question

Hi @Alistair Warburton

Try turning off 'Weak AC' if you can get away with it.

See also this thread and my answer there: https://community.victronenergy.com/questions/67792/generator-not-charging-batteries.html?childToView=67797#answer-67797

This fellow doesn't say re Weak AC, but you'll likely see similarities with your issue (and mine).

I tried 'Weak AC' Off but it then has issues maintaining sync, or even recognising AC for that matter. When it connects, usually after a couple of attempts, it will drop out again when the passthrough load alters.

Its a little better with Wide VF on but to be honest I have mucked about with several combinations of settings and nothing seems to give a charge above kW

Wide and UPS are currently OFF, Weak is ON

Theoretically

Al

I would like to clarify what is actually going on...

I anyone knows what limitations the charger has please feel free to let us know or point to a spec. Anticipate conversion loss and and limits based on power quality woud be nice as a start...

It cant just be an efficiancy thing or I would be seeing just shy of 4kW on the DC whilst the genny was loaded up well beyond that.

Interestingly I do see 500W-600W of 'losses', when looking at reported power which I attributed to power factor. Although now i think about it I dont actually know if that figure is W or VA in actualiy.

I suppose what I am getting at is that I dont know much and feel that I need to...

Any and all help would be apriciated, I am struggling to believe that I/We are the only two folk seeing this or even that it isnt documented somwhere!

Cheers,

Al

Just a quick update... I have been fiddling.

'Weak AC' is defiantly introducing a hard limit at about 2kW into the battery.

Turning it off introduces loads of noise into the control loops for both battery and generator current and the oscillation eventually upsets the 'system' enough to cause the charger to drop out.

I managed to get several minutes of charge at 2.5-3kW by carefully tweaking both AC and DC current limits and setting the systems target AC voltage to a value closer to the genny output.

The dynamic current limiter seems to help rather than hinder as I thought it might but honestly the entire thing is unstable when weak AC is off.

I suspect that the issue is harmonic distortion messing with the instrumentation which then destabilises the PID loops but that is just a guess. If it was a PLC doing something in the world that was behaving like this I would be looking at filtering the PV, process Variable not solar :-), or getting rid of the noise on the item being measured/controlled.

I happen to have some big ferrite cores kicking about so I may try a common mode choke and a couple of reactors with a cap between them on the AC to see if I can decouple whatever nonsense is messing with the charger input and or the AVR.

Of course I have no idea how many turns will work if the plan has any merit in the first place so I will likely go with 'some - whatever I can get on there' turns as opposed to trying to be any cleverer.

The cores are about 80mm Dia with a 20X20 cross section, just in case anyone can shed light on an actual design.

Please feel free to tell me if I am missing something or just talking rubbish... I will learn eventually with a bit of a leg up.

Cheers

Al

Update.... The bodge sort of works, not perfect by any means but far better.

I tried several configurations, classic filter with wo chokes and a cap between them was my first attempt and it didnt help much at all.

In fact a cap anywhere seeemed to generally upset things, audably, although a couple of configurations stabilised both AC and DC current whils it was connected.

I have ended up with a choke in both L and N, not coupled, and that is making a big difference, all be it far from perfect.

Weak AC is off as is dynamic A limit. AC limit is set to limit th genny to about 4kW give or take and the battery is now taking its full 70A when the base load allows.

I think the chokes are around 12mH each but as the cores were scrounged up I cant be sure of the permiability so that could be an over estimation.

I have just wound a common mode choke on a core half the section which I will try on the inverter side of the two units I have in now...

If anyone can suggest some actual values / arrangement that will be optimal I would be very interested... Electrical design by tinkering is seldom a good plan I know, but I seem to be moving in the right diredtion.

I just cooked tea... 2kW induction hob and the fan oven cycling between 750W & 1;5kW... Another 600W or so elsewhere and it went in and out of assist and bulk without much of an issue.

Feel free to tell me how to do this properly if I am missing a point somwhere. I am not saying this is the right aproach or even a good one. It is however the only one I could think of without aditional kit.

Any and all comments welcome as always.

Al

Started a new more targeted thread...

Power quality, from generator, limiting charge... Solutions?

Started a naw thread...

Power quality, from generator, limiting charge... Solutions?