DIY Serial battery driver for Victron GX

I’ve created a driver for Victron GX devices (anything running VenusOS, like the Raspberry Pi of VenusGX) that interface with a serial battery BMS(something communicating on RS232 or RS485 serial). Bluetooth serial does not work yet, as the Pi’s bluetooth is disabled and the VenusGX does not have bluetooth.

I don’t sell the BMS and there are no warrantee on the driver. It is free. Gratis.

You can up-vote for your BMS to be added next in the issue list on github

Currently it works with

  • LLT Power
  • JBD Battery
  • Overkill Solar BMS
  • Daly Smart BMS (from v0.5)
  • ANT BMS (from v0.6)
  • MNB spi BMS (from v0.6) - disabled by default as it requires extra libraries installed to work. Contact @Mike Dorsett for information

These are the values that is populated in the Venus device from the driver. (This is from an LLT BMS. Other BMS’s might not have all the data available)


Some items that are available and not shown in these images are:

  • All the alarms
  • The battery Cycles

I’m looking for people willing to help with testing this driver for other BMS like AntBMS and Daly.

What is needed:

  • If you have a battery that use any of these BMS (or if you have the communications protocol for your BMS) and your battery BMS has either RS232 or RS485 UART for communications.
  • If you use a Victron GX device or built in GX inverter model or Raspberry Pi with VenusOS
  • You need serial communications cable / converter for your BMS (VE.Direct or USB). Buy or build your own.

You don’t need lots of technical know how, but that might help. (You will need to connect the battery using the serial cable to the GX device and run some Python scripts on there)

Send me a PM if you are interested to get involved.

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@Louisvdw are you in Cape Town side of the world?

That depends how big the sides are :smiley:
I’m in George / Mossel Bay area

Wel, dit is nog steeds in die grense. hahahahaha!!! HHHMMMMmmmmmmm, I wonder I wonder. I got a 3de ANT Smart BMS that arrived after 7 months in slow mail that I want to build in my 3de battery bank. maybe maybe we need to test this.

If you have a Pi 2/3 laying around, then that would be all we need. You don’t really need a Victron inverter, just the GX device (which you can install on a Pi thanks to @plonkster)

does it have to be a pi running the os or can it be an actual gx device?

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Anything with a USB port that runs Venus-OS will work. In other words, any GX will work.

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The Pi is just if you do not have a GX device. Either will work.
Gman as far as I know is not a Victron user so does not have a GX device.

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Jip!!! Not in the blue side but in the Big Grey side. Hahahahahaha. MLT. And some Microcare Mppts that I’m planning to sell and get a something better.

@Louisvdw I am still waiting for my AntSmart BMS, once I have it, I will give you some feedback :slight_smile:

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ok will keep this in mind for sure.

Final stages of ordering this BMS: https://www.alibaba.com/product-detail/Sales-promotion-smart-7S-24V-10s_1600120114722.html

I want a BMS that:

  • Can handle any lithium battery cell technology, not just Lifepo4, if I want to change my mind one day.
  • Has a built-in shunt for accurate SOC measurements.
  • If I want to buy 280amp cells x 16 later, then I don’t want to swap the BMS.
  • And if the salient system required values are sent to the Venus, now THAT is a bonus, for I want to set the parameters, just like with lead-acid batteries, not be forced by pre-programmed values.

And my logic says:

  • Being 200amp, it will idle most of the time.
  • Up to 260mA balancing.
  • Can handle up to 85V, so that sorts that teeny titbit out.
  • Am told that because it has a relay/contactor, that it is good.
  • CANbus, Bluetooth and UART ports included, so that is also sorted.
  • Programmable via phone/PC, not that is very good.
  • And most probably will interface with Venus thanks to Louis and Co - which just makes so much more sense to get one. :smile:

And all the above, delivered, for $110.50 excl SA taxes and goeters, who is going to argue.

O, that brings an idea to mind: If anyone else wants to also get one, I can increase my order.
It is a risk, can stand to lose some money, but it is with Alibaba’s Trade Assurance - if that means anything.

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Trialing a new feature for the driver at the moment. Reducing the charge/discharge current limits when reaching the upper/lower limits of the battery SOC.

image

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This is all good and well, just something I want to note: When you enable the option to feed excess DC-coupled PV into the grid, the CCL will be ignored and the MPPTs will remain unlimited. So while many batteries use a CCL, getting the voltage control part right is the most important (in a Victron system at least).

I’m still working on my voltage control function.
The problem is that I have 1 bad cell (#10) that freaks out while the rest is still at 3.34V and it makes testing my function almost impossible. Once I replace the cell my Voltage control can be enabled for testing.

That’s not necessarily a bad cell. I see this sort of thing frequently with new batteries. After a few weeks, the other 15 cells finally catch up (slowly pulled up at whatever small current the BMS supports). While this is quite frustrating, the truth is also that if the BMS has more bypass/transfer capabilities, you’d be paying more for it… and then use it exactly once (when the battery is new). :slight_smile:

That is what I thought initially as well, but it’s been 6 months x 50mA balancing and I can’t see any improvement.
Cell #10 is also only the highest cell after 80Ah. Before that it is just one of the average members. Either a bad cell, or a lower capacity cell to the rest.

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My cells and BMS have arrived, I will start the building process this weekend and report once I am done :slight_smile:

Nice. Do you also have a USB-RS485 cable for it?

Have you tried simply removing the cell, cleaning terminals, and reassembling? This fixed the imbalance issues in my pack. In one case the terminal surface was damaged, so I included a tinfoil ‘washer’ for a compliant mating surface.

You might be surprised by how the tiniest connection resistance affects cell voltage measurement.

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