Hey, I’m seriously thinking of doing a Subaru whose engine went at 150k to a series diesel hybrid.
I’m totally hung up on the charging/controller aspect of this. I bought plans from Mother Earth where a guy did this in the 1970s with a DC starter and generator from an aircraft. Lots changed since then.
My question, if you have a second is I’d like to stick to maybe 48 volts of batteries for running around town or for when the generator failed to start and run it as a diesel electric on the highway or on longer trips.
I’m baffled as to what type of a controller to use and wondering if the batteries could be charged by the generator and used for situations like higher speeds, passing or mountainous terrain.
It is certainly possible, but its practicality is limited by what type of driving you do and which hybrid configuration you mean. The amps required at 48 volts to power up a hill at 70mph would be enormous, over 1000A quite likely. In this configuartion a series hybrid would hardly be practical. The combined losses of generation, switching losses in a controller, and resistance losses in the motor rob much of the engines output. If you spend a significant portion of your useage at speed or under extreme demands like hill climbing, then a parallel hybrid configuration with the diesel engine working together with an electric motor to drive the wheels is much more practical. If your subaru is AWD you have a unique option; You could keep a diesel under the hood driving the front wheels through a standard transmission while simultaneously driving the rear wheels with an electric motor. This means you could take the engine out of the loop for short trips, low speed usage, there would be no need the idle the engine at a stoplight or when stuck in construction and rely on the rear mounted motor instead. If it were an AC, PM, or BLDC motor you could have regen breaking too, lowering maintenance for the conventional brakes while improving your efficiency.
I would probably stick a pair of high-powered PM motors like the Etek, Perm, or Agni coupled to the rear differential. These would each by controlled by a regen capable controller, Kelly makes the only one available right now. Though I think you can get a Sevcon MilliPaq for 48v that does regen. The controller would be fed by a pack of high-power LiFePO4 batteries that can charge and dischange quickly to take maximum advantage of regen; Probably A123 cells or Headway 10ah cells. The pack size would depend on your needs, the amount of electric use versus engine. The minimum would be 50ah for any practical range at lower voltages. A 50ah * 72 volt system yields 2.88kw of usable energy to 80% dod. At 250wh/mile that is about 12 miles of range. A pack that size would only weigh about 100 lbs, and a pair of PM motors around 50lbs.
If you’re married to the series hybrid configuration then you’d need to go much higher voltage, 144v or more. >300v for a AC setup with higher efficiencies (and higher price tag).
Wow, I really appreciate the reply. I will be on Google researching all of what you have written. How long have you been doing this and what books have you read or where did you get so much knowledge? Most impressed!
I like the idea of putting the electric motor(s) in the rear.
Just to clarify, I didn’t explain what I was trying to well. I live 1800 feet above the valley. The roads at their steepest grade are 10 degrees. Our travel is usually 15 miles down hill. Coming home we go 15 miles of which, about 7 is uphill. Speeds at 65 mile per hour for 5 miles up that hill. The 45 miles per hour for 2 miles, slight incline.
What I was thinking, and I don’t know if it was feasible was using a WarP 11 motor (or something you’d recommend) http://www.evsource.com/tls_warp11.php with a diesel motor spinning directly a DC generator that would put out 150-160 volts.
For getting down the mountain and around town I was thinking of a 48 volt battery system. Coming home, going on our 180 mile twice a week trek we’d fire up the diesel, power the generator and the controller and the motor.
My problem is absolute utter ignorance. The EV book I got from Amazon deals with pure EV’s. This is about the first blog I found after a week on Google that shows someone who has done a hybrid in series.
I’m really curious if I could get the batteries to work when the generator is working for the hills, passing etc. And if so could the generator charge them when coasting or going down grades?
Any ideas about chargers and controllers for such an application would be super. I’m an ex airline captain so I have some electrical/system understanding, and I wired our house. Other than that I’m in the dark.
Other days we need to go 180 miles or on a 350 mile vacation.