Having not used a kit car I can but only assume youve set it up correctly but I wouldnt expect that ratio to accelerate very quickly anyway. What I don't get is your issue with RPM. I would have thought that gear ratio would have seen your motor running very nicely at 2000RPM. Is your motor in good working order? My only other thought could be over tight bearings. Have you altered the wheel size? Also are you testing in an open area or tennis/sports court?

The supplied gearing is quite low and the car shouldn't struggle to pull it although it may not manage to reach 2000rpm on the flat. If you're sure there's more resistance than seems normal then you need to be looking at possible binding brakes, tyres pressures, wheel alignment, driver train alignment.

Have another look at the motor performance graph in the technical section of the website; you need to be taking about 18A in a race & that will be at 1800rpm (ish) - the 2000rpm figure is with no load.
Faulty motors, paradoxically, spin faster (off load) than good ones - either because of reduced flux or a reduced number of windings (short circuit somewhere on the armature)
edit - I can't find the motor performance graph on this new website, the technical section just has the A-Z in it - anyone know where it is or has it got lost in the move? If so can it be reinstated?

thanks for the quick comments. 20" wheels without any body work just for reference. @no.12 we were testing in out car park about the length of a 2-3 tennis courts length ways. brand new electric motor in good working order ( i assume) but it doesnt seems to move very quickly i might put my cycle computer on it to monitor speeds whilst testing(are cycle computers allowed during races) . @farnorth no brake binding and tyre pressures are maxed out at 40PSI for the kit car tyres. wheels are alligned with a normal amount of camber.

That may well be why it seems slower than you expect. We have test in a sports area a similar size and what seems slow was actually faster than expected. Cycle computers are allowed, we use one, thats how we were able to know the speeds were higher than initially thought, a very useful tool on and off the track.
As for your motor issue if its working ok unfortunately I cant help on that sorry.

Here's the graph:

http://www.greenpower.co.uk/node/193

@no.12 very useful thankyou even though it felt like the motor was maxed out and at top speed it wasnt. thanks. @mattt just as usefull thanks. one last question before i bore you all silly is there any way to have a progressive increase in throttle becuase we currently just have a on off switch which seems quite harsh on various comonents.
manythanks from the guys at Archbishop Holgates Sixth Form College

The on/off switch: ours causes a loud 'thunk' as the chain engages with the sprocket- this is fine, our homemade sprocket has lasted eight years, and is still fine

Not sure what electrical knowledge you have but if if anything like mine (limited) theres the 4qd motor controller, I use the pro-150, some people don't like them but I think there very good if you want a quick solution to easing in the power with limited knowledge as all you need to do is connect 4 wires and alter the ramp up time (all explained in the instructions) I brought mine with the sole intention of allowing an ease in at the start.
http://www.4qd.co.uk/prod/index.html

was it only me that was thinking off a scalextrix triggger, seems that way.if were allowed a 2 step push start then i see no need for a ease in start. just my ideas for a heatsink due to the motor being too hot to hold you hand on it after being run with cold air running over it due to no body work: i have made a semi circle alu plate with about 20 1 inch high full length of motor fins, however with just two rivets holding each plate to the backplate i think cpu heat sink compound will be needed. ps. my part time job it fixing computer so i have acess to any computer parts so getting hold of heatsinks and fans wont be a problem i have thought about putting heatsink fans connected to one of the batteries when we have body work put on it

Just a thought Mike. Are the tyres you're using rated at 40psi? Seems very low. Most I know race at 100psi and quite a lot go to 120.

yes they are rated at 40PSI which is ridiculously low, but thats what there rated at

It won't solve all your problems, but harder tyres does make a significant difference.

Hi mike -- Unless the tyres are really cheap n nasty you can probably pump the tyres 20 -50 % higher than the rating ------it really depends on bravery !!

Mike, We also tested on a 3x tennis court and nearly melted the motor. It's too small to get any speed up and the constant on/off/on/off warms the motor up more than being held half-on... which you need a motor controller to do. We use 4QD, not sure which model (no doubt the cheaper of the two!)

We practiced on the tennis courts with the same ratio we ran at the final, yet the motor was much cooler at the final than during testing (even allowing for different ambient temperatures).

In a similar way, running without bodywork may actually increase the motor temperature as the motor has to work harder to push the less aerodynamic car along. With ambient temps at the moment this is unlikely, but on a warm day it's quite possible.

@wheels not sure becuase they do seem cheap and nasty i dont want to risk it with our budget being £0. final question are you allowed any other forms off power eg: small battery for a cooling fan on heatsink and possibly a speedo.

You're not allowed to use an additional battery for a cooling fan, but if you use something like this:

http://www.ebay.co.uk/itm/2pcs-Temperature-Switch-Thermostat-KSD301-40-C-NO-/150648528320?pt=LH_DefaultDomain_3&hash=item23135a1dc0

You can connect a fan to the main batteries (via the necessary fuse) and it will only come on when the motor temperature gets high enough operate the switch. Computer fans take very little power, certainly far less than you'd waste through the drop in efficiency of a hot motor.

If you're using a bike speedo the internal battery for that is allowed as it's not part of a control system or cooling

I wouldn't reccommend using a bike speedo- the driver becomes distracted and doesn't drive as SMOOTHLY as they need to- being smooth is the key, so you don't waste speed in corners.

Just had a quick look at the link from farnorth above and the sensor is rated at 110V AC TO 250V AC. Would this still work in a Greenpower application? ie does the sensor justr act as a switch and the voltage is not important!

a good driver can watch the speedo and drive smoothly though, it just needs to be built into the training programme

Crag Rat, for switching 12 or 24v DC at less than 0.5A it'll be fine. There's no rating on that link but they usually range from 2A to 10A so plenty headroom for use with a fan.

Terry, totally agree with you. A speedo is the simplest way for a driver to make sure they're not scrubbing off too much speed in the corners.

and to make sure they arent speeding in the pitlane

Hi all. I must admit I was going to fit two small computer type (box fans in the Rapid catalogue) to our car this winter and having looked at the Ebay link above my thermostat is likely to come from Hong Kong as well. Seems to me the power draw of two fans is so small it could well be worth it. I will need to duct the air carefully so all of the fan output is utilised. Maybe I could run the fans from PV cells ?
Ashley

We run purely passive cooling on the motor, plus the horn, speedo, datalogger and rear light run off their own batteries (some share the same battery) - we find it works for us. I do want to improve the heatsink this year though.

Just noticed this is in the F24+ section. The 12:72 gear ratio I think is for F24 cars, but if you are running an F24+ gear ratio, this would overheat even worse in a tennis court as you'd never get close to the 1800rpm, so constantly be drawing too much current, so overheating the motor. Be careful, it's £150 per mistake!

Ok.... can someone tell me what Gear ratio they run in the F24+? I know things will be different this year with the new batteries. Also when can you start testing at Greenwood with the new Batteries to see what type of changes your team will have to make for the F24+. Any info you can give will be helpful. It is awesome to see what all these teams are able to do over the past year.

We've worked out our gearing for 2012 - now to get one of these laser cut.
http://www.velominati.com/blog/technique/sur-la-plaque-physics-of-the-big-ringle/
Wishing you all a Merry Christmas & puncture-free New Year.
Brian

Looks just like ours!

CC

coming back to the speedo thing-you can ride a bike without crashing so why not a green power car plus the driver is probably just as likly to crash

just a quick question; our steering on our standard chassis is really heavy and the turning circle is pretty poor becuase of this. we have built it too the designs and looked at the pictures provided by GP but it still struggles to turn around less than a double width road

sorry i realise that is a really broad question and we have fixed it now - overtightened bolts doh!