Success! Reading smart battery data
- Thread starter PdxSteve
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Truthfully I'm not really sure and haven't given it too much thought. This is just a fun and challenging project and proof of concept at this point. I've even ordered a 3D printer to build the housing with almost a cubic foot of build area lol (I have many other uses for it as well).
My fear would be on the charger side, and starting a fire and burning someones house down. I am not an electronics engineer (although my father is and is helping a bit when I get stuck). I also only have 10 real Molex battery connectors, and normally you have to order them with a min. qty of 1,000. That's pretty prohibitive for an individual, but I do also have an idea to make my own based on my test rig before the real connectors arrived. I know there is interest in this - so it is in the back of my head.
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Is there a known source to buy just the connector for the primary +/- terminal? I'd like to pick up a few to make my own cables for charging multiple batteries off my big ass power supply.
Will the battery self-regulate the recharge rate? In other words, I have a 16.8v 30 amp power supply. If I just plug it in directly, will the battery allow itself to recharge too fast? Or will it only allow itself to charge a safe rate? I can always use my balance charger in non-balance mode to limit current if needed.
Will the battery self-regulate the recharge rate? In other words, I have a 16.8v 30 amp power supply. If I just plug it in directly, will the battery allow itself to recharge too fast? Or will it only allow itself to charge a safe rate? I can always use my balance charger in non-balance mode to limit current if needed.
See this post for the Battery Charging connector (without data port). They are the same as the charger plug that comes with the solo except there isn't the additional black tab to keep the plug orientated: Hitec X4 AC Plus Four-Channel AC/DC Multi-Charger
I can't answer that definitively, but personally I wouldn't try that without CC/CV. The battery does have some protections built in, but I don't know what it would do with a 30A load. I've heard the battery limits itself to a 5.2A input current, but don't quote me on that. My CC/CV power supply hasn't gotten here yet to test various charge loads, but the one I ordered will do up to 20A/350W max so I can experiment with larger lipos (when they come out
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Well you could sell the plans with a disclaimer
but sadly someone would buy them and leak them everywhere
but sadly someone would buy them and leak them everywhere
I looked on the 3dr Dev Github and found a link to the smbus driver and it was updated 15day ago. Didn't do a comparison yet to see what if anything has changed. PX4Firmware-solo/src/drivers/batt_smbus at bf80a499d230cf6c773930bd4556931a8b187709 · 3drobotics/PX4Firmware-solo · GitHub
There are a couple arduino sketchs I've come across that let you reprogram the smbus module but I don't have an extra battery yet to crack into
I'll be looking into reprogramming the SMBus chip when my basic charger is finished, which it almost is Just working on the 3D design of the base right now so the batteries can slide into the charger like the do the Solo instead of connecting a charging cable.
@STMPNGRND Thanks for the heads up on github. The recent change was trivial and didn't provide any actual functionality.
Just working on the 3D design of the base right now so the batteries can slide into the charger like the do the Solo instead of connecting a charging cable.@STMPNGRND Thanks for the heads up on github. The recent change was trivial and didn't provide any actual functionality.
found two interesting reads on the interwebs that may be of use....
http://www.batteryspace.com/prod-specs/5646.pdf
https://media.blackhat.com/bh-us-11/Miller/BH_US_11_Miller_Battery_Firmware_Public_WP.pdf
http://www.batteryspace.com/prod-specs/5646.pdf
https://media.blackhat.com/bh-us-11/Miller/BH_US_11_Miller_Battery_Firmware_Public_WP.pdf
@PdxSteve Well I finally picked up a used battery really cheap on ebay to experiment with. I'm having issues communicating with it however. Just getting jibberish data like there is some sort of i2c interference. Tried both PC and MAC with a micro and nano duino same result
Did you make any changes to the pack probe code to establish comms?
Did you make any changes to the pack probe code to establish comms?
I've been playing around with the Solo's Smart battery, and thanks to PdxSteve and others I've been able to read out the data from the SMBus using an Arduino nano. I then put together another Arduino sketch to simulate the battery. I started with some old non working code I found via StackOverflow. It now simulates all the parameters that the Solo's firmware asks for, and through the serial console, you can change Voltage, Current and others. I've attached the sketch here so others can benefit from it. I've also hooked up a current sensor to one of the analog inputs so it will be able to provide real data to the Solo, Haven't gotten around to adding the voltage scaling resistors or code yet, but it should be straight forward.
Enjoy...
BTW I have tried it with a real Solo and it does work. The real trick was calculating the PEC (checksum) which the spec. says is optional but the PX4 Firmware wont recognize the battery without it.
Added picture, this Solo had a very bad crash (I didn't crash it, I bought a crashed one), but the Pixhawk and computer are ok, so I thought I'd do some battery work.
Enjoy...
BTW I have tried it with a real Solo and it does work. The real trick was calculating the PEC (checksum) which the spec. says is optional but the PX4 Firmware wont recognize the battery without it.
Added picture, this Solo had a very bad crash (I didn't crash it, I bought a crashed one), but the Pixhawk and computer are ok, so I thought I'd do some battery work.
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Is there any starter code available out there that will allow me to read the battery status information? I have 5 batteries and I'd like to know which of the batteries have been charged the most cycle, and the condition of each battery.
Here is what I started with:
PackProbe Documentation
Runs fine on an Arduino Nano.
Be sure to pull up both SDA and SCL to the nano's 5V and connect the Battery - to the nano's ground.
PackProbe Documentation
Runs fine on an Arduino Nano.
Be sure to pull up both SDA and SCL to the nano's 5V and connect the Battery - to the nano's ground.
Using this information I was able to modify this code and read data from Solo Batteries.
I am having a small issue though. It seems that I can only read data from the battery if the battery is turned on, and if the battery has been freshly recharged I can't read any data at all. I was able to read data on partially depleted batteries though. HAs anyone else seen this?
I haven't looked at that particular code yet, but yes, the battery needs to be on to power the smbus in order to read/write to/from it. I haven't run into any issues reading from a battery that was on, regardless whether it was just charged or not so not sure what could be causing that for you. Once the battery charges to 100%, it turns itself off though so you do have to turn it back on to read from it again, but it should show like 99.9% or 100% charged when you do.
I tried it again. Had a fully charged battery powered on, and could not read any data from the battery. I placed the battery on the solo and let it drain to 95% and then put it back on the arduino, and I was able to read data.
I'll have to try that. My attempts have been very inconsistent yielding mostly jibberish values.
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