Generator and Weak AC questions

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wnoeth asked Nov 19, '22

Generator and Weak AC questions

I own a generator (BXGND6300E diesel with AVR) which like many others is only accepted by my
Multiplus 2 48/5000 if Weak AC is selected in VEConfigure.

I have read the generator FAQ and have experimented with different settings on the Multiplus as well as a stabilizing load (400W construction light) on the generator parallel to the Multiplus connection,
but the output of the generator seems to be of too low quality for the charger.

Here are my questions:

1. With Wéak AC the generator shows a load of 2.800W while the Multiplus charges the battery with only 2.000W.
There is no other load connected to the generator or the Multiplus AC out. That means that 800W disappear somewhere inside the Multiplus. It is also running quite noisy in that configuration.
That cannot be a healthy state for the Multiplus. Is this not detrimental to the inverter / charger?

2. I do not think I can configure the Multiplus to accept the generator output as it is (without Weak AC).
So I want to improve the generator output, might be possible since the generator itself is quite powerful.
To do that however, I must know, what is the problem with the generator voltage / frequency.
Where can I get that information in my Victron system (Cerbo GX, Multiplus 2 48/5000, 2x Pylontech US3000C)?

Thanks in advance,

Winfried

Multiplus-II Generator

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Answer 1 · 2022-11-19T22:00:32Z

Kevin Windrem answered · Nov 19, 2022 at 10:00 PM

I believe Veconfig may provide an indication of state of the incoming AC power and help diagnose your problem. Unfortunately, there is no indication on the GX device and IIRC nothing in VictronConnect either.

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Answer 2 · 2022-11-20T06:43:34Z

JohnC answered · Nov 20, 2022 at 06:43 AM

Hi @WNoeth

1. The Weak AC setting fools with the Power Factor, so your 2800W is actually VA. No unusual lost energy. The Multi applies this itself, so it shouldn't hurt. But it's not a great place to be, as it also limits the power. You may also find some loads like fans might change tone too on gen passthrough.

2. The V and Hz you can see in the GX..

From memory the ACIN shows even under rejection, but not something easy to confirm for you.

*Warning- Anecdote*. I once suffered this, until I changed out the plugin powercord from the genset to a heavier wire, custom length one. Problem gone! Investigation revealed signs of heating in one of the plugs of the old cord, a 'dry joint'. So the issue may well extend further than just the genset.

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Answer 3 · 2022-11-24T16:59:46Z

gr0mit answered · Nov 24, 2022 at 04:59 PM

I am having the same issue. Strange thing is that as soon as I connect the input to the grid again, it charges at the full 4.3 Kw. So what is it about the genny output that the victron doesn't like? I've got a 10kva generator and have a ballast load on the generator of a 1 kW electric heater. Anyone else finding this?

Cheers

Tim

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JohnC ♦ commented · Nov 25, 2022 at 06:24 AM

@gr0mit

There's usually a reason. So I went back through some of your previous posts to see what kit you may be running. Mightn't be yours, but I saw mention of multiple phases and ESS. If those in play it could be anything. To pursue it, perhaps best to start a fresh question and tell us everything.

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Answer 4 · 2022-11-25T10:14:55Z

stubbs answered · Nov 25, 2022 at 10:14 AM

I have the same issue; to an extent. Single Ph 230v Quatro II. Adj' the AVR to 241v and Run/Gov. Speed to 51Hz. Getting 3.8-4.1kW now Should be ^</₌5kW @75% Gen. Power.

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