Scangauge II mounting location and battery fan modification PCB

I did a lot of work today but it looks like the work has paid off. There were two things I wanted to do. Mount my scangauge in a location that I can reach, is out of the way and someplace where it looks good. I hate when I can see any wires so that was important to me as well. I also wanted to permanently install the PCB for the battery blower fan. I talked about it here:

High Voltage Battery Blower Modification - "Plug and Play" module | PriusChat

I first started with the PCB. I decided to mount it inside the storage area of the trunk. I drilled a hole through the plastic storage holder and ran the wires to the battery, the battery fan and to the front console. The finished mounting looks like this:

Here is another view:


It's out of the way here but I need to be aware if I do put something in this area. I rarely use it but I may add a hard plastic cover over the PCB in the future. My work in the back of the car is done so I moved to the front to complete this install and mount the scangauge, which I will show first.

The radio on the Prius is so damn big but it's useless. Toyota could have added a screen on the radio for something, anything, but it's just a PCB behind the plastic cover and could have been condensed much smaller. I disassembled the dash (Yes, I use the passenger area as a garbage can):

I took apart the radio hoping to find what I thought was behind that mammoth plastic piece. I lucked out and it was what I expected - A PCB for the buttons and knobs and a wide open area beneath the actual electronics. I first drilled a 1/2" hole (just big enough for the scangauge cable) into the front of the radio:

Then I had to disassemble the plastic cover from the actual faceplate. If you drill into it and you don't take them apart there will be debris inbetween the two pieces that is very noticeable and looks bad. The two pieces are glued together but also held together with four small screws. Here is the faceplate with the plastic cover removed and a 1/2" drilled (you can see the glue around the outer edge):

There is little clearance behind the faceplate and the PCB. When I first tried to run the cable inbetween the faceplate and the PCB, it didn't work so well and there was a gap between the user buttons and the PCB, which means the buttons are useless. I took everything back apart and started cutting a path for the wire to follow. This was the best route to use:

When I installed the PCB back onto the faceplate, the end of the scangauge wire does push on the PCB slightly but nothing that I would consider an issue. There is just enough room and it's almost a perfect fit. From the outside you can't see anything but I know it's there. Here are the two pieces assembled and ready to mate:

I put those two pieces together and they mate perfectly. There are no bulges or any issues with the radio. I installed the radio back into the car and put everything back together. I mounted the scangauge with 3M plastic velcro (the type that EZ Pass uses). It snaps right on and it's easy to remove as well. It looks great! I may get a small visor for the scangauge for glare and heat but it'll do for now.

The only thing left were the wires for the battery fan button and the LED. Those were a piece of cake and I decided to use the area where I put my EV button. The EV button is in that specific location because that's exactly where my right forefinger stays when I drive. Putting the car into EV is second nature and there are many circumstances where I use it (that's another discussion within itself).

The battery fan button won't be used as often so putting it in the cup holder area wasn't a concern. To take an extra second to look and push the button is not an issue. The two plastic pieces over the cup holders have no obstructions when closing since the button and LED are small.

I programmed my PCB for three things.

1. I can push the button and start the battery fan. In this mode, which is the "ON" mode, I still included a timer. I have to think that I'd hear the fan when exiting the vehicle but if not I don't want the battery fan to drain my battery. It's similar to the way your rear defroster works. Once it times out you can push it again. In this mode, the LED is steady on.

2. I can push and hold the button to enter the timer mode. This will allow the battery fan to run for three minutes after I leave the car. In this mode, the LED is blinking at 250 mS. I'm still not sure if this is enough time but I'll do more testing over the summer. I modified the software so I can use the button to increase or decrease the timer. I'm lazy and don't like dragging my laptop and programmer to the car.

3. In either mode the fan can be shut off by simply pressing the button.

Simple but very effective. Since I put it in the car, I don't see the high battery temps anymore. If you don't have a scangauge you don't realize how hot the battery actually gets. I wonder how much damage I did last summer. Two weeks ago I parked my car and my battery temp was 105. I came back about two hours later and the temp was 125. The windows were open but the temperature will still rise.

Anyhow, here is a picture of the final installation:

Hope you guys enjoy!

 

Yup. If you read my other post, I have about 200 production boards from a project that the buyer backed out on and now I'm stuck. I reworked it, which takes longer than I'd like, but maybe I can breakeven on the parts......I hope.

I'd say $25 (shipping not included) is reasonable with custom programming. I'm only selling the board with the screw down terminal blocks. Just let me know what you want the board to do and we can go from there. ​

 

I uploaded some videos on YouTube.

John Smith - YouTube

 

The board should work for any Gen II Prius. It may work for a Gen I or Gen III but I would need the schematics and a car to test on. I could probably search the internet and find out but I haven't done that.

When you are ready to order, send an E-mail to [email protected] and let me know what you are looking for as far as what you want the board to do.

P.S. - Enough with the comments about Jersey! And no, I don't have a blowout, a dark tan or wear a ton of gold

 

I added another mode today. I call it "heat extraction mode." When set, the fan will come on for 30 seconds once every hour for a total of eight hours (or whatever the user selects). I tested it yesterday and it actually cools the car down a little bit too. I have no clue if this will keep the battery cool on a really hot day but it's something I'm going to test over the summer.