TXT w/ Pi4 8g and Racks

[Imapled]

Hi All,

Per request from CGTech here is some info on my layout for my build off cart which I lovingly call "Nux".

General info about the cart:

- It was originally a 1995 Medalist DCS (TXT).

- I removed all the original wiring, harness, charge port, etc...

- I installed a TXT48 (625805) harness and swapped out the speed sensor plug, ITS plug and other ones to Deustch plugs to adapt to new motor speed sensor, different style Molex on the ITS etc...

- I used a Club Car President F/N/R switch and housing to replace the old throw switch. I put it right where the original F/R switch was. (5$ for the housing and 11$ for the switch.)

- The motor on this cart is a 72v Shunt AMD EQ7-4003 double brushed monster motor.

- Ugly custom built rear battery rack that is frame mounted. The cart has 9x8v batteries in it. (I can't weld. So it is Lego assembled but solid. Maybe too solid.)

- The controller is a Navitas TSX3.0 600amp 72v DC controller. This is not the standard 36/48 that most people have. It is a special model, that they do retail but, you have to make sure you request the 72v version. OTS and TXT48 harness adapter.

- Delta-Q QuiQ Icon 912-7254 Charger w/ 72v to 12v 30a buck converter built in.

- Lots of fuses, wires, components, 12v to 5v buck converters to run these components etc... to support the install of a Raspberry PI4 8g that runs OpenAuto PRO to provide a Android Auto capable head unit. 7" touch screen up front.

- Working on a custom lead-acid battery monitoring system that is composed of 2x ESP32 microcontrollers that are connected via an I2C bus to 9x Arduino Nanos all on a custom PCB. (More details in reply to this initial post.)

- Custom racks to hold all that nonsense together in the cart. :)

I will focus mostly on the last three points. All the other stuff is just context and probably already covered off in detail in other threads on this site.

Cheers,
Impaled

[Imapled]

On the driver side:

1. Onboard charger
2. Power layer
3. Battery Monitoring System (Still in development)

This side needed 2 additional layers to house the fuse box that the main 12v 30a from the buck converter and a layer to house the lead acid BMS that I am building.

On the bottom I put the Delta-Q QuiC 72v charger, middle the fuse box and wiring for accessories.

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This is the first rough in of my idea. I decided to use 4x 1/2" threaded rods to hold the racks. This would allow me to move the layers up and down and add more if needed. Nuts lock washers etc... are used to float the layers.

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A more completed view of what the layers described above would look like. I just used diamond plate (aluminum) that I had and flipped them. Aluminum is great for heat management etc. It is also easy to cut in your garage and smooth out the edges on. (I am a hobby home builder with crappy tools.)

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Noticing all the cooling blades and the lack of room for the charger I decided to mount some fans under the second layer to put over each of the cooling blades on the charger. I put them on a switch on the top plate so I can run them when I plug in the charger. When I get time I will put a thermal sensor on the charger so they can activate when they get hot etc... For now turning on a manual switch is fine. :P

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This is a rough in body so mind the ugly colour, scratches, etc... I have a nice body that once I figure out all these cuts on that I will do properly. This is something that I am not fond of... fans and holes that will take in dirt. I have covers for them but, I may put a better more weather resistant setup on this. For now I am moving all the air out of the bay when the cart is charging. It is way overkill but, as JohnnyB would say... "Overkill is underrated."

I sealed up the entire bay with aluminum flashing and other stuff. If anyone is interested let me know and I can make a new thread about what I did. Its way overkill but, I use this cart for ice fishing in the winter and it mostly only see's trails. (No pavement princess for sure.) So, when the batteries charge I wanted to get any off gases out of the bay as they will surely collect. This works and if you have wet hands dries them quite fast too!

More to follow...

[Imapled]

The middle layer is where I put all the 12v stuff into. This next picture is unfortunately in an incomplete state but, gives you the idea of what I am doing.

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The 12v 30a comes into that fuse box and all the accessories, lights, under lights, etc go there. As well as the main 12v that goes to the dash to a switch and then back to the passenger side where the PI4 8g unit is to run the 7" touch screen and all the accessories for it.

I had to place the threaded bolts where they lie because well, I couldn't put them through the charger. :) It provided a bunch of space for what I needed. On the other side I pushed them out to the corners as I didn't have to deal with a big charger on that side.

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This is the empty top plate. There is more stuff on it but, this is the best picture I had of it. What you see is a USB charge port and its switch. I put this there because I will use it to charge the sound bar that I will eventually put on and for any other USB charge component. Also (not shown) I have the switch for the cooling fans (above) and a black light setup that is under the seat that lights up all the fun stuff under the seat. (Pictures in a later reply.)

What is going to go on this is the BMS... Next reply will have that detail.

[Imapled]

The Lead Acid BMS:

My good friend and I are currently working on it so here are some prototype photos of the PCB and some of the microcontrollers that we are using to do some core functions:

1. Relays to control the T/R switch, key switch and other switched components.

- The main microcontroller is an ESP32. On an ESP32 you get bluetooth and wifi. Its an incredibly powerful microcomputer.

- All of the sensor data and controls are controlled by RESTful web-services that the Raspberry Pi4 uses to gather the data and display it and control the relays and other stuff. We are piping the speed sensor, F/R, and any other element we can of the harness through it as well.

- On the head unit will be a custom web-app in IONIC that will hit the web-services and provide a nice fun UI for everything.

- The entire BMS design, pcb, software (both for the microcontrollers and UI) will be released under a BSD or Apache2 license and posted to GitHub once done.

The Design Concept:

There are two ESP32s... One ESP32 is connected via an I2C bus to 9 Arduino Nanos. There are 9 lead acid batteries in the setup at 8v to make up 72v total operating power. One thing I learned the hard way is that when you have a high-amp draw that battery posts like to melt. I also learned that pushing a cart filled with lead acid batteries through the bush up steep inclines sucks. So I wanted to attempt to solve for this problem in some way.

So, we are putting thermal sensors on each battery post and any other thing that can heat up and cause a failure. So, that is why there are 9 Nanos.

Each Nano is responsible for a battery monitoring. They monitor:

1. Thermal on the - and + post.
2. Voltage of the individual battery.
3. Providing this information to the ESP32 in near-real-time requests when asked by the ESP32.

The head unit will have a fun pic of the battery layout and ask for this data on a regular basis and if they go out of bounds to the thermal range will alert the driver immediately. As we have the throttle sensor wire we could even cut the voltage on it to put the cart in limp mode too if wanted. Lots of things can be done now that we have most of the harness flowing through.

8.JPG

This is the main ESP32 (on the end) and 9x Nanos mounted to risers on the PCB. We did this because if a Nano or ESP32 bites the bullet we can simply pull it out, program another one and drop it into it. The design is highly modular for serviceability and programmability purposes.

9.JPG

Better shot of the modularity of the hardware components.

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Operating... Red lights all show the I2C bus activity. In this photo its just sending acknowledgements via wifi to a web-app from each nano on the I2C bus. No sensors are hooked up to the Nanos.

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Bottom side of the prototype PCB. We will eventually put everything into Fritzing or Eagle and have proper PCBs printed so we have minimal soldering to do.

I have to take some photos of the wire harness and sensor hookup. Still working on them at the moment.

[Imapled]

Motor Controller and PI4 8g:

On the passenger side where the mounting blade on a TXT is I decided to remove it and recapture all the lost space to that setup so I could put a PI4. I needed a touch screen on the cart because (a) for the app that shows the BMS data and (b) overkill is underrated. :)

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This is what one of the plane Jane plates look like. This is the one that I am mounting the Navitas TSX3.0 72v 600amp controller and solenoid on to.

13.jpg

As overkill is underrated I mounted a PC CPU cooling blade under where the controller would be. Not necessary as on a CC install the TSX3.0 controller doesn't mount on a blade like in a TXT and they don't heat up. In fact, the TSX3.0 doesn't heat up much at all. I have opened one up and the design (being a computer nerd) I am stunned at the quality of components that they use in them and the board level design and layout.

I did hit this with a heat gun and thermal sensors. Amazingly the CPU cooler pulls heat from the area which I wasn't expecting. I thought it would be totally vanity thing to do. The plate and cooling fin equalize (same temp) at a temperature well beyond the operating temp of the controller. As well, the controller has a thermal sensor in it and will shut down before anything bad happens. I suspect it will provide an additional 9% better cooling on versus off but, my knowledge of thermal dynamics is horrible so I may be calculating it all wrong.

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Rough in view of the controller and solenoid mounted to the plate without all the noise (wiring) around it. I mounted the plate right to the frame and put holes through it for the threaded bolts that hold up the PI4.

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Top view of it wired up. Yes, that is an extra 3rd wire for a AC setup. What I realized is that this setup is "somewhat" modular as well. I can pull the plates and swap out a Navitas TAC2 600amp AC controller and solenoid setup or an ASI Oak setup, or a SME or even another DC setup like an Alltrax. So I ran the additional motor wire for that eventuality.

Another side view of this setup in the next reply...

[Imapled]

16.jpg

More detailed side view of the controller setup that provides more detailed view.

I put the skull on the controller to "make it look mean". :)

Now on to the fun!

Raspberry PI4 8g Running Bluewave Studio's OpenAuto PRO

More on OpenAuto PRO software can be found here:
https://bluewavestudio.io/index.php/...uto-pro-detail

Why put a PI4 on a cart? Why not? Many people mount their phones on carts these days. Many use their phones to connect to bluetooth speakers. Android has an awesome Auto platform for mirroring and using apps for cars. Why not have that on my cart?

In addition, why not have a full computer to do it that can emulate SNES and a multitude of other game systems, play movies, run custom apps, etc? (Yes I have run Jump Man Jr. from the Commodore 64 on the head unit and some other classic games from my childhood just cause... :P)

What I used:

- Raspeberry PI4 8g
- 64 gig of storage chip
- USB-C PD Charger for powering the PI4 (inside the box that houses the PI4)
- Another fuse box for all the components that need to be hooked up to the PI4
- USB-C PD Charger in the glove box for powering the USB 3.0 hub in the driver side passenger glove box.
- 12v to 5v 3a buck converters (2x of them) for powering the BMS
- Project box to house it all
- 7" touch screen that is also powered off the USB charger in the glove box.

Each individually powered component has its own proper fuse in the box. The whole fuse box is controlled by a power switch on the dash. That way you can turn the BMS, PI, Screen, etc all on one switch. I did not use the main buck converter switch wire to do this as it doesn't operate in the 72v range that the key switch now operates on. Which I found odd but, I think this charger is used in mostly EV setups that have different power setups.

16.jpg

This is a rough view of the PI4 in the project box. You can see the USB charge port that powers the PI4, the USB3.0 cable that goes to the USB HUB and the HDMI cable that goes to the touch screen. I also put the PI4 in an overkill cooling case as well.

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This is the completed setup of the PI4. I tried my best to label all the components so hopefully it provides a "good enough" view into what I did. If not, feel free to ask questions.

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This is a view of the wiring that it takes. You need to be patient with the wiring and take your time. I am obsessive with wiring and wrap and tape everything. I also label each wire at each end and every 2 feet so I know what it is in case I need to pull it for any reason. All of the cables you see here run through the standard runs on a TXT. You just have to be patient and run the big bulky ends through first (like HDMI and USB) first and then the smaller power wires in the left over space.

Continued...

[Imapled]

20.jpg

This is what the wire runs look like on both sides of the cart up to the dash. They will fit just takes time.

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I don't have a better photo of the cleaned up front dash of my wiring. This is a bit of a mess and I spent a lot of time cleaning it all up. But, you get an idea of what I did. You can see the USB charge port going into the glove box that powers the USB 3.0 HUB.

The USB 3.0 HUB:

Now, you need a specific USB 3.0 hub to work with a PI4. Do some research on ones that are TESTED AND WORK with a PI4. To work with OpenAuto PRO you need a USB sound card, microphone, USB camera (reverse), USB, Bluetooth, to charge your phone and connect your phone to the head unit for AndroidAuto (and mirroring) and for touch screen control.

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This is the USB HUB setup. I ran an additional USB3 cable to the back of the cart for a reverse camera. I also have a USB game pad in there too now to play games.

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Head unit working. That is a screen mirror from the Android Phone in the glove box. I don't have any photos of the Android Auto running on it but, it does. :)

It also has a full Raspbian OS with web browsers... Can do anything a normal PC does.

[cgtech]

Wow, sweet. I'll have to dig into this some more.

[Imapled]

Here is a shot of the black light stuff I did under the seat.

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Yes... I did paint with black light reflective paint "I live! I die! I live again!"... You can't see it with the body on from most angles but, why not. :P

You can get all this fancy stuff to make wires glow at a high-end electronics supply shop or one of those fancy car stereo places. The internet has all the stuff to do this too.

[Imapled]

Originally Posted by cgtech

Wow, sweet. I'll have to dig into this some more.

If you need other photos of stuff I still haven't put the back body on so I can take better photos of stuff if you need to see them.