question

jengstro avatar image
jengstro asked

Multiplus2: Grid assist only when battery soc is less than ~10%

As the title say, is it possbile to do such configuration where grid Input kicks in only when battery level is below, lets say 10%... and then when reached 98%, grid would turn off. I've been playing round with ESS, but this seems to be solution for a bit different scheme.


Multiplus-IIVenus OS
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9 Answers
shaneyake avatar image
shaneyake answered ·

The answer is yes.

But can you give more details about your system like do you have a GX? Mppts? CAN managed batteries or SmartShunt?

Also what is your reason for wanting to disconnect from grid rather than just run in normal ESS mode with no grid consumption?

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jengstro avatar image
jengstro answered ·

I have Venus OS on rasp + Smartshunt + SolarCharger + Batteries.

My setup is in independent garage (with grid also). So Victron stuff mainly is there for heating. I have my own backend server, where I can remotely trigger air-heat-pump on.... based on electricity market price and coming weather. When there is "absolute" need (min temp in garage reached) to heat up Garage + No solar/batteries -> then I need to feed in from Grid.

I just want to get everything first out of the Solar+Batteries.... before using the grid (as last resort).

Dunno is it just me :-) Let's say the documentation for the ESS is not the most "simpliest" ones... I thought I configured ESS right, but now its like favoring grid all the time.

So, everything is configurable via Venus-OS raspberry interface? and what to define?


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JohnC avatar image
JohnC answered ·

Hi @jengstro

ESS isn't really necessary with simple needs. Take a look at the Generator Start and Stop Assistant. Instead of a generator, use it to control the ACIgnore function.

You can use SOC to switch on/off ACIN, but there's other options too.

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jengstro avatar image
jengstro answered ·

Ok, there is another assistants for this! Thanks for the tip!

Im just trying different ESS setups. And allways! this endups drawing grid power, even the battery is full.

- edit -

Now, it seems to work! "Optimized (Without batterylife). Still wondering what is this Grid Setpoint? I'm now having it -10Watts... but can it be 0 Watts?


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jengstro avatar image
jengstro answered ·

And after ESS test... the battery went < ~68% and started to pull grid fully.. Pretty weird. Ok, I give up. I'll look the other assistant for this

-- Edit --

As soons as I put solar charger back on (I switched it off, so I could run my batteries empty)... even solar produces less Watts now than I'm consuming... the Grid went back to ~0W. And its again drawing from batteries mainly SOC is now 69%. Go figure this out.

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shaneyake avatar image
shaneyake answered ·

ESS is the correct thing for this application.

Grid will fluctuate, this is normal. On average it will be at the setpoint. You don't have to worry about the short bursts from grid.

Can you post a screenshot of your ESS settings?

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jengstro avatar image
jengstro answered ·

Cannot attach pictures "forbidden"...

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jengstro avatar image
jengstro answered ·

https://drive.google.com/drive/folders/1Dk2RFwooO6vJ_IpUMUMhWFtJ2kaXv-J-?usp=sharing

Lets do this hard way then. There are the ESS settings. The grid set point is now 20W. I guess this is needed to have so that Victron can sync with grid phase?

Also, earlier why the Grid jumped in, was propably that I was drawing so much amps out of battery, so that there came warning on low voltage. Even though battery SOC was ~60%. I guess in ESS the grid will assist, if low voltage warning comes?. Also SOC truth is propably hard to measure with LifePo's.

I guess this ESS (constant small grid in all the time) is better than having brutal relays clicking when "generator" kicks in/off, in that other option what you proposed.

Still wonder the Minimium SOC. So, if SOC < 10% grid kicks in ? (unless the low voltage warning comes in first)

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Okay, you settings look correct.


You can set the grid setpoint at any value you want. The inverter will try hold that regulation.
However you have a limit of 1000W so if that is exceed it won't be able to hold at setpoint.

What components are you using?
Inverter?, MPPT, Battery, Etc.

Yes, it is better for the inverter and your loads to not be connecting and disconnecting from grid if it can be avoided.

Have you programed your inverter correctly for your battery? You should never get a low voltage error at 60% SOC.

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jengstro avatar image
jengstro answered ·

Just to conclude this... ESS is working really nice. After bit finetuning and understanding all the configuration parameters. Positively amazed how nice and automatic the Victron/ESS assistant is. That only confusion what I had... the system was drawing huge amps (drops bat voltage to low limit temporarely.. and SOC jumps down and up) this will confuse bit the ESS (naturally). My current battery capacity is not enough for some peak loads what I have (I've now disabled such cases). Anyway, I can understand that it is not lightning fast operation that Grid is able to patch the battery in huge peaks of ouput consumption...specially the case where I prefer the battery not the Grid In.

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What size inverter do you have?
What size battery bank are you running?

Have you tired the limit inverter power option on the ESS menu?

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Excellent tip! Indeed there is such a feature in ESS menu :thumbsup
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