MultiPlus rejecting generator power

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question

tom-galletti asked Aug 11, '21

MultiPlus rejecting generator power

I've got a MultiPlus set to charge a bank of 24V batteries (no inverter required).

In accordance with this: https://www.victronenergy.com/live/multiplus_faq

My charge controller is 1600VA, and my generator is 4.5kVA and AVR so should be fine. My generator is running fine, with no stuttering or difficulty starting.

These are the details for the inverter/charger:

Despite all this, the MultiPlus doesn't accept the power coming in from the generator. There are no alarms reported:

But the charger reads "Fault":

And so the AC in claims it's disconnected and at 0W:

The same is true when I move the switch to Inverting, only it claims there is no fault:

It seems when the generator runs, the batteries jump temporarily up to 28V, but then fall immediately back to about 22V, so haven't actually been charged...

Any suggestions would be greatly appreciated.

Multiplus-II Generator fault

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seb71 commented · Aug 11, 2021 at 08:45 AM

Upload here your Multiplus configuration file.

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harold commented · Aug 11, 2021 at 09:11 AM

Check your settings in VE.Config, suggestions:

Switch of the UPS function
and/or
Switch on accept wide range

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tom-galletti harold commented · Aug 11, 2021 at 09:34 AM

Unless I'm wrong I can't access VE.Config remotely and I need to buy a proprietary adapter for it?

I will test these settings as soon as I'm next at site.

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harold tom-galletti commented · Aug 11, 2021 at 10:05 AM

If your site is connected to VRM you can download the settings file, change the settings and upload it again

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seb71 tom-galletti commented · Aug 11, 2021 at 10:07 AM

How you configured your Multiplus, in that case?

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JohnC ♦ seb71 commented · Aug 11, 2021 at 01:26 PM

I suspect all is still at default. As the 16A Input Current Limit, which is the first thing I'd change (from the GX), like way down to maybe 3A for testing..

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tom-galletti JohnC ♦ commented · Aug 12, 2021 at 08:44 AM

Intuitivelly I assumed "current limit" was to avoid overloading my generator. My generator can put out about 18A at 240V so what's the logic behind reducing the input limit?

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JohnC ♦ tom-galletti commented · Aug 12, 2021 at 12:15 PM

@Tom Galletti

I did say for 'testing'. Many gensets will distort power at high amps, and most can't handle an instantaneous demand. There's a setting in the Multi called Dynamic Current Limiter, and I expect you'll need to use it.

The Multi is picky about bad power, and the rejection symptoms are as you describe. I have 2x gensets, and when I change over I need to send new settings. (Thank you VRM).

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tom-galletti seb71 commented · Aug 11, 2021 at 03:24 PM

My MultiPlus was only configured using the Cerbo GX. The site is connected to the VRM but doesn't seem to come online after a low voltage event until I powercycle the gateway (a separate issue...).

When I next visit I'll powercycle the gateway and download the settings file from the VRM. Will reupload the config file to both the MultiPlus and this forum with UPS function disabled and Wide Range acceptance enabled.

Cheers.

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seb71 tom-galletti commented · Aug 12, 2021 at 09:26 AM

How is your Cerbo GX accessing the Internet? Via Wi-Fi or via LAN cable?

Which firmware version it has?

One reason AC In (from generator) is rejected could be the 52Hz frequency - depending on how your Multiplus is configured. This is why it is very difficult to investigate without even knowing how it is configured.

A Mk3-USB interface (and VE Configure 3 software running on a PC) might also give you some clues in real-time.

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Modifications Space

Node Red Space

Answer 1 · 2021-08-12T09:18:12Z

Paul B answered · Aug 12, 2021 at 09:18 AM

Also if the above suggestions dont work I would upgrade the firmware from 430 to the latest 482 on the multiplus

Also if it still does not work then TRY turning off power assist. I have had to do this on one of my sites that kept loosing generator sync and that fixed the issue.

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Paul B commented · Aug 12, 2021 at 09:26 AM

You also Mention this "It seems when the generator runs, the batteries jump temporarily up to 28V, but then fall immediately back to about 22V, so haven't actually been charged... "

You may find that the battery voltage is going two high and thus the charger is going into fault mode and turning off (just a guess). So try another battery and test this possible issue. as The charger maybe sensing that there is NO battery there because its SO flat - or something silly like that.

if it is jumping to 28 so quickly it could sort of points to a battery fault as well. (ie it may need a very low trickel charge. Also you dont mention the battery type, If its lithium then the BMS maybe opening because of a internal battery issue.

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tom-galletti Paul B commented · Aug 12, 2021 at 11:17 AM

My batteries are all lead acid car batteries - I'll take a couple of new ones down and see if they're the issue, but I've got 8 of them so would be dissapointing if they're all dead...

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klim8skeptic ♦ tom-galletti commented · Aug 12, 2021 at 11:20 AM

Do you have a mk3 to properly program your multi?

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