New pure sine wave inverter causing led light pulsation / flicker ... Help?

[blacklake]

Hey guys. So I just replaced my modified sine wave inverter at my cabin with a pure sine wave one and it is causing all the led bulbs to flicker. Ironically this did not happen when I had the modified sine wave inverter running for past couple years.

I basically built the same 2000w 24v system following one of Will's videos. Everything remains the same except I've changed out the inverter type now to a pure since wave. With the new inverter connected, l am getting an annoying flicker in the cabin lights. This happens with no other load on the inverter except the two or three bulbs. Is it possible I just got a bad inverter? From my reading over past few days, this issue can sometimes happen with modified sine wave inverters which is why I am really puzzled. I expected the pure sine wave to be an upgrade! The brand is Novopal 24v 2000w pure sign wave inverter off Amazon.

 

[billt1827]

It's possible that the inverter's output voltage isn't stable. Some LEDs seem to be very sensitive to voltage fluctuations, when my batteries are full some of my LEDs flicker.

You could try adding a more substantial load, that can sometimes stabilise things.

 

[Lt.Dan]

It sounds like with only 2 or 3 LEDs, the inverter is having a hard time with such a small load. Maybe it is going in and out of a sleep/eco mode? Try turning on just another 10-15w and see if the problem goes away

 

[blacklake]

It sounds like with only 2 or 3 LEDs, the inverter is having a hard time with such a small load. Maybe it is going in and out of a sleep/eco mode? Try turning on just another 10-15w and see if the problem goes away

Ok ill give that a shot

 

[RCinFLA]

AC voltage flickering on all-in-one HF inverters is usually caused by PV SCC and battery charging. If the internal high voltage DC supply varies too much during charging and PV sourcing, it can clip the sinewave voltage peaks on AC output.

Since most LED lights are just simple rectifier-filter capacitor for AC to DC conversion, they are very sensitive to sinewave peak voltage of AC input.

 

[blacklake]

AC voltage flickering on all-in-one HF inverters is usually caused by PV SCC and battery charging. If the internal high voltage DC supply varies too much during charging and PV sourcing, it can clip the sinewave voltage peaks on AC output.

Since most LED lights are just simple rectifier-filter capacitor for AC to DC conversion, they are very sensitive to sinewave peak voltage of AC input.

Any idea why there wasn't the same issue when running with the modified sine wave?

 

[blacklake]

It's possible that the inverter's output voltage isn't stable. Some LEDs seem to be very sensitive to voltage fluctuations, when my batteries are full some of my LEDs flicker.

You could try adding a more substantial load, that can sometimes stabilise things.

Thanks I'll give this a shot. If that turns out to be the case, it's a bit disappointing as some nights we might only have a light or two on.

 

[efficientPV]

The individual LED are usually placed in series. That makes like a big zener creating a large offset voltage. In turn that makes every voltage change exaggerated. I have a trick I use for a hall light. Across the light switch I put an .047uF capacitor. That provides enough leakage current to just barely light. Makes a nice night light and consumes less than a fraction of a watt. Depending on the switch I have a nite light or full power. It has a noticeable flicker on grid power as voltage varies. Not all LED lamp will do this. Some will not work at all, while others will flash on and off at a slow rate making nice Halloween or emergency light for first responders. The solution may be to change brands of lamps.

 

[Hedges]

Any idea why there wasn't the same issue when running with the modified sine wave?

HF sine wave inverter architecture may be forcing current to achieve a voltage (into a load), has regulation issues.

HF modified square wave inverter runs a PWM ratio to achieve target HV rail, then switches H-bridge to make output waveform. Under light load, its boost converter would be in discontinuous conduction mode, maybe would still vary. But into bulk caps which smooth it.

LF modified square wave inverter just pulls transformer winding to battery voltage, no attempt to regulate.

 

[RCinFLA]

The sinewave PWM H-bridge chops the HV DC then filters it through a toroid inductor and capacitor. When the HV DC changes due to a load current, the PWM must modify its PWM cycling to compensate for lower or higher HV DC. The HV DC must never slump below the level required for peak of sinewave waveform (plus some PWM switching device loss) or it will clip the sinewave output peak.

The HV DC is fed from Battery to HV DC converter and PV SCC controller. Typically, 250-280vdc for 120vac output inverters and 450-500vdc for 230vac output inverters.

The sinewave AC output voltage has a feedback control circuit and lookup table to make the PWM modifications when HV DC changes. This takes a little reaction time to correct the AC output voltage fluxuations due to HV DC bounce.

Greatest disruption is when HV DC sags below the level necessary to support the peak voltage of sinewave output. Result is a clipping of sinewave peaks. This happens on an inverter-generator in ECO mode when rpm's has been reduced based on existing load and then a sudden load is applied. There is a momentary clipping of sinewave output while engine rpm speeds up to supply the additional load.

 

[Lilikoi_Heavy_Industries]

My reliable WZRELB 12v 2000w (pure sine) inverter starts doing this when the DC voltages start hitting around 14.6 if I remember correctly. Stopped using it and moved to 48v instead. I might try using that inverter with some lithium batteries in the future, because it definitely couldn't handle being turned on for a lead acid equalization.

It has a little red light that flickered when it hit this condition, next to the power LED

 

[MajicDiver]

Hey guys. So I just replaced my modified sine wave inverter at my cabin with a pure sine wave one and it is causing all the led bulbs to flicker. Ironically this did not happen when I had the modified sine wave inverter running for past couple years.

I basically built the same 2000w 24v system following one of Will's videos. Everything remains the same except I've changed out the inverter type now to a pure since wave. With the new inverter connected, l am getting an annoying flicker in the cabin lights. This happens with no other load on the inverter except the two or three bulbs. Is it possible I just got a bad inverter? From my reading over past few days, this issue can sometimes happen with modified sine wave inverters which is why I am really puzzled. I expected the pure sine wave to be an upgrade! The brand is Novopal 24v 2000w pure sign wave inverter off Amazon.

I used to have a problem with my LED lights flickering in my basement. This only happened at certain times and was when weather was mild. And, only in daytime because that’s the only time I’m in it. After I installed solar and connected my grid-tie inverter the problem has completely disappeared. I attribute the problem to sagging utility voltage during low load periods when they have nearby generators off line and power is coming in from further away. The slight amount of local (house) voltage support provided by the gridtie inverter must be enough to stop the flickering- that’s my strong suspicion anyway. That leads to my suggestion to you: If your off grid inverter allows you to adjust voltage you might try increasing very slightly a little at a time- of course monitor it and stay within the normal voltage range but higher in the band.