# VW Bug conversion - semi auto



## madderscience (Jun 28, 2008)

I'm in USA so I can't give any regulatory advice, but I can share some technical recommendations and experiences.

40-60 mile range: 40 miles is doable with lead acid if you keep your speeds down. 60 miles is not, for a practical, reliable bug chassis. However a 100AH, 144v lithium system is really state-of-the-art these days for conversion, and would get you 40 miles easily (300WH/mile battery to wheels), and 60 miles if the car is well engineered and dialed in (200-ish WH/mile) and driven conservatively. 

If you are going with a DC conversion, if you will be keeping speeds under about 50mph, you can probably get away with using only 2nd gear. Most DC traction motors redline around 5000-6000 rpm, and in most cars that works out to about 50mph in 2nd gear. In my car, 5000 rpm redline is about 45mph.

You can use 3rd gear only if you have either a good controller with big amp capability (and the batteries to back it up) or if you live in a flat area. In most cars, that gives top speed of 60-65 at redline.

I rarely use any geasr except 2nd and 3rd in my car, which is a 1985 toyota MR2. If I had lithium instead of lead, the car would actually perform pretty well, even with its wimpy curtis controller and I probably could use only 3rd since it would weigh almost 1000lbs less than it does with lead acid.

If you go with an AC conversion, then redline may be as much as 10000RPM, and 2nd gear will be all you need. 

If you go DC, keeping the clutch is the typical recommendation for a first time conversion. Clutchless is fine with AC.

The DC/DC converter replaces the alternator in an ICE car and performs exactly the same purpose; charging the SLI battery and running all the lights and accessories when the "ignition" is on. Low budget EV conversions sometimes leave it out, but its sort of like trying to save money in a gas car by leaving out the alternator. Not the best plan, long term.

Zivan and Manzanita micro make 230VAC chargers. I imagine there are plenty of others too. I would presume they all function on 50Hz, but you would need to research that.

Tons and tons of VW bug conversions to look at in the "garage" section of the wiki, and at the austinev.org/evalbum.

cheers


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## EVfun (Mar 14, 2010)

Since you have an autostick your frame tunnel lacks a clutch cable tube. Going clutchless is certainly the easier way to go. Keep the coupler light and the motor a little smaller (lighter armature) and the Beetle transaxle shifts quite well without a clutch. 

The autostick has the 2nd, 3rd, and 4th gears from 4-speed so gearing wise it would work. You can swap it for a IRS 4-speed but you may not have to. You don't want to keep the torque converter though. I would consider the possibility of removing the torque converter and clutch and making an adapter to fit the shorter input shaft. 

I can't really help you on UK regs or range as my Beetle EV is a lightweight beach buggy. It is clutchless using a 40 HP 4-speed. 10 Optima group 34 yellow tops gives it about an 18 mile range.


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## corbin (Apr 6, 2010)

Hi Khx,
I'm in the process of converting my '69 bug. I've purchased all the parts, and right now I'm waiting on all the parts (mainly batteries) while I do the restoration. I documented my selection process.

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

corbin


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## khx (Jun 3, 2010)

Thanks all for the detailed information. I have some learning to do!

I've sourced an IRS gearbox to replace the semi-auto, so that problem is solved!

I'll start a blog with progress soon!


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## cruisin (Jun 3, 2009)

I am glad to see somebody doing the same as I did, convert a VW (70) bug. The restoration was the most work and I will never do it again. Anyone considering a restoration or conversion should at least change the brakes to disk front and back. CAUTION: DONT USE THE CHEAP EMPI CONVERSIONS AS THE BRACKETS FOR THEM ARE DEFECTIVE. Here are some pictures of my finished conversion. 117vdc 225ah Li-ion Impulse 9 and NO clutch. 0-40 2nd, 40-70 3rd, and that is fast enough. Range is 50 - 100 miles depending on all the varables. All LED lights and 2 100watt DC-DC converters. One is for the VOLT meter to keep it isolated. Next project, BOXSTER and a 914 which is already started.


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## khx (Jun 3, 2010)

Crusin - thanks for the pictures and the inspiration to get started! I see yours was a semi-auto originally, or you've changed the brake pedal.

Still pricing up hardware here, I'm liking an AC system, but may be too expensive.

Thanks,


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## Qer (May 7, 2008)

khx said:


> 3. Anyone in the UK aware of any regulatory issues with converting?


I guess that you'll mainly run into the same regulation as most of the EU, which is a general pain to handle. The best advice in Sweden is to try to get the car registered as a converted vehicle, but to manage that you have to change something more than replacing the engine. Also changing the brakes might do it, but if UK is like Sweden when it comes to getting conversions street legal you might still have to fight the bureaucrats for as long as several months before you can take it out on the streets even if you've done everything by the book.

So a very good idea is to do your home work before you even consider buying a donor car or any parts.



madderscience said:


> You can use 3rd gear only if you have either a good controller with big amp capability (and the batteries to back it up)


Um. The amount of battery power will be pretty much equal for the same speed no matter what gear you use. At low RPM's it will rise, but that's mainly because the efficiency of the motor will drop at higher motor currents. Until the inefficiency starts to become a serious issue you'll just trade voltage for current to keep the same power.

Ppack = Upack * Ipack = Umotor * Imotor = Torque * RPM

At least in theory, in real life some of the power of course will be lost in the transformation from battery power to mechanical power. The car will need a certain power (P) to keep momentum, if you change gear the U and I will change, but P will be pretty much constant as long as the efficiency doesn't get too shot (which it will be at very low RPM's no matter motor).



madderscience said:


> If you go DC, keeping the clutch is the typical recommendation for a first time conversion. Clutchless is fine with AC.


Um. Why would AC versus DC matter in that aspect?

True, AC has a wider RPM-range, but that comes at the expense of torque since power still is RPM multiplied with torque. There's nothing magical about AC that makes it generate 10k RPM out of the blue, the laws of physics are still in command.

If you have enough power, you can drive without a clutch no problem. If you have a low power system, you'll have to shift gears and that will be more tedious without a clutch than with. Cheap DC-systems and most AC-systems are low power, high power systems will cost more, AC-systems will be even more expensive and the motor will typically be heavier too.


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