Electric cars, why 48-144V? Why not >400V?
- Thread starter jag
- Start date
frodus
10 kW
Cost, Components under 200V are far cheaper than above 200 when you get into IGBT world.
Connection losses between series batteries
EMI does some funky shit when you get higher voltages switching at high frequency.
There aren't many available DC motors above 144V, The conversions that are AC are usually above 300VDC
Connection losses between series batteries
EMI does some funky shit when you get higher voltages switching at high frequency.
There aren't many available DC motors above 144V, The conversions that are AC are usually above 300VDC
spinningmagnets
100 TW
48V is around the limit where above that some people may die from an electrocution, however if proper precautions are taken higher voltages can be very safe as seen by every household using 120V (though its AC).
72V is a mass-production limit, and controllers for voltages above that are less popular, and as a result are much more expensive. Another reason 72V is a popular is if you are using lead/acid batteries (still a large percentage of small EV's) it is difficult to package any more than six of the 12V batteries on a Bike, scooter, or motorcycle.
Whether using lead or Lithium, there's a reasonable argument for using 108V (nine times 12V) in a small car. Most trips are short, perhaps to the grocery store, Home Depot, or a restaurant (so most dont need freeway speeds)? I live only 7 miles from work so I'm a very good candidate for an EV. However, the public remains very concerned about short range in EV's. On those rare occasions where more range is desired, it may be useful to attach a very short trailer with a engine-generator. During the 90% of your driving miles, you wouldnt have to haul around the extra weight of the series/hybrid generator.
These are cheaply available producing 120V and also 220V. There is a small conversion loss, so the generator should be of a slightly higher output than the EV's battery-pack voltage. So, 108V and 204V would seem to me to be valuable prototype voltages.
The Tesla roadster doesn't currently use its original prototype 2-speed transmission, and one of its "wealthy early adopter" demographic design goals was snappy acceleration and a high top speed from one gear. They use 324V, so I imagine for a vehicle that only needs adequate power, 204V would be more than enough for decent acceleration and a 75-MPH top speed, and performance would be even better if you added a 2-speed.
FrankG swapped a small motor onto a light 175cc motorcycle while still keeping the stock transmission, he ended up using only 2nd gear and 6th gear, but he got suprisingly good top speed and acceleration from a small motor and only 48V.
NEDRA electric drag racers use unusually high voltages, but of course they build their own custom controllers and are not concerned with range. "Killacycle" used 375V
http://www.nedra.com/record_holders.html
72V is a mass-production limit, and controllers for voltages above that are less popular, and as a result are much more expensive. Another reason 72V is a popular is if you are using lead/acid batteries (still a large percentage of small EV's) it is difficult to package any more than six of the 12V batteries on a Bike, scooter, or motorcycle.
Whether using lead or Lithium, there's a reasonable argument for using 108V (nine times 12V) in a small car. Most trips are short, perhaps to the grocery store, Home Depot, or a restaurant (so most dont need freeway speeds)? I live only 7 miles from work so I'm a very good candidate for an EV. However, the public remains very concerned about short range in EV's. On those rare occasions where more range is desired, it may be useful to attach a very short trailer with a engine-generator. During the 90% of your driving miles, you wouldnt have to haul around the extra weight of the series/hybrid generator.
These are cheaply available producing 120V and also 220V. There is a small conversion loss, so the generator should be of a slightly higher output than the EV's battery-pack voltage. So, 108V and 204V would seem to me to be valuable prototype voltages.
The Tesla roadster doesn't currently use its original prototype 2-speed transmission, and one of its "wealthy early adopter" demographic design goals was snappy acceleration and a high top speed from one gear. They use 324V, so I imagine for a vehicle that only needs adequate power, 204V would be more than enough for decent acceleration and a 75-MPH top speed, and performance would be even better if you added a 2-speed.
FrankG swapped a small motor onto a light 175cc motorcycle while still keeping the stock transmission, he ended up using only 2nd gear and 6th gear, but he got suprisingly good top speed and acceleration from a small motor and only 48V.
NEDRA electric drag racers use unusually high voltages, but of course they build their own custom controllers and are not concerned with range. "Killacycle" used 375V
http://www.nedra.com/record_holders.html
dogman dan
1 PW
Ever priced a 400v contactor? 120 volts is about all most cars need to perform as good as a gasser. Increase amps as needed.
Drunkskunk
100 GW
battery cells are 1.25 to 3.7 volts each depending on chemestry, and 400 volts worth of cells is a lot. More parts, more chance for failure of some part.
High voltage can arc across the windings inside the motor, the componants needed to handle it are expensive, and when combined with high frequency, can have some bizare side effects like reflected waves, harmonic induction, and wire harnes capacitance.
there isn't much efficancy gain by going from 144 to 400. your resistive loss at 144 is pretty small. Sure, its less than half that at 400, but its such a small percent of your power use at 144, its mot worth the expense. you could just use a battery 1% larger and offset the loss, saving a lot of money on the cost of a 400 volt system,
High voltage can arc across the windings inside the motor, the componants needed to handle it are expensive, and when combined with high frequency, can have some bizare side effects like reflected waves, harmonic induction, and wire harnes capacitance.
there isn't much efficancy gain by going from 144 to 400. your resistive loss at 144 is pretty small. Sure, its less than half that at 400, but its such a small percent of your power use at 144, its mot worth the expense. you could just use a battery 1% larger and offset the loss, saving a lot of money on the cost of a 400 volt system,
TylerDurden
100 GW
As per gizmag:
Aptera 2e will have a 60 ft/lb (81 Nm) electric motor driving the front wheels through a 10:1 single speed gearbox with power provided at 336 volts by a 10 – 13 kw/hr Lithium iron phosphate battery pack.
Still no details on battery supplier, motor type or power output at this stage. Without knowing the motor type (the Aptera does have regeneration, so the motor is either a BLDC or AC Induction type) or the torque curve we can only calculate an educated guess based on the torque figure and gearbox ratio information provided. The 2e electric motor power output could be in the range of 100 hp (75kw) at over 13,000 rpm. While that might not sound like much, with such a lightweight chassis and super low 0.15 Cd drag coefficient much less power is required to equal the performance of a heavy conventional steel vehicle.
Full released specs:
Dimensions:
53" high x 91.0" wide x 173" long
111" wheelbase
80.5" front track
Other specs:
0.15 Coefficient of drag
5" ground clearance
1500 lbs curb weight
Electric motor torque: 60FtLb torque
110v 15A charge time: 8 hrs
Battery output: 10-13 Kw/hr battery pack
Battery voltage: 336V DC Nominal Traction Voltage
Transmission: Gearbox 10:1 ratio
Battery Type: Lithium Ion Phosphate
Chassis:
Front Suspension: Independent unequal length A-arm
Rear Suspension: Swing Arm
Steering: Manual Steering, tilt steering column
Brakes: Manual Brakes, dual circuit brake hydraulics, mechanical brake proportioning, 3-wheel disc
Wheels: 14-inch High Strength Stamped Steel wheels
Size: P165/65R14
Performance:
Range: Up to 100 miles per charge
Warranty:
Basic: 4/50,000
Powertrain: 4/50,000
Corrosion: 12/unlimited
Roadside: 4/50,000
Features: (S=standard, O=optional)
Interior:
Push Button Start: S
Electronic shift PRNDL (shift controller): S
AM/FM/MP3/WMA with 5 speakers and MP3/Smart Phone Connectivity: S
DVD Navigation System: O
Power up/down windows with Driver side one-touch and anti-pinch: S
Power automatic door locks with anti-lockout feature: S
Center console armrest with two cup holders: S
Overhead mounted LED Dome Lights: S
Recycled Fabric-trimmed seats and door panels: S
Leatherette (recycled materials) trimmed steering wheel: S
Defroster-linked CFC-free automatic climate control with electric inverter compressor air conditioning: S
One 12V auxilliary power outlets and One 12V USB Outlet: S
Retractable passenger-assist grips at all doors: S
Exterior:
Dual color-keyed power outside mirros: S
Aerodynamic multi-reflector halogen headlamps: S
Washer-linked variable intermittent windshield wipers: S
Rear window defogger with timer: S
Rear Electronic rear hatch locking system (sic): S
Solar Energy-Reflecting glass: S
Smart Key System (Proximity locking/starting) Maintenance key & cylinder to prevent accidental lock out: S
Safety:
Remote keyless entry system with 2-stage unlocking, panic function and remote illuminated entry: S
Backup camera: O
Driver and front passenger Airbag System: S
Front and rear crumple zones and side-impact door beams: S
Engine immobilizer: S
Center high-mount stop lamp: S
Emergency Tire inflation system: S
3-point front outboard seatbelts with adjustable shoulder anchors and driver-side Emergency Locking Retractor (ELR), front passenger Automatic/Emergency Locking Retractor (ALR/ELR): S
Driver and front passenger seatbelt with seat belt starter interlock: S
Direct Tire Pressure Monitor System (TPMS): S
Anti-theft system: O
Paul Evans
Via Josh on Apteraforum.
http://www.gizmag.com/aptera-2e-specification-released/10903/
Aptera 2e will have a 60 ft/lb (81 Nm) electric motor driving the front wheels through a 10:1 single speed gearbox with power provided at 336 volts by a 10 – 13 kw/hr Lithium iron phosphate battery pack.
Still no details on battery supplier, motor type or power output at this stage. Without knowing the motor type (the Aptera does have regeneration, so the motor is either a BLDC or AC Induction type) or the torque curve we can only calculate an educated guess based on the torque figure and gearbox ratio information provided. The 2e electric motor power output could be in the range of 100 hp (75kw) at over 13,000 rpm. While that might not sound like much, with such a lightweight chassis and super low 0.15 Cd drag coefficient much less power is required to equal the performance of a heavy conventional steel vehicle.
Full released specs:
Dimensions:
53" high x 91.0" wide x 173" long
111" wheelbase
80.5" front track
Other specs:
0.15 Coefficient of drag
5" ground clearance
1500 lbs curb weight
Electric motor torque: 60FtLb torque
110v 15A charge time: 8 hrs
Battery output: 10-13 Kw/hr battery pack
Battery voltage: 336V DC Nominal Traction Voltage
Transmission: Gearbox 10:1 ratio
Battery Type: Lithium Ion Phosphate
Chassis:
Front Suspension: Independent unequal length A-arm
Rear Suspension: Swing Arm
Steering: Manual Steering, tilt steering column
Brakes: Manual Brakes, dual circuit brake hydraulics, mechanical brake proportioning, 3-wheel disc
Wheels: 14-inch High Strength Stamped Steel wheels
Size: P165/65R14
Performance:
Range: Up to 100 miles per charge
Warranty:
Basic: 4/50,000
Powertrain: 4/50,000
Corrosion: 12/unlimited
Roadside: 4/50,000
Features: (S=standard, O=optional)
Interior:
Push Button Start: S
Electronic shift PRNDL (shift controller): S
AM/FM/MP3/WMA with 5 speakers and MP3/Smart Phone Connectivity: S
DVD Navigation System: O
Power up/down windows with Driver side one-touch and anti-pinch: S
Power automatic door locks with anti-lockout feature: S
Center console armrest with two cup holders: S
Overhead mounted LED Dome Lights: S
Recycled Fabric-trimmed seats and door panels: S
Leatherette (recycled materials) trimmed steering wheel: S
Defroster-linked CFC-free automatic climate control with electric inverter compressor air conditioning: S
One 12V auxilliary power outlets and One 12V USB Outlet: S
Retractable passenger-assist grips at all doors: S
Exterior:
Dual color-keyed power outside mirros: S
Aerodynamic multi-reflector halogen headlamps: S
Washer-linked variable intermittent windshield wipers: S
Rear window defogger with timer: S
Rear Electronic rear hatch locking system (sic): S
Solar Energy-Reflecting glass: S
Smart Key System (Proximity locking/starting) Maintenance key & cylinder to prevent accidental lock out: S
Safety:
Remote keyless entry system with 2-stage unlocking, panic function and remote illuminated entry: S
Backup camera: O
Driver and front passenger Airbag System: S
Front and rear crumple zones and side-impact door beams: S
Engine immobilizer: S
Center high-mount stop lamp: S
Emergency Tire inflation system: S
3-point front outboard seatbelts with adjustable shoulder anchors and driver-side Emergency Locking Retractor (ELR), front passenger Automatic/Emergency Locking Retractor (ALR/ELR): S
Driver and front passenger seatbelt with seat belt starter interlock: S
Direct Tire Pressure Monitor System (TPMS): S
Anti-theft system: O
Paul Evans
Via Josh on Apteraforum.
http://www.gizmag.com/aptera-2e-specification-released/10903/
TylerDurden
100 GW
As per WIRED:
The iMiEV uses a 16-kWh, 330-volt lithium-ion battery that weighs 550 pounds. It’s located beneath the front seats. Mitsubishi is developing and building batteries under a joint venture with the Japanese firms GS Yuasa and MMC called "Lithium Energy Japan."
http://www.wired.com/autopia/2008/11/the-imiev-is-a/
The iMiEV uses a 16-kWh, 330-volt lithium-ion battery that weighs 550 pounds. It’s located beneath the front seats. Mitsubishi is developing and building batteries under a joint venture with the Japanese firms GS Yuasa and MMC called "Lithium Energy Japan."
http://www.wired.com/autopia/2008/11/the-imiev-is-a/
frodus
10 kW
the AC systems (aptera and imiev) are all above 300V....not many except the ElectricMotorsport AC motor/controller combo are below 144V. DC limit is usually around 156V unless you've got 2 motors in series.
Doctorbass
100 GW
dogman said:
The recent Kilovac Ev100, EV200 and EV500 model solved that voltage problem.. they are sealed and can cary up to 900vdc make or brake! !
at 500A the EV200 can cary 320V.. and at 250A it can cary 900VDC... nice for a 70$ availlable contactor !!
Doc
RoughRider
100 W
- Joined
- May 17, 2009
- Messages
- 208
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Anonymous
Guest
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frodus
10 kW
RoughRider said:
You're just not good at shopping
www.ebay.com
search for EV200
Doctorbass
100 GW
RoughRider said:
At ebay they are around 70$.. dont buy them at evparts or similar.. they are too expensive!!!
Yes the killacycle have a BMS.. it's a shunt type BMS similar desing than Ggoodrum but it's a transistor that shunt the overvolt.. not a resistor.
I have some of their first BMS batch version .. they only shunt 70mA... but their new version is alot better.
RoughRider
100 W
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- May 17, 2009
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- 208
this guys on evparts are getting rich on this parts...
i hate that...220$ for sale and they pay under 40$...thats a shame
shame on you evparts
i hate that...220$ for sale and they pay under 40$...thats a shame
shame on you evparts
RoughRider
100 W
- Joined
- May 17, 2009
- Messages
- 208
i got 2 contactors and a dc-dc-converter just for 180$ shipped to germany...thats a very nice price
dragonfire
100 W
- Joined
- Apr 14, 2009
- Messages
- 112
The "Twike" is running on 366 volts and is street homologated in europe and sold worldwide since the mid-90ies.
gets 55 mph topspeed and 80 miles range, stuff is pricey, though.
but it´s the only vehicle actually legal to drive with most controlls in a joystick ( including steering and braking), pilotes love it.
it can be had pure electric or as pedal assist
the controller is a sophisitcated piece of technique, it permanetly monitors several batterie states ( alone 5 characteristicals of discharges) like temperature, has excellent BMS for LiPo, cruise control, true regen braking and starts up from 20 k ( 20 000$) USD.
gets 55 mph topspeed and 80 miles range, stuff is pricey, though.
but it´s the only vehicle actually legal to drive with most controlls in a joystick ( including steering and braking), pilotes love it.
it can be had pure electric or as pedal assist
the controller is a sophisitcated piece of technique, it permanetly monitors several batterie states ( alone 5 characteristicals of discharges) like temperature, has excellent BMS for LiPo, cruise control, true regen braking and starts up from 20 k ( 20 000$) USD.
317537
10 kW
- Joined
- Oct 19, 2008
- Messages
- 939
The old argument that had Telsa and Edison at each others throats. Is DC more dangerous than AC? I agree with the tesla side. I got a bad boy charger rated at 72v 2 amps and I have to be just a little careful with that one.
Imagine 144v DC at 500 amps. Some batteries can kick out over 1000 amps. Human resistance from left finger to right finger is approx 160000 ohms that takes max amps down to around .3 amps. That’s about 42 watts heating a the current path straight through your heart. At 400 volts that would equate to 126 watts. Get a sharp wire prick to finger or add sweaty hands and you could lower that resistance of 160000 ohms quite considerably.
EV tech is a something one need to observe with extreme caution when dealing with the higher volts. At 48v if the terminals on my ebike get wet the smallish shock is quite annoying and the euphoria is a little scary for the older geeks like me.
Imagine 144v DC at 500 amps. Some batteries can kick out over 1000 amps. Human resistance from left finger to right finger is approx 160000 ohms that takes max amps down to around .3 amps. That’s about 42 watts heating a the current path straight through your heart. At 400 volts that would equate to 126 watts. Get a sharp wire prick to finger or add sweaty hands and you could lower that resistance of 160000 ohms quite considerably.
EV tech is a something one need to observe with extreme caution when dealing with the higher volts. At 48v if the terminals on my ebike get wet the smallish shock is quite annoying and the euphoria is a little scary for the older geeks like me.
48-144V is the range of voltages used in the forklift industries. This is the mass market for motor controller manufacturers, and this is what drives cost down.
The cheapest MOSFETS are in the 12-24V as these are used in mass by the automotive industries. Safety has always been a significant influence for forktrucks where batteries are swapped between shifts. 400V DC would kill you very effectively. For mass production electric cars the high voltage makes every sense. As discussed, lower losses, less copper, sealed batteries. At the moment though only a few of the large car manufacturers have products for sale. Toyota have their gen 2 hybrids now and must have learnt a lot by getting into the market early. The other small city cars are from small companies who try to keep costs sensible by using off the shelf products. I am sure it will all go high voltage when the big players decide that they can earn more money from EV's rather than from the oil burners.
The cheapest MOSFETS are in the 12-24V as these are used in mass by the automotive industries. Safety has always been a significant influence for forktrucks where batteries are swapped between shifts. 400V DC would kill you very effectively. For mass production electric cars the high voltage makes every sense. As discussed, lower losses, less copper, sealed batteries. At the moment though only a few of the large car manufacturers have products for sale. Toyota have their gen 2 hybrids now and must have learnt a lot by getting into the market early. The other small city cars are from small companies who try to keep costs sensible by using off the shelf products. I am sure it will all go high voltage when the big players decide that they can earn more money from EV's rather than from the oil burners.
webfootguy
100 W
My twike (daily driver) uses 280 nicad cells in series per pack (2 to 3 packs). I charge at 425v and drive at between 300v and 385v most of the time. The advantage of the higher voltages is that the wires can be light and small and carry lots of watts (i.e. power). The downside is you must be much more careful when working on batteries and high voltage connections. As far as the potential to deliver lots of power to do damage (melt stuff, etc) I don't see a big difference between low voltage high amperage and high voltage low amperage situations. Both are destructive to dead shorts. I have blown the fuse on one pack when I touched a grounded soldering iron to a battery contact when another part of the pack was grounded (whoops). It blew the fast blow fuse just as it was supposed to and prevented more damage. Layers of protection is not only important, it is essential.
