pearley avatar image
pearley asked

Multiplus 3000 mains dropping out.

3kw Multiplus with 50a transfer switch and 6 kva Onan generator. 3 way selector switch, gennie, off, shoreline.

Spent a week in marina plugged into shoreline with no problems. 5 days off grid running off gennie and solar, no problem. Into another marina and plug in, rcd on shoreside pillar trips, reset, trips again. Disconnect mains in and mains out on inverter and join together and now have mains in boat with no rcd tripping.

Speak to company that supplied it 7 years ago and then took it for repair. The pcb nearest the front replaced and power connected to show it is now passing mains through. Back to boat and refit. Now works ok except that periodically the mains from the Multiplus will just drop out with no lights showing on the display. Wait a few seconds, between 10 and 30, and back it comes. The dropping out always coincides with a high load switching on. Ie kettle, iron, oven.

Usually run it with inverter set to charge only but if we switch to inverter it still drops out, just switches to inverter with overload and low battery lights flashing alternately. If we run a load of 1800w with fully charged batteries and engine running the overload light flashes.

I will reitrrate that for 7 years this has performed with no prkblems2.

MultiPlus Quattro Inverter Charger
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3 Answers
Mark avatar image
Mark answered ·

My guess is that the firmware might have been upgraded and accordingly your configuration settings may need to be reviewed and reconfigured to better accommodate your setup and usage.

VE.Configure software with a MK3 to USB cable is required to check the current configurations and make any required changes.

There are MANY potential causes of why the MultiPlus is rejecting the incoming power supply &/or overloading (in addition to a true constant overload), so its a bit hard to recommend what to change without monitoring the system while the issue occurs and knowing what the current settings are.

Some suggestions of what settings to possibly review (in no particular order);

- 'Dynamic current limiter' option (generally better ON with a gen-set)

- 'Power Assist' option (generally better ON with a gen-set)

- Assist current boost factor

- UPS function option (generally better OFF with a gen-set)

- 'Accept wide input frequency' option (may be required if gen-set has an inconsistent AC output frequency)

- 'Weak AC input' option (may be required if gen-set has a poor AC waveform, but less efficient)

- AC1/AC2 input current limit

- System frequency

- Inverter output voltage

- AC low & high voltage disconnect/connect voltages

- DC input low shut-down voltage

- 'Shut-down on SOC' option

- SOC low shutdown %

- Any 'assistants' you may be running

These settings should really be reviewed and altered if necessary by an experienced INSTALLER or DEALER - ideally after properly monitoring any related parameters live to better understand the primary cause of the disconnection/error (rather than by trial and error).

Running with the MultiPlus fully ON (inverter & charger mode) should also help - as if the incoming power supply is insufficient or limited then the inverter will assist (even if it's only temporarily to cover a high start up load). This will also not draw any additional current from your battery during normal operating conditions, as the MultiPlus will typically always be in 'charger' mode anyway.

For further reading refer to;

- MultiPlus Generator FAQ

- New VE.Configure online manual

If its found to not be setup/configuration related, then I would refer back to the dealer/service agent that completed the recent repair.

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ejrossouw avatar image
ejrossouw answered ·

Fault finding for me starts with what has changed even before the board was replaced. How old are the batteries? Also 7 years?

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pearley avatar image pearley commented ·

Batteries, 4 x 135 amp/hr are 2 years old. No problems before repair.

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pearley avatar image
pearley answered ·

Have reviewed settings via Mk 3. Will try Dynamic Current Limiter. Power Assist doesnt make any difference, Sat there watching the lights on the inverter and you can see, with for instance the iron, the mains just dropping out for 30 seconds or so then coming back on. Normally when the mains is connected the blue mains indicator flashes fof 30 seconds before the mains is established in this case there is no flashing, it just comes back.

I had thought about frequency variation but I can see no option to set it, anyway, watching the display the input frequency only varies by 0.1 hz when + or - 5hz is the default.

The thing is that for the first hour or so everythkng works ok. After that, switching on a high resistive load causes the shutdown.

If you leave the load connected when the majns comes back on line it powers everything as if nothing had happened. Could it be a temperature related problem.

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Mark avatar image Mark ♦♦ commented ·

So to confirm 100% - the issue occurs when your using a gen-set, correct?

Have you tried to/can you reproduce it with a mains/shore AC supply?

When you last tested/had the issue;

- What current did the load/iron draw?

- Was the unit fully 'ON' or in 'Charger only' mode?

- What was the AC input current limit set to?

- Did you have the UPS function on or off?

- Did you have wide AC input on or off?

- Your reply implies that dynamic current limiter was off...

- At the time of the issue, what was the approx AC voltage & was it stable?

- At the time of the issue, what was the approx DC voltage & was it stable?

This is very difficult to troubleshoot over a forum - your best bet is still to get an expert in...

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