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Thomas Müller-Guttenbrunn avatar image
Thomas Müller-Guttenbrunn asked

I have Problems with th MPPT rs450/100 with error 29 "battery overcharging protection"

My ESS System consists of 3 Multiplus 5kW (3-phase) a RS450/100 MPPT a Cerbo GX with Touch and 3x38 150 Ah NiFe Batteries (in parallel). A Fronius Symo 10kW with 8kWp PV (no Problem).

The MPPT has 2 Strings with 5 Canadian Solar (in series) 2250 kWp each.

Vmax: 230 V, Imax : 10 A for each String

Allthough voltage, current and total power is far below the maximum specs i get error 29 from the MPPT which says "battery charging protection". Battery has maybe 92% SOC reached and the Multis are further loading the batteries. Meawhile the MPPT has switched(idle) off.

I'm new to this forum and hope to get an answer for this annoying Problem.

Thomas

PS: excuse my rusty english


ESSMPPT SmartSolar
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4 Answers
Alexandra avatar image
Alexandra answered ·

@muegu

How is the mppt set? I assume you have read the troubleshooting section for error 29, by your post.

Is DVCC on maybe what is happening is you are exceeding the charge current limit of the batteries? Even though you are at 92% SOC your batteries are full and the SOC has drifted?

Or the settings are not quite right.

Does it happen with the MPPT not talking to the GX device?

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Thomas Müller-Guttenbrunn avatar image
Thomas Müller-Guttenbrunn answered ·

Hi Alexandra, thank you for your fast response!

I have read installation guide and looked for error 29 description

MPPT PV-Panels are 5 pieces in serial with Vmax 225V and Imax 10A (each string)

MPPT is connected to GX via VE-direct and it's remote controlled.

MPPT configured to Absorbtion Voltage = 58V max current 50A

DVCC is on, max charge voltage = 62V, max charge current = 100A

(62V because of equalization of NiFe batteries)

In VRM statistics i can see Imax = 76,98A and Vmax 58,14V before switchoff from MPPT


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Thomas Müller-Guttenbrunn answered ·

Addition: VRM statistics:

Consumption from Battery 5,8 kWh -> Battery loaded with ~4,8kWh 30min after switch off (10:30)

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Alexandra avatar image Alexandra ♦ commented ·
@muegu

Is this happening when a larger load drops off suddenly? Especially when the batteries are full? Or other conditions.

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Thomas Müller-Guttenbrunn avatar image Thomas Müller-Guttenbrunn Alexandra ♦ commented ·

It looks like a short voltage drop (4V) followed by voltage rise because of load-deload (eg. at noon - cooking)

Today i installed FW 1.04 and had no error 29. Let's see if there is a difference

I will watch and give a status next days.

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Thomas Müller-Guttenbrunn answered ·

error 29 seems to be solved by FW 1.04. I had no error message "battery overcharging protection" since 3 days.

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