Two 250/100 MPPT controllers in parallel - One staying dormant....

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kiwisolarfuture asked Jul 6, '22

Two 250/100 MPPT controllers in parallel - One staying dormant....

Hi there,

just installed a 10kWp PV system (6 parallel strings of 4 PV modules in series) feeding into 2 MPPT controllers (250/100), which again feeds a BYD LVL battery bank (2 parallel modules of 15.4 kWh each):

After firing up the system, only one of the 2 MPPT controllers is feeding into the batteries (solid blue BULK light on). The other one remains in an OFF state (blue BULK light blinking slowly), also as shown by the VictronConnect app:

I'm at a loss why this is happening.

The OFF MPPT controller is correctly connected to the battery bank and PV arrays and breakers / isolators are switch ON.

I have also made a "Smart Network" connection between the 2 controllers through the VictronConnect app, hoping this would have the 2 controllers talk to each other, but it didn't make any difference. One of them remains inactive.

I'm wondering whether the BYD BMU has anything to do with this, since that is the unit in overall control of the system.

Hoping anyone of you can shed some light on this. Thanks very much in advance! :-)

MPPT Controllers BYD mppt state

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klim8skeptic ♦ commented · Jul 06, 2022 at 08:31 AM

Keep an eye on those DC breakers on the output of the mppt. They are prone to trip below rated current.

Also check that the jumper is in the remote port on the LH mppt. hard to see..

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Answer 1 · 2022-07-06T08:17:19Z

Guy Stewart (Victron Community Manager) answered · Jul 06, 2022 at 08:17 AM

Hi @kiwisolarfuture,

VictronConnect indicates that there is no PV voltage reaching the MPPT that is off. The next step would be to get a multimeter and check the voltage at the PV input terminals of the MPPT yourself.

If it indicated 0V, there is a wiring, fusing, or switching issue from your panels to the MPPT.

If it is indicated as 160V, there could be an issue with the MPPT itself and you would need to get in touch with your installer and/or Victron dealer.

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Answer 2 · 2022-07-06T10:19:07Z

seb71 answered · Jul 06, 2022 at 10:19 AM

Also check if the PV polarity is correct ("+" to "+" and "-" to "-").

Do not trust the wire colours. Check with a multimeter.

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