Anyone working with the Overkill Solar Arduino lib?

[John Frum]

Not exactly what you asked for but you could put 16 AA cells in series and put the balance leads between every other cell.

 

[Symbioquine]

Wow, that is really odd. But I think it might have to do with what I wrote about the fixed current amount it's trying to drive into each resistor to "balance" it. Seems to be oscillating as a result. Thanks for putting it together and testing it. What size resistors did you use?

100KΩ

 

[Symbioquine]

Wow, that is really odd. But I think it might have to do with what I wrote about the fixed current amount it's trying to drive into each resistor to "balance" it. Seems to be oscillating as a result. Thanks for putting it together and testing it. What size resistors did you use?

Also, I don't think it can be the balance current (unless I'm really misunderstanding things) since that oscillating occurs even when I set the balance threshold voltage to 5v. (The default value was 3.4v)

 

[jbatx]

[UPDATE]
I've pushed some improvements to the sketch in the repo. Now, the larger single MQTT message has been split into smaller packages for pack, cell voltage, balancing, temp and protection. This gets around a size limit that I guess Amazon has. Also, the json formatting is fixed and is processed by the MQTT server properly.

History for overkillbms_json_publisher.ino - jbatx/overkillbms_json_publisher

Using an esp32, pull data form an overkill solar bms, format it as json and post it to AWS IoT Core (MQTT). Then, get that data into AWS Timestream and then into Quicksight for a realtime solar b...

github.com

I have been able to use IoT Core rules to get the data into Dynamodb and also into Timestream. I bailed out on dynamodb after realizing what a pain it was going to be to get the data into any visual. However, Amazon QuickSight can use a Timestream table as a direct query data source. Here's a simple dashboard I created last night using the IoT Core --> Timestream --> Quicksight method.

The up ticks are the sun coming up. The down spikes are my fridge turning on. The cell voltage diff is in milliamps

BASIC setup instructions have been added to the Readme for everything. You'll still have to do some of your own research and study I'm sure

 

[jbatx]

Also, guys would you mind terribly starting a different thread for the bms testing set up? It's not really relevant to this topic.

 

[Surferdudemi]

Have you seen Zack's thread on data from Outback Skybox?

Outback Skybox API: on github

I wanted to access my Outback Skybox from a simple python API. I saw a few other people, here and elsewhere, were interested in the same, so finally got around to getting a project going on github. Right now, it can query most of the metrics from the skybox, for example get the current loads, pv...

diysolarforum.com

He uses influxDB and it looks like it provides some pretty sweet visuals.

 

[jbatx]

Have you seen Zack's thread on data from Outback Skybox?

Outback Skybox API: on github

I wanted to access my Outback Skybox from a simple python API. I saw a few other people, here and elsewhere, were interested in the same, so finally got around to getting a project going on github. Right now, it can query most of the metrics from the skybox, for example get the current loads, pv...

diysolarforum.com

He uses influxDB and it looks like it provides some pretty sweet visuals.

Yep, that was helpful in charting my course in this project

 

[jbatx]

Here are some updated screenshots of the dashboard as I've refined it. This is working really well

 

[jbatx]

It's fascinating to see in realtime what I've learned academically. For example, voltages of series wired LiFePO4 modules drift apart as voltage rise above 3.5 when there's continued input current. As I understand the chemistry, internal resistance decreases and this is to be expected. Likewise, they converge as input current drops and cell voltage drops. Here's to top balancing!

 

[Orangesauce]

Agree with you about Raspberry Pi being overkill if it's just communication with BMS needed. Both too much power usage and more prone to failure than microcontroller in my humble estimation.

Apologies for the late reply (first post here), but wanted to add $0.02... Agree that microcontrollers can provide no-frills intimacy with the task at hand and the task here is pretty tightly scoped.

OTOH, a "larger" rPi-based system has the benefits of language and library support. For instance, input parsing and validation libraries for tons of different object serializations (JSON, XML, Protobuf, etc) are easily available in most languages that would compile down to an ARM binary or even run interpreted. Higher level languages have far better support for exception handling and processing, feeding into monitoring systems like Prometheus. These are all possible with embedded controllers, but the total cost of ownership (TCO) when development costs are included are likely going to be far higher.

This is definitely a YMMV based on the personal experience of the user. Just bringing it up for consideration...

 

[curiouscarbon]

Thank you for providing additional context!

It's interesting to see the data architecture that each person uses. Sometimes transporting data over UART, sometimes I2C,USB,wifi,ethernet, etc.

Thank you!

 

[curiouscarbon]

Here are some updated screenshots of the dashboard as I've refined it. This is working really well

omg that looks amazing!!!!

 

[Orangesauce]

omg that looks amazing!!!!

Would be amazing to have that as a panel in Homeassistant....

 

[jbatx]

Totally agree about the possibilities with pi being greater. Not sure I can agree about the tco. I'd put money on requiring just as much time needed to hack and code. As for maintenance, it's probably a wash. Power consumption on the pi would be higher though - can't prove that, just speculation.

I took the route of esp32 over pi for this project because I wanted to learn how to use these little $7 computers. I figured if I got comfortable with them and they entered my bag of tricks, it'd be pretty powerful. So far at my offgrid retreat I have 5 in play. For a total chip cost of about $35. ...then there are the 3 that I fried trying to solder sma jacks before buying esp32-wroom-32u with the built in ipex port. So, $21 lost due to mistakes.

...I digress

Two are connected to overkill bms's.

Two are acting as wifi nat repeaters to get wifi to the other units from my 4g hotspot.

One is monitoring water flow and usage and turning on/off my uv sterilizer when water flows from the rain water filtration system. This is a power saving move. Otherwise the uv bulb just produces heat all the time.

Next steps with these chips is to monitor the Vermaposting toilet conditions and try to use the ac condensate for cooling and moisture in there.

... next next step is to create a monitoring system for wildlife and muthuh f'in' poachers that I know sneak onto the ranch at night. For that I'll be using some or the mind blowing projects and platforms for image classification that are compatible. I'm thinking drones with ir cameras and image recognition sending data back.

....finally, I'm ditching AWS in favor of blynk.io. it's free for developers and better suited for what I'm doing.

JB

 

[jbatx]

Here's the updated version. No more bread boards.

 

[jbatx]

Would be amazing to have that as a panel in Homeassistant.... View attachment 70173

Can one write new ui screens for home assistant?

 

[Surferdudemi]

Here's the updated version. No more bread boards.

Have you tried out the ones with OLED display attached? They are around $12. I got a couple to try out (ESP32 and ESP8266). Sometimes it's useful to have a local display.

 

[jbatx]

Yep!

 

[curiouscarbon]

awesome work! ?

exemplary even! ?

any JBD/overkillsolar bms user should take note, in my humble opinion!

wow! so inexpensive to build and such functionality

 

[Porch]

Anyone get this working with generic MQTT server? I could not find an option with the AWS_IOT for none MQTT/S, so I started with a normal MQTT client (PubSubClient), but everytime I even load in the BMS with "OverkillSolarBms bms = OverkillSolarBms();", it boot loops with "Guru Meditation Error: Core 0 panic'ed (StoreProhibited). Exception was unhandled."