Contraptionators, geek??

unjonharley · Post by **unjonharley** » Tue May 08, 2007 8:48 pm

If I run a converter 6 hrs. a day.. Input 115v ac.. Output 44v @1.3A dc .. On average one month the house used 16.6 kWh per day @ $1.49.. How much am I paying a day for the converter??

This is the charger for my electric transporter..It will not take 6 hrs. a day on average.. I will have to sample it a few times.. I'm hopeing to use the electric for 2/3s of my travel.. It has a 25mile range @ 15 MPH.. Don't laugh just yet.. I beat a guy home in traffic over 12 blocks and three lights.. I passed the cars by using the bike lane..

I'm building a trailer from stuff around the shop.. It started with a set of wheel my kid had.. Then a hard plastic wheelbarrow, Turn the handle over to make the tongue.. Now to find another one the same size for a top..

Next a seat post that will be the draw bar for the trailer.. I travel standing up.. But it's nice to rest the legs after a distance.. Wait till you see the seat..

MikeVDS · Post by **MikeVDS** » Tue May 08, 2007 9:29 pm

To get exact numbers we need to know how efficient the converter is. I'll estimate 100%. You can get much lower depending on the type and if it's used correctly or not. Around 95% is probably the best you can hope for and you'll likely get lower, but you can scale it. If done right 95% is realistic.

At 44v and 1.3A you're using 57.2w

57.2 watts over 6 hours is 343.2 watt-hours per day or 0.3432 kw-hours per day.

At $1.50/kw-hour that's roughly $0.50 per day.

If the transformer is runner at only 50% efficiency you'll draw twice as much from your house to get the same output and it'll cost you $1.00 a day. You'll probably run somewhere between $0.50 and $1.00 a day.

dragonfly Jafe · Post by **dragonfly Jafe** » Wed May 09, 2007 7:57 am

...you pay $1.50 per kWh? That's insane! In Boise it's $0.054251 per kWh (thats 1/30th the price you quoted)

In Boise your vehicle would cost less than 2 cents per day....

unjonharley · Post by **unjonharley** » Wed May 09, 2007 8:56 am

dragonfly Jafe wrote:...you pay $1.50 per kWh? That's insane! In Boise it's $0.054251 per kWh (thats 1/30th the price you quoted)

In Boise your vehicle would cost less than 2 cents per day....

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Yeah, I just saw that myself.. The rate is $1.49 for 16.6 kWh.. 2¢ a day is not bad on the pocket..

Anyway, Just got up and workng on a dream I had.. It was a all weather cab for the transporter.. In the old Star Treck there was a guy brought in as a wittness in one.. He was completely surounded in a box with just his head sticking out .. I'll give it a quick sketch and cork board it for now..

Post by **mdmf007** » Wed May 09, 2007 9:19 am

Highest priced power is in Hawaii at 9 cents a kilowatt hour.

1.50 a kilowatt hour must be a typo. A generator from home depot would be cheaper than that burning gasoline from the gas station.

dragonfly Jafe · Post by **dragonfly Jafe** » Wed May 09, 2007 10:00 am

unjonharley wrote:Yeah, I just saw that myself.. The rate is $1.49 for 16.6 kWh.. 2ï¿½ a day is not bad on the pocket..

That comes out to a tad over 9 cents a kWh, or about 4 cents a day for your vehicle.

In comparison, for 4 cents, my honda civic will go about 1800 feet (around 6 football fields)

My RV would go about 240 feet for 4 cents (not even a football field). It doesn't get out much these days.

gyre · Post by **gyre** » Wed May 09, 2007 11:52 am

Finding out the actual charge per kwh can be very tricky with varied rates, base fees and so on.
We used to pay 6 cents, now it is closer to ten and they want an increase.
Finding out about gas rates is far worse here.
The utility actually has to refer you to an engineer who can break it down.

A small electric vehicle (not a car) can be very cheap over time to run, because of the lower maintenance costs.
Battery replacement should be the main expense.
You have to factor that into cost per mile.
I will spend more on maintenance than fuel this summer on my car.

MikeVDS · Post by **MikeVDS** » Wed May 09, 2007 4:57 pm

It has a 25mile range @ 15 MPH.. Don't laugh just yet.. I beat a guy home in traffic over 12 blocks and three lights.. I passed the cars by using the bike lane..

I'm not sure why anyone would laugh. A bike was my main transportation for a long time and in town within about 10 miles I could usually beat or match vehicles because I wouldn't obey traffic laws (even though I was technically breaking the law). Also traffic and short cuts helped.

Mind sharing the actual vehicle specs that you're using? If it only takes 6 hours to charge, drawing 57w and you drive it for 3 hours; that's only about 1/6 hp. I don't think it could carry me at 15MPH. Unless you charge it at work too, which would make it 1/3HP. Still pretty wimpy.

dragonfly Jafe · Post by **dragonfly Jafe** » Wed May 09, 2007 5:23 pm

my electric scooter from last year is a 450w motor @ 36 volts. That's about 5/8 HP and I can go ~15mph on it. I can go about 3 miles before a new charge is needed, never have broken down the charging rate but it only takes a few hours to fully recharge. Pretty useless, though, without a greater range. Nifty for the porta-potti runs at BM tho' it is illegal to use in Boise (cops hate them here and love to give tickets)

unjonharley · Post by **unjonharley** » Wed May 09, 2007 5:57 pm

This scooter has a 350w 36v motor.. Run on two 36v 10.5ah batteies..Has up to 25 mile range.. I never have run it that far yet.. So far I have put on larger tires.. Now I plan to put on a seat and double the batteries.. The book said 4to6 hours to charge..

Now for the good part: I need it listed as a mobility cart.. This gives me free bus..They have a lift on each bus.. It is all up hill to my daughters house.. Ride the bus up and coast down..

Dragonfly, is your scooter two wheeled?.. The one I have is three.. The motor is in the center of the front wheel..

Speaking of three wheel... Today I finished reworking the trike.. Front and rear derailers, different rear end, seat and handlebars.. I think that thing needs to be called a contraption too.. The art work for it is almost finished.. I'm going to try to put together a wild styled 12v generator that will run off the front wheels and powwer the stereo.. There will be pictures

phil · Post by **phil** » Wed May 09, 2007 6:29 pm

Watts = Volts x Amps. Your electric moter is 350W at 36V, so it's
W = V x A
350 = 36 x A
350 / 36 = 9.7222 Amps.

If I understand correctly, that'll flatten your 10.5 Ah battery in a little over an hour, all things being perfect. With 2 10.5 Ah batteries in parallel, you double that time, but you might be better off using one at a time.

According to the battery salesman who spoke to my emergency radio club, you should divide the battery's capacity by 10 to get a rough estimate of how many milliamps to recharge it. Your battery's rated capacity is 10.5, so divide that by 10 and get 1,050 milliamps (which I think means your 1.3 A converter is in the ballpark); he said a hundred milliamps either way won't harm the battery, but too much charge going in can overheat the electrolyte. He said it _should_ take a half-day or longer to charge a battery without damaging it.

It may be that I'm completely misunderstanding your post or that guy's speech, but it doesn't appear to me that you'll be able to get the range you're thinking nor will you recharge in 6 hours with a converter. Take a look at a summary of his talk at
http://www.cieux.com/bm/batteryWreck.html

25 mile range at 15 MPH is 25/15 = 1.666 hours.
10.5Ah battery at 9.7222 draw is 1.08 hours. If you use both batteries in parallely, of course, you get your estimatte time of 1.666 hours taking into account friction and playa dust and such - less than the projected 2 hours. But 6 hours time 1.3 Amps is 7.8 Amps into that 10.5 Ah battery. If you're not fully discharging them, then all is wonderful, but will you have two batteries to charge?

I guess I'm confused.

gyre · Post by **gyre** » Wed May 09, 2007 7:11 pm

He probably has a very efficient motor controller.
You can't assume full throttle.
Many of these motors won't sustain full throttle.
The control keeps them from melting down.

MikeVDS · Post by **MikeVDS** » Wed May 09, 2007 7:42 pm

You're right phil, at 350 watts and 15mph it wouldn't make the 25 miles, but the 25 miles is probably under ideal conditions. 5% rider in weight, slight backwind and nice flat road. I doubt it'd get me 25 miles around my town, but I only live 12 miles from work and much closer to my normal destinations anyway.

Thanks for the info. So the motor is about 1/2 HP under full load. I need to just ride my bike more and I'll make a little bit of a smaller load for things like this.

I just keep thinking about trying to ride a 1/2HP motor up a hill. Poor little motors of mine.

unjonharley · Post by **unjonharley** » Wed May 09, 2007 7:57 pm

The scooter has two batteries.. I am adding two more..I have run it wide open 6 miles to a store.. Then creep around Walmart for an hour.. Home again 6 mile wide open.. Home to another store about a mile.. Shop at three stores. Then back home .. Still it indecated plenty of juice.. I think I have a odometer around here some place..

MikeVDS · Post by **MikeVDS** » Wed May 09, 2007 8:22 pm

Wide open might just mean max RPM and not necessarily max amperage. Stick a biggy on there and then clamp on a meter.

unjonharley · Post by **unjonharley** » Wed May 09, 2007 8:34 pm

MikeVDS wrote:Wide open might just mean max RPM and not necessarily max amperage. Stick a biggy on there and then clamp on a meter.

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Your right, after It gets up to speed I can let off about half an it will maintain speed..