Februar 2007 von EV America
Horsepower
1. Electric motors are rated at their point of maximum efficiency; they may be capable of 2-4 times their continuous rating but only for a few minutes (acceleration or hill climbing). Internal combustion engines are rated at the peak hp. For example, the FB1-4001A motor is rated as 30 hp continuous at 144V and 100 hp peak. The 5 minute rating of the FB1-4001A motor is 48 hp.
2. 6-8 hp is required for each 1000 lbs of vehicle weight after conversion. This is the continuous rating of the motor. So a 3000 lb conversion requires a motor that is rated at approximately 20 hp. More hp is required for higher speeds, heavier vehicles, and steeper terrains.
3. The available horsepower of a motor increases with voltage; for example, the FB1-4001A motor is rated at 18 hp continuous at 72V but is rated at 30 hp continuous at 144V. As the voltage is increased the rpm increases. Hp is a function of rpm x torque.
4. Although electric motors are rated as “continuous”, the motor can run at less hp. If only 10 hp is required for the speed then the motor runs at that reduced load. This is the function of the motor controller.
5. Operating continuously above the rated hp will eventually overheat and damage the motor. A motor that is rated at 150 amps can run at 300 amps for a short time (minutes), but longer periods can easily damage the motor. Do not buy an undersize motor for your vehicle for your application – it will not last long. Current is what overheats components.
6. Highway speeds require greater hp. The hp required at 70 mph is 4 times the hp required at 35 mph. That means the current required is 4 times also; which means less range.
November 2006 von Mike Hoskinson
Hello Josef
Greetings from the Frozen North. Sorry about the gghc server, which is no longer available to me. I do have some pictures but not with me today. I will try to answer some of your questions.
With respect to battery placement, I am in the process of changing this. Originally I had 4 batteries in the front instead of a spare tire, and 12 in the back in the gas tank compartment and in the trunk, with 2 in front of the back seat. Unfortunately, the batteries were too tall to allow me to have a back seat; I covered the batteries with a carpeted plywood platform and that is where the dogs rode (I have 2 dogs, a poodle and a Bernese Mountain dog). The new arrangement, which I am working on, has batteries in the gas tank compartment and in a row from back to front between the front seats. The original seats were too wide to allow for this arrangement, so I have replaced them with some Audi seats. I have not quite finished the mounting arrangement for the new seats, and I will also have to do some other interior work like carpets and door panels. In the engine compartment, I installed a small generator as a range extender. I have since changed my mind about that and am planning to take out the generator and install some lithium-ion batteries which should give me greater range without the stinky gasoline engine.
My Citroen is the ID model with manual transmission. This reduces the complexity of the conversion to electric compared to the hydraulic-shifting version. I have a 1.5HP treadmill motor with a pulley arrangement to drive the original hydraulic pump. The motor runs from pack voltage (96 volts). I control it with a pressure switch that was custom-made for me. The switch turns the pump motor on and off to keep the hydraulic pressure in a reasonable range. I use the original hydraulic accummulator/regulator as "safety valve" in case the motor does not shut off. If that happens, the accummulator/regulator will bypass the pump output directly to the reservoir in the usual manner. In other words, the hydraulic system is unchanged from stock except that the pump is turned by a small electric motor.
I do have another Citroen, an ID Break, but have not converted it. It is in need of a little body work but mechanically it is sound. I have no plans to convert another DS. "If I had it to do over again", as they say, I would convert a lighter car with a simpler suspension and not have to worry about hydraulic leaks, etc. Having said that, whenever I power up the "D" and drive away with it I get a big grin on my face because it has such a beautiful ride quality.
I do not drive the "D" in the winter because of the sand and salt that is used on the roads. I have driven it only about 5000 km total.
There was a problem with one of the original batteries and it took me a long time to get around to making it work again. Which is to say, I had many pressures of work and other issues that kept me from working on it until recently, and now that winter has come there will be further delays before I get her finished completely. I have another electric vehicle, a small pickup truck, that I drive in the winter. I have recently converted it to run on 96 volts like the Citroen and plan to share some or all of the batteries between the two vehicles.
With its 96 volt system the acceleration performance is about the same as with the original gas engine, which is to say slow. It can go 105km/hr without straining the batteries too much. The range with the original batteries was about 45km of combined city/highway use. This was limited by the capacity of the flooded lead-acid batteries, of course. The new sealed batteries that I have now will likely get a little less range than that, but they should allow better acceleration.
Regarding cooling, the motor has a fan built into it. This is the only cooling required. There is also a fan on the motor controller, which requires some air flow to keep it cool.
In the end, the Citroen is more of a hobby car than a daily driver.
This is mainly because I have not yet got it "just right" in terms of the hydraulics (it occasionally leaks, and the fitting that I made for the pressure switch has an annoying leak). Also, I was not happy with the original battery pack. Next spring I hope to have that problem sorted out.
Mike
