I think a proper registered trike would be good because it has a bigger, more stable platform for batteries and i believe i could ride it on a car licence (no bike licence yet) Does this fit the bill? I don't know if there are any on the road but they say it can be road-legal and they say they will...
by andylaurence
Wed May 20, 2009 12:34 pm
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

You can get a lot of weight out of a Mini shell, but not without causing a few other problems. I removed all the glass, except the windscreen, and replaced it with Perspex, cut the centre of the door skins, roof panel and rear bulkhead out and replaced them with pop riveted in alloy sheet, replaced...
by andylaurence
Wed May 20, 2009 9:38 am
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

Doubling the power of your Smart Roadster would increase the top speed by about 28mph, or about a 26% increase in top speed. If that power increase was obtained by increasing the engine max rpm, without changing the rpm/torque characteristic, then the acceleration times would remain similar to thos...
by andylaurence
Tue May 19, 2009 3:23 pm
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

Yes, you've shown that if you are running the batteries at 3C for mean motor power, then peak will be 9C. However, what if mean power is 20C? I'm not planning to commute to work in this car, I'm planning to get from A to B as quick as possible. If your mean current draw is 20C, then your endurance ...
by andylaurence
Tue May 19, 2009 10:53 am
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

Andy, I think Deker is right, you need to consider carefully what your specification actually is. You say you want 10 mile range and you might be operating the cells at 20C average. 20C corresponds to 2 or 3 minutes discharge time. For 10 miles that's an average speed of 200-300 mph. And you want e...
by andylaurence
Tue May 19, 2009 10:05 am
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

Re: Fast Car

Andy. I feel that you should slow down a lot, have a considered look at what your'e trying to achieve. I understand what your'e getting at with flywheel/s, however, Jeremy is quite right, let the batteries do the work. How are you going to power the flywheel/s ? You want high acceleration ? then yo...
by andylaurence
Tue May 19, 2009 9:52 am
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

My thinking is that the batteries are a limiting factor. Even at 40mph, whilst only 10hp may be needed to maintain speed, a much larger amount will be needed to overcome the grip of the tyres. That will be limited by the batteries, unless a large number of them are used. But I've just shown that, e...
by andylaurence
Mon May 18, 2009 12:17 pm
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

I understand the desire to use the flywheels to boost peak power, but can't see how it would be of benefit when the ability to deliver instantaneous power isn't down to the batteries, it'll be limited by other parts of the system way before the batteries present a problem. My thinking is that the b...
by andylaurence
Sun May 17, 2009 3:38 pm
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

Yes, I understand that I could pootle along for 10 miles with just a few kW of power. My project is not for a commuter vehicle. I'm aiming for a lot of power as a bit of fun for motorsport. I'm looking for a range of a few miles but to be able to utilise a lot of power over that period. I'm planning...
by andylaurence
Sun May 17, 2009 12:39 pm
Forum: General
Topic: Flywheels For Short-Term Power
Replies: 23
Views: 51929

So, taking an example. I've found some 30C lithium cells. They're 3.7v and 2.2Ah, the max. current is stated as 66A. Each cell weighs 54g. By my reckoning, if I wanted to achieve 100KW, I'd need 410 cells, which would weigh 23KG and store around 3KWh in total. I'd need to shell out over £5000 on ...

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