[major]

...........thus I would like to be certain of the exact costing that I would incur driving my EV.......

Your accurate answers to these 3 questions will accurately determine the cost per KM driven.

Hi batalatex,

Welcome to the forum. Been here a while myself. And I have yet to see anyone who can answer your questions exactly and accurately. I suggest you study this section http://www.diyelectriccar.com/forums/showthread.php?t=669 There you can find how long it takes to charge batteries and how to figure how much energy is required to travel in an EV. Then you can come up with some estimates as to the operational cost of your EV.

Good luck,

major

 

[rillip3]

Hi Everyone,

Deeply impressed with this forum, I am thinking of building my EV. However, the facts & figures posted on this forum are mostly about US and thus I would like to be certain of the exact costing that I would incur driving my EV.

Anybody, who has build his EV, can you please give me the following information -- based on the assumption that we have installed 6 Batteries of 12 Volts - 50 AH .......
1. How much time will it require for the Batteries to get 100% charged - considering they were brand new i.e. with 0% charge.
2. What Ampere at 220 Volts AC will the Battery Charger draw in order to charge the batteries.
3. Now, based on the 6 Batteries of 50AH - what will be the maximum travelling distance ??

Your accurate answers to these 3 questions will accurately determine the cost per KM driven.

Thanks.

If I spent a lot of time I could maybe figure this out, but there are some bad assumptions here. 1) A new battery wouldn't be at 0% charge. If they are, return them immediately. A new battery should be at 100% charge. If it's a lead-acid chemistry, you wouldn't want it below 20%, or it's taking permanent damage.

2) 72 volts is very low for an EV. Not unheard of, but low. What performance goals are you looking for? The low voltage will cause a higher amperage draw, but if your controller can't handle that draw, you won't get full acceleration. That impacts any sort of range calculations.

3) Your charger documentation should have that information. There are too many variables in how you build the thing that we can't know that determine how fast/how much amperage it would draw. The charger most likely uses somewhere between 10 and 20 amperes to charge the batteries. It's only going to use around 90v if it is safely charging lead-acid batteries. So it can only put out 1.35kw/h at 100% efficiency, so more realistically, 1.08 kw/h. A 72v/50A battery pack has 3.6kwh, so it would take three and a half hours if it's using an average of 15 A.

4) a 72v system with 50 Ah batteries, if kept to 50% depth of discharge (assuming flooded lead acid), would only have a 4.8 mile range, assuming an average number of 300 Wh/mi, which may or may not be a good estimate considering I have no idea what this system is in. The number is a little better if they're AGM or lithium, but you didn't provide much information about the batteries, so I'm assuming worst (reasonable) case. Hardly seems worth the effort at that point to me, but I suppose it depends on your driving situation.


There are all sorts of assumptions and estimations in this because there's not enough information to say anything with 100% accuracy.

 

[Coley]

No. 1
They should not be at 0 (as mentioned)

No. 2
My 220 volt charger is rated at 10 amps draw.
After a 8 mile run home, they recharge to full in 2 hours.

No. 3
Not enough mentioned about your ev, such as weight, motor size etc.

Mine, with GEL batteries can go 12 miles @ 50 mph on flat road.
Can hit 55 mph for 8 miles.

 

[dtbaker]

...I would like to be certain of the exact costing that I would incur driving my EV.

Anybody, who has build his EV, can you please give me the following information -- based on the assumption that we have installed 6 Batteries of 12 Volts - 50 AH .......

There are a lot of variables affecting operational cost per mile (Km). The weight, speed, road grade, aero, tires, how hard to accelerate, pack voltage, and type of batteries are all major factors. For the true operational cost you need to factor in the cost of replacing the batteries at the end of their expected life, which can vary a lot depending on how you use them....

So, I don't think you can get an exact answer. The best we can do is document our personal situation, and let you extrapolate to your situation.

For instance... I am currently using a 96v 'floody' pack in a Suzuki Swift. I rarely drive more than 15 to 20 miles a day, on mostly gentle grades at urban/suburban speeds between 25-50mph with fairly frequent stops/starts. A lot of the miles are around 40mph. I found that while my rolling consumption averages less than 200 Whr per mile, the average charge 'at the plug' was much closer to 400Whr per mile with losses in the charger, internal resistance of floodies, and because the floody charge cycle includes an 'overvoltage' charge period to gas and balance with every cycle.

In calculating MY cost per mile, I use our local residential electric rate of $.09/kWhr and the 0.4kWhr/mile plus the cost of the batteries spread over the expected life... which is highly dependent on average depth of discharge, and good watering practice for floodies.

.... more depth at http://www.envirokarma.org/ev/01.Design.shtml

and in my particular case the cost of the Electricity is nil because I have a grid-tied PV system, and the Utility company pays me to claim credit for renewable energy production.