Trying to deeply investigate LED pulsing flickering with HF off-grid inverters

[Quattrohead]

I have setup my new home panel with the lighting on separate breakers from everything else precisely for this very reason. But I am hoping that the EG4 18k PV will have the same regulation performance that we are seeing with the 6000 XP.
I don't mind the brief dip that you see when a heavy load kicks on even on utility but it is the nervous flickering lights that I don't like.

 

[Brett V]

My experience is it depends on the lamp. I have approximately 30 LED lamps branded GE Lightstick that are a soft white, indistinguishable from 60 watt incandescent bulbs. Whether on the grid or running on solar from a Growatt SPF 12000T, they never change brightness or even blink when switching from grid to solar or when heavy loads kick in such as the well pump or air conditioning. I have a friend who is hyper sensitive to LED lighting but can't tell these aren't incandescent bulbs. They are not dimmable but I've had them in my home for about 8 years and not a single one has failed. They're expensive but seem to be a one time investment. https://www.amazon.com/GE-Bright-St...703385715&sprefix=ge+lightstic,aps,97&sr=8-10

 

[sunsurfer]

more and more I think I will focus on DC led lighting going forward.

 

[Checkthisout]

more and more I think I will focus on DC led lighting going forward.

They make some super cool fixtures for 12v.

 

[rhino]

My experience is it depends on the lamp. I have approximately 30 LED lamps branded GE Lightstick that are a soft white, indistinguishable from 60 watt incandescent bulbs. Whether on the grid or running on solar from a Growatt SPF 12000T, they never change brightness or even blink when switching from grid to solar or when heavy loads kick in such as the well pump or air conditioning. I have a friend who is hyper sensitive to LED lighting but can't tell these aren't incandescent bulbs. They are not dimmable but I've had them in my home for about 8 years and not a single one has failed. They're expensive but seem to be a one time investment.

View attachment 184816

Can you provide a correct link?

 

[Brett V]

Can you provide a correct link?

Thanks. The insert link always seems to give me problems.

 

[SparkyJJO]

Most of this way above my head but what about a small high quality pure sine inverter dedicated to the lighting? Did I read correctly that the problem is worst when the inverter barely loaded? You can probably run every LED light in most houses on something like this 375 VA inverter from Victron. Ignoring that hassle of rewiring would something like this make sense?

A problem is when some of the lights are not on dedicated circuits (plug in lamps etc) hard to split all lighting off to a different inverter.

I think it we all just stuck with good LF inverters we wouldn't have this problem lol.

 

[hwy17]

10 years ago the LED bulbs I was buying were these heavy Philips bulbs where the whole base was a heat sync. They're still going, never flicker, etc.

Nowadays they weigh less than an incandescent, flickering, and burn out about as fast as incandescent.

 

[OzSolar]

A problem is when some of the lights are not on dedicated circuits (plug in lamps etc) hard to split all lighting off to a different inverter.

I think it we all just stuck with good LF inverters we wouldn't have this problem lol.

I know.... I should have mentioned that it would be a challenge is most cases, (I've been an electrician for many years)

 

[fmeili1]

deleted

 

[fmeili1]

Would a single resistive load (like an incandescent light bulb) somewhere in the system do the trick?

Maybe like a 25 watt draw?

I've tried different loads and the pulsing goes away if I use a resistive load of about 300W-350W. Lower loads does not stop the pulsing.

 

[fmeili1]

I'll try to show some schematics to make the problem more "visible".

Btw. I will use the wording "dirty" load for loads which interact in a negative way with the HF inverter to make some LED loads pulsing.

This may be a typical example situation:


There are one or more split phase inverters (in my case 3 in parallel for L1 and 3 in parallel for L2). Typically there are different type of 120V loads (Load1-Load4) distributed over the two phases and some 240V loads (Load5 and Load6) connected. The loads are a mixture of resistive, capacitive, inductive characteristics (motors, lamps, electronic equipment, etc. everything which is possible in a typical house).

Let's assume that as soon as Load2 is connected and it is a "dirty" load which causes the "LED Load" to pulse (other LED loads on the same phase may not pulse because they may have better build quality).

Now I ask myself if it's possible to put a filter in front of the "dirty" Load2 like shown in the following picture to stop the pulsing of the "LED Load" (to stop the 3-7Hz interference oscillation between Load2 and the HF inverters which causes the "LED Load" to pulse).


It may also possible to put a "generic" filter just at the output of the inverters to stop any kind of LED pulsing (on the same phase) from whatever "dirty" load it may be produced, like this. This would be the optimal solution because one filter for each phase would be enough instead of one filter per "dirty" load.



I'm pretty sure that any "dirty" load is a bit different but because the pulsing is always between about 3-10 Hz, a generic filter may be possible - but not sure.

About all your suggestions and answers, I'm still not really sure how an RC filter in this situation should look like. I assume this picture...


So to summarize some of your comments, the Capacitor C1 must not be an polarized (because of AC) and it should be a foil type to be reliable and longer lasting. The Resistor R1 should have an extremely low value or it should better be 0Ω because it would heat up with higher loads. I think R2 would be required to reduce the current through the capacitor.

Which values would you choose for C1 and R2 (and possibly R1 if not zero)?

 

[AntronX]

This is better.

 

[Steve_S]

I just caught up on this thread.... Gotta toss something in here.

I run Samlex EVO LF Inverter/Charger. LF because it handles my well pump, compressor, MIG Welder & more and never any flickering or noise on the 120VAC line. If Charging from Genset, Pure Sine Inverter type, again No issues, no flicker or noise. If Charging from my Big Construction genny (not inverter) the EVO passes the sinewave through and there is some flicker & noise. You can actually hear motors (fridge, freezer etc) "grumble" and LED's (cheapo's not the Phillips or EcoSmarts) do flicker terribly. The cheapo "Walmart"ones actually BUZZ, tossed them fast.

Finished a new offgrid solar install for a neighbour on the 23rd. I installed a different LF Inverter for him, a Value Grade 3024 (identical to an AIMS 3000W/24V LF model) and he has a "filthy" 15 year old Basic Genset... Oi, it floats from 100V to 125V and frequency floats from 52Hz to 67hz... okay, it is quite fugly, the Pure Sine inverter still passes that mess through and I have Never Ever seen such horrible flicker, even with low watt incandescent.

Inverters/AIO's when taking "non-grid" power are subject to whatever the AC Source is putting out, they will NOT fix the sine wave or clean it up. HF Inversion is Hyper Sensitive and in a sense delicate - it is really NOT intended for motors & heavy devices unless way over built and that would push their costs above LF Inverters. LF Inverters with the large capacitors & Torodial Coils are designed to handle light to extreme & even "hard" loads like motors, this is also why they can handle 3X surge vs HF's 2X surge.

HF systems are attractive for ONE Reason - COST ! They are Cheaper & Lighter than LF.
Sadly, this is where "Dollar Wise & Penny Foolish" comes into play!. Spend the $ and get LF and suffer No Issues with all gear in your home or save a few pesos and suffer issues, especially if "motor heavy" with Big AC, Fridges, Freezers & Pumps, let alone Commercial/Industrial applications. FYI, if you look at Industrial Solar Systems, they are ALL Low Frequency.


Good article that sums it up.

Inversion Methods Explained: High Frequency vs Low Frequency | Magnum Dimensions

Understand the difference between high frequency and low frequency inverters with this quick article.

www.magnum-dimensions.com

 

[AntronX]

This not going to work. It's a low pass filter. I don't think high pass filter will work either.

 

[fmeili1]

This is better.
View attachment 185018

The drawback for this solution would be to place a filter in front of every pulsing LED. In my situation we have 9 ceiling fans with integrated LED lights and they all pulsing. So it would be nice to find a filter in front of just the (one) "dirty" load or a global filter directly on the phase (where the "dirty" load is connected) to stop all LED's to pulse.

 

[AntronX]

Your filter will have to pass the current of all 120V and 240V loads. Not good. Forget this whole filter idea and instead split off all your flickering loads to separate panel and power them from clean 120V inverter.

 

[fmeili1]

Your filter will have to pass the current of all 120V and 240V loads. Not good. Forget this whole filter idea and instead split off all your flickering loads to separate panel and power them from clean 120V inverter.

I still have hope to find a simpler solution.

What do you think about putting an isolating transformer in front of the dirty load which may reduce the interference between the inverter and the "dirty" load?

My "dirty" loads have a max. of 100W (old slot machine) and 300W (my 3D printer) so these would cost not very much. Maybe I should give my "diry" 100W load a try.

 

[AntronX]

You are looking to fix this problem from wrong end. This problem is caused by poor voltage feedback loop design inside the inverter. No amount of tinkering on the outside will fix that. You can try bruteforce way of rectifying to DC like I suggested earlier but that requires adding those rectifiers in front of every LED light which is a lot of work. Much easier to add small 800VA Victron LF transformer inverter and a sub panel.

 

[Steve_S]

Your filter will have to pass the current of all 120V and 240V loads. Not good. Forget this whole filter idea and instead split off all your flickering loads to separate panel and power them from clean 120V inverter.

AND there is the "Penny Wise & Dollar Foolish" part coming up... Buying HF instead of getting LF.

Filters have been tried by many, the result was never as hoped. Many here tried filters & conditioners & failed - some of it is in threads.
I am sorry BUT do not shoot the messenger... You are free to explore it and chase the proverbial tail while spending cash but it will never be what you expect.

1 quick test, go out and get a High Quality Phillips or Sylvania LED light bulb.... These are pretty much the Best retail residential bulbs currently available and they do have better electronics.

Sadly, the reality is that people look at the $ and see a 5000W HF for $1000 and a 5000W LF for $1500 and they do not pass "think about why" and buy the $1K unit because it's "better cause its cheaper". Fine if all you run is digital like computers etc but No Motors or other Inductives.