Generic Battery + Arduino = Happy Solo

[just_bruce]

My word you have been productive!

This is quite the gift to the Solo / Ardupilot community. Since this should theoretically interface with a number of AP rigs....

Thank you for undertaking this work.

 

[webbs]

Thanks just_bruce, I have been looking for an interface and this one works but is large size-wise. If anyone else has a serial PC interface that will work with arduino let me know and i can have a look.

I have just done a test with a USB to serial adapter and found i can connect with an arduino running this code using 3 pins, GND to GND, RX to TX and TX to RX. This way you can carry out the settings and calibration without adding the USB 5V to the mix on the circuit.

 

[webbs]

I am about to test out my new version of the code with the serial option to calibrate the values and set pack capacity so hopefully should be able to post the code in the next day or so.

I have come across these from Banggood when i was looking at the ZOHD dart...

ZOHD LIONPACK 4S2P 18650 14.8V 7000mAh Li-ion Battery Pack for RC Airplane Spare Part RC Drone Accessories RC Parts from Toys Hobbies and Robot on banggood.com

It is a ready made 4S2P 7000mAh LION pack for NZ$132 which is similar to a 5000mAh Lipo pack. It is listed at 409g so lighter than the Solo battery and with 1800mAhs more.... Shame they won't ship to NZ....

Based on this i would say that there will be other brands on or close to coming to the market.

 

[Professorpip]

Hi

Looks interesting. At 10A max per cell, at 4s2p it won't have enough current capability for the solo... At 4s2p you'd need something like the Samsung 30Q cells which can do 15A per cell.. At 10A per cell the solo would need a 4s3p pack. 4s3p is what I run (with Sanyo cells), and I still get extended flight time vs stock. But agree there are more options coming to market which is a very good thing.

 

[webbs]

Hi Professorpip, I knew the 10A came in somewhere, but it was per cell rather than the pack. Hopefully there will be more coming so it will be easy to get them off the shelf...

Here is a new version of the code with a serial interface for setup and calibration. It takes up less memory so will give me a chance in the future to add the OLED support back in.

Type
?
will give a list of the settings and current values. To make a change enter the text and the new value
leds 16
This will make the change and update.

To save the data to EEPROM
save
and the changes will be locked in.

The calibration works well if you enter in c1m and the measurement
c1m 4150
it will work out the voltage divider ratio so the voltage reading is 4150mV. Start with Cell 1 and work through the other 3 as the previous cells are used for the current cells value.

I am also looking at adding in a better discharge/pack % equation for both Lipo and Lion which will be selectable.

 

[spieky]

HI guys

Is there any difference between disconnecting the battery and turning it off with a button, like the original has?
Does the button just inform the contoller or does the controller do something with that info?

Thanks for your contributions, all of you!

 

[webbs]

Hi Spieky,

The button is controlled internally by the BMS and it will disable the output from the actual battery cells to the external terminals which is the same as unplugging the battery.

 

[spieky]

Thank you
I just finished soldering the module with NeoPixels.
I just tested it by plugging into Solo. It works

Thanks!

 

[webbs]

Awesome. Are you able to put up come photos of what you have done?

Let me know how you find the Arduino code and if you had any issues with it.

 

[spieky]

Sure

I went with super glue approach I had an original 3dr APM power module also, so I used that, and an Arduino Micro.
It was supposed to be just to test stuff, but it's just tooooo good heh. I might put some seethrough shrink tube over it, and use it as is. The only things I changed were NeoPixel pin from 6 to 9, just because I automaticallt soldered it to D9 ?‍, and voltage dividers. I had some tiny SMDs, that were a bit higher in value, but it's ok. Calibration was quick and simple.
Those neopixels are there just for fun, I will probably not use them later on, but they do look good

Im now waiting for two gensace 6750 Lipos.

Great work ?

Edit
Oh, the code. Actually this was the first bit of code, that I havent checked before uploading to arduino... I just read through the thread here, and BAM! Solo Battery!

 

[webbs]

Great work Spieky!

You have managed to get than nice and compact. Higher resistor values are fine, it just the ratio you need to keep similar to give the most range on the 0-5v decoding.

Is that a new Solo plug or one you salvaged from a dead battery?

 

[just_bruce]

So... how much to make up a dozen or so of that setup? And maybe shorten up some of the wiring to neaten things up? Because with a proper printed case that looks a lot like a new smart battery to me....

 

[spieky]

Great work Spieky!

You have managed to get than nice and compact. Higher resistor values are fine, it just the ratio you need to keep similar to give the most range on the 0-5v decoding.

Is that a new Solo plug or one you salvaged from a dead battery?

Thanks
I wanted it to be smaller at first, but it does not need to be really. My plan was to make a PCB, like you did, but you did it already
FOr the voltage divider, I was aiming at around 3.3v, it's a personal preference hehe.
I actually got that plug from a guy from Canada, it was cheaper than anything I've found online. like 20eur with shipping. Not cheap, but 10eur for the plug seems like a good deal.
I still have the original BMS, it's still working... I might try to dump the FW at some point, try to tikner with it, reverse engineer it, if possible. Seems like a practice for the brain

 

[spieky]

So... how much to make up a dozen or so of that setup? And maybe shorten up some of the wiring to neaten things up? Because with a proper printed case that looks a lot like a new smart battery to me....

I dont know if this was meant for me... but here... I dont really want to sell something that is not really mine to sell
Plus, selling from Slovenia would make an amazingly high shipping. "Luxury" of a small country with only one real post, I guess.
but yeah, properly long wires and a case, would look smart. I need to reassemlbe my Vulcanus max now hehe

 

[webbs]

Hi spieky, do you have a link for purchasing the plugs? I was going to use a salvaged one but as you only need 1 for this project it might be nice to have a new one.

 

[spieky]

oh btw, I was looking into BQ76942 Texas Instruments...and since there is a certain lockdown in the near future... I just might try to make something that resembles a BMS. I can do voltage without a divider, balancing, temperature sensing. If we can do charging also...

 

[spieky]

Hi spieky, do you have a link for purchasing the plugs? I was going to use a salvaged one but as you only need 1 for this project it might be nice to have a new one.

sure

3DR Solo Battery female Molex 171090-0048 connector BMSone | eBay

Find many great new & used options and get the best deals for 3DR Solo Battery female Molex 171090-0048 connector BMSone at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[webbs]

oh btw, I was looking into BQ76942 Texas Instruments...and since there is a certain lockdown in the near future... I just might try to make something that resembles a BMS. I can do voltage without a divider, balancing, temperature sensing. If we can do charging also...

I looked at many different options for this but you would still need something to interface with the chip to the Solo as i couldn't find anything with SMBUS coms built in. This chip looks good in being able to carry out all the measurements and then could be integrated with and Arduino or similar.

Some of the chips that did have the SMBUS options then would have to stay with the battery as they report the capacity etc. based on counting current in and current out so this would be hard to move between batteries.

Great if you can get something like this working giving a more accurate cell reading along with current and temperature.

Thanks for the link, I have requested shipping costs for the plug to NZ so will see what that comes in at....

 

[webbs]

Looks like he has had issues shipping the plugs to Oz before so not shipping outside of the US or Canada.

 

[spieky]

Yeah, he made me promise to not bitch about the shipping time (his exact words haha). I honestly didnt care, I was on holiday. I t9ld him that, and he sent me one