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DELETED (Inactive)
7 Posts |
 Posted - Dec 21 2002 : 01:17:33 AM
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Hey peoplz how's it going. May I just say this site rocks, since this is my first post and I have gotten a lot of ideas off this site this has become my favorite site.
That being said I'll get to the point. Fot the past few weeks I have been turning my electric scooter into a hybrid and have run into a number of problems that I mostly solved when I finished. I'll start from the beginning. I started out making mounts for a 21cc weed eater engine I got from Wal-Mart, and also made mounts for an alternator. When I finished it pieced together fine, I had modified the shaft of the engine so I could screw in a bolt and mount on a v-belt pully, that worked perfectly, problem was the pully on the altornator was to small and the engine didn't have enough power to turn the altornator. Not to mention I tested the altonator and only managed to get 2V out of it and it was spinning at no less than 2K RPM. So I scrapped the alternator idea and proceeded to a wrecking yard for my second larger pully and I figured since all electric motors with a magnet could be used as a generator I grabbed an electric radiator motor that I mounted and planned to use as a starter/generator for the engine/system. Anywho, I managed to mount it and it workes decently, aside from some misbalance and vibration it works. The tricky part was wiring it to the battery system the scooter has at the voltage I configured it to produce, 13.5V. There are 2 batteries connected in series to eachother to produce 24V each battery having only 12V. Now the purpose of my modifications is to increas the range of the scooter since it only goes 12 miles on one 4 hour charge, and since I live where there are hills that cuts the range in half. So what I came up with is fairly unique to my knowledge since I do not know if this had be attempted before. I managed to connect the 'generator' in a parallel circuit to the two batteries and still keep the series circuit of the power going to the scooter by using a set of diodes so the negative terminals didn't exchange electical current, the diodes blocked the electric current coming from the negative terminals so power could only go to the negative terminals on the parallel circuit and also a set of diodes on the positive end of the batteries so only power can come from the positive terminals for charging and to prevent a short circuit. The end result was I had kept the to batteries series circuit intact providing 24V to the scooter and charging both of them at an even 13.5V. After that I connected two wires to the + and - terminals at the 24V end of the series circuit so I could use that power to start the engine with that small radiator fan motor (12V wouldn't cut it). So I had a parallel charging circuit and a series starting circuit I had to mesh together to connect to the starter/generator. Problem was they had to remain seperate in order for it to work properly. The problem was easily resolved using a center off switch I got from Radio Shack. The center connectors of the switch I connected to the starter/genorator, one end connected to the charge circuit, the other to the starter circuit. I am pleased to say that that one end worked beautifully, the starter end. The charge end however ran me into some problems, as soon as I flipped the switch to that end the engine would stall because it didn't have enough power. From this point I had 2 options, 1 I could redo the v-belt pully ratios to give the engine more torque this increasing the RPM to get the same power as well as the noise it mad and the gas consumption. That just wasn't an option. The 2nd option I chose was to control the output of the starter/generator by using the 13.5V it produced to power my 350 Watt AC power inverter. Connected to the power inverter is a 386 laptop power supply that gives out 12V 1.5A. Well it gave me almost all the results I wanted except for one, it didn't charge the battery faster than it was being drained. The usage rate of the batteries is 24V 18.5 Amps. In order to charge it faster than it drains I need to supply 13.5V 10 Amps. This is where I am stuck currently, and would appriciate any advise as to how I should proceed. Any insight would be helpful, thanks
Edited by - Aaron Cake on Dec 21 2002 12:00:41 PM |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Dec 21 2002 : 12:03:22 PM
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This sounds very cool. I will reply when I have time to read the whole thing.
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Dec 21 2002 : 6:34:46 PM
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OK, I read it. Sounds OK, but quite hacked.
How about just using a 24V motor as a generator? That way you get your 24V directly without all this (unnecessary, inefficient) messing around with a power inverter.
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n/a
DELETED (Inactive)
7 Posts |
Posted - Dec 21 2002 : 8:15:38 PM
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I thought of that, but didn't know where I could find one first off, second this was all I could afford. I was thinking I could hook the generator directly to the batteries if I could control the amount of amperage going out without changing the voltage, all I need is 10A out of it without changing the 13.5V and it would meet the requirements. Which leads me to one other question, the power consumption of the scooter is 24V 18.5A. Would it charge faster than it is being drained at the power I specified since it is hooked in parallel to the batteries? or would the 10A of it be cut in half?
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Dec 22 2002 : 11:47:42 AM
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24V motors are very easy to find at surplus stores and eBay. Pretty cheap too. I'm not sure of what you mean by your question about charging series vs. parallel, but there is no difference between the two. It will take the same time to charge whether series or parallel.
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n/a
DELETED (Inactive)
7 Posts |
Posted - Dec 22 2002 : 2:00:07 PM
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Thanks for the info on the motor, I'll see if I can find one. As far as the question goes, the solution is moot. I found a very bad flaw in my wiring which explains why my generator chokes. The parallel circuit shorts because of the series circuit, so they cannot be connected in the same circuit. I thank you for your help, I would not have seen the solution otherwise.
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n/a
DELETED (Inactive)
7 Posts |
Posted - Dec 24 2002 : 2:42:45 PM
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Here is an update for the scooter project. I removed the parallel circuit and am about to impliment an old computer monitor power supply that has 3 outputs, 36V, 24V, and .6V. I plan to use my inverter to use the power from the generator, and the monitor supply to use the power from the inverter, we will see how this goes. Hopefully it works  . Once again I thank you for your help Aaron
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Here's something new for you people
