Joined
·
1,472 Posts
Re: Noob Intro: High Schooler, want advice for first conversion (VW Karmann Ghia)
Hi, and welcome!
Confirm that conversion grant- sounds way too good to be true! But if it is, and you get all the rules and meet them, it's a sweet deal!
For someone with modest skills and experience, the EV West kit will be a good start. Presume that would be an HPEVS AC35 or AC50 plus Curtis controller, the latter of which is what I have in my E-Fire Spitfire (you can find my build thread here by finding the car in the Garage). It would rock in a Karman Ghia, assuming it will fit and you keep the transmission.
AC is modestly more efficient than DC and also gives you regenerative braking which can be a 10-15% range boost. They're also durable- no brushes or commutators to damage or wear out. But DC is the king for raw torque and power and is (modestly) less expensive unless you go the home-built kit controller and forklift motor route. Not for the faint of heart, and although Duncan did it, I would not recommend a huge DC motor controller as a first electronics project...
As to batteries: Li-ion are your only real choice. These days, the cheapest option is a used Leaf or Volt pack out of a wrecked car- easy enough to come by in the US. Don't mix and match cells- keep it simple.
You also need a charger, and I strongly recommend a BMS as a basic safety feature. The BMS will warn you if any cell goes low during driving, and will shut off your charger when any cell goes high voltage during charging- that's a critical safety feature. Others can chime in on what BMS options there are for the used Leaf or Volt batteries. You don't need anything fancy- just high and low voltage alarms on each cell or group of cells in parallel.
Prismatic LiFePO4 cells are very DIY friendly, safe and can be reliable, but more than double the cost of a used pack from a wrecked EV.
Forget about the onboard generator or modular battery packs. Just build the range you need for 90% of your trips, put in a J1772 port so you can plug in but ALSO keep a 115 volt plug and a long 12 ga extension cord with you all the time, and get the Plugshare app on your phone. Rent a gas engine car for those few times you need to go on longer roadtrips all in one go with no charge stops along the way.
Size your battery pack based on the range you want x ~250 Wh/mile, then divide by 0.7- you don't want to take your pack below 70% depth of discharge if you want it to last.
Plan on heating your batteries- pet heating pads are often used, with a thermostat- and removable insulation.
You'll need a heater- not sure how the Ghia cabin was heated. Most people here use ceramic space heater elements running off their main battery pack, plus a fan. You need a DC rated contactor to turn the element on and off.
Note that you also need some other goodies: either a small 12V battery and an isolated DC/DC converter or a larger battery and a small dedicated charger. An amp-hour meter to use as your gas gauge is the most critical. Most of the obvious stuff (contactor, fuse, main disconnect, shunt to measure current, transmission mounting plate and motor coupler etc.) are probably already in the EV West kit, but they can add up to a fair bit of money if not.
It's a big project, but a fun one with tons of opportunity for learning- and I'd say that a smart, motivated high schooler could do it, assuming they have a) the budget b) a place to work and c) some mentors to help out and help you keep safe- especially a mechanic and someone who has a good background in electrical.
Don't forget about insurance- talk to some other Colorado converters here to find out what they did and who insures them. It can be a real bear to get insurance in some places- next to impossible where I live, but I managed. Have a quote in hand for insurance before you spend a cent on conversion parts.
Keep a sharp eye here on the Classifieds- a project someone has lost interest in can be a cheap source of parts.
In the meantime, read and learn- and keep asking informed questions!
Best of luck!
Hi, and welcome!
Confirm that conversion grant- sounds way too good to be true! But if it is, and you get all the rules and meet them, it's a sweet deal!
For someone with modest skills and experience, the EV West kit will be a good start. Presume that would be an HPEVS AC35 or AC50 plus Curtis controller, the latter of which is what I have in my E-Fire Spitfire (you can find my build thread here by finding the car in the Garage). It would rock in a Karman Ghia, assuming it will fit and you keep the transmission.
AC is modestly more efficient than DC and also gives you regenerative braking which can be a 10-15% range boost. They're also durable- no brushes or commutators to damage or wear out. But DC is the king for raw torque and power and is (modestly) less expensive unless you go the home-built kit controller and forklift motor route. Not for the faint of heart, and although Duncan did it, I would not recommend a huge DC motor controller as a first electronics project...
As to batteries: Li-ion are your only real choice. These days, the cheapest option is a used Leaf or Volt pack out of a wrecked car- easy enough to come by in the US. Don't mix and match cells- keep it simple.
You also need a charger, and I strongly recommend a BMS as a basic safety feature. The BMS will warn you if any cell goes low during driving, and will shut off your charger when any cell goes high voltage during charging- that's a critical safety feature. Others can chime in on what BMS options there are for the used Leaf or Volt batteries. You don't need anything fancy- just high and low voltage alarms on each cell or group of cells in parallel.
Prismatic LiFePO4 cells are very DIY friendly, safe and can be reliable, but more than double the cost of a used pack from a wrecked EV.
Forget about the onboard generator or modular battery packs. Just build the range you need for 90% of your trips, put in a J1772 port so you can plug in but ALSO keep a 115 volt plug and a long 12 ga extension cord with you all the time, and get the Plugshare app on your phone. Rent a gas engine car for those few times you need to go on longer roadtrips all in one go with no charge stops along the way.
Size your battery pack based on the range you want x ~250 Wh/mile, then divide by 0.7- you don't want to take your pack below 70% depth of discharge if you want it to last.
Plan on heating your batteries- pet heating pads are often used, with a thermostat- and removable insulation.
You'll need a heater- not sure how the Ghia cabin was heated. Most people here use ceramic space heater elements running off their main battery pack, plus a fan. You need a DC rated contactor to turn the element on and off.
Note that you also need some other goodies: either a small 12V battery and an isolated DC/DC converter or a larger battery and a small dedicated charger. An amp-hour meter to use as your gas gauge is the most critical. Most of the obvious stuff (contactor, fuse, main disconnect, shunt to measure current, transmission mounting plate and motor coupler etc.) are probably already in the EV West kit, but they can add up to a fair bit of money if not.
It's a big project, but a fun one with tons of opportunity for learning- and I'd say that a smart, motivated high schooler could do it, assuming they have a) the budget b) a place to work and c) some mentors to help out and help you keep safe- especially a mechanic and someone who has a good background in electrical.
Don't forget about insurance- talk to some other Colorado converters here to find out what they did and who insures them. It can be a real bear to get insurance in some places- next to impossible where I live, but I managed. Have a quote in hand for insurance before you spend a cent on conversion parts.
Keep a sharp eye here on the Classifieds- a project someone has lost interest in can be a cheap source of parts.
In the meantime, read and learn- and keep asking informed questions!
Best of luck!
