DIY plug-in conversion Gen1 Prius

Denis,
Here are the relays and fuses, I hope this helps.

 

I have been trying to complete my service manual, I now have the volume for the 2003 troubleshooting volume and want to get the wiring diagram volume. I have the file in pdf form and can send it to you if you do not have it. It is too large for this site to send but If you email me at [email protected]. I will send it to you.
I realize you cannot send your paper manual - thanks for answering my post.

Roy from Canada

 

oops here is the page that should have been with the first one

 

I have been avoiding comment on this thread up until now but, I have decided to give my two cents. Take it for what its worth. I'm not trying to be a downer or naysayer but, this has been tried numerous times and here's my assessment.

The Prius in general (Plug In excepted) is not a good candidate for "PHEV" conversion unless you use the "Enginer" (now called MD Tech, even that one has its issues and will only net you about 65 mpg max) type of conversion. Here's why:
1) It is designed as a gasoline (primary) car with electric assist. It is for this reason that the electric motors do not have enough power to safely propel the car in many traffic situations. With electric mode only, the car is really underpowered and not safe or comfortable to drive on the streets
2) The Prius has advanced, high-tech monitoring systems (called ECU's) that all work together to make this engineering marvel work. Adding more battery capacity requires modifying what one ECU sees which causes multiple problems with other ECU's.
The old adage that "every time you fix a problem you have to solve another" has major application here. A typical scenario may go like this:
Problem/Fix: The battery runs out or low in "EV/GolfCart" mode, I need a bigger battery (thousands of dollars)
New problem: Adding a bigger battery requires spoofing or/reprogramming the Battery ECU
Fix: Then I will reprogram/spoof the ECU so I can use the bigger battery (hundreds of dollars and lots of time)
New problem: Now that I have this bigger battery and the ECU spoofed, the ICE still wants to come on when I accelerate normally
Fix: I can use OutOfGas mode to stop the ICE from coming on (cheap)
New problem: The stock electric motors/inverter setup are not strong enough to power the car in many situations and... if I want to use the ICE, I have to pull over, turn the car off and then back on to allow the ICE to be used (then you have the above problem of the ICE coming on too much)
Fix: I need to install a larger electric motor (thousands of dollars)
New problem: The inverter cannot power the new motor
Fix: I need a new motor controller/inverter (thousands of dollars)
New problem: I've spent so much money on converting my Prius that there is no return on investment and I can't sell it b/c no one wants a car that's had this many mods
Fix: I need to take every mod off and return the car to its original state (thousands of dollars)

It reminds me of a story I heard in grade school where a king had mice in his castle and wanted to get rid of them. So... he brought in cats then, he had too many cats so... he brought in dogs. This continued until he brought in elephants. Having too many elephants, the only thing he could think of to get rid of the elephants was mice. He brought back the mice, the elephants left and he lived happily ever after

There are other numerous reasons why the Prius shouldn't be converted unless you're going to gut the HSD and add an electric drive system that can handle the requirements. The stock Prius electrical system is not designed to operate independent of the ICE. It needs the gas engine and the gas engine needs the electrical system. They have a symbiotic relationship, no amount of batteries can change that.

 

I know that the gen 1 is not the most desirable candidate for ev only mode, and that it has limitations. It must be the challenge that is the fun part. With that said, I think just controlling the brake line will keep the gas motor of, and let the car drive on battery only. I get in stop and go traffic that just is crazy trying to feather the gas pedal to keep the gas engine from starting. It would be nice to just have it off for those periods, I am just crawling on the roadway.

 

Its not only the Gen I, all Gen's are undesirable candidates for EV only mode. They are all designed the same with very few differences.

I'm not sure if I see how controlling the brake line will keep the gas motor off? Can you expound on that?

Additionally, keeping the ICE off as you state will ultimately result in the ICE coming on to charge the battery (resulting in decreased mpg).

 

Well I think that when you put the brakes on the ICE turns off most of the time, and would turn itself back on when needed. As like when you are stopped at a traffic light. I'm wondering if the Gen 1 has an OOG mode? Maybe that is the way to go?

 

The Gen I has an OOG mode but its def not the way to go. When OOG mode is tripped (usually by removing the fuel pump fuse), all kinds of codes will come up. Then you will be able to drive for a while on battery (albeit at a very slow acceleration and limited max speed of 52 mph). I highly discourage you from proceeding with this conversion. Unless you like wasting money and time, then I highly encourage you to proceed.

 

Well I don't want to pull the fuel pump fuse, to try this out. I just want to go in golf cart mode around 25mph. Would the engine try to start with the fuel pump fuse pulled?

 

No, it will not. Once the ECU recognizes a lack of flow/pressure in the fuel line, it will not attempt to start the ICE.

How far do you want to go in golf cart mode? And... How much are willing to pay for this capability?

 

What do mean by “I wanted to drive a car in EV mode, but the car ICE won't start.”? If you want to drive in EV mode ICE shouldn’t start? How do you even get it to EV mode, stopping the fuel pump? Doesn’t that cause fault code?

I would think that powering the high voltage line might cause high voltage contactor (relay) fault code. Do you have fault light? Did you read fault codes?

 

You can just try disconnecting 12V battery for some time to see if that clears the codes and gets it to work. But Mini-VCI is so cheap that you should just get one.

 

The Mini-VCI is less than $20 on ebay.

 

Are you running the power wire to Power Inverter without fuse? How about those wires to HV-battery?

 

So when are you going to start selling them?