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Multiplus Intermittent Overload alerts on shorepower

Hi, I've tried to word this question several times and never get an answer. I'll try again.

I have 3000/12/120 (230) MP connected to 400ah lithium bank and 2000W Isolation Transformer.

I'm getting an issue with high loads (well within the limits) when on shore power (I have the multi control limiter set to 8.0A to be conservative).

So for example 9 times out of 10 when the kettle (2000w) is turned on it's fine. However every now and then you see the red overload light flash and I get an email alert via VRM emailed to me.

I've tired with shore power off and never get this on just the inverter alone, so I think there is an issue with power assist, but no one can confirm or deny that, so I'm a little stuck.

Planning long term cruise on the boat, so don't feel happy with this - even though I won't be using shore power much. I would like to know the MP has no gremlins before I set sail.

Hope someone out there can help with this!

I've checked all of the maximum power inputs on my appliances and the highest is the microwave oven that can pull 2600W. I think the max peak on the MP is 6000W, so with shore power on I don't see why I'm getting this over load warning.



MultiPlus Quattro Inverter Chargershorepower
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Try a firmware update. There seems to be a lot of discussions about the spurious overloads recently. Firmware 481.

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Paul B answered ·

Hi, I dont think there is a fault in the Multiplus, but its still worth trying to find the real cause.

the overload warnings can occur for many reasons and they will show if you go over the units base rating not the max overload ie 6000

The below are some comments that may or may not help, and others may have diferant ideas as well.

note that a 3000Va inverter is not a 3000 watt inverter it all depends on the Power factor at the time.

1. The 3000VA rating is at 25 deg so if the unit is at say 40 deg then the warning could start at say 2000va or lower.

2. also if the battery voltage drops and the current rise's then it can also occur.

3. does it happen when you are using your generator ???? as well

4. another is whats the incoming AC voltage at the time, especially coming into the multi if you have a long power cord etc

5. you may want to check the power factor also especially when the shore power is connected as the incoming power factor maybe a possible cause.

set the vrm to 1 min updates and see if you can see any power spikes

updating the firmware as suggested in a prior post is a possible solution, so thats worth a try.

but really to fully isolate the issue you need to be able to duplicate it and thus you can then work out the cause, measure everything you can

Watts and VA ratings can differ significantly;

with the VA rating always being equal to or larger than the watt rating. The ratio of the watts to VA is called the “Power Factor” and is expressed either as a number (i.e. – 0.8) or a percentage (i.e. 80%). This power factor is what really matters when sizing a Inverter for your specific requirements and it also then affects when a inverter warning would occur.

a 1:1 power factor is when the volts and amps are in sync in the 60hz sign wave you get out of the inverter and it should be the same on shore power as well. but this can drift a lot especially when you are receiving bad shore power, and depending on the appliance you are using.

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