# My new EV 1973 Beetle (Aka Super Beetle)



## Biostudent (Jul 13, 2010)

Hello,
I am new to the forum and I just bought my first electric vehicle. I am switching to solar power and planning on starting a company for it so I when I saw the car on ebay I pounced on it. It needs some work on the body and interior but its an awesome car.

This forum looks great. I wanted to come here and find out some info about doing a conversion into hybrid. Is it possible with a DC engine? *(Yes) * What kind of controller would I need to allow it to run the engine and the batteries(?) Can I run it at full throttle then for max speed? I tried looking around but having trouble finding info.*(check some post links below)*

Heres a link to the auction I won for the car. http://cgi.ebay.com/ebaymotors/ws/e...0507865279&viewitem=&sspagename=STRK:MEWAX:IT
D&D Motors ES-15A Series Motor 40 HP Peak, 12 HP Continuous 
Kelly Controls Controller - KDH07600A,24-72V,600A series/PM 
Kelly Controls Contactor - Main Contactor Compatible SW200 12VDC Coils 400Amps 
Kelly Controls DC/DC Converter - HWZ Series DC/DC Converter 72V to 12V 300W 

The previous owner told me as is the car gets about 12 miles to the charge. He said with a smart charger that should increase to 40 or so miles. If hybrids not an option can I add more batteries to increase the range? What about a trailer with batteries and motor? I would most likely need a stronger motor.


I am going to be updating the original post here to try to keep it making sense and for me to follow along and organize my thoughts while hopefully getting pointers 
*Update on Hybrid aspect: 

Some links to hybrid posts* 

http://www.diyelectriccar.com/forums/showthread.php/engine-charging-question-43273.html
http://www.diyelectriccar.com/forums/showthread.php/generator-trailer-36040.html
http://www.diyelectriccar.com/forums/showthread.php/building-series-hybrid-generator-16758.html
http://www.diyelectriccar.com/forums/showthread.php/series-vs-parallel-hybrid-15678.html

Not sure if I can link to off-site forum posts but in another post a racing team, installed a generator in the electric car by hooking it directly to the engine with a manual switch installed. They produced 72 v, it eventually died when the car ran out of gas and it 
There is more but here is some of the post.Rusty,
The generator puts out about 80 Volts. This can be adjusted down by manipulating the throttle on the ICE.
The generator/ICE combo outputs about 7 HP (5 kW), meaning it puts out about 70 Amps between 70V and 80V. The motor draws 50-200 Amps depending on load, acceleration, etc.
Due to simplicity and time constraints, we'll probably start by trying to connect the generator straight to the batteries with a disconnect relay to decouple it when it is off or when the batteries are charged and the car is not moving, etc. I hope this will keep the generator providing extra current when accelerating (and maybe charging the batteries in the CC parts of the Lead Acid charging curve) while allowing us to disconnect the generator is situations where it would be detrimental (ICE out of gas, batteries fully charged), etc.
What do you mean "BTW is the Motor designed for Generator"? I'm afraid I don't understand this.
Thanks for the help! More thoughts are always welcome...
-Andy​"Hi James,
We ended up running the generator in parallel with the battery bank driving our motor and using a switch/contactor to insure it was only connected to the bank when we were drawing current (i.e. driving). This was done to avoid force charging the battery bank, possible damaging it, and to keep us from spinning the generator as a motor when the ICE (responsibly for during the generator) was shut off.
It worked okay, albeit with the kinds of problems you would expect from such a 'kludge' of a solution. Most notably, we ended up damaging our ICE when it ran out of gas during one of our runs. The driver failed to disconnect the generator and as the ICE started to die, the generator turned into a motor, reverse spinning the ICE and shearing the ICE drive shaft.
In the future, we'd look to the more graceful solution of actually having a charge controller between the generator and the battery bank. This would avoid the reverse-flow problems, as well as allow us to do maximum power-point tracking and other control schemes to maximize the efficiency of the system. Unfortunately, such controllers arn't exactly off-the-shelf components, so designing and building one is a project in and of itself.
Cheers,
Andy"

" We were using a Marshall ME0709 COTS generator (http://www.marselectricllc.com/me07091.html). It's a DC generator that we ran at about 125 Amps and 72V (I wish it had been 80, fewer back-flow issues that way...). It was driven by a Briggs & Stratton 150212-256-B8 Horizontal OHV Engine (250cc 1150 Series 11.5 Gross Torque) (http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200355693_200355693).

--- Andy Sayler
Tufts Hybrid Racing
Tufts University
Medford, MA​*Plan for range extension - Please note this project is green I will be using home brewed fuels as much as possible. 

* The Ultimate Deciding Factor Cost

15kw generator for under $400 + coupling material and some sweat. 
Generator: $200
Engine: $150-200
Cost:$400 +
Gained weight: 140lb
Details: 

Placement in engine compartment

I will use pulleys or chains to link the generator to the ICE. The ratios will be increased on the ICE and decreased on the generator motor.​*Getting the volts from the DC Generator*:DC to DC converter - up the voltage from what the generator produces into the ideal range. If possible I will install a variable voltage regulator, however, that is probably not needed or possible. 

*Note*:While driving I am having trouble getting the car up to speed on hills. I still have some confusion about whether adding voltage here would make a difference in my overall top speed and acceleration. I am not sure if my motor is capable of running a higher voltage. I know my controller isn't​* From the DC DC converter* :After the converter is where I fall short on exactly what to do. I believe I will need a custom controller here. Its main function would to not allow back flow of electricity back into the generator when the motor isn't running.

Perhaps an intelligent system that will turn on the generator if the batteries discharge to a certain point unless I have it set to ev only. Sort of how modern hybrids work I guess. I am assuming this part could actually be done with a state of charge meter and some switches.​*From controller to Motor:*Direct connect from controller to motor. I am hoping this will charge the batteries but my controller contains a regeneration feature. I could conceivably assume that it will handle incoming current and use it for charging the batteries. How this will work under driving conditions is unclear. The flow of electricity should go to the area with greatest draw but what about extra current? I suppose I could create a DC - DC battery charger that woul adjust its draw based on a few factors. One being the state of acceleration and the second the power level of the batteries. Perhaps it will even drop power level to controller in favor of batteries if state of charge is at certain level. 


​*Questions still looking to be answered:*What voltage is optimal for my car?
How many amps am I consuming during driving conditions?
I am ordering ammeter and voltmeter gauges
Can I afford to order smart charger now and is it worth it?
​Step 2

When I can afford to upgrade batteries

Add lifepo4 and BMS and quick charge for sure


Photos( Will update as everything updates):



























































































This is a work in progress.....Thanks for all the help everyone!


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## Biostudent (Jul 13, 2010)

Also, wondering what kind of smart charge would be best. Any way I can get the top/cruise (47/35) speed higher? 

How much would it cost to convert to batteries that are lighter? Was looking at this one http://www.kellycontroller.com/hwc4b-series-72v15a-charger-p-375.html


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## frodus (Apr 12, 2008)

a new charger alone is not going to increase range.... just charge time.

Adding capacity to the battery pack (or replacing with one of higher capacity) and making the electronics/wiring more efficient is about the only way to get more range (aside from stripping off weight).

if you want more range, get lifepo4 and lighten it up. With lifepo4, you'll need a new charger, batteries and potentially a BMS system (I wouldn't run without at LEAST something that'l avoid overvoltage and undervoltage.

those cells you were looking at for $3600 are way too expensive. Thats $150 a cell, plus shipping. You can get them elsewhere for much less, and get better batteries.


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## corbin (Apr 6, 2010)

Great buy! I'm in the process of building my own EV Bug. Check out a lot of the info my website for the decision's I've been making (go back to the first few posts to see lots of data).

http://www.corbinstreehouse.com/blog/plug-bug/

corbin


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## Biostudent (Jul 13, 2010)

> a new charger alone is not going to increase range.... just charge time.
> 
> Adding capacity to the battery pack (or replacing with one of higher capacity) and making the electronics/wiring more efficient is about the only way to get more range (aside from stripping off weight).
> 
> ...


Hmm, thats really something I didn't want to hear. While I can afford to buy a charger right now I was going to wait a while( as long as I could) to switch to lifepo4 batteries. I'll have to get creative and see about stripping weight.

So a smart charger won't increase range at all? How much time does it decrease the charging too? I belive the PO said it took twelve hours.



> Originally Posted by *corbin*
> _Great buy! I'm in the process of building my own EV Bug. Check out a lot of the info my website for the decision's I've been making (go back to the first few posts to see lots of data).
> 
> http://www.corbinstreehouse.com/blog/plug-bug/
> ...


Awesome







I will check it out


Anyone have any links to range extended hybrids? I really want to figure out how much engine I need and how to wire it up. If I needed a larger engine I could use diesel and run it on veg oil. Also could have it powering a hub motor on a tow behind. That could help increase my top speed while increasing range. I would prefer to keep the engine inside the engine compartment. Anyone point me to a wiring schematic or any other info?

Thanks everyone


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## mhud (Oct 19, 2009)

If you are only getting 12 miles because the batteries are unbalanced or they're not maintained, you may be able to increase the range by addressing those problems.

I have a '73 super beetle as well. I was hoping to get high freeway speeds but it tops out at 65, which I guess is pretty good. My range is about 20 miles, but because my AGM batteries don't stay balanced, I rarely get even that. Installing some PowerCheq modules to keep the batteries balanced should help me with range and generally increase the lifespan of my batteries. 

With flooded lead acid batteries you don't need to be so worried about balancing -- just make sure you check the water levels often.


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## Biostudent (Jul 13, 2010)

mhud said:


> If you are only getting 12 miles because the batteries are unbalanced or they're not maintained, you may be able to increase the range by addressing those problems.
> 
> I have a '73 super beetle as well. I was hoping to get high freeway speeds but it tops out at 65, which I guess is pretty good. My range is about 20 miles, but because my AGM batteries don't stay balanced, I rarely get even that. Installing some PowerCheq modules to keep the batteries balanced should help me with range and generally increase the lifespan of my batteries.
> 
> With flooded lead acid batteries you don't need to be so worried about balancing -- just make sure you check the water levels often.


So I should be getting more than 12 miles than? 



I have 9 8V golf cart batteries energizer. The cars weight is suppose to be 1800lbs with batteries. Motors 15hp 10hp continuous. 

I really need around 50 mile range. A lot of places I go are 15-20 miles away. So I am really looking to beef the range as much as possible without spending too much. My budget is $500 and I was planning on buying a smart charger with that since I thought that would increase range.

Would switching to 6V batteries increase my range? I read that in the "Build you own electric car" book. What would that cost to buy 12 6V batteries?

Sorry for all my newb questions. I have been reading as much as possible to try and catch up. In a way I wish I built the car instead. That way I would have had a chance to gain all the knowledge. But this way works too


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## mhud (Oct 19, 2009)

The voltage of the individual batteries wont affect range by much. 

The key number you're missing is: amp-hours. Do you know the AH rating of your 8V Energizers? Post the model number of the batteries too. That will also tell us the battery chemistry.

You can't know what range you're supposed to get until you know the voltage and AH rating for your pack. We know the pack voltage is 72V. The practical AH rating drops over time and with use, so any indication of the age of the batteries and whether they've been mistreated is important, too.


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## Biostudent (Jul 13, 2010)

mhud said:


> The voltage of the individual batteries wont affect range by much.
> 
> The key number you're missing is: amp-hours. Do you know the AH rating of your 8V Energizers? Post the model number of the batteries too. That will also tell us the battery chemistry.
> 
> You can't know what range you're supposed to get until you know the voltage and AH rating for your pack. We know the pack voltage is 72V. The practical AH rating drops over time and with use, so any indication of the age of the batteries and whether they've been mistreated is important, too.


_The batteries are Energizer GC8_ (Golf Cart) 8V, *105 AH* or could be 170AH not sure don't see it anywhere. But they are GC8

With this battery what should the max voltage I charge to be? Also max discharge?


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## Biostudent (Jul 13, 2010)

Just wanted to mention I will be updating my original post from time to time with notes and my current plans/progress.


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## Duncan (Dec 8, 2008)

Hi Biostudent

If you want a cheap range extender - look at pusher trailers

basically a FWD car (a rear engined rear wheel drive would do as well) chopped and turned into a trailer, when you are on the highway you engage the trailers drive and use its throttle to push your car

Using a motor and generator adds a lot of cost and inefficiencies


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## Biostudent (Jul 13, 2010)

Duncan said:


> Hi Biostudent
> 
> If you want a cheap range extender - look at pusher trailers
> 
> ...


I have seen these and while I love the idea. Its not what I am looking to do. I want an electric car. If I have to burn alcohol with an engine to produce electricity, I would rather have some mechanical loss of efficiency then not be driving via electric. A push trailer that is an EV is an idea. But it would cost too much.

After measuring my engine compartment...I very well may be building a trailer. Or I may have some engine parts sticking out the back of my car. That may not be such an issue though...since it would air cool the engine.

But, it will be a generator and not a mechanical assist.

Side note... today I was electrocuted a few times. My extension cord needs to be upgraded.


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## Biostudent (Jul 13, 2010)

physics question - 

weight in a car vs weight in a trailer towed by car? Which is more of a draw back?


I am guessing adding a trailer adds not just weight but drag as well. Which most likely is worse. But how much worse exactly. If I am able to build a fiberglass hull to go around the trailer and tow it close enough it might not be to bad. I'd have to see where the wind blows in a beetle wind test to know for sure.

If I make a trailer it will be very small...but will need shocks to avoid excessive bouncing. I was thinking a bicycle frame or two could be adapted. I could use the metal frames at least. They are relatively lightweight. The tires would be beefed up by adding some sort of suspension.

The towing weight would be something like 250 - 300 lbs with engine, generator, and trailers parts (Guess). 

Once I get my motor I will see. If its to large then trailers the way to go.


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## Biostudent (Jul 13, 2010)

I came across this on ebay. If I can find one at a bit lower price I found my solution. No trailer needed! I may cover it with a fiberglass hull. Also...the best part is it is removable. So once I upgrade my batteries ( a couple years from now) I will be able to leave it in the garage except on long trips.


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## ewdysar (Jun 15, 2010)

Biostudent said:


> I came across this on ebay. If I can find one at a bit lower price I found my solution. No trailer needed! I may cover it with a fiberglass hull. Also...the best part is it is removable. So once I upgrade my batteries ( a couple years from now) I will be able to leave it in the garage except on long trips.


I own one of these trailer hitch platforms for when I'm camping in my Chevy Suburban. Your challenge will be loading it into and out of your receiver when the generator is fully assembled. You also need to consider how the car will handle with a couple of hundred pounds behind the rear bumper. My truck with an 8500 pound GVWR doesn't mind much...

Eric


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## Biostudent (Jul 13, 2010)

Duncan said:


> Hi Biostudent
> 
> If you want a cheap range extender - look at pusher trailers
> 
> ...





ewdysar said:


> I own one of these trailer hitch platforms for when I'm camping in my Chevy Suburban. Your challenge will be loading it into and out of your receiver when the generator is fully assembled. You also need to consider how the car will handle with a couple of hundred pounds behind the rear bumper. My truck with an 8500 pound GVWR doesn't mind much...
> 
> Eric


I am hoping the batteries will help counter balance the weight while driving.

As far as putting on and off. I will be leaving it on for a while. Once I move into the phase where I can take it off. I figure I would make a stand for it with wheels.


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## Biostudent (Jul 13, 2010)

I tested my batteries today and it came out a bit strange.
I had it on my iphone notes with specific volts but for some reason ever since I upgraded it to the 4 software it won't work right...and deleted my note with all the info 

So I'll redo it. However, I do remember for the most part.

All of them in the back (6) were between 8.15 and 8.20..averaging to 8.16

The ones in the front(3) were 8.13 average.

Any ideas what could cause the difference in volts between the two areas? Or is this normal


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## frodus (Apr 12, 2008)

yes

charging batteries in series will do that. They'll be all over the place unless there are balancers on the batteries, or you use a charger for each battery. It's the price you pay for wiring batteries in series, and we all must deal with it.

They're not that far out of balance, just use a 8V battery charger on each and bring them back up.


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## Biostudent (Jul 13, 2010)

Okay, well thats good. I was worried it may be something more sinister.

looked into hitches and saw that I will not be able to use a hitch basket. So that kills that. Which puts me back into using a trailer for this method.

I may just leave the generator plans to the side until I get my range up and figure out why its only 12 miles as it is. I need to get some amp meters asap.


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## Biostudent (Jul 13, 2010)

I received my amp meter. 

I was wondering where I should hook it up? It came with a shunt. Do I hook it up in series with the Negative line or parallel? Also, what gauge wire do I need? I have 4 gauge now and was hoping that would do it.


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## Guest (Aug 26, 2010)

Biostudent said:


> I received my amp meter.
> 
> I was wondering where I should hook it up? It came with a shunt. Do I hook it up in series with the Negative line or parallel? Also, what gauge wire do I need? I have 4 gauge now and was hoping that would do it.




Does the image below help? Use what ever wire you're using for connecting your batteries. Most here use 2/0 with lead batteries. You can use either the negative side or positive side.


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## PatricioIN (Jun 13, 2008)

this is my chart for fyi...


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## Biostudent (Jul 13, 2010)

Thanks that will do it. 

Anyone know a tutorial on changing the voltage of a sepex motor?


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## Guest (Aug 26, 2010)

Biostudent said:


> Thanks that will do it.
> 
> Anyone know a tutorial on changing the voltage of a sepex motor?


Well thats easy. If it is a 48 volt motor I am sure you can go to 120 volts. Just be sure you cool it well. Kelly offers a nice SepEx controller that will do 120 volts. Less if you want. Do a 96 volt conversion instead. If your motor is 36 volts then 96 volts might be your max you should use. Adjust the amperage to the field via the software. Don't be overly aggressive. 

Is that what your after? How is the 72 Volts working out? Kinda anemic in my book but a doable voltage. I know as I started out with 72 volts. 

Pete


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## Guest (Aug 26, 2010)

My little D&D will do fine at 72 volts or less. I would not go more than that with the tiny one I have. Perfect for the 72 volt Kelly SepEx controller. Plenty of amps and plenty of volts. More than this motor would ever need. Perfect for our Cushman Truckster EV.


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## Biostudent (Jul 13, 2010)

gottdi said:


> Well thats easy. If it is a 48 volt motor I am sure you can go to 120 volts. Just be sure you cool it well. Kelly offers a nice SepEx controller that will do 120 volts. Less if you want. Do a 96 volt conversion instead. If your motor is 36 volts then 96 volts might be your max you should use. Adjust the amperage to the field via the software. Don't be overly aggressive.
> 
> Is that what your after? How is the 72 Volts working out? Kinda anemic in my book but a doable voltage. I know as I started out with 72 volts.
> 
> Pete


I am talking about getting the sepex motor to generate power for my batteries while I drive. This will be used as a range extender.

The motor is rated at 30 volts 500 amps as a generator. From what it was advertised as at least.

Now that you mention it though I was going to see what everyone thought about that. If I up my voltage I would need a new controller and a bunch of new things. 

Is it okay to stick with 72 volts? If I switch to lithium can I run them in parallel or to get more watt hours on board?

If I get my range extender working well enough then it should matter as much


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## Guest (Aug 26, 2010)

Have you figured out how much voltage your generator will generate? You must have the field powered before it will generate. No need for much. Before anyone here can answer that question your voltage output will need to be known and if you can figure out your amperage that would be good too. I just never did that. I have two of these motors. These motors can't be used with the normal controller either. Don't need a controller if used as a generator. If you are using a 72 volt controller for you main drive motor then you will need another one unless your main drive motor controller is rated for higher voltages like my controller. My controller has an operating range of 72 volts to 156 volts. 

So if your controller is only a 72 volt controller and you want to run that motor at like 96 volts you will need another controller that will operate at that range.


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## Biostudent (Jul 13, 2010)

Thanks Pete 
I believe my controller has a tolerance up to 80 volts. I probably will keep the generator at the voltage. Keep in mind I will be connecting the generator to the batteries and not directly to the series motor. So my controller should be good.

I know this may sound super newb of me... How do I test the motor? Can I hook it up to a drill somehow? I bought an rpm laser gauge but can't figure out how to spin the thing.

How do I power the field ?


-James


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## frodus (Apr 12, 2008)

You need to control the output of the sepex motor, you can't just hook it up to the batteries.

I think you're still a bit new to this to be really doing this large of a system. You've barely got the batteries charging with the new charger. Learn more about the system before you start jumping all over the place.

Many of the people with range extenders have been at this for many years. I think you need to learn more about motors and generators before attacking a larger task like this.


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## Biostudent (Jul 13, 2010)

gottdi said:


> Well thats easy. If it is a 48 volt motor I am sure you can go to 120 volts. Just be sure you cool it well. Kelly offers a nice SepEx controller that will do 120 volts. Less if you want. Do a 96 volt conversion instead. If your motor is 36 volts then 96 volts might be your max you should use. Adjust the amperage to the field via the software. Don't be overly aggressive.
> 
> Is that what your after? How is the 72 Volts working out? Kinda anemic in my book but a doable voltage. I know as I started out with 72 volts.
> 
> Pete





frodus said:


> You need to control the output of the sepex motor, you can't just hook it up to the batteries.
> 
> I think you're still a bit new to this to be really doing this large of a system. You've barely got the batteries charging with the new charger. Learn more about the system before you start jumping all over the place.
> 
> Many of the people with range extenders have been at this for many years. I think you need to learn more about motors and generators before attacking a larger task like this.


Well I am in contact with people who have made range extenders and that exactly what they informed me I should do. Attach the output of the generator to the batteries. Preferably at 80v or a tad higher to help with charging. I will also have a relay switch to avoid over charging of the batteries once they reach a certain voltage. The relay switch will disconnect the power supply and either stop the ICE or drop it down to a fuel efficient idle.

I appreciate your advice but I am building the range extender now. I want it perfected while I have these batteries before I upgrade. I refuse to accept the range limitations and see no reason why everyone doesn't have one. I am getting a lot of people telling me its not going to be efficient and that its a bad idea. Of course none of those people have made one. I will make it and if it doesn't work or is horribly inefficient then I will be satisfied. 

As far as lack of knowledge is concerned, I am learning as I go...


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## Guest (Aug 26, 2010)

You have a 72 volt controller. 72 volts is the nominal voltage. A fully charged pack will have about 76 volts and within range of your controller. You don't want to be too close to it's max so what you have is it. It won't handle an extra fully charged battery with out excessive risk of blowing it's magic smoke. 

I'd hook it up like I'd do for regen braking. These motors will only turn on direction. Connect up a wire to the + A terminal and connect it directly to the B+ terminal. Then take the negative side of the battery and connect it to the E- terminal. You should have a contactor on the + side between the battery and motor. Spin the motor up then engage the contactor and you should get voltage out as long as your motor is spun up fast enough. You should also have good contactors for this. Kilovac or the old style military ones should do fine. Those use 24 volts. You could do this with 24 volts too. Or 12. If you have kilovac use 12 volts. If the old military ones use 24 volts. Make sure you have an output to the batteries. Have a voltage meter connected. I have not done this yet. 

Pete


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## Biostudent (Jul 13, 2010)

gottdi said:


> You have a 72 volt controller. 72 volts is the nominal voltage. A fully charged pack will have about 76 volts and within range of your controller. You don't want to be too close to it's max so what you have is it. It won't handle an extra fully charged battery with out excessive risk of blowing it's magic smoke.
> 
> I'd hook it up like I'd do for regen braking. These motors will only turn on direction. Connect up a wire to the + A terminal and connect it directly to the B+ terminal. Then take the negative side of the battery and connect it to the E- terminal. You should have a contactor on the + side between the battery and motor. Spin the motor up then engage the contactor and you should get voltage out as long as your motor is spun up fast enough. You should also have good contactors for this. Kilovac or the old style military ones should do fine. Those use 24 volts. You could do this with 24 volts too. Or 12. If you have kilovac use 12 volts. If the old military ones use 24 volts. Make sure you have an output to the batteries. Have a voltage meter connected. I have not done this yet.
> 
> Pete


Alright I just need to get a contactor and I can test it.

Just to make sure I understand. The E contact is 1 of 2 large contacts. The A contact is just below the E. 



I attached an image with labels of my generator to make sure its right.









Where would the voltmeter hook up at this point? From B to E?

Is it safe if I use a drill with a socket on the spindle to get the motor going? I noticed its 28mm


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## frodus (Apr 12, 2008)

> Well I am in contact with people who have made range extenders and that exactly what they informed me I should do. Attach the output of the generator to the batteries. Preferably at 80v or a tad higher to help with charging. I will also have a relay switch to avoid over charging of the batteries once they reach a certain voltage. The relay switch will disconnect the power supply and either stop the ICE or drop it down to a fuel efficient idle.


Don't let us stop you..... but here's a few things to consider:
You know if you disconnect/connect under load its going to create a rather large arc. You won't be using a relay, you'll be using a large contactor. If its large enough, it'l blow that contactor apart. Nothing limits that current from flowing.

Since you're not using something in between the generator and the batteries, what regulates current? Voltage? What happens when the engine isn't above the RPM where the generator actually starts generating? well, it'l act like a motor unless you use large diodes to block current flow into the motor.

Sepex and PM Generators output a voltage based on RPM. If you run the generator at a high RPM to get your voltage up, then close the contactor, you're putting a very large inrush through that contactor.

I'd consider getting another "controller" for the sepex motor and set it up to do variable regen, and never have it driven from the batteries, just use it as a charge controller. 




> I appreciate your advice but I am building the range extender now. I want it perfected while I have these batteries before I upgrade. I refuse to accept the range limitations and see no reason why everyone doesn't have one. I am getting a lot of people telling me its not going to be efficient and that its a bad idea. Of course none of those people have made one. I will make it and if it doesn't work or is horribly inefficient then I will be satisfied.


Its a fun project, I realize that. But there's no escaping that it won't be efficient. Sepex motors as generators might be 65-75% efficient generating power, power conversion from generator into the controller and then to the ground might be 60-70%. Then there's the whole "how much gas does it use to generate that electricity".... and most gas engines aren't much more than 20% efficient. So, from engine, to generator, to controller, to motor, to transmission to road.... don't expect anything more than ~10% efficiency. 

You might be better off having the engine push you


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## Biostudent (Jul 13, 2010)

frodus said:


> Don't let us stop you..... but here's a few things to consider:
> You know if you disconnect/connect under load its going to create a rather large arc. You won't be using a relay, you'll be using a large contactor. If its large enough, it'l blow that contactor apart. Nothing limits that current from flowing.
> 
> Since you're not using something in between the generator and the batteries, what regulates current? Voltage? What happens when the engine isn't above the RPM where the generator actually starts generating? well, it'l act like a motor unless you use large diodes to block current flow into the motor.
> ...


Yea I know the efficiency will be horrible. I just want to see how it goes. I've got almost everything for it now so its a commitment. I can then find out its efficiency and go from there. A diesel engine running on waste oil is what I really want there for the ICE but didn't find one in the price range I was looking in. Maybe later.

As far as regulation. I will have diodes and thats pretty much all I am going to put there. I will just have to kill the ICE whenever needed. I can design a switch that turns it on at 77 volt pack charge and then shuts it off when its at 80v. I am hoping at least.


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## Guest (Aug 27, 2010)

efficiency is out the window if you want to extend your range. It is not about efficiency but getting that extra range. But I'd almost bet it would be better than using a full sized ICE to do the same distance. Anything that is better than what exists is always good. Not good for big business but good for us.


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## Biostudent (Jul 13, 2010)

*Bumps in the road: Update*

Alright a bit of an update. With school going on I have very little time. Now I will be moving to a house with no garage so I am racing to get a few things finished so the cars a bit more functional.

My seats were destroyed when I bought the car so I repadded them with memory foam and covered them with new seat covers from a beetle restoration company. I actually was able to get a "complete" interior kit for $440. Which is pretty damn good. When I looked for just seat covers for other cars it cost that much. I will be waiting to do the rest of the interior now that the seats aren't stabbing my bum, I can focus on the important components of the car.

Questions if I may  

1. My old accessory battery went dead on me so I bought I high capcity deep cycle from walmart. I now realize that it doesn't charge from the dc-to-dc converter. I was wondering if there is a way to have a built in charging system for the accessory battery? I have solar panels I was working with. Can I wire them straight up? Or do I need a box to regulate? 

2. Also, the contactor that switches and disables the car when it is plugged isn't flipping right now. I am assuming it is caused by the 11.5 volt accessory battery and not anything else. So hopefully if I get this battery situated that will be fixed.

3. I am not sure if this is related to the contactor not flipping when I plug in the charger, but I am getting current flowing through the body of the car when it is charging. This obviously is the biggest problem out of all the problems I described. I had this happen before but it went away. I thought it was related to my extension wire but now I am not to sure. Is this from the contactor? Or is it something more diabolical? Oh, I knew it was doing this because when I went to open the door I was getting zapped by a low level current. I had to zap my self a couple of times to figure out that it wasn't the wire. I suppose it may be the wires connected from the charger itself to the batteries if it isn't the contactor issue. Any advice would be greatly appreciated  Any ideas on how to check the body for voltage without zapping my self would be good too 

4.Lastly, I had a digital amp meter but it gave me all kinds of problems so I bought one of these... Problem is the wiring diagram shows me connecting it to a shunt with a negative to positive connection to my battery. I currently have the shunt installed to the negative terminal of my battery set up. What can I do to get it to work? I attached the wiring diagram.

Generator
I did lots of research and couldn't figure out a way to get the voltage up on the sepex motor. I decided to buy a pancake PMA for the generator aspect of my project. It is rated for about 7000 watts at 80 volts DC which makes it "ready out of the box" compared to my other options. It has a max output of 300a at 12,000 RPM. I will be using an 8inch pulley on my ICE in order to achieve the 6800 RPM's or so I believe I will need. I decided to use a trailer basket since now the weight isn't an issue anymore. If it becomes one I will adjust and weld some more supports if I need to. I have a feeling the hitch I have installed can handle a lot more than 100 pounds at tongue weight but isn't recommended because of steering purposes. I don't believe I will have an issue with steering because of the counterbalance of batteries through out the car. Plus if I go over it will only be by about 20-30 pounds.


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## Guest (Oct 7, 2010)

*Re: Bumps in the road: Update*

Your amp meter is for your aux battery and not your HV pack. Those are wimpy. If it is of high enough amperage for your main pack then you connect your shunt on your positive or negative line then connect your amp meter to those little screws on the side of the shunt. If the meter goes backwards then you just switch the wires and your good to go. The amp meter is always just hooked to those small screws on the side of your shunt. Nothing more. What kind of voltage did you get from your starter/generator and what kind of amps did it produce? 

Pete


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## ElectricBoston (Oct 8, 2010)

Wow, great work! I'm just getting started and this was a great post to read, thank you!


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