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mysik avatar image
mysik asked

ESS - Strange behavior when fully charged

I have a problem with my Victron.

When the batteries are fully charged, Victron is switching between charging and discharging. at 100% SoC it starting discharging about with 250W for few seconds, then slowly reducing the discharge, then switching to charge again, charging with 250W slowly reducing the charge and start discharging again. There is excessive PV power so the discharge is going to the grid. See video below.

Just in case I'm also attaching my settings from VE Config:

Is it "normal" behavior? is it healthy for the batteries? Should it just charge to 100% and stay there until there is not enough of PV power to balance the load???

Multiplus-IIESSbattery
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Alexandra avatar image Alexandra ♦ commented ·

@Mysik I dont see a PV inverter programmed into your ess assistant there. If you did you should see something similar to the picture. What PV inverter are you using?


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Alexandra avatar image
Alexandra answered ·

@Mysik Because your PV yield and loads are always changing the ESS is having to work to recalculate all the time, it takes a few milliseconds for ESS to react. So when a load increases the inverter will pull from the battery to meet the new demand then replace the charge as soon as possible using the pv to meet your keep battery charged setting. In a DC coupled inverter system the battery is there for reactive power.


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laurentiupitran avatar image laurentiupitran commented ·

hello,

not very clear for me your sentence :

"" In a DC coupled inverter system the battery is there for reactive power.""

i will attach also a diagram for reactive power in an ESS system.

thank you,

laurentiu


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laurentiupitran avatar image laurentiupitran commented ·

hello again,

regarding regulator reaction in a ESS system, is appear for me and attached diagram that increasing time for more load demanding is OK , but for decreasing power on load ,time on regulator reaction is too long.

during day time and enuff sun on sky can be OK, but for night time when energy injected in grid is from battery, is NOT OK.

laurentiu

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laurentiupitran avatar image laurentiupitran commented ·

i was waiting for an answer of Victron specialists that need to be involved in the problems related to their products.

is to less or too much?.....

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Alexandra avatar image Alexandra ♦ laurentiupitran commented ·

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwje3cSO2b_pAhUEqXEKHeLVA5AQFjAAegQIARAB&url=https%3A%2F%2Fwww.fronius.com%2F~%2Fdownloads%2FSolar%2520Energy%2FQuick%2520Guides%2FSE_QG_Setting_%2520Reactive_Power_Control_On_Fronius_Inverters_EN_AU.pdf&usg=AOvVaw2nL1JPIliMw_jw4-cvUBcG

Since most issues seen on Victron systems are settings related or installer error it may be best to check over the system if you are unhappy with it, or discuss it with your installer.

This is an article explaining a bit about reactive power

https://pure-electric.com.au/news/17-december-2019/how-correct-reactive-power-settings-your-inverter-can-increase-your-solar

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dray22 avatar image
dray22 answered ·

@Mysik

I don't know if you ever got this solved, but you probably need to lower your absorption and float voltages. I had the same problem. Your lithium pack voltage is spiking and causes it to discharge and then it drops so much and it starts the charging again. See my post here:

https://community.victronenergy.com/answers/120714/view.html

I finally figured it out after setting up midpoint voltage monitoring in VRM.

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