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Old 01-26-2012, 04:44 PM
marklaken marklaken is offline
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Default '69 VW Beetle Electric Grocery Getter on the cheap

I recently bought an unfinished vw beetle electric conversion off craigslist and intend to follow through on a basic, short distance, fair weather, in-town, electric car for my wife. It'll be her birthday present which comes up in mid-May, so i got my work cutout for me. I am an air-cooled vw car restoration enthusiast and do all my own welding, mechanical, body, electrical, hydraulics, etc.

My goal is to put together a quality electric Beetle for as little cost as possible. It needs to go 40mph for 25% of the time, 30mph for 75% of the time, and have a range of 20 miles.

I want the vehicle to be stupid simple. For my non-mechanically inclined wife, I would like to just have a single outlet for the charger and a simple driver/car interface. I do not intend to install a voltmeter or amp meter. I would like to install a range indicator (I saw one for around $50 online somewhere).

My value system is as follows and will dictate my system purchases:
Safety > Durability > Simplicity > Range > Speed > Comfort

I am currently thinking of following through with the EV Wilderness setup of a 72 volt Alltrax 450Amp controller powering an ES-15A Series Motor (40HP peak, 12 HP continuous).

I already have the EV Wilderness VW adapter plate and shaft coupler for the ES-15A motor and also the throttle box and Kilovac EV200 Contactor (these parts came with the beetle).

Any other recommendations or thoughts on controller and/or motor?

I could use help sizing the batteries for my requirements. My general thought is either 9 - 8volt golf cart batteries or 12 -6volt golf cart batteries. Any opinions? Would 9 - 8v batteries cut it for my needs (I had read somewhere that 8v batteries need to be replaced more frequently (less charge cycle life). I had also read that a rule of thumb is about 3 miles/battery for in town driving - which I am sure is an oversimplification)

I also am torn between spending the money for a 72v to 12v converter for 12v accessories or maintaining a separate 12v deep cycle battery (came with the car) with a separate 12v charger (I have an old marine battery charger). Basically the converter option costs a couple hundred bucks, but is simpler to operate. Any major disadvantage to the converter? Better to spend my money elsewhere and stick with the second charger and battery which i already own? - Can I wire both chargers to one plug-in location? Does the 12v charger need to be connected/disconnected from the battery every time the 12v battery is charged?

I have not shopped for 72V battery chargers and am open to suggestions.

I am currently cleaning the body and repairing the floorboards. I have also ordered a front disc brake conversion to help stop the heavy beetle. No power steering, power brakes, AC or heat on VWs, so that part is really easy.

I'll post some pictures tomorrow...

Mark
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Old 01-26-2012, 05:20 PM
piotrsko piotrsko is offline
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

Everybody here is going to try to convince you to run lithium chemistry batteries, citing all sort of nefarious schemes, but you won't be able to do really dirt cheap. Your conversion. I'm doing lead acid, and I don't care what they think. YMMV. Sounds like you have done some homework, which is a good thing. stick around some more, enjoy the forum, and welcome aboard. I am running 12 v batteries, because I think it suits the Kostov motor more, but the opinion is that if you have the room, the 6 or 8 v batteries are better. I went with an alternator since it was mostly dangling in the engine compartment waiting to be used. Others will chime in with their different thoughts soon and they are all valid for their application. remember YMMV..

Last edited by piotrsko; 01-26-2012 at 05:26 PM.
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Old 01-27-2012, 10:35 AM
Ace_bridger Ace_bridger is online now
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

Quote:
Originally Posted by piotrsko View Post
Everybody here is going to try to convince you to run lithium chemistry batteries, citing all sort of nefarious schemes, but you won't be able to do really dirt cheap.
How refreshing. Yes, lithium makes complete sense but I too am going for lead, cheap lead, for my mk1 car. I will go lithium in the long run and, yes, it will cost more in total but I want to get up and running and I only have a 12 mile commute (in total) so will go big on lead to reduce the C loading on the pack. I am going for lead and, I hope, won't be struck down for it!!!

Good luck with the bug and tell your wife to go easy on the gas pedal and try to drive in such a way that she'll never need to touch the dreaded brake pedal!!! Nice christian driving is what we need!!
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Old 01-27-2012, 10:45 AM
marklaken marklaken is offline
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

Some quick back of the envelope calcs show rapidly escalating cost if I go 72v, lithium battery powered with a controller and motor that can be upgraded to 96v in the future (Extra cost of roughly: $2k in batteries, $900 on motor, $1k on controller, $200 on charger). I don't know if it would still be "on the cheap", but I do understand the reasoning and it is a significant dilemma.

I hope to have it figured out and parts ordered by the end of February - I doubt I can find $4k in a single month, but I will start looking!

It sounds like there is general agreement that the best single item splurge would be to go with lithium batteries - I understand they require different chargers, but do they require Battery Management Systems?

Is there any sense in looking for a motor that offers more HP at 72volt, or is my controller/amperage going to be the controlling factor on speed (at 72v)?
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Old 01-27-2012, 01:09 PM
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

Quote:
Originally Posted by marklaken View Post
It sounds like there is general agreement that the best single item splurge would be to go with lithium batteries - I understand they require different chargers, but do they require battery management systems?
Well, no... but yes!!.

Some guys drives her lithium pack without BMS and some others with BMS.... you can find many debate on forum...

I personnaly use a BMS because I don't need to care about battery. My BMS stop the charger when single cell hit 3.6v and advertise me if a cell go too low. So, I simply plug my charger each day and I forget about it.
Great advantage for your wife.
I think the Mini BMS is a really good and simple one. For 72v (24 cells) you will need 24 cell module (294$) and a master module (30$).
You can also buy a simple ''fuel gauge'' for 189$ (Absolutely usefull if you ask).

Quote:
Is there any sense in looking for a motor that offers more HP at 72volt, or is my controller/amperage going to be the controlling factor on speed (at 72v)?
You will be limited by controller voltage. Because top speed is related to power = Volt x Amps.

Bigger motor don't produce more power if controller don't supply more power. Bigger motor can only take more amps for longer time, so with a fix 72v they can produce higher power for longer time than a smaller motor.
So I think you will need to choose between 72v systems and forget about highway or going for a 120-300v systems for more power.

An interesting link here about 72v conversion: http://www.diyelectriccar.com/forums...car-68596.html
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Old 01-27-2012, 06:07 PM
piotrsko piotrsko is offline
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

See, i warned you about the others on this forum..... The venerable Curtis forklift controller also comes in different voltages, and there are cheap 96 to 144 v other controllers also ( none of which were mentioned. SURPRISE!!). I think there may be a paul and sabrina DIY controller for sale still over in classifieds. A used forklift motor can be had for scrap value {look over in the motor subforum at the sticky at the top} so actually the major expense will be for whatever battery choice you desire. I do recall the words "on the cheap" in the title and responded accordingly with my caveats.

The important thing is to do the conversion and feel good about it when you drive it quietly down the street.
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Old 01-27-2012, 09:46 PM
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

You bring up some interesting points and are seeing a lot of opinion about which way to go. You don't have to use top line parts on everything up front.

Quote:
Originally Posted by marklaken View Post
Some quick back of the envelope calcs show rapidly escalating cost if I go 72v, lithium battery powered with a controller and motor that can be upgraded to 96v in the future (Extra cost of roughly: $2k in batteries, $900 on motor, $1k on controller, $200 on charger). I don't know if it would still be "on the cheap", but I do understand the reasoning and it is a significant dilemma.
A good motor for a Beetle is the Netgain Impulse 9 because its shorter length fits without cutting the rear apron, even with a clutched conversion. The motor makes a little less torque per amp so a little more rpm per volt. The Impulse 9 is just 58 ft-lb at 400 amps (published number.) That means a little more rpm at any given voltage so it will better match the stock VW gearing at lower voltages. At 72 volts you would still struggle on the freeway because peak power would be at a lower rpm than 4th gear at 60 mph.

If you have the right motor then you will have the right motor adapter. It would be easier to upgrade the battery pack, controller, and charger in the future. Used controllers and chargers have some resale value. There are a range of controllers available. I'd suggest either a Soliton or Zilla, but those are >$2000 controllers so I can understand they may not be in the budget. You can use Altrax up to 72 volts, Curtis 1221 or 1231 up to 144 volts, and the Synkomotive controller up to about 175 volts. The price range of these options go from about $600 to about $1700.

Quote:
I hope to have it figured out and parts ordered by the end of February - I doubt I can find $4k in a single month, but I will start looking!

It sounds like there is general agreement that the best single item splurge would be to go with lithium batteries - I understand they require different chargers, but do they require battery management systems?

Is there any sense in looking for a motor that offers more HP at 72volt, or is my controller/amperage going to be the controlling factor on speed (at 72v)?
It would be best to use Lithium batteries. They offer more range and less weight. You can avoid having to beef up the suspension or brakes. You save that money to partly offset the greater battery cost, and the vehicle drives a lot better without the lead. If you can't, well... many of us, myself included have done lead conversions. Many of us won't do one again after trying Lithium (including me.) Does Lithium need a BMS is a huge debate on this list. I don't think a BMS is required with modest operator monitoring.

Horsepower is set by voltage and current available. The motors you would want will have no problem with current for acceleration. Usually it is limited by either the battery pack or motor controller. For example, the cheapest controller on the list I gave puts out up to 450 amps from up to a 72 volt pack. 72 volts times 450 amps is 32,400 watts. The motor will be about 85% efficient at 450 amps so about 27,500 watts makes it to the motor shaft. 27,500 watts divided by 746 (746 watts is equal to 1 horsepower) gives about 37 horsepower. Plenty of old bugs moved just fine with 36 horsepower, but having driven a couple of them I can tell you they don't impress in the performance department.
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Old 01-26-2012, 06:37 PM
marklaken marklaken is offline
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

Golf cart batteries are my only option at my price point - spend now or spend later, I guess I am in the spend later camp...I hope to do the entire conversion for under $4k. So far I have $750 invested in the car and partial conversion and $250 invested in a disc brake conversion. a quick online window shopping trip puts me around $1300 for motor and controller, $900 to $1200 on batteries, $300 on misc electric parts, and $400 on a charger.
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Old 01-26-2012, 10:30 PM
marklaken marklaken is offline
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

I put a couple pictures in an album.

Regarding meters, what advantage do the meters provide over a range meter? Is it for diagnostics?

Thanks for the heads up on the downside of the lead acid battery - is acid spray and venting an issue with a gel based lead battery? The decrease in performance at half charge is especially noteworthy and would push me to 12 - 6v batteries as my minimum criteria.

As far as Lithium, are there good sources for used lithium batteries and what are some of the more affordable charger makes/model. I will have to do some research here...

I know I won't need a 65 mph car, but I would want acceleration to be acceptable for street use (35 mph streets with lots of stoplights). I have old vws and am used to being the slowpoke, but will my general setup be worse than say a split window bus (0-40 mph in about 30 seconds)?
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Old 01-27-2012, 08:05 AM
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Default Re: '69 VW Beetle Electric Grocery Getter on the cheap

Quote:
Originally Posted by marklaken View Post
Regarding meters, what advantage do the meters provide over a range meter? Is it for diagnostics?

I have old vws and am used to being the slowpoke, but will my general setup be worse than say a split window bus (0-40 mph in about 30 seconds)?
Definitely for diagnostics, but also for driving. What range meter are you looking at? The issue there is that range is a factor of many things, which can be difficult for an electronic device to figure out. With a voltmeter and experience you know what range you have left based on the sag (For lead, for lithium you need to measure in and out).

Being used to a slug you should be fine performance-wise. I don't know your motor specs, but running my 31B on 120V lead I can do 0-40 in ~6 sec.
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