# generator to controller?



## Guest (Apr 2, 2011)

Lots of lithium batteries. Matching the generator to your pack will not be an easy task. Is the generator producing AC or DC? Is it producing voltage within the voltage range of the controller of choice? Usually generators are used to charge the batteries while driving or stationary then pull from the pack. While driving the output must be clean enough for the controller so it won't kill it and it will also be required to put out enough amps to keep the car going at least at minimum freeway speeds. So if you have a 156 volt system you will need a generator that will provide more than 156 volts so the pack can be charged and it will need to provide enough amps like around 150 amps. That is not an unheard of amp draw at freeway speeds. This is just a basic idea but it can be done. I'd say if you can afford the generator and all the requirements to make it work properly you could do better by buying a pile load of lithium cells to give you the range and power you need without the generator. Just plug in when you need an extra boost and extra range. Go have some coffee, charge it up and then go back to whence you came. 

If you insist on the generator it will be expensive and a whole lot of work. But for a project it would be perfect if you get it right. 

Pete


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## Roy Von Rogers (Mar 21, 2009)

Have you looked what kind of power output any generator has, and what kind of power it takes to run any electric vehicle ??

If you do, it will explain itself.

Roy


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## Guest (Apr 2, 2011)

For the most part you get either a high voltage out put with maybe 60 amps or a low voltage DC generator with high amps like 400 but usually you don't find any in the middle. Mostly what you find are cheap junky generators that are all AC and enough to power some home items. Most generators for vehicles are custom built generators and are integrated into the engine/tranny. Usually an OEM thing. Not cheap by any means. 

Spend your money on lithium batteries. Build a totally cool vehicle conversion. You will be a happy camper. 

Pete


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## hokieEVer (Apr 2, 2011)

I know that there are diesel generators that will produce the power I need and that there are regulators and filters to get that power usable so the only issue there would be time and money, both of which I don't really have lol. The main thing that is attracting me to this idea is the practicality of the system. This is still definitely in the beginning stages so I'm just playing with ideas. My dad is a diesel mechanic and master electrician and he brought up the idea of adding the generator. I haven't looked too far into it mainly because I didn't know where to look. I did know though that alot of heavy machinery use this technique so i knew the concept would work just didn't know if it would work for this application. I also want to just throw a crap ton of batteries and a high power motor/controller into my '87 BMW that is currently without a motor haha. Thanks alot for ya'lls help!


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## Guest (Apr 2, 2011)

Most of the industrial generators that are diesel are quite large and heavy. Yes, they can do the job. What you need to do is figure out what the power output of a specific generator is and then taylor around that. It's still not such a good idea buy mostly because of finding a good inexpensive high voltage high amperage out put generator that if fuel efficient and will fit with in the vehicle without taking up too much room. Ever think of a mileage extender trailer? They have been done successfully. Not many but some have done this. That way you only take the generator trailer when you know you really need to go further than your batteries can take you. 

I still suggest a boat load of batteries over the generator but if you find a good generator you can do the trailer and just go. I've thought about the trailer idea myself.


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## Anaerin (Feb 4, 2009)

What you will need is:

A generator that can generate enough power to move the vehicle (+ a bit to top up the batteries)
A charger that can take the power from above, rectify it into something your batteries can take, AND provide enough power to be able to also directly power the motor.

You'd then have something like this:

```
[    AC   ]     [                 DC +                 ]
      
     +~~~~~~~~~+     +--|>-------+---------+        +-------+    
[Generator]   [Charger]     [Batteries]   [Controller]   [Motor]
     +~~~~~~~~~+     +--<|-------+-------------+------------+
                         ^             
     [    AC   ]     [   |             DC -                 ]
                         |
                         +- Diodes
```
The AC could be any voltage you like, though it'd probably need to be 240v to make it easier to find parts that work with it while still delivering the needed power. I haven't shown the contactors, fuses and the like that would also be necessary, and the plug to charge from the wall would go where the generator is, in parallel with it (So, yes, you could use the generator to power other things too).

The generator could also be (and I'd recommend it is) on/built into a trailer, so that when you don't need the extra range, you don't have to carry the extra weight.

Finding a generator with enough power shouldn't really be that hard. 9KW+ would do the job for most smaller and medium-sized conversions. The problem will be getting a charger that will rectify enough power to run the system at full bore. Most are in the 30-amp range, which probably won't be enough. You will have the batteries in place to act as a very large smoothing tank, so if you hit a hill the batteries will be drained as well as the genny running at full bore.

Personally, I've always wondered which is "better": Mechanically linking the ICE to the wheels and running it outside it's peak power band (as a "Pusher" trailer), or running the ICE at it's peak power band all the time, and generating electricity with it (With the losses therein). Both techniques are going to be lossy, but which one is the least lossy?

Hope this helps some.


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## hokieEVer (Apr 2, 2011)

Yea that helps alot actually. I hadn't thought about putting the generator into a small trailer. I wonder how legal it would be to put fuel tanks in there as well? I'm from a pretty large military town and a larger city so I'm sure when the time comes to get this show on the road I will have a decent supply of used parts to at least create a proof of concept.


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## algea07 (Oct 1, 2010)

hokieEVer said:


> My question is whether or not you you could take a generator and connect that straight to the motor controller?
> -Thomas


i had this idea a while ago but i decided that it was above my capability, and that the time and money would be better spent making an electric car that would make people happy enough to swap with there petrol car if i ever need to make a long trip.


i though of a few way that you might be able to do this, and i’ll let you figure out if they are feasible.


1. you buy a small SepEx or PM dc motor and controller set, you’ll need at least 15kw to drive indefinitely, then connect the motor to a 400-500cc motor bike motor. 400cc should be enough to to produce 15kw continuously and then use the controller to charge the pack. with this setup you are limited in voltage maybe 120v max. 


2. buy one (or two) small 8kw generator of ebay for under $800, they are 240v 10amps, run it through a three phase ac to dc rectifier, then build a battery pack to match the voltage that comes out of the rectifier.
to my understanding if you have a 200v pack and you can produce 200v DC you will be able to charge the battery without a charger or controller. 




both of these will add about 150-200kg to the final weight of the car (no more then a lead conversion), over $1000 and you might have to give up the back seat or your boot space to fit the batteries.


but if it’s what you need it could work.


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## algea07 (Oct 1, 2010)

a also just remembered this which i thought was pretty clever.

this guy built a hybrid BMW 

he uses a warp 7 and puts it between the engine and the diff i don't know how much room you have under your car but you might be able to fit 2 warp7 and that would be enough to run the car as an EV then if you run out of batteries turn on the engine then put it in gear and you've got yourself a hybrid.

Also bmw engine + two warp 7 = hella good acceleration


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## Anaerin (Feb 4, 2009)

hokieEVer said:


> Yea that helps alot actually. I hadn't thought about putting the generator into a small trailer. I wonder how legal it would be to put fuel tanks in there as well? I'm from a pretty large military town and a larger city so I'm sure when the time comes to get this show on the road I will have a decent supply of used parts to at least create a proof of concept.


Given that generators are put in/made from trailers all the time, there's no issue with a generator being on a trailer. The sticking point might be _running_ the generator while it's being moved/towed. AIUI, most places are fine as long as the generator is secured so it won't fall out (obviously), and the generator has to pass emissions tests. The exact details of this obviously vary from place to place, so I'd definitely check with your local authorities before doing it.


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## wherethere42 (Feb 28, 2011)

i've been looking into this myself... without going into too much detail about my planned conversion, i will not have a large bank of batteries to power my vehicle. i will have a small 24 volt pack to power some things while the vehicle is parked. The vehicle needs to be capable of daily long journeys with no chance for a recharge. A hybrid electric will be a dramatic boost in economy from the current ICE in my donor. Was mentioned by someone else, there are not many off the shelf generator options that arent huge and expensive. my idea for an efficient generator will use a very small gas engine coupled to the vehicles transmission with a big generator head on the backside. anyone out there thought of or tried something of the sort? I dont see much talk of gear reduction around here?


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## scoobysmak (Apr 17, 2010)

Well I admit I would love to have a smaller bank of batteries and have a generator for long trips but doing the math just has not seemed reasonable to even think about a generator.

I admit I am no math wizzard so if my numbers are off or a formula is wrong feel free to let me know.

If I ever make an EV project I doubt it would be as aerodynamic as a prius so I am going to use that as my base line for now. Hunting around here for formulas to calculate watts per mile I remember seeing even a prius has to have roughly 250 WPM at 60 mile per hour. Okay now take that 250 and mulitiply it by 60 to get KW per hour. At 250 watts per mile I would need a generator that can put out at least 15KW, needless to say that could power a small house. 

If I drive faster it gets way worse for two reasons. One I am trying to push more air so the watts per mile increased and then I am now going to travel more miles in one hour. So say I increased to 70 MPH, and say it takes 300 watts per mile (I pulled this number out of the hat so take it with a grain of salt). At 70 MPH I would need a 21KW generator on board to keep up. This is just making general statements, if you want to get technical on something have fun.

I looked at smaller generators for fuel consumption and from what I found a 11KW generator ran 4.8 gallons per hour at a full load. Okay that didn't quite give me my 60 MPH speed but I will use it anyway. If you burn 4.8 gallons and only went 60 miles in that hour you got roughly 12.5 miles per gallon. I get way better mileage in a 1 ton truck than this. 

About the only thing I could see if someone puts a smaller generator on a trailer and tow it, plus has a pack with a 200 mile range from the start. They could say drive 400 miles that day get a hotel room and then start on another 400 mile trip the next day. They would have to let the generator run all night to recharge the pack and of course run it while traveling to get the extra 200 miles in, need to stop for fuel and eat a few times to let it catch up in the process. 

Maybe I have lost my mind but this setup just doesn't add up to saving anything for me. Like before if someone shows me an error in my thinking or my math by all means I would love to be proven wrong so I could actually use this concept but so far I don't see it as an option. I usually travel 750 mile trips at a time so for the moment the EV concept is just that.... a concept.


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## DIYguy (Sep 18, 2008)

I've actually done this. I have a 7kw generator feeding a 6 kw charger that charges while I drive. It wont run the truck entirely on it's own of course...but can extend the range significantly and also charge while u are waiting, stopped, or whatever and it does work and it does extend the range a lot. You could go bigger than I went and make a bigger difference also. 
I would like to caution you though before you proceed. Generators are VERY loud. I didn't buy the $700 cheapy either. I bought an $1800 + tax Rigid unit. This has a Honda engine. It's VERY loud. Remember this thing is under power and really given er'. It's not even the engine that is so loud, but actually the generator itself that make a lot of noise. I put it in the back of my pickup truck. I was planning to put a tonneau cover over it as well as feed the exhaust though to another resonator. I even spent a lot of time to chop the genset into a lower package (and it turned out quite nice I might add) I converted it to propane as well. Another couple hundred bucks. Yup it works. Too loud and annoying. People look at you going through town like u are really weird (true enough lol). 

Before you do this, go find a generator that would work. You don't even have to buy it. Just find one. Then wait or arrange to have it under full load. Now park your car in front of it. Now once ur there, close your eyes and imagine driving down the road and the noise does not stop.

Now do as some suggested, and go buy lithium and make a real car out of it...


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## aeroscott (Jan 5, 2008)

scoobysmak said:


> Well I admit I would love to have a smaller bank of batteries and have a generator for long trips but doing the math just has not seemed reasonable to even think about a generator.
> 
> I admit I am no math wizzard so if my numbers are off or a formula is wrong feel free to let me know.
> 
> ...


wow that's about as bad efficiency as it gets . 11KWA/ 4.8 gal= 2291watts/gallon . 35KWA in a gallon divided by 2291watts = 15.277 (100/15.277= 6.54%) dam that's so bad .primitive gas turbines are better . added; 2291 watts divided by 746 watts/hp = 3.07 , 6 lbs/ gallon , 6 divided 3.07 =1.95 lbs of fuel / hp hour . diesels are .35 lbs/hp hour


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## scoobysmak (Apr 17, 2010)

Okay I was a bit off on my numbers it was 4.1 gallons an hour, but yet again that would not be able to keep me running for my entire trip either. 60/4.1 =14.6 my truck still gets equal or better towing a 6000 lbs trailer doing 65 MPH not just 60. 

Here is a link to what I found, I was looking for a diesel, usually they do better on making power per the same amount of fuel; in this case I might be wrong.

http://www.kubotaengine.com/products/gl/gl11000tm.html


......EDIT big time.......

Okay now I feel dumb, uh needless to say on that link there is a difference between liters per hour and gallons per hour (guess they should have put a star by it and marked it with a helmet just for me) sorry for the oops. I left my message so I can learn from my mistake. 1.09 gallons per hour makes better numbers, at that rate is around 60 miles per gallon but remember this is being conservative on the aerodynamics of my project and the fact if I run 60 miles per hour I will get run over.


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## gdirwin (Apr 7, 2009)

Has anyone had problems plugging big chargers into gas generators? The chargers now are power factor correcting controllers(ie fancy controls) and the generator also has controls (speed and voltage regulation etc...).

Also I think some generators may output modified sine waves, not nice clean computer quality power that the fancy chargers expect...

Put 2 fancy devices together (without a nice clean/solid grid) and I would not be surprised if there were problems... I work on large wind farms, solar inverters and HVDC links (1000s of MW) and this is a big area of concern which requires us to do specialist studies...

Has anyone done this and experienced problems? Or is it pretty much plug and play?


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## aeroscott (Jan 5, 2008)

gdirwin said:


> Has anyone had problems plugging big chargers into gas generators? The chargers now are power factor correcting controllers(ie fancy controls) and the generator also has controls (speed and voltage regulation etc...).
> 
> Also I think some generators may output modified sine waves, not nice clean computer quality power that the fancy chargers expect...
> 
> ...


that's one reason I like pm generators volt/amps are dependent on speed . All inverter generators run pm generators .


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