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Lights Flickering After Powerwall Install [info to help troubleshoot]

In the case of a multi-wire branch circuits, Tesla did keep those two circuits together and installed them on a handle-tied breaker, which ensured that one was on the A-leg and one was on the B-leg (though they may have swapped the legs). But, other circuits were moved haphazardly from one panel to another without regard to whether they were on the A or B leg.

The very newest LED bulbs run directly on AC, without any kind of voltage step-down. Those bulbs are incredibly efficient. They generate almost no heat whatsoever, but they tend to be much more prone to flickering with voltage changes. I don't think it has to do with "cheap" versus "expensive," but rather efficient vs. inefficient.

An inefficient bulb will step down the voltage, generating heat in the process. 120 -> 118 is two volts difference at full voltage and results in a noticeable drop in light output when none of the energy is converted to heat. Stepped down to 12 volts, it's a decimal point (from 12.0 to 11.8 volts) and much of the difference is noticed in heat change, not light change. I admit that this is speculation. If anyone finds efficient, no-heat bulbs that don't flicker, I'd love to know about them.
 

wwhitney

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Nov 2, 2017
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The very newest LED bulbs run directly on AC, without any kind of voltage step-down.
LEDs always run on DC, preferably a constant current driver. Self contained LED screw bulbs fit the LED driver into the screw base and lower portion of the bulb. The flicker with AC input voltage variation is going to depend on the quality of the driver. It can be challenging to fit everything into the limited space available in the bulb.

Have you tried a high quality bulb, e.g. one from Cree? Are your bulbs CA JA8-2019 rated? The latter is sometimes labeled on the package as just Title 20 or Title 24 compliant. That standard includes a limit on flicker, although I don't know if the standard address brightness fluctuation with incoming AC voltage fluctuation.

Cheers, Wayne
 

cali8484

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Jul 8, 2018
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But, other circuits were moved haphazardly from one panel to another without regard to whether they were on the A or B leg.
If this is Tesla SOP then it's bound to cause problems.

The very newest LED bulbs run directly on AC, without any kind of voltage step-down. Those bulbs are incredibly efficient. They generate almost no heat whatsoever, but they tend to be much more prone to flickering with voltage changes. I don't think it has to do with "cheap" versus "expensive," but rather efficient vs. inefficient.

An inefficient bulb will step down the voltage, generating heat in the process. 120 -> 118 is two volts difference at full voltage and results in a noticeable drop in light output when none of the energy is converted to heat. Stepped down to 12 volts, it's a decimal point (from 12.0 to 11.8 volts) and much of the difference is noticed in heat change, not light change. I admit that this is speculation. If anyone finds efficient, no-heat bulbs that don't flicker, I'd love to know about them.

"Cheap vs expensive" and "efficient vs inefficient" may be the same as more stable designs (e.g. more voltage regulation and ride through capacitance) may require more power consuming components at higher cost that also lead to lower efficiency.
 
LEDs always run on DC, preferably a constant current driver. Self contained LED screw bulbs fit the LED driver into the screw base and lower portion of the bulb. The flicker with AC input voltage variation is going to depend on the quality of the driver. It can be challenging to fit everything into the limited space available in the bulb.

Well, this gets pretty technical, but there is a newer variant of the LED bulb that doesn't need a driver at all, and can connect directly to a household 120V AC connection. They're also sometimes referred to as "driverless" LED bulbs.

On a technical level, since a LED is a diode, it can only accept current in one direction. But, if you want to get really,
really technical, 120V AC isn't even really AC. 240V volts connections involve current that actually alternates directions, but 120V in the U.S. merely pulses on and off from the hot to the neutral 60 times per second.

So, technically, all household current is DC, and technicall, all LED bulbs use DC. But, when I talk about AC LED bulbs, I'm referring to the newer, more highly efficient driverless design that uses standard household "AC" current (which is really DC) without a driver and without a step-down transformer.

 
If this is Tesla SOP then it's bound to cause problems.



"Cheap vs expensive" and "efficient vs inefficient" may be the same as more stable designs (e.g. more voltage regulation and ride through capacitance) may require more power consuming components at higher cost that also lead to lower efficiency.

The same is often said about technological innovations that reduce costs. There's often a trade-off that causes people to label the less expensive variation as "cheap." I think that may be the case here as well.
 

wwhitney

Active Member
Nov 2, 2017
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Berkeley, CA
Well, this gets pretty technical, but there is a newer variant of the LED bulb that doesn't need a driver at all, and can connect directly to a household 120V AC connection.
The article you link to simply speaks of integrating an inexpensive driver into the circuit board with the LEDs. Notice the reference to "bridge rectifier diode," that's doing the AC to DC conversion. So it's driverless only in the sense of not having a discrete driver component that is field wired, the driver is integrated.

120V AC isn't even really AC. 240V volts connections involve current that actually alternates directions, but 120V in the U.S. merely pulses on and off from the hot to the neutral 60 times per second.
That's incorrect. 120V household power is, in fact, AC, and the current through a fixed impedance will also be AC.

Cheers, Wayne
 
The article you link to simply speaks of integrating an inexpensive driver into the circuit board with the LEDs. Notice the reference to "bridge rectifier diode," that's doing the AC to DC conversion. So it's driverless only in the sense of not having a discrete driver component that is field wired, the driver
is integrated.

Where in the article does it say that? From the article:

While not prominent in the marketplace yet, Driverless LED light systems are starting to gain traction. AC driverless LED bulbs can be directly plugged into AC mains without an LED driver needed. This eliminates the power loss experienced during the AC to DC conversion, in addition to taking out one of the costs in manufacturing the LED. As mentioned above, one of the biggest considerations is the flickering caused in older LED lights, which can generally be attributed to the old LED driver circuits.

Driverless LED lights are powered by an AC LED light engine, which converts the electrical energy to the lumens of the light. These AC LED light engines can be a circuit board with LED chips mounted in it, allowing it to be easily affixed into an AC socket.
 
Here's an article that describes in detail the various kinds of "driverless AC" LEDS and the tradeoffs that are made with the different circuit topologies.

Yeah, that first article was a little vague and confusing, seemed like it was just moving the driver onboard with the LED (much like compact CFL's (remember those?) moved the fluorescent ballast from fixtures to onboard the bulb). This one was more explanatory, I guess what we used to consider the LED "driver" they now call the "light engine", with the old light engine designs being termed "drivers" and the new designs "driverless".

Anyways, cool how they're continuing to up the efficiency and brightness of LED's, not just with newer and brighter LED diodes, but with better AC-DC conversion. Makes sense now how a few years ago I wasn't able to find good, bright LED bulbs in tiny MR16 form factor to retrofit into my 4" recessed overhead lighting, I tried so many and they also ran really hot; but last year finally found some excellent ones on Amazon that seem at least as bright as the 50W halogens they replaced. Also probably the reason so many of the newer ones are non-dimmable, it's because of these efficient "driverless light engines".

So I finally replaced all the recessed overheads on non-dimming switches with MR16 LED "bulbs" about a year ago, not a single bulb has failed; so just ordered more of the same and will replace the ones on dimmers (will sacrifice use of the dimmer functionality and run them full brightness).

EDIT: Oh, and speaking of CFL ballasts, last hurdle are the special energy efficient CFL recessed can housings that were be put in on my laundry room and balcony. Tried using socket adapters on the special CFL sockets, but couldn't find any LED bulbs that would work because CFL ballast hidden deep in the bowels of housings.
 
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wwhitney

Active Member
Nov 2, 2017
1,117
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Berkeley, CA
Also probably the reason so many of the newer ones are non-dimmable, it's because of these efficient "driverless light engines".
FWIW, that wouldn't comply with the CA energy code in many locations within a house, where dimming is required. Also I am somewhat doubtful that the tradeoffs discussed in the article would allow compliance with the CA energy code's JA8 standard for LED performance. Something to be aware of for new construction or major remodels; still likely a win to replace an incandescent bulb with a "driverless" LED.

Cheers, Wayne
 
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wwhitney

Active Member
Nov 2, 2017
1,117
1,482
Berkeley, CA
The two paragraphs after the ones that I quoted were referring to "initial attempts" and "the next attempt", and not to the current products that were discussed before those paragraphs.
Yes, but the subsequent attempts retained the features previously mentioned, and the upshot is just that the driver is moved onto the LED circuit board. The parts they are talking about adding are the normal parts of a driver.

Cheers, Wayne
 

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