simonr Posted August 9, 2009 Share Posted August 9, 2009 My eleccy Freelander is now finished - and it's existing tyres are a mixture of nearly and probably illegal! I need to buy some more tyres so figure I might as well get the ones which will give the best mileage on a charge. I can't find any data specific to this - I guess it's not a 'sexy' parameter for 4x4 tyres? They are currently 215/65 R16. Si Quote Link to comment Share on other sites More sharing options...
GBMUD Posted August 9, 2009 Share Posted August 9, 2009 IIRC it was Michelin who offered an 'eco' type tyre with a claimed reduction in rolling resistance. I would suggest any tyre with a fairly 'aeroplane' looking tread and plenty of air in. I guess a thinner tyre will probably be better, same as racing bikes seem to have thin tyres. Chris Quote Link to comment Share on other sites More sharing options...
smo Posted August 9, 2009 Share Posted August 9, 2009 What kind of tyres Si?? If its road tyres most manufacturers make "eco" tyres, continental eco-contact SP, michelin energy, goodyear eagle ls etc etc. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 9, 2009 Share Posted August 9, 2009 going narrower will certainly help reduce drag, as will increasing the air pressure. Going from the normal 32psi up to 40psi on our A4 (thats the normal and "heavy load" settings) shaved the MPG from around 32 to around 35 on a run. Quote Link to comment Share on other sites More sharing options...
ashtrans Posted August 9, 2009 Share Posted August 9, 2009 I would remove the rear prop and run it front wheel drive, this will eliminate the drivetrain wind up they suffer from even when the viscous coupling is good, Quote Link to comment Share on other sites More sharing options...
simonr Posted August 9, 2009 Author Share Posted August 9, 2009 I would remove the rear prop and run it front wheel drive, Actually, I've removed the engine, IRD, gearbox and VC - and have a BIG electric motor driving the rear diff via a Suzuki transfer box which only acts as a high torque reduction. 4x4 was too much of a luxury in an eleccy car. There is a write up on what I've done here.... I've looked on a number of manufacturers web sites and in general their 'eco' tyres are not available in Freelander size. I need something for road only use - so they can be skinny and don't need chunky tread. Low noise is also a consideration. The freelander is so quiet you can hear the clock ticking - and it's digital Si Quote Link to comment Share on other sites More sharing options...
bishbosh Posted August 9, 2009 Share Posted August 9, 2009 Si, post up some piccies - you have to register on that site to see them :( Quote Link to comment Share on other sites More sharing options...
simonr Posted August 9, 2009 Author Share Posted August 9, 2009 OK Charles - here is my original post on DIYElectric..... I had an amazing stroke of luck and found a Siemens AC motor and controller at my local junk yard - which had apparently come from a scrapped hybrid bus. They only wanted $100 for the pair - so I couldn't walk away. It took me a year to gather together enough information to even find out if it worked (and it does). I must thank Eddy Hustinx from HEC who filled in the last missing pieces - and supplied me the RS232 interface and 68way connector required to wire it up. Other retailers of the same motor / inverter were at best unhelpful! Once it was running on the bench - I obviously had to build it in to a vehicle. Since the motor and controller had come from a junk yard - I'd see how much of the rest of it could be made from recycled junk. I asked the yard to look out for batteries - and they came up with a load of Optimas that had come from the local Jeep dealer. I went along with my Midtronics battery tester and found 20 that reported good - and they only charged me $3 each. They are less than ideal as a traction battery - but at that cost - who cares! They have an ongoing supply and they will give me $2 back on them when they have died. I run a company manufacturing accessories for Land Rover vehicles - so the vehicle had to be a Land Rover. I settled on a Freelander as they are cheap and (compared to other models) fairly light. Mine weighed 1500kg when I bought it. I removed the engine and all of the transmission apart from the rear differential. Originally it was 4x4 - but it's going to become RWD (I've never much liked front wheel drive!). Quote Link to comment Share on other sites More sharing options...
Lara Posted August 10, 2009 Share Posted August 10, 2009 Interesting Simon! Why don't you rig up a big alternator arrangement to engage and spin up when braking in order to charge the batteries somewhat while driving, A bloody big alternator would also save on your brakes too! and you could always connect the alternator up to a high speed flywheel and one way clutch that engages when you touch the brakes, to give you even longer charge period by using more of the kinetic energy available from braking. Just to make things more complicated for you this project was obviously far too easy as you have almost finished Lara Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 10, 2009 Share Posted August 10, 2009 Can the motor controller do regenerative braking? Quote Link to comment Share on other sites More sharing options...
simonr Posted August 10, 2009 Author Share Posted August 10, 2009 Can the motor controller do regenerative braking? Yup - the motor just acts as a honking big 3 phase alternator (50kw or so). It's activated when the brake lights come on - so if you just touch the brake pedal you get regen but as you push harder, you get progressively more mechanical braking. Si Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 10, 2009 Share Posted August 10, 2009 Awesome! If its designed to power a bus, and you've geared it to provide less torque and more speed, what kinda top speed do you think it will be able to provide? Quote Link to comment Share on other sites More sharing options...
hoarebag Posted August 10, 2009 Share Posted August 10, 2009 Goodyear Efficient grip are available in a 225/60/16 which i believe would work on the rims and have a similar RC. Quote Link to comment Share on other sites More sharing options...
nicks90 Posted August 11, 2009 Share Posted August 11, 2009 thats fantastic! any idea on what sort of range you'll be able to get from this thing? Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted August 11, 2009 Share Posted August 11, 2009 You too clever Si ! Mo Quote Link to comment Share on other sites More sharing options...
Lara Posted August 11, 2009 Share Posted August 11, 2009 Yup - the motor just acts as a honking big 3 phase alternator (50kw or so). It's activated when the brake lights come on - so if you just touch the brake pedal you get regen but as you push harder, you get progressively more mechanical braking. Si Hi Simon, That answers my question on regenerative breaking but are you intending to use capacitors etc in order to harness as much energy as possible as obviously the batteries will not be able to take all that power in such a short time? Very interesting project, Trying to find out, How "techie" are you getting or is the idea "just" to make a simple electric vehicle? ("just" meaning I know it isn't "that" simple ) Lara Quote Link to comment Share on other sites More sharing options...
simonr Posted August 11, 2009 Author Share Posted August 11, 2009 Lots of quesions! are you intending to use capacitors etc in order to harness as much energy as possible as obviously the batteries will not be able to take all that power in such a short time? Very interesting project, Trying to find out, How "techie" are you getting or is the idea "just" to make a simple electric vehicle? I decided (for once) not to over complicate it - there is enough to do without adding computers and ultra-capacitors! Although the regen can generate huge currents, it's limited in software by the controller to whatever you specify. I have limited it to 100A - which will be OK. That's still 20kw as the vehicle runs at quite a high voltage. any idea on what sort of range you'll be able to get from this thing? I only 'need' a range of 6 miles to get me to work and back - and that was one of the motivations for the project. I estimate about 20 miles with this set of batteries. If its designed to power a bus, and you've geared it to provide less torque and more speed, what kinda top speed do you think it will be able to provide? In high range it should reach about 90mph @ 6000rpm In low, about 55mph - but with diff breaking torque (hopefully!). The motor delivers the highest efficiency at low rpm - so I went for higher gearing as the motor is not short of torque (450Nm peak). A couple more piccies: Where's the gearstick? It's one of the switches in the centre console! I'm using an electric PAS pump from a new style Mini - it has the controller built in that switches it on and off as required. Nice little bit of unnecessary CNC machining to adapt the Freelander PAS pipe to mini pump. DIY brake vacuum pump - the pump is from a Series 2 Diesel and the motor from an electric scooter. Quote Link to comment Share on other sites More sharing options...
Daan Posted August 11, 2009 Share Posted August 11, 2009 Interesting project, Simon. Does this mean you are exempted from road tax? Daan Quote Link to comment Share on other sites More sharing options...
simonr Posted August 11, 2009 Author Share Posted August 11, 2009 Goodyear Efficient grip are available in a 225/60/16 which i believe would work on the rims and have a similar RC. Thanks! Have you seen the price of them? £120 per tyre! We're obviously spoiled with the cost of 4x4 tyres! Daan - I've spoken to DVLA and they say if I turn up at my local office (Brighton) with a report along the same lines as for an SVA giving details of the conversion they will decide if it needs an inspection (if there is a doubt that it has been converted). They will reclassify it and I'll get free tax thereafter. The woman I spoke to said the report / inspection are just to stop people trying it on "I can drive it on the starter motor - so it's a hybrid" kind of thing. I don't think there will be any doubt there - so I'm hopeful! Si Quote Link to comment Share on other sites More sharing options...
Lara Posted August 11, 2009 Share Posted August 11, 2009 Hope all goes well with the project Simon, I would not want to be doing it! I am sure it is a lot more complicated than your post suggests! When it all works as intended I wonder how long it will be until you start wondering "IF I JUST" It's not what starts you thinking it's what stops you thinking, bet you can't! Lara Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 11, 2009 Share Posted August 11, 2009 If it helps with tyre choice, I've got a set of 15" alloys here. Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted August 11, 2009 Share Posted August 11, 2009 If it helps with tyre choice, I've got a set of 15" alloys here. Based on the above a set of 195/80/15 would work well - looking around I've found the following manufacturers do this size in a road type tread: Goodyear Falken General Toyo Hankook Commercial van tyres would also be good, if you can get them in a suitable size. Continental Vancocontact 195/70/15C would be about 5% smaller diameter than standard, narrower for lower resistance and harder rubber compound again for lower resistance. Or on the 16" wheels Continental van tyres in 205/65/16 are available and 2% smaller than yours. Quote Link to comment Share on other sites More sharing options...
simonr Posted August 11, 2009 Author Share Posted August 11, 2009 Thanks for all your help. Fridge - cheers, but I'm going to stick with 16" - slightly more efficient for a given outside diameter - it all makes a difference! Van tyres are a good plan! Si Quote Link to comment Share on other sites More sharing options...
landroversforever Posted August 11, 2009 Share Posted August 11, 2009 what a great project si!!! looks great. any videos yet? Quote Link to comment Share on other sites More sharing options...
simonr Posted August 11, 2009 Author Share Posted August 11, 2009 what a great project si!!! looks great. any videos yet? A video wouldn't be that interesting! Tell you what - you could get a flavour by looking at a black freelander drive by, holding your breath and sticking your fingers in your ears! So long as you remember to breath again - you'll have a pretty good idea what it's like Si Quote Link to comment Share on other sites More sharing options...
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