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marcus513 avatar image
marcus513 asked

Multiple BMV-712s in one system with multiple batteries

Hi everyone


I'm new here and have been trying to find some answers to a BMV-712 challenge. I'm building 4 large (51.2V 270Ah), separate batteries for my off-grid house. Each will then be wired in parallel to a Lynx Power In attached to a Lynx shunt.


I would like each battery to be a completely separate unit, so that I can disconnect and do maintenance on one without loosing power to the whole house. Each battery will have a separate BMS (BMS123 Smart) connected to a Contactor for disconnection in an emergency. In order to keep a separate eye on each battery's SOC, I would like to add a BMV-712 to each battery as well (with temperature monitoring).


I realise, that only one BMV can be available to show the SOC of the whole bank on a GX, so I'm fine using the Lynx Shunt for this.


1. Is there anyway of showing the other 4 BMVs (one per battery) on a main display, or will I have to use the small display on each BMV to check that the state of their individual battery SOCs, temp. et cetera?


The 712 Data sheet says:

“A maximum of four BMVs can be connected directly to a Color Control GX. Even more BMVs can be connected to a USB Hub for central monitoring”?


I have added a diagram, hope it makes sense. Any advice would be greatly appreciated.


Thanks, Marcus



bmv-712-smart-questions.jpg

BMV Battery Monitor
bmv-712-smart-questions.jpg (297.2 KiB)
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ruben avatar image ruben commented ·

Hi Marcus,

did you got some news in the meantime. You wrote:

¨1. Is there anyway of showing the other 4 BMVs (one per battery) on a main display, or will I have to use the small display on each BMV to check that the state of their individual battery SOCs, temp. et cetera? ¨


I would like to do similar things as you are/ where planning (putting indiviudual BMS´s after the ´main´ BMV/ Lynx for all batteries). To me this kind of monitoring per bank makes sense (also especially with respect to lead-acid batteries), to have a better insight of the behavior of each bank)


BR,

Ruben

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mrhappy avatar image mrhappy commented ·
If you like tinkering, you can try VeonusOS Large, preferrably on a raspberry Pi with a powered USB hub and Victron VE.Direct to USB cables to connect all shunts and MPPT's, MK3-USB to the Quattros. It includes Node-Red where you can make your own dashboard with all information you could ever need from all units available.
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ruben avatar image ruben mrhappy commented ·
Hi Mrhappy,


thanks for your suggestion. I indeed like tinkering, although I don´t have experience with Rasberry PI yet and I don´t have too many time to invest investigating. But I really appreciate the suggestion, as this would be something for in the future for sure.

Ruben


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2 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

Whilst the latest versions of Venus OS will cope with this concept, The GX units do not have sufficient VEdirect ports - and I don't think that they will connect by bluetooth. You could run Venus on a Raspberry Pi with a USB expander.

You could use bluetooth and the Victron connect ap to look at each smart shunt.

OR you could move to a more intelligent BMS system that shows the state of each of the batteries connected to the system. this then has one port that provides data to the GX / Venus system. However, you would have to arrange for the BMS units to remain powered whilst you remove a battery for service - I don't know any inteligent BMS systems that cope with 'hot plugging' of BMS units - most will raise an alarm and shut down the system if they loose contact with one unit.

I've been working on a BMS design that will cope with up to 32 units, each with 8 - 14 cells.

Mike.

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ruben avatar image ruben commented ·

Hi Mike,

good point regarding keeping the BMS powered somehow.

I have already been searching a lot for more (intelligent BMS solutions. Especially with the ability to read the data out in a clever way (with a good overview), in order to be able to read indeed something like 4 or up 32 (or even more) battery voltages and depending of adding a shunt per bank also the SOC. etc.


Would you like to share in more detail what you already have been doing: ¨BMS design that will cope with up to 32 units, each with 8 - 14 cells. ¨

I am really curious how you are doing this (and also with respect to the costs ;) )


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Voyager I avatar image
Voyager I answered ·

Is there an update on this? I am currently trying to achieve the same thing but on a boat.
48V System + Inverter + MPPT Charger + DC / DC Converter + DC / DC Charter

12V System

I can monitor the 48V system. Can I also connect a smart shunt from the 12V system to the Cerbo GX and monitor that one as well? I guess it will not be shown in the dashboard on the touchscreen, maybe in the web console? Or in the list of the devices?

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