# VW beetle cheap conversion build experience



## rmay635703 (Oct 23, 2008)

The nissan leaf would do it and a similar configuration would drive your beetle likewise.

But 24kw of battery is not cheap.

Unless your definition of cheap is different than mine.


----------



## Moltenmetal (Mar 20, 2014)

Cheap is impossible with your requirements. The pack alone will cost you enough that failure on the rest will no longer be an option financially. Many people here have cheaped out at first and then gone back and paid yet more money to replace broken or unsatisfactory components. If the car is going to be drive able rather than just a project toy, it will be expensive. My suggestion is to not do it if your motivation is merely fuel savings, as expensive as fuel can be in Europe you're probably looking at a very long financial payback period. But as a fun project and learning experience with a useful vehicle at the end? Definitely a very rewarding project!


----------



## onegreenev (May 18, 2012)

Before we go off on a tangent on cheap we need to know what your (cheap) budget is for your build. Cheap is a very vague term. 

Do you already have your VW? Is it ready to convert? Meaning does it need restoration first? 
Do you want to go AC or DC? 
Lithium is pretty much the way to go. 
Getting good used Leaf Packs or Volt packs may be the way to go or just knuckle down for some CALB cells. 
Speed should be easy to attain. 
60 miles should be attainable as well. 
Not many used AC systems available with inverters on the cheap. 
DC there is plenty but it won't be in my book "cheap" It won't cost you an arm and both legs either. 

If you have your vehicle your well on your way. 
A good motor. A 9" GE motor, 9" Warp Impulse motor, 9" Warp9 would do just fine or an equivalent from a forklift. 
You will need an adaptor and unless you can make your own it will cost you around 8 to 9 hundred bucks. 
Batteries are the most single expense you will have. 
Controller is a must. Not many to pick from that are legal in your neck of the woods. Soliton1 would be good but they are expensive. 
You will need at least a 24kWh pack and yes it will fit in the Bug and not be too heavy. 


Check my youtube channel and blog if you like. 
There are many here that have done VW's and your in good hands. 
Each build is unique and yours will be no different. We all have differing needs. 

Pete


----------



## Eugene (Aug 14, 2014)

Thanks for the reactions. I am now ending a restoration project of a Mini Cooper and looking for a new project. An electric car has always fascinate me and therefore I was looking on the internet and saw a lot of DIY electric cars build, so one and one is two….

First I want to know what exactly what I need, to convert the VW into an electric car that meets my specs. 
Every motor has it’s own specs., but which specs. needs to have my motor? I saw a forklift motor on the internet whit these specs:
dc motor
57 64416-001
756051
900.013.0132
24 volt 67.4 amp
1616 1.5 kw
Can I use this motor? If not can anyone tell me what I need to look for.
What kind of adaptor, charger, controller do I need (specs.)?
What batteries, and how many do I need?
How do I connect everything together?
I need more specific data to be able to look and find the best parts to make my own electric VW.


----------



## lithiumlogic (Aug 24, 2011)

As a long time lurker, I'll make a start with some basic numbers. More experienced voices should be along soon.

Ac and DC are both about 80% efficient. In AC, most of the loss is in the motor controller, so it has a lot of waste heat to remove. Fortunately, there are liquid cooling systems to take care of this. The AC motor itself is very efficient.

DC is opposite. Controller is very efficient and doesn't need much cooling, most of the loss is in the brush/commutator assembly. Unfortunately this is hard to cool. They can put enormous amounts of power down in a drag race, but driving longer distances at motorway speeds can overheat the motor. This might be your biggest problem.

You're in Europe so trucks are limited to 55mph/90km/h yes? This means you can sit in the truck lane and cruise at that speed if you have to drive on the motorway. 55mph/90km/h is about 15 horsepower continuous, or 11.5kw. The beetle has horrible aerodynamics compared to more modern cars, which isn't helping you here. Maybe an underbody shield, and blocking off grills, you can improve that a bit?

The motor you linked appears to be rated for only 1.5kw, continuous. People successfully use forklift motors, but maybe that one is too small? Most conversions use 9inch diameter motors. Apparently you can advance the timing on the brushes and double the voltage, which will increase the power handling a similar amount. Still looks like a bit of a stretch though.

How much battery? Well, if you're using 11.5kw to do 90km/h, then in theory, an 11.5kwh battery can do that for one hour giving you a 90km range. 

http://www.ev-power.eu/Sinopoly-40Ah-300Ah/SP-LFP300AHA-Lithium-Cell-LiFePO4-3-2V-300Ah.html?cur=1

Each of these cells holds 3.3 volts x 300 amp hour = 1kwh of energy, roughly.

15 of those would be a 15kw/h pack , which would get you the range you want with a reasonable safety factor. 15 of those cells in series would be 50 volts, weigh about 150kg and cost just under 4000 euros. A low voltage system like that would not pose any electrocution risk, and the motor should be able to handle it easily. It would be easy to add more cells in series at a later point in fact, and still be well within the lmiits of your controller or motor.

The biggest concern with a 50Volt system is RPM - Warp 9 motors develop max power at about 2000 rpm at 72v, so on 50v it will be at even lower RPM. Does power tail off above max power RPM like with an internal combustion engine, or simply remain constant as torque declines?


----------



## Duncan (Dec 8, 2008)

Hi Eugene
Motor too small!
Read the - using a forklift motor thread - I know its long!

You need about 50Kg of motor

Battery
100Km - you will need ~ 200Watthours/Km - more if faster
100 x 200 = 20,000 = 20Kwhours 
But you can't use all of your charge (will kill the battery)
So 20Kwhrs = 80% - means you need 25Kwhrs

Voltage

The more the merrier - your controller will reduce the voltage to that needed by the motor

But you will need over 100v for 100km/hr
And probably over 140v for 130km/hr


----------



## Moltenmetal (Mar 20, 2014)

For an AC setup, the motor itself may be in the 90-95% efficient range, but the controller will definitely be better than 90% efficient- so that's better than 80% overall efficiency for sure, unless you're also counting the drivetrain losses which again should be less than 5-10% depending on what you have in there. If my Curtis controller were only 90% efficient, it would need way more heatsink than it has. The heat dissipation I computed from the Curtis datasheet for the controller I'm using with my HPEVS AC50 motor is about 240 watts, which is way closer to 1% than it is to 10% of my nominal expected highway speed draw (~100 battery volts, ~200 A = 20 kW. If that controller was expected to dissipate 2 kW to the air via its heatsink, it would fry immediately. I'll be losing more than that 240 W via ohmic resistance in my main pack cables alone.


----------



## lithiumlogic (Aug 24, 2011)

Duncan said:


> Battery
> 100Km - you will need ~ 200Watthours/Km - more if faster
> 100 x 200 = 20,000 = 20Kwhours
> But you can't use all of your charge (will kill the battery)
> So 20Kwhrs = 80% - means you need 25Kwhrs


Not to dispute your numbers, on Tesla Model S blogs etc, 200Watt hr/km is a good figure.

But that produces an estimate almost double what you get from vehicle performance calculators, where you input weight, frontal area, drag coefficient and cruising speed. 

http://www.wallaceracing.com/Calculate HP For Speed.php

using numbers from 

http://www.mayfco.com/dragcd~1.htm

Using a 2000lb weight (850kg stock + 150kg for batteries)
A 0.48 Drag Coefficient
19.37sq ft frontal area

We get 14.37HP to maintain 55mph

1hp = about 0.75kw

So that's 10.77kw, or 10.77kw to go 55miles at 55 mph (theoretically)

So what "padding" factors need to be built in to get a real world result?

1. Motor, Controller, Wiring and Transmission losses - 20%-25%?

2. His range requirement is 100km, not 88km - so another 12.5% there

3. Battery won't give fully rated capacity at near 1C rates - 10%

4. 10% buffer to avoid over discharging cells, since we're BMS free.

On top of that ofc, you're not going to use an EV with a range of exactly 100km to do a 100km journey. If this 100km is not a "goal", but a journey that has to be undertaken several times a year, you need even more padding to allow for headwinds, low temperatures, rain, headlights etc.


----------



## loopylupine (Jan 1, 2014)

Hi Eugene,
I have a recent VW Super Beetle build. My pack is 23KW and cost about 5,000 USD. I found a Warp9 for about $1000 and an older Netgain controller for $900. Motor adapter was I think $800. Cables, instrumentation, etc probably another $2,000.
So, if cheap is about $10,000, then you can do it and have lots of power and about the right range. 
I live in Alaska, and have to go through a 1500 foot elevation change every day. On the flat the bug will only use 200 wh/mile like others say, but really it averages about 350 wh/mile because of the hills, stopping and starting, hauling kids around, and the way I occasionally like to feel the torque... My average is about 2.4 AH/mile according to the trusty JLD404 meter- that's on a nominal 144v pack of 45 160AH Voltronix LIFEPO4 cells.

A great thread is Corbin Dunn's, he details his build nicely, and has a blog about it also.

Cheers and good luck,


----------



## Eugene (Aug 14, 2014)

Thanks a lot guys, this is the information that I was looking for. I already informed about the legislations in my country.....dam that are they strict over here.


----------

