Gazzar Posted January 7, 2020 Share Posted January 7, 2020 Yes, the electric motor sits where a diff would sit, outputting, via a reduction drive, to two drive shafts. Repeated at the other axle for AWD. The torque is available throughout the rev range hence no need for gears, thus it's effectively in top gear all the time. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted January 7, 2020 Author Share Posted January 7, 2020 The Tesla 3 that I drove has two motors. I didn't look at any details except that it appears to use both together normally but is able to drive using either one on its own. Quote Link to comment Share on other sites More sharing options...
Badger110 Posted January 7, 2020 Share Posted January 7, 2020 4 hours ago, David Sparkes said: That is incorrect. The BMW i3, and I am sure many other pure BEVs, have only one motor, in thiscase driving the rear wheels via a differential and unequal length drive shafts. I'm not sure about the 'motor per wheel' solution you advocate; it creates a terrific unsprung mass to control, but putting the electric motor output through 'standard' gearboxes is a recipie for inefficiency, therefore a waste of battery power. Gear trains get hot as power passes through them, the power taken to produce that heat comes from the power source, whether an IC engine or battery. Regards. I knew I had seen it somewhere individual motors for each wheel. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted January 7, 2020 Share Posted January 7, 2020 I think the conventional motor in place of the engine is easier as you don't have the weight or bulk to fit near the wheel, you have space for the required gearing (a car wheel will by maybe several hundred rpm and a motor several thousand rpm), and you can buy one off the shelf motor and fit it to an existing platform (as most car manufacturers do) rather than 4 bespoke ones and you don't have to run high voltage / current cables down moving suspension, steering etc where of course they will fatigue over time, especially with the environmental factors. I'm sure you could come up with a great hub motor which only has one moving part rather than a motor connected to the hub which would save you the losses of the gearbox / drive shafts / CVs (10%?) and have the brake as part of to the same device but I don't know how far along they are with it? There seems to be lots of amazing electric vehicles from unknown companies that you can put deposits on but can't get the exact details of or see yet. I think I will wait... I think the way Tesla have got product on the ground is pretty impressive, although their finances all seem to be based around keeping investors excited around what's going to happen... Quote Link to comment Share on other sites More sharing options...
reb78 Posted January 7, 2020 Share Posted January 7, 2020 I think I said similar in another thread, but I dont really understand why someone isnt developing an off the shelf conversion for LR products - One motor (or a variety with different powers), bolt to either the gearbox or transfer box (there werent that many gearbox variants that adapter plates couldnt easily be machined) and then plenty of room for batteries. Still wouldnt suit me unless we can get 500 mile ranges though. 300 miles is cutting it fine some days and if cold/need heaters etc, then that would drop to lower than useable. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 7, 2020 Share Posted January 7, 2020 Two things: 1) an EV needs to built almost from the ground up to be an effective/efficient EV with decent range. Things like diffs and transfer cases kill efficiency. 2) no-one wants to spend north of £20k to convert unless they are extremely enthusiastic about EVs. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 7, 2020 Share Posted January 7, 2020 Here's an example, note all the compromises because of the original vehicle design: https://wattsinwheels.com/2018/electric-range-rover-conversion/ Quote Link to comment Share on other sites More sharing options...
reb78 Posted January 7, 2020 Share Posted January 7, 2020 Yes, I guess that video is what got me thinking about it in the first place really. I suppose, like you say, the gearing setup will all be wrong - but then they used the original gearbox back in that RRC didnt they? Whats the main price of their conversion? Is it batteries? (I am just curious... If it really is the answer, its odd that noone is subsidising conversions yet?) Quote Link to comment Share on other sites More sharing options...
Gazzar Posted January 7, 2020 Share Posted January 7, 2020 8 minutes ago, reb78 said: Yes, I guess that video is what got me thinking about it in the first place really. I suppose, like you say, the gearing setup will all be wrong - but then they used the original gearbox back in that RRC didnt they? Whats the main price of their conversion? Is it batteries? (I am just curious... If it really is the answer, its odd that noone is subsidising conversions yet?) Why would they subsidise? Think of the vested interests. HM Govt get more revenue and contributions from the sales of new cars. Plus the major German corporates still have huge influence in German politics. Quote Link to comment Share on other sites More sharing options...
reb78 Posted January 7, 2020 Share Posted January 7, 2020 40 minutes ago, Gazzar said: Why would they subsidise? Think of the vested interests. HM Govt get more revenue and contributions from the sales of new cars. Plus the major German corporates still have huge influence in German politics. I guess so! I just naively assumed that if they wanted people to switch to what is badged as greener technology then they should help. I guess they will just tax the older stuff and force people to move. Its like DPFs... I know they are just plain awful things, but if they were truly good for the environment it would be good to have a 'green subsidy' to make them easier and cheaper to replace before they ruin your car and perhaps even to retrofit them to older vehicles.. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 7, 2020 Share Posted January 7, 2020 Yes, batteries will be ~£15k for a decent amount. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted January 7, 2020 Share Posted January 7, 2020 If you ever believed that they care, take a look at the vat rate on home insulation, and compare it to the vat rate on home electricity. Big business wins. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted January 7, 2020 Share Posted January 7, 2020 I've driven a Tesla Model-S; it was really rather impressive. Torque - and acceleration - on-tap instantly, all in impressive silence! Its owner describes the throttle as the Orgasm-pedal. But as others have noted, if you're running the heater or the aircon seriously it really does reduce the potential mileage-per-charge. Fortunately my friendly Tesla-owner has 3-phase AC power at home and can set things to turn the aircon or heater on for an hour before he needs his car in the morning, so it's pre-heated/cooled to the right temperature [running off mains not battery] for his morning commute, which saves a bit of charge. For a small business, offering "electrification kits" commercially would be a nightmare - apart from the need to do a SVA/IVA-style test and some sort of HMRC-assessment for each vehicle converted, you'd also need to have some serious product-liability insurance in-place - - all the more so if you were offering 'kits' to be fitted by backstreet mechanics rather than by any sort of accredited dealer-network. I can just imagine someone trying to get insurance for their home-fitted electric-kit - sane insurers would expect a certificate-of-competence from the installer, and an inspection of the workmanship of the particular fitment. Let's say £1000? And, let's face it - would it really be worth spending £10K plys VAT to electrify a 20-year-old car that's only worth £5K, and will ** still ** only be worth £5K after the electrification? I'm reminded of the late-80s/early-90s emissions-kits that were offered to 'de-tox' old London Taxis that had been supplied with the Land-Rover/Freight-Rover 2.5-Diesel engine fitted as standard. They were really not that successful - smart cabbies dumped their old taxis and bought ones with the 2.7-Litre Nissan lump. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted January 8, 2020 Share Posted January 8, 2020 Plus the electric stuff weights more than the petrol stuff and in different places so the suspension design would have to be reconsidered to make sure it can take it, and the frame to see what would happen in a crash. Image people being crushed by a boot full of badly mounted batteries which then catch fire Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 8, 2020 Share Posted January 8, 2020 Just skimming this... Motor per wheel doesn't have to mean hub motors - racers have been putting brake discs on the inboard end of a driveshaft for decades, no reason a motor and driveshaft per wheel couldn't work well. The EV motors still tend to have a reduction drive and must also have a diff or you couldn't turn corners. Some of them have changeable gears but only 2 speeds. The vast proportion of the cost of an EV is the battery, 15-30k easily, and it's huge and heavy and very explodey in a crash, which is why I think Tesla etc. get very good NCAP scores - if they didn't ace it the battery would explode in test centre and they'd get null points compared to an ICE car. All these EV conversions make me at least as nervous as LPG conversions - an EV battery pack contains thousands of cells and needs VERY careful charging, balancing, heating, cooling, monitoring and protection to keep it not-on-fire, and just plugging random bits of EV and 3rd party BMS, chargers, etc. together gives me the heebies. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 8, 2020 Share Posted January 8, 2020 What could possibly go wrong ? 😂 Mo Quote Link to comment Share on other sites More sharing options...
BogMonster Posted January 8, 2020 Share Posted January 8, 2020 8 hours ago, FridgeFreezer said: All these EV conversions make me at least as nervous as LPG conversions - an EV battery pack contains thousands of cells and needs VERY careful charging, balancing, heating, cooling, monitoring and protection to keep it not-on-fire, and just plugging random bits of EV and 3rd party BMS, chargers, etc. together gives me the heebies. Should be good with big Li-Ion batteries Quote Link to comment Share on other sites More sharing options...
lo-fi Posted January 9, 2020 Share Posted January 9, 2020 12 hours ago, FridgeFreezer said: The vast proportion of the cost of an EV is the battery, 15-30k easily, and it's huge and heavy and very explodey in a crash, which is why I think Tesla etc. get very good NCAP scores - if they didn't ace it the battery would explode in test centre and they'd get null points compared to an ICE car. Tesla quoted me 10k for a battery swapout when I questioned that. I was surprised. As far as safety ratings... The lack of boat anchor at the front means they could make the crash structure and crumple zones huge and not have to worry about said anchor flying into the cabin either. Part of the advantage of being designed from the ground up as an EV, not just a golf with a large starter motor and a few extra batteries. Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 9, 2020 Share Posted January 9, 2020 On 1/7/2020 at 3:29 AM, Badger110 said: My thoughts on electric cars are they are built with power to individual motors which control the wheels and not as a ' replacment ' for the diesel/engine with one single motor? I do wonder if you were to use a single motor into a gearbox of a Series/defender/disco like some have said here, the motor wouldn't work no where as efficient as 4 seperate motors to the indiviual wheels. Only the Rivian has that. As for the numerous comments of attaching a motor directly to the transfer box, it has been done by several people and all regretted it. On a car conversion, you need a regular gear box or two speed reduction box, and on 4wd vehicles, you need that before the transfer box. That applies to Tesla, Leaf and generic engines alike - with direct drive into the transfer box, it’ll drive, but it doesn’t have quite enough torque to pull the high range gearing. But on a Series vehicle or Defender with standard transmission, you end up only ever using 3rd and 4th on the road - the rest become superfluous; overdrive or 5th, which is an internal overdrive on most, just create inefficiencies and the electric motor runs more efficiently at higher rpm, with well over 7000rpm being within a healthy range. Cold weather is a problem. It severely limits battery output while also requiring more ancillaries like heating, lights and wipers. Tesla and some others have battery heaters, some using pads, others like Tesla using the battery coolant through a heater initially to warm the batteries until the heat from other components can be used, even using that heat for the cabin. Most conversions use seat heating as it uses less heat than electric cabin heaters, but we have the space for fuel based heaters like eberspacher. The biggest problem with cold weather is charging - if you try charging Li Ion batteries below 1-2 deg C, they will be destroyed. They need preheating for charging. Solid state batteries are in the late stages of development, and should deal with those thermal issues as well as overall lifecycle depletion, charge rate limits and price. Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 9, 2020 Share Posted January 9, 2020 17 hours ago, FridgeFreezer said: Just skimming this... Motor per wheel doesn't have to mean hub motors - racers have been putting brake discs on the inboard end of a driveshaft for decades, no reason a motor and driveshaft per wheel couldn't work well. The EV motors still tend to have a reduction drive and must also have a diff or you couldn't turn corners. Some of them have changeable gears but only 2 speeds. The vast proportion of the cost of an EV is the battery, 15-30k easily, and it's huge and heavy and very explodey in a crash, which is why I think Tesla etc. get very good NCAP scores - if they didn't ace it the battery would explode in test centre and they'd get null points compared to an ICE car. All these EV conversions make me at least as nervous as LPG conversions - an EV battery pack contains thousands of cells and needs VERY careful charging, balancing, heating, cooling, monitoring and protection to keep it not-on-fire, and just plugging random bits of EV and 3rd party BMS, chargers, etc. together gives me the heebies. The batteries won’t explode, a.t least not for a while, but the fires are hard to extinguish are tend to reignite if the batteries are mechanically damaged and runaway. As for conversions, they can be very safe IF done correctly, which is like the LPG example you mention, but also any other conversion (not just engines) - how many butchered vehicles do we see on the internet, or even at shows? More conversions are done badly than properly because individuals have too tight a budget, overestimate their ability and underestimate the risk. Human nature, sadly. But I think that quite a few of us on this board could do high quality conversions to a very safe standard, at least once battery prices (the main cost as you rightly say) come down, since most of us have the right attitude to research, check, double check and then get and expert to check our work, ie enough awareness and humility to do it right. Quote Link to comment Share on other sites More sharing options...
elbekko Posted January 9, 2020 Share Posted January 9, 2020 18 hours ago, FridgeFreezer said: All these EV conversions make me at least as nervous as LPG conversions - an EV battery pack contains thousands of cells and needs VERY careful charging, balancing, heating, cooling, monitoring and protection to keep it not-on-fire, and just plugging random bits of EV and 3rd party BMS, chargers, etc. together gives me the heebies. Can't wait for the sketchy blue wire in EV conversions. Although your LPG example proves to me more the opposite... I haven't seen a single LPG install that wasn't at least slightly sketchy, and how many have blown up? Quote Link to comment Share on other sites More sharing options...
steve b Posted January 9, 2020 Share Posted January 9, 2020 Time for this ? I'll get my coat Steve b Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted January 9, 2020 Share Posted January 9, 2020 When I bought my range rover the LPG tank in the boot was held in place with a brick and there was no electronic shut off valve on the tank and it was completely fine. You all worry too much. Atleast the tesla fires are self cleaning, the heat melts the aluminium and the car just disappears. Quote Link to comment Share on other sites More sharing options...
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