Update on battery blower control board - Wanting to include the kitchen sink

I've spent the last week learning about the Prius and I find this car really interesting. There's so much tinkering that you can do and I've found myself staying up until 1 or 2am searching for information when I have to get up at 4:15am for work. That's catching up with me now.

I think I have a solution for an almost plug and play control board. The user would not have to cut or splice ANY OEM wires. Not including the removal of parts to gain access to the blower motor, the installation could be done in about five minutes. I'll know for sure in the next few days.

This control board led to other investigations. I decided to write a USB to PC program for controlling the battery blower board while also monitoring other things on the car. It's not complete yet but it looks like this:



I also created an LCD version that looks like the picture below. (Don't mind the keypad or black goop around the LCD screen. It's a generic box that I use for prototyping.) I haven't decided what values will be on the main screen yet but I'll make it be able to scroll through different pages to access information.

Here is a picture of something that about 99% of people will find useless but I found it interesting. I mounted the USB transceiver on a wireless board and can communicate with the Prius up to about 1500 feet away, depending upon obstructions. I tested it this week in straight line distance and I was able to achieve about 1800 feet. Again, useless for most people but I had a lot of fun creating it. Here is a picture of the USB wireless transceiver (Sorry I have crap pics. When everything is completed I'll take better ones):

So all of this playing around with different signals has peaked my interest with CAN. Writing the USB stuff was hard enough so I'm sure the CAN won't be easy for me. My thought is, if I have the availability to use a computer to display information, why waste it!? In addition, why make the installation harder by splicing into components like the temperature sensors when they are available on the CAN?

This led to two more thoughts. When I was researching this, I found that there are many people who have similar systems so why attempt to reinvent the wheel? Not only that, why spend a ton of time on it when the market won't support any sales? I supposed if there's enough interest I would go ahead and complete the project. Perhaps I may do it for my own interest - not sure yet.

Anyhow, here is what I have so far. Keep in mind this isn't the final document but where my thoughts are going:
The only board that's available right now is the standalone version without the LCD screen. If the plug and play version works out like I want it to, that would be available starting next week. Again, when I first started this, it was to make something useful out of production circuit boards that my buyer backed out on. That focus was on the battery blower and running the blower for a specified amount of time when the car is on OR off. I've accomplished that and it works perfectly. I like challenges and the CAN is definitely a challenge.

That's all for now. I need some sleep....

 

I did some testing over the weekend and had one very clear thought. Only a small percentage of people would be willing to or have the knowledge to tap into all of the sensors needed for any type of meaningful display. I think I've come to the decision to make two types of boards.

1. A simple "no cut/splice" method of controlling the battery blower fan. This will allow the user to operate the fan at any speed desired, for any amount of time desired. There are two main benefits to installing this board.

1. 1. You don't have to cut (splicing as well) any OEM wires.
   2. Once the right, rear panel is removed (the one covering the blower), installation of the board should take less than five minutes. The hardest part, which isn't that hard, will be running a momentary push button to the front so the board can be operated.
      1. I should mention that the user doesn't even have to use a button and I've designed it to use the buttons on the steering wheel. With this method you would have to splice into the wiring though but it would be stealth and OEMish.

2. A complete CAN transceiver board that polls and controls CAN communication. It will use USB to laptop as a form of communication, but you can also use an LCD screen if you wish. I have some other ideas that I will explore but I want to do this right and it's probably best that I just take all of the information from the sensors off of the CAN. Tapping into all of the sensors would take too long.

I have some other cool ideas that I want to try. Not sure if they will work but I'm going to at least try. I've ordered the parts so I'm going to start this weekend.

As for the simple "no cut/splice" board that controls the battery blower, that will be ready to sell next week if anyone is interested.

 

This isn't a yes or no question as there are a few layers to it. The first question is, which board are you referring to? I'll answer one at a time.

If you are asking about the simple board (no CAN) then yes, I can have the OEM battery control software take over or I could have my board compare its own output to the request on the CAN and take the higher of the two. This is easily done.

If you are talking about the more complex board, I'm not sure I can factually answer it. Keep in mind that I have zero experience with the CAN network but I'll give my opinion. I know others on here would be able to provide a more factual information than me.

I'm assuming that the battery ECU is the main ECU to control the fan. We know that other devices (Scangauge is one of them) can put a request to force the fan on and it works. So even though the battery ECU may be requesting level 2, you can force level 6 with the Scangauge. I have not tried this in reverse (SC request of 2 and battery ECU request of 6) but I'll see if I can try it out. My guess is that someone has the answer already.

So I can't fully answer your question about overriding the OEM battery fan control if an external device is requesting a level lower than the battery ECU request. However, this is something I could test and get back to you on. If there are any more questions, let me know and I can put them into a spreadsheet and provide answers to them as I go along.