# cheapest practical conversion?



## Ziggythewiz (May 16, 2010)

Have you measured the effects of your regen? That's not usually considered in a value build...

If you really only need 30 mph you can turn any small car into a 48v golf cart for a few $k...but is that really what you need and want? I'd consider 120V a minimum for city drving, and 144V+ preferrable.


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## GrowleyMonster (Apr 7, 2014)

Ziggythewiz said:


> Have you measured the effects of your regen? That's not usually considered in a value build...
> 
> If you really only need 30 mph you can turn any small car into a 48v golf cart for a few $k...but is that really what you need and want? I'd consider 120V a minimum for city drving, and 144V+ preferrable.


No, I havent. I am still running the original folding prop so no regen is possible until I can afford a new fixed 3 blade 12x8 prop. But it would be negligible at less than 6kts. And now I am planning on removing mast and rigging and going all solar. So I could have saved some money by not worrying about regen for the boat.

I know higher voltages are advantageous in a car but I am much more familiar with 48v systems and components, and they are cheap and readily available. For a highway driver I would probably go with 144v. But essentially, yeah, looking at a street legal golf cart that looks like the car next door cause that's what it is made from. And I am looking at bottom line, not high performance.


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## nimblemotors (Oct 1, 2010)

You don't need to convert anything, you can buy what is called a "NEV",
which is a 30mph limited street car, which are basically golf carts with lights and horns and seat belts. A used GEM can be bought for a few thousand,
sometimes much less when they have issues.
I tried driving not over 30mph one day, and found it INTOLERABLE.


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## piotrsko (Dec 9, 2007)

I figure since your boat was $2500, the car should cost about the same conversion wise. So the other unknown cost is the costs associated with the vehicle to convert. Back in the dark ages of contractors and FLA, 48 to 96 volt vehicles were common because the battery size and weight were the big issues. In a warehouse the forklift drivers scream about as fast as they can, otherwise they could be fired for goofing off. They move a ton or three in addition to the couple ton forklift on relatively low voltages. I am running a high voltage conversion because I erroneously thought it was more efficient.

My guess is about 3 grand total for a vehicle, freeway capable, depending on how well you scrounge.

My $0.02 YMMV


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## Vanquizor (Nov 17, 2009)

If I were starting over I think I could duplicate my neon from a functional standpoint for 3k including the vehicle. Given what I learned along the way I'm sure it would be a better car the 2nd time around. This is a 144v system capable of breaking the speed limit anywhere in North America, with a drop dead range of ~45 miles in good weather.

I'm sure you could do something practical for less, but I think you'd probably be talking about finding some one off deals to make that happen (or be a hazard in traffic). For 3k you should be able to get everything off the shelf new or high quality readily available used.


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## Woodsmith (Jun 5, 2008)

I suppose 'practical' means different things to different people.
Also possibly limited by local regulations and traffic conditions.

I am scratch building mine as I can't find an affordable practical equivalent for what I want.

For just a 'grocery getter' and local runabout. You can use a very small and light vehicle, maybe a small kit car or beach buggy type thing, if you don't mind an open top.

Alternatively any small car could be converted with used forklift parts, a decent controller kit, and some lithiums. 

I have been very tempted to 'acquire' Beryl' from my wife's previous employer.








Beryl only had a top speed of about 12-15mph on 48v or lead but I reckon I could get her up to near 30mph and be considerably lighter at the same time.


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## GrowleyMonster (Apr 7, 2014)

Vanquizor said:


> If I were starting over I think I could duplicate my neon from a functional standpoint for 3k including the vehicle. Given what I learned along the way I'm sure it would be a better car the 2nd time around. This is a 144v system capable of breaking the speed limit anywhere in North America, with a drop dead range of ~45 miles in good weather.
> 
> I'm sure you could do something practical for less, but I think you'd probably be talking about finding some one off deals to make that happen (or be a hazard in traffic). For 3k you should be able to get everything off the shelf new or high quality readily available used.


Thanks for this and all the other positive and informative replies. On this basis, I think if I go forward with this, I will try to work with a budget of 3k not counting the cost of the base vehicle, and go for the most capability I can squeeze out of that amount. If I end up with a short range 55mph capable car, cool, but no biggie. If I only get my original spec capabilities, that's cool, too.

Wow and I recently sent my old beater of a Ford Ranger to the junkyard, with a destroyed engine. Would have made an interesting base vehicle. Standard 5 speed, too. Well, plenty of engineless or dead engine small vehicles around for cheap.


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## GrowleyMonster (Apr 7, 2014)

Woodsmith said:


> I suppose 'practical' means different things to different people.
> Also possibly limited by local regulations and traffic conditions.
> 
> I am scratch building mine as I can't find an affordable practical equivalent for what I want.
> ...


Hah! "Beryl" is a pretty cool looking vehicle! Yeah the 15mph issue would have to be addressed, though. Would be great for tailgate parties. Maybe with a 48v fridge, and a gas grill?


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## Woodsmith (Jun 5, 2008)

Yeah, Beryl is cool!, She even had her own Twitter account @BeryltheEV

Beryl is retired now, dead batteries and some body rot. She has been replaced with a Goupil G3. 
I am still hankering after restoring her as I am quite attached to her funny character.


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## Vanquizor (Nov 17, 2009)

GrowleyMonster said:


> Thanks for this and all the other positive and informative replies. On this basis, I think if I go forward with this, I will try to work with a budget of 3k not counting the cost of the base vehicle, and go for the most capability I can squeeze out of that amount. If I end up with a short range 55mph capable car, cool, but no biggie. If I only get my original spec capabilities, that's cool, too.
> 
> Wow and I recently sent my old beater of a Ford Ranger to the junkyard, with a destroyed engine. Would have made an interesting base vehicle. Standard 5 speed, too. Well, plenty of engineless or dead engine small vehicles around for cheap.



If I were doing it over here is how I would do it using a relatively small light vehicle:

Batteries are a potential budget breaker- I was able to get some new Group27 no name brand deep cycle batteries for under $50 each but I think that was a pretty good deal, worst case you should be able to grab marine batteries below $80 shopping at your local wal~mart or equivalent. These are not really top shelf batteries but warranty is good and they will pay for them self before you need to buy replacements if you drive the thing.
Call it $600-$1000 there - shop this first and buy it last. 

Big ticket Item I couldn't think a way around is the Controller- The P&S diy kit is probably the best buy at $600, I went with a used Curtis 1231C which seem to go for ~$800.

The motor is an area where you can save a ton from what I did first go round- on a budget controller I think my impulse 9 is overkill but I don't feel bad about it as I plan the car to grow. Forklift motor may be the way to go if you have an in, or again something used. I would target less than $500, worst case you can get new and overkill for $1200: http://www.cloudelectric.com/product-p/mo-me1002.htm

After the big 3 you should have over $500 in your budget to cover contactor (sub $100), fuses( sub $100), coupler ($20-$400), adapter ($20-$400) charging ($80-$200) and fabrication/wiring ($Free- $Ridiculous). If you are industrious or have friends you are good to go. If not you may have to be a better shopper for the big 3 to make it work.


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## GrowleyMonster (Apr 7, 2014)

Vanquizor said:


> If I were doing it over here is how I would do it using a relatively small light vehicle:
> 
> Batteries are a potential budget breaker- I was able to get some new Group27 no name brand deep cycle batteries for under $50 each but I think that was a pretty good deal, worst case you should be able to grab marine batteries below $80 shopping at your local wal~mart or equivalent. These are not really top shelf batteries but warranty is good and they will pay for them self before you need to buy replacements if you drive the thing.
> Call it $600-$1000 there - shop this first and buy it last.
> ...


The propulsion bank I put on my boat is made of 6v GC2 golf cart batts from Sams Club, $85 each, about 220ah. Do you think that would be ovrrkill? And how, do you feel about a 12kw motor, whether brushed or brushless? Would that just be a dog, or would it work okayish, coupled to a manual transmission? I see some forklift motors, rebuilt, at $400+ on the bay. I'm liking the Motenergy motor I put in my boat, so I was thinking about the bigger size Motenergy BLDC motors. I have the 5kw 4201 motor in my boat with a Kelly controller,


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## Vanquizor (Nov 17, 2009)

If thats a 12kW continuous rating it is probably sufficient, if its 12kW peak it had better be a 300lb chassis (spare locost chassis in your garage?). Also keep in mind that peak is just that- 1 glorious point where it all comes together. In theory my controller puts out a peak of 72kW, but in actual practice 35-40 is the top end in most conditions. In a boat you have the luxury of dialing in where it runs with the prop and can get it close to ideal, in a car it needs a broader powerband.

In my car (neon 2600lbs) accelerating with traffic I pull 15-20kW, when I need to get into the next lane or something pulling 25-30kW is the ticket. Now that its winter here I pull 7-9kW cruising on surface streets.


For the battery I think you'll have to balance that based on the chassis and your range needs- the golf cart batteries are probably better from a cycle life standpoint, but you will be carrying more weight to get the voltage (i.e. performance) up. I think I could back off the voltage a bit with little impact on performance as I am peaking beyond the redline of my motor in the first 2 gears. With careful chassis choice 120V or even a little less might be o.k.

I went 12V batteries to keep the performance up and weight down knowing that range wasn't really a limitation for me- you'll have to make your own determinations on whether you want to go 6v batteries, carry more lead and try and get more range also increasing your battery cost for the same voltage.

The other thing to add is this is my opinions based on 5 years of e-biking and 1 full sized car conversion, it would be nice if those with a few more miles would chime in as well on what they are seeing for real world power draws accelerating and cruising.


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## Caps18 (Jun 8, 2008)

I'm more interested in hearing more about your boat honestly. 

But, unless you plan on charging the batteries outside your home, I think you could leave the charger in your garage. At least in the beginning.

I don't have any experience with 48V conversions or 72V ones. I would pick a small Honda Insight or something like that. It might be quite a bit of work though. Battery cost, weight, range, and cycle life will be the first thing to look at.

I think the best bet would be to find an existing conversion that just needs to be worked on or have the batteries replaced. There are some that go for not a lot of money.


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## GrowleyMonster (Apr 7, 2014)

Caps18 said:


> I'm more interested in hearing more about your boat honestly.
> 
> But, unless you plan on charging the batteries outside your home, I think you could leave the charger in your garage. At least in the beginning.
> 
> ...



There is a thread in cruisers forum on my sailboat conversion.
http://www.cruisersforum.com/forums...g-cal-2-27-to-electric-propulsion-129944.html. 

Also some posts on the yahoo electric boat forum. But basically I stuck with generally proven technology and didn't really do any trailblazing. 48v is popular in smaller boats, under 35 feet, because at 50 volts you get into a whole nother set of electrical standards, and 48v stuff is easily sourced. For obvious reasons, 48v is preferred over lower voltages though there are 36v boats using multiple trolling motor setups. Brushed motors are generally not used due to explosion risk involving propane and gasoline accessories, and I used a BLDC setup with a 5kw Motenergy motor and Kelly controller. Bank is 8 GC2 6v batteries in series for about 220ah. Reduction is via a 2:1 Baldor enclosed gearbox, and prop is the existing 2 blade 12" folding prop, but a prop change is planned. Top speed at 60 amps is about 4.7kt. Boat is about 7600 lbs. I usually run at about 10 amps, seldom more than 20 amps. Total cost was about $2500, after selling the old still running Atomic 4 engine for $300. A new Beta diesel would have cost me about $7k. 

An existing car conversion might be a good thing, yeah. I don't think we have too many here in New Orleans, though. I'm kinda leaning toward a small light car and a forklift motor at this point, but still not locked in to anything.


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## Yabert (Feb 7, 2010)

GrowleyMonster said:


> I'm kinda leaning toward a small light car and a forklift motor at this point, but still not locked in to anything.


I think it's the way to go for your ''cheapest practical conversion''.
You can probably find 8 or 9 inchs used forklift motor for 100-200$ and a good Alltrax SPM 72v controller cost less than 500$. So you can have a complet drive system for around 1000$. After, it's you to choose the proper battery pack (cheap lead acid/short life, lot of extra weight OR lithium without the lead disadvantage).

72v parts (fuse, contactor) are cheap and easy to find. A 72v conversion will give you more power and speed and will be very practical in a small light car with top speed around 50-60 mph or more with good lithium battery.
Example here: http://www.diyelectriccar.com/forums/showthread.php/72v-systems-small-car-68596.html


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## philt (Sep 7, 2014)

We have 600 12 V 5AH lead acid batteries we use in our test cart. These are used external to our project and connected via an "umbilical cord" just until we get our final batteries sometime Q1 2016.

We will be donating these batteries to a financially disadvantaged person with the passion to use them in their EV project. 

They are too heavy to ship so likely someone living near Orlando FL and having a PU truck makes most sense.
You can put these in Series Parallel to produce 360V at 200 amps or 720V at 100 amps.

We will be donating these sometime near the end of 2015.
If you are interested, keep in touch. 

https://www.facebook.com/pages/Total-AUTOmation-Works-LLC/599825060053495

Gods speed.
Phil


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## GrowleyMonster (Apr 7, 2014)

philt said:


> We have 600 12 V 5AH lead acid batteries we use in our test cart. These are used external to our project and connected via an "umbilical cord" just until we get our final batteries sometime Q1 2016.
> 
> We will be donating these batteries to a financially disadvantaged person with the passion to use them in their EV project.
> 
> ...


I will absolutely keep in touch, Phil. That's quite a battery bank! What do u estimate for total weight?


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## philt (Sep 7, 2014)

Very heavy.
Maybe 1800 lbs? guessing.


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## DavidDymaxion (Dec 1, 2008)

I ran my car this way for a while: I did 48V across a Kostov sepex motor. It would idle around 2000 rpm. The clutch was used to get going, and speeds were changed by shifting. Downshifting gave great regen, downshifting multiple gears would even skid the wheels with the regen. There was no controller, I just used a contactor to switch it on and off. Acceleration was better than a friend's 120V 500A Curtis Rabbit conversion (my car was much lighter and had no current limit). Top speed was just over 40 mph on level ground (with a field weakening resistor it went 55 mph on level ground once). In my city with 35 mph speed limits it was fine. I didn't hold up traffic on level ground, but would a little up hills.

While not as polished as using a silicon controller, it was fun in an old school way, and cheap, and educational. If I didn't need highway speeds (and didn't want to race) I'd probably just have kept using it in that mode.


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