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fernanci avatar image
fernanci asked

System restarting after adding second mppt

Hi, until 2 weeks ago I've not any problem with my installation (has been working without problems for the last 9 months).

2 multiplus II 3000 in parallel

Cerbo GX

Smartshunt

150/35 mppt with 2s2p 550w panels, with VOC of 98v.

2s2p id3 8s lithium batteries.

2 jk BMS, but not connected to the cerbo

This is an off-grid system, configured at 64v fully charged

2 weeks ago I added a second mppt with another 4 solar panels, the same that the first one, same mppt, same panels, same everything. But since then, the system is restarting everytime there is sun and charging, not when is cloudy. Both mppts have the same settings, id3 lithium config settings from the menu

All the mppt and smartshunt are connected with ve.direct cables to the cerbo gx,, smart network is not active, the 2 multiplus are connected to cerbo gx with ve.can.

I tried DVCC, I tried smart network, disconnecting ve.direct cables, but anyway the system keeps restarting because voltage spikes in the victron system, but there are not spikes in the jk BMS.

When I disconnect one mppt, there is not problem, any of the 2, it doesn't matter which one, but both can't work together.

Here is a picture of my installation.

1000027827.jpg


And here are 2 videos, the first one is with one mppt active, everything perfect.

https://drive.google.com/file/d/1AfVl0nqZ48t8Nje-whcxFKndjXMuDLlV/view?usp=drivesdk

And in the second one, I turn on the second mppt, the smartshunt voltage spikes till 69.99v and all the voltages are different

https://drive.google.com/file/d/1AllxBzATWsbTeePjXjAiCE7g-Gsk4p3W/view?usp=drivesdk

What is the problem here? or how can I solve it? thanks in advance.


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2 Answers
Alexandra avatar image
Alexandra answered ·

@fernanci

It sounds like a charge current related issue

Are the JKs set to take the charge amps?

Possibly try lower charged voltages slightly?

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fernanci avatar image fernanci commented ·

I checked the BMS and maybe you're right. Each one is rated to 25amps of continued charge current

1000027832.jpg

I changed it to 40, so I have 80amps with both BMS and I'll give it a try. I also set the mppts to 30amps max charge current.

I'll report the results after next sunny day, thanks


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1000027832.jpg (424.2 KiB)
fernanci avatar image
fernanci answered ·

Yeah, that was the problem, all is working perfect, thanks

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