Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 02-10-2012, 06:53 PM   #1 (permalink)
Master EcoModder
 
Join Date: Mar 2010
Location: london, on
Posts: 305

The Antichrist - '95 Land rover Discovery Plain Jane
90 day: 12.7 mpg (US)
Thanks: 3
Thanked 6 Times in 6 Posts
So how much power do you use?

Wondering how many volts and amps (watts) an ev uses while cruising the highway at different speeds. Maybe hint as to the weight of the project

Also, how long do golf cart batteries last compared to rv deep cycle batteries? Cycles of half discharge and recharge

Got a land rover discovery I love to drive but nets only 10.5 mpg. Just a thought. I can get deep cycle rv batteries at $30 a piece and electric motors at discount. 3 years ago I was offered 20 batteries for free but had no place to pu them

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 02-10-2012, 07:27 PM   #2 (permalink)
Master EcoModder
 
Ryland's Avatar
 
Join Date: Jan 2008
Location: Western Wisconsin
Posts: 3,903

honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
Thanks: 867
Thanked 433 Times in 353 Posts
430 watt hours per mile at 50mph (80kph).
Aaron's 1995 Land Rover Discovery

At faster speed I would guess you might use 500 to 600 watt hours per mile.

Deep cycle RV batteries are not traction batteries, they are not designed for high discharge rates that it takes to drive a vehicle down the road and the people I've seen who use RV deep cycle batteries tend to have them last 3 years or so before their capacity has degraded to half of what they were new, golf cart batteries should be 5 years or more if you don't over discharge them or leave them sit discharged for days at a time.
  Reply With Quote
Old 02-10-2012, 07:30 PM   #3 (permalink)
Master EcoModder
 
Join Date: Mar 2010
Location: london, on
Posts: 305

The Antichrist - '95 Land rover Discovery Plain Jane
90 day: 12.7 mpg (US)
Thanks: 3
Thanked 6 Times in 6 Posts
I don't get watts per mile that's why I asked for volts and amp reading
  Reply With Quote
Old 02-10-2012, 08:53 PM   #4 (permalink)
Master EcoModder
 
Join Date: Dec 2011
Location: Boise Idaho
Posts: 842
Thanks: 39
Thanked 89 Times in 69 Posts
watts is volts times amps. in theory, you can take 48 volts at 50 amps and get 2400 watts, or you can take 96 volts at 25 amps and get 2400 watts, and go the exact same speed and acceleration.
Further, if you spend enough time pricing batteries, you find it all about works out to about the same cost and has the same distance and capacity.
  Reply With Quote
The Following User Says Thank You to drmiller100 For This Useful Post:
Ryland (02-11-2012)
Old 02-10-2012, 11:38 PM   #5 (permalink)
Master EcoModder
 
Join Date: Mar 2010
Location: london, on
Posts: 305

The Antichrist - '95 Land rover Discovery Plain Jane
90 day: 12.7 mpg (US)
Thanks: 3
Thanked 6 Times in 6 Posts
alright, still not quite what I'm asking for. if i were to look at an instantaneous reading, volts and amps, what sort of readings would a vehicle get. If I have 12 12v batteries, 144V available, not all will be across the motor, voltage and current would be limited by the controller.

I'm still trying to wrap my head around this watt/mile. 600W a mile for 60 miles (1hr@60mph) would that be 36000 watts? it cannot be 1000A at 36V, or 360A at 100v.
  Reply With Quote
Old 02-11-2012, 12:14 AM   #6 (permalink)
Master EcoModder
 
Join Date: Dec 2011
Location: Boise Idaho
Posts: 842
Thanks: 39
Thanked 89 Times in 69 Posts
aaaahhhhh sorry bout that.

somewhere on this site is the horsepower calculator. It is a pretty good one. You plug in car size, weight, speed,etc, and it tells you how much horsepower it takes to cruise at steady speed.

From there, a horsepower is about 750 watts, and a watt is a volt times an amp.

So, lets say it takes 10 horsepower to cruise at 75 mpg. that would be 7500 watts.

If you are using a 100 volt system, that means 75 amps. If you are using a 48 volt system, that means 150 amps.
  Reply With Quote
Old 02-11-2012, 01:01 AM   #7 (permalink)
Master EcoModder
 
Ryland's Avatar
 
Join Date: Jan 2008
Location: Western Wisconsin
Posts: 3,903

honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
Thanks: 867
Thanked 433 Times in 353 Posts
Quote:
Originally Posted by bandit86 View Post
I'm still trying to wrap my head around this watt/mile. 600W a mile for 60 miles (1hr@60mph) would that be 36000 watts? it cannot be 1000A at 36V, or 360A at 100v.
That is exactly what it would be and because 1000 amps is a whole pile of amps to be pulling and it would make even a cable the size of your thumb warm after a few minutes, and it would tend to burn out the smaller wires going to the carbon brushes in a motor after a few minutes you tend to go with higher voltage to reduce the amps while keeping the wattage the same.
  Reply With Quote
Old 02-11-2012, 05:40 AM   #8 (permalink)
EcoModding Apprentice
 
3dplane's Avatar
 
Join Date: May 2008
Location: Florida
Posts: 158

14 Mirage - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 68.74 mpg (US)
Thanks: 35
Thanked 107 Times in 38 Posts
Quote:
Originally Posted by bandit86 View Post
I don't get watts per mile that's why I asked for volts and amp reading
You are right Wh/mile sounds confusing if you don't practice thinking about it.
That is the way of figuring the fuel economy of an EV.

In the above link for the Land Rover the owner claims 430Wh/mile at 50 MPH.

How did he get that figure?

430(W) X 50(MPH) = 21500 W (or 21.5 KW).

The Land Rover's nominal voltage in the link says 240 Volts.

So 21500(W) / 240(V)= 89.5 Amps!

Therefore it looks like the vehicle is pulling an average of about 90 Amps at 240Volts at 50MPH.

So let's reverse this to see how he got the figure! (rounding numbers).

At 50MPH his Ammeter shows 89.5A and his Volt meter at 240V = 21480 W!

If he held this speed for an HOUR then he used 21480 W/h of energy and covered a distance of 50 miles!
Now divide the number with 50 to see the Wh/miles figure: 21480/50=429.6Wh/mile! (close enough).

There is a thread on real world volts and amps figures at various speeds and cars ( EVs) here:
Highway cruising amps? - DIY Electric Car Forums

Barna
__________________

  Reply With Quote
Old 02-11-2012, 08:56 AM   #9 (permalink)
Master EcoModder
 
Join Date: Mar 2010
Location: london, on
Posts: 305

The Antichrist - '95 Land rover Discovery Plain Jane
90 day: 12.7 mpg (US)
Thanks: 3
Thanked 6 Times in 6 Posts
Now I got it, thanks!
  Reply With Quote
Old 02-11-2012, 09:09 AM   #10 (permalink)
Master EcoModder
 
Ryland's Avatar
 
Join Date: Jan 2008
Location: Western Wisconsin
Posts: 3,903

honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
Thanks: 867
Thanked 433 Times in 353 Posts
Not to confuse you more but a lot of people measure their watt hours per mile at the outlet, just like you figure out your gas mileage at the pump, they put a watt hour meter on the outlet they are charging from and see how much it takes to fill their batteries then they look at how many miles they covered.
There is also a brand of meter called the E-meter that some people use because it can log how many amp hours you have used out of your battery pack and tell you how full it is, but I think that meter also converts it's readings in to watt hours as well, so you can figure out your watt hours per mile at the end of a trip even before charging, I like to factor in the energy that is wasted in the battery charger too so my watt hours per mile (about 300 WH per mile) is higher then if I were to log the energy that I was pulling out of the battery pack, I do it that way because I have a meter that gives me a state of charge in percentage, so I just do my best to make sure to recharge before I get to 50% full.

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com