Optimum motor package for 1200lb EV

[fosterkane]

Hi,

I am planning a reverse trike substituting an electric motor for a 250cc engine. I want a simple reliable system with range more important than speed. My build would work out to 1300lbs w passengers.

A search through Alibaba shows a number of vehicles being produced in this weight range with motors from 3-7.5 KW.

I know that regular autorickshaws are driven in rallies all around India on a 7HP engine - which is roughly equivalent to 5 kw These vehicles are equal or heavier in weight to mine. There are a bunch of them on Alibaba with 500-1000 watt systems. Cheap kits with controller, pedal etc too. Anyone ever tried one?

So I am leaning towards 5kw. Also, based again on my priorities, what advantage/disadvantage 48V v 60v v 72 system?

I am perfectly happy to go 25-35 mph but I will need to climb some hills.

And finally, has anyone ever played with one of the Chinese electric rickshaw motor kits? The apparently push around vehicles similar in mass to mine with 500-1200 watt systems http://www.alibaba.com/product-gs/373165833/motor_kit_for_tricycle.html

Thanks

[Hillhater]

It hard to imagine an auto rickshaw weighing 1300lbs..even with 3, 200lb occupants !
1300 lbs is a lot of weight to move
5kW may get you to 25mph eventually, but it is going to be painfully slow on any kind of hill...if you can gear low enough !

[jonescg]

I think an Agni motor would satisfy your needs perfectly. Controller from Kelly, batteries - lots of options... and you're laughing.

[fosterkane]

With a fuel cell generating 5kw per hour, a 1300 lb gross weight vehicle and a 5 kw battery pack, does anyone have any thoughts on what the optimum motor size and voltage be for long range at relatively low speed? The vehicle could use a bit more that 5kw an hour - but not so much that the battery would be depleted in 3-4 hours.

Thanks.

[Hillhater]

Can you define "Long range" and "low speed" ?
..20 miles ?...100 miles ?,...more ?

[REdiculous]

5kw per hour is basically human-level output...

[fosterkane]

For my purposes;

Long range = 200 miles, low speed = 20-35 mph

RE: Human power

I am basing my power assumptions on this excerpt from a Fuel Cell info website:

"As an example, take a vehicle with a 200Wh/mi average driving energy consumption (equivalent to a 25 to 33 mile per gallon gasoline ICE vehicle). To travel 100 miles throughout the day, the vehicle would require 20kWh batteries. If a 5kW fuel cell system were added and allowed to charge the vehicle batteries without limit throughout an 8 hour day, it would be able to add 40kWh of energy to the vehicle. The daily range of the vehicle would be 200 miles from the fuel cell and 100 miles from the battery. "

from http://www.fuelcellmarkets.com/enerfuel ... 28640.html

[REdiculous]

5kw per hour isn't the same as 5kwh per hour. It looks like they meant '5kwh' though. *shrug*

[John in CR]

No it's 5kw, like a 5kw charger.

FosterKane,

Do you already have pricing for big fuel cells like that? What kind of uphill grades are you talking about, primary roads which are typically limited in grade or steep stuff? Do you need that 35mph going uphill too?

I take it that you're talking about you plus a passenger, in which case 1300lb seems way too heavy to me unless you 2 are really large people. The weight is going to kill you on the hills. eg Even just 15mph up a 10% grade is going to take about 5kw. Minimize the weight everywhere you can, because you have to design for the hills. Then you might as well put plenty of effort into aero, so you don't have to be stuck with the pitiful limit of 35mph. Sure cruise slow like that for distance, but the vehicle can get a lot more practical use around town with some real performance. You'll already have plenty of battery, so give it performance that impresses people, because ice wagon performance from a license EV only strengthens existing misconceptions about EVs.

John

[REdiculous]

With a fuel cell generating 5kw per hour

That's what had me scratching my head. You might say it's just semantics or whatever, but there's a definite difference.

[fosterkane]

My weight approximations: vehicle = 450lbs, 5Kw fuel cell = 400lbs, 5 kw lithium batteries = 100lbs, 2 passenger 350 lbs.

This configuration is not for around town - it is for a long trip where range is crucial and the roads not good enough for high speed anyway. So I am trying to determine what is the most efficient motor size in kilowatts and voltage is best suited to this trip. Would 5Kw/48V be suitable, or would 10Kw/60V or 72V have important advantages? A dependable hub motor would be my preference to avoid the noise and maintenance of a chain and save weight and space on the chassis.

Thanks for any input.