Ways to Field Test or Repair my Multiplus 3000?

DIY
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1

Greetings all - I have a Multiplus 12 | 3000 | 120 - 16 | 230/240V. Marine installation with Digital connections to a Lynx BMS/Cerbo and a digital Multi Control. Last night we had a thunderstorm and power outage at the marina, with the following sequence of events:

  1. Shore power out: The Multiplus seemed to be working fine in inverter mode, but the multi control panel had all eight LEDs lit simultaneously, the current limit display was dark and the charger/off/inverter switch appeared to have no effect. I tried to reset things by switching off the DC power to the unit and power cycling the Cerbo, but this had no effect.

  2. Power on intermittently. The lights on the multi control were still all on. I tried to disconnect the LAN cable from the multi control and reconnect it but no effect.

  3. Connected to PC with Victron Connect. Connected to Multiplus successfully, showed status as input disconnected and inverting. Noticed that input voltage was at 277 volts. I went into settings to lower the threshold to 260 volts - my aim was to ensure that high voltage was not passed through to any of our devices plugged into the AC system. Within a few minutes of changing this setting the AC output from the Multiplus went dead and a battery low voltage warning was displayed on Victron Connect which showed the Multiplus status as ‘off’.

According to the Cerbo, our (600Ah 12v) lithium bank was 98% charged and the multiplus off. I disconnected the multi control, and went to access the multiplus itself, which was showing a red inverter undervoltage warning light. The front panel On/Off/Charge only switch had no effect. I cut the main AC breaker and cut the DC breaker to the multiplus. On reconnecting the DC to the multiplus there was nothing, no lights or anything and unable to connect with PC. The unit has effectively been dead since this.

A brief visual inspection with the main cover off did not reveal any obvious damage, but I have not gone so far as to remove any boards or components to investigate further.

We are in cruising in Mexico and have no good options for professional help, but I have basic electrical test and repair equipment on board. Any advice on things to try would be most appreciated, before we bite the bullet and have a new unit shipped to us.

2

And there was battery voltage at the terminals?

What batteries do you have?

1 of 2 scenarios could be the issue

  1. DC Fuse blew
  2. Batteries tripped
3

Thanks for the response .

I have a bank of three Victron 200Ah 12v smart lithium batteries connected in parallel. All seem to be working and powering our DC system as normal, no errors or issues showing when I connect to them or the Lynx via bluetooth or Cerbo.

I did measure 13.5V at the DC terminals of the dead Multiplus. Have yet to test this with a load applied which is my next move in case there’s some problem with the upstream wiring.

4

The basic pre rma testing is here. It has a good checklist