# Newb Looking to Convert ICE 84 VW Vanagon



## bblocher (Jul 30, 2008)

Welcome to the forums!

I don't think you'll find anybody here who thinks your ideas are crazy. A 30-50 mile range is a typical conversion range with lead acid. Since you need significantly less you could do this conversion for much under your budget.

Check out the wiki section here for tons of great info to get started. http://www.diyelectriccar.com/forums/forumdisplay.php/diy-ev-wiki-21.html (I think that's the link) After going through all of that if you still have questions then post away and you'll find many people eager to help.


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## madderscience (Jun 28, 2008)

Here's what around $20K can do with a vanagon:

http://www.evalbum.com/1727

Only thing I would have done different would have been flooded batteries and a watering system to minimize the extra maintenance. Flooded are cheaper and have better cycle life than sealed/AGM batteries but with that many cells (150) a watering system becomes a necessity I think.

He's got an AC system and a 300 volt traction battery. The van will go around 40 miles (with the benefit of regen) in moderately hilly seattle.

While the vehicle size and weight is more than some other conversion candidates is isn't that much worse than a pickup truck, and vanagons have such high GVW that you can carry a lot of weight without exceeding GVW. Sounds like you don't plan a lot of high speed driving so aerodynamics aren't a concern either.

As for the solar/wind charging from your original post it sounds like you've already familiarized yourself with the disadavantages of carrying solar panels or a pop-up wind generator on the car, but it is true that the vanagon roof is big enough for a few hundred watts of solar which in sunny CA could give a significant charge boost over the course of a day parked in the sun though it might take a few days to get a full charge.

Another fellow (also in seattle) has a solar array on his EV pickup conversion up on a roof rack and it will charge his 120V battery at a couple of amps in full sun. The downside is the extra weight and drag (he does use the freeway.

Good Luck.


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## Wiredsim (Jul 4, 2008)

If your really willing to spend 20k you can now start to get a LifePo4 or Lithium Manganese setup with an AC drive that will more then meet your range requirements.

Its really about how DIY you want to get, and how good of a hunter you are. Do you want a off the shelf type setup or a scrap yard build? These are really at two ends of the spectrum, but the really awesome thing about EV DIY right now is you can really pick and choose where on that spectrum you want to be. For example you could get a scrapyard forklift motor and jerry-rig a controller, or you could buy a DC motor / controller combo from a supplier with a warranty. 

Since you already have the donor vehicle you really could put together a decent city speed lead battery based DC drive EV for I think less then 4-6K with made-for-ev parts.

Good luck with your build! I think that would be an awesome setup for what you want.


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## terrificKid (Sep 19, 2008)

Thanks for the input all! Great link to the VW bus conversion!

I've done a good amount of reading now and could use some tips.

Specifically confused about AC vs. DC and optimal system voltage. I'm leaning towards an AC system currently. As I understand, AC motors are more efficient, run at higher voltages (higher V = more efficient?) and Regen breaking is an AC only thing? 

However, higher voltages seems to equal more batteries and space is a surprisingly large concern to me. I found this conversion: http://www.solarvan.co.uk/how.htm - which is an AC bus with LiFEp04s runing at 96V. 

I thought a low voltage AC system is like shooting yourself in the foot? What are the disadvantages of a low Volt Ac system?

A LiFEp04 battery system is intriguing, but is it really worth it right now? The $ per kWh is way higher than typical lead acids. Can it make up for it in weight or space? Also, if I go with LiFEp04s I'll need a BMS system. If I'm going to have onboard solar charging, the BMS system will be running round the clock. Does a BMS use up much power as it regulates the batteries?

Thanks,
TK


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## madderscience (Jun 28, 2008)

AC systems are generally designed for higher voltages, meaning they work best (best efficiency, best power) at higher voltages, often 200-300 volts. DC motors used in EVs usually are rated at 72-120 volts though often they are driven to higher voltages than that, but rarely more than 156 or so unless the car is a dedicated dragster.

The efficiency difference between AC and DC is really rather small (a few percent difference) and can easily be eclipsed by other factors like chassis selection, gear ratio and driving style. Regen will only help you if you do a lot of stop and go or have to deal with hills that are steep and long enough that you would be riding the brakes going back down them. Regen might buy you 10% additional range over a setup without. That 10% is what people who have it usually claim.

Regen is difficult to do with the type of DC motor (series wound) most often used in DC conversions. There is information in the wiki regarding why this is.

Higher voltage does mean more batteries but often they are also smaller, so the energy capacity (watt hours, which is basically proportional to battery pack weight) may not be any different. 288V at 50AH is the same as 144v at 100AH in terms of energy storage.

In a conversion, higher voltage batteries have the advantage of being able to use smaller and lighter cabling, and the disadvantage of possibly more expensive batteries (often AGMs are used in very high voltage packs) and more expensive components like fuses, circuit breakers, etc. to handle the rated voltage. 

I won't be convinced that LiFePO4 is worth in until I see some systems that have been in operation long enough to pay back the cost. I can buy 3 or 4 lead acid battery pack replacements right now for the cost of one equivalent lithium pack for my car and its associated BMS. This means if my lead acid pack lasts 3-5 years (1 year old now) then at minimum the lithium setup needs to be good for 10 years. Of course lithium has an immediate benefit of being much lighter and more compact. For the same weight in lithium vs. lead you would triple your range. for the same range as a lead pack, your lithium would weigh 1/3 as much.

Given the goals and usage you described, I'd take the extra $10K for lithuim and plow it into a grid tied PV system for your house and a couple of panels on top of the van.


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## Madmac (Mar 14, 2008)

The efficiency difference between AC and DC is not that great, less than 10% at the best (excluding regen).

The one big advantage and why all serious commercial electric vehicles use AC (or BLDC) is that it is fail safe. Any fault in an AC system the motor will stop. In a DC system the failure mode will be full power to motor, if you are lucky this will then blow the faulty devices apart and the motor will stop.

If you expect other people to drive the vehicle who may not be up to hitting a stop button or pulling a breaker trip cord in an emergency then go AC.

Down side is the cost.

Madmac


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