question

gawan avatar image
gawan asked

Continous Power Drops from MAX to zero ?

Hi,

my system consists of 3 x Multiplus II 3000, two MPPT250/100 (16x330 Panels each) and one MPPT250/60 (8x330 Panels).

In total I have 13kW (three compass orientations) on 3 Inverters with 8500-8700 W max.

Whenever my system reaches max power (approx. 8700 Watt), it drops down to 0 W for a few seconds, goes back app to MAX, drops again and continues this behaviour as long as it is close to max power.

The green line is the total output of the system and as you see it jumps from 8800+ down to zero again and again and again.

Is the panel power outage too high ? Do I have to / Can I limit PowerMAX of the MPPTs ?

Shouldn't this be done automatically by my Inverters ?

BR

Gawan


Multiplus-II
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3 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

What size and type of batteries do you have?

Can you check to make sure there is good connection between the batteries all the way to the inverter terminals (fuses intact, nothing is loose)?

Check your graphs in the Advanced section to VRM to make sure that battery voltage is remaining consistent and stable under load and under charge.

If it varies, there could be an issue with the DC wiring, or the batteries themselves.

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gawan avatar image gawan commented ·

I am using 4 pcs quite old and used lead-acid batteries with a total of approx. 1,2 kWh.

This is not the reliable longterm solution, but a "hotfix" to allow me to start my Victron Infrastructure.

I do not want to draw and load energy to them - they should just allow me to run the system. Thats why I set the To-Be-Load-% to 100.

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klim8skeptic avatar image
klim8skeptic answered ·

3 x 3000w multiplus II, 3 x mppt/13kW array, on a 1.2kWh battery is never going to be a stable system.

The battery certainly can not handle the charge currents, or the discharge currents.

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chebanov avatar image
chebanov answered ·

I have the same situation with my MPPT 100/200. I'm using LiFePo 48V 100Ah battery with built-in third party BMS (not connected to CCGX). My max solar power can be around 1.8 kW. Total load equal 300W. When the solar power goes above 800W it drops every 20-30 seconds to 0. Have you found a solution

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samurai avatar image samurai commented ·
Just a 'me too' message. In my case an easy solar II gx 5000 , 2 times US5000 pylontech battery and 4800 wp solar aray.
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janieronen avatar image janieronen samurai commented ·
Could you show advanced page graph about battery voltage & current and solar production in a same picture? What is SOC during time when solar production is ramped down? Two US5000 are close charge limit with 100A MPPT. Have you checked pylontech cell level SOC? As if one cell is over voltage during max charge it will throttle charging down.
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samurai avatar image samurai janieronen commented ·

Seems the 'advanced' graphs are not detailed enough to catch the 0w ehh lows. You can see them when you look in the Dashboard. But I do monitor the system in Home Assistant and there you see the drops:

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There are no alarms shown about the battery and the min and max cell voltage only differs by 0.04V

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