DIY plugin prius

There is a big flaw in the argument. "Cal Cars spent 5 years coming up with a plugin design, so why bother trying to improve it".

It is kind of like saying. "everything worth inventing has already been invented"

Or like saying "people smarter than you have tried and failed, so you might as well give up"

Or how about, "I know more about the Prius than you, and I don't think it will work, so dont waste your time"

Also, so what if someone else has done what he wanted to do. That is what hobbies are for.

I say forge ahead with your idea. It might work, it might not, but you will have fun and learn something.

 

I completely agree. My plan is to do a cal-cars conversion, then start working on an improved version such that by the time my lead acid pack wears out (1-2 yrs hopefully) I am ready to upgrade. I figure I will learn a lot from doing the conversion by a recipe that is already known to work, and have the benefit of having a phev to drive the whole time I'm working on improvements. Since this is an all volunteer, open source project, my attitude is why not get the benefit of the huge amount of learning and experimentation that has already occurred, and then try to help move the collective learning forward. In no way did I intend to imply that there's no point in trying to improve upon the design. Just that there isn't much point in trying things others already have tried and proved don't work

Given that there is a high probability that this project could kill you (by electrocution, plasma fire, or unsecured 300 lbs of lead flying around the passenger compartment) or blow up very expensive parts of your primary mode of transportation I'm inclined to take a fairly conservative approach on this project. There is also a lot of concern about the negative publicity that will be generated for phevs and bevs when Bubba (no offense to anyone on the list named Bubba) puts 20 old starter batteries in the back seat then gets in a wreck and blows himself up in a ball of plasma, hydrogen gas and vaporized sulfuric acid.

Rob

 

Actually, I think there would be a lot of people who would pay to see that happen...

I also asked about losses in this proposed system. I can't read German, but I don't see the numbers there that he's wanting to use (namely 230vac to 230vdc conversion), nor am I 100% sure that's even possible.

But I am only an electronics mechanic, so what am I supposed to know about engineering?

 

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Keep in mind its probably more like 2x that, or 260Ah due to Peukert Effect of lead battery.

Peukert's law - Wikipedia, the free encyclopedia

Also, again if you don't get above 242V, the HV battery controller won't let you use any of the extra battery " The 2004 - 2006 Prius begins to Drift at approximately 242v."

State Of Charge Drift - EAA-PHEV

IMHO, you are going through a lot of trouble to go from ~1 mile to ~2 miles of EV range. But whatever floats your boat I guess

Rob

 

Most of them on the payroll of GM or Texaco no doubt

Rob

 

you really need to make a "smart charger" able to sense when floating voltage goes above the standard, you wouldnt want to blow up the battery. I believe julian edgar did from autospeed.au.

i have a charger all it needs is a controller to keep it at 200 volts or 273 for old prius

 

As a general strategy this is probably good, but there are going to be some challenges:

1) The main HV controller monitors both current in/out of the battery and current in/out of the motors. If they are not exactly equal the controller throws an error code and disables the entire hybrid system. This is done to protect against a short circuit in the system, basically its like a GFI outlet.

2) In order for the HV controller to decide to use more electric drive, the battery controller needs to be telling it the SOC is ~74%. If its lower than that, the car will just use the normal ratio of gas/electric and you really won't get much of any improvement in mpg. If its much higher than that, the car will start running the engine more to run the battery down and mpg will get worse.

3) If you force EV mode (to get around problem 2), current draw will probably be in the ~100A kind of range. At 2kW, you will be sourcing <10A, so you will extend EV range by <10% over stock. This is because the OEM battery will still be sourcing 90+ amps, and the battery controller will drop SOC based on amps*time even if the voltage is being propped up by the extra battery (which I'm not sure it would be). If your converter acts as a constant current source limited to 10A, it will allow the voltage to fall with the oem battery. If it acts as a constant voltage source, it will quickly need >10A to keep its voltage up. This will cause the converter to overload and either shut down or burn out. You might get around this with a carefully sized current limiting resistor, but then you are losing efficiency heating the resistor.

Rob

 

be very careful use a low amp charging rate or you risk overheating the battery

 

This is just my personal opinion...
I don't know how much you know about PbA battery chemical, NiMH battery chemical, electric/electronics circuit and others...
However, my bet is you'll need more than three years and more than US$5k to finish your project, and a good car manufacturer, like Toyota, will introduce a plug-in hybrid by then with less than US$5k premium.

Ken@Japan

 

Looking forward to hearing a good news of you in three years.

Ken@Japan