Hi Everyone,
I had two Powerwalls installed in early 2021 and since then have experienced quite a few flickering issues. Some happened even when I was on grid power, and some happen when I was timeshifting (powerwall supplying power with the grid up), and some only happen when I'm totally off-grid on powerwall only. I've gotten most of them resolved, but am still hunting down one of them. I wanted to share my experience and what I've learned so that it might help others who come along after me. Here's what I've learned:
Residential service in the USA is delivered as 240 volts at 60 hertz. The voltage is delivered on two 120-volt legs. For convenience, I'll call them the "A" leg and the "B" leg. In a typical electrical panel, each set of two breakers alternates between the A and B leg. In other words, the first two breakers are pulled off the A leg. The second two breakers are pulled off the B leg. And so on.
When Tesla installs your Powerwall (and Solar system), they move many (sometimes all) of your circuits to a sub-panel. When they do this, they pay no attention to which leg the circuits were on before. That is to say, if your LG washing machine was on the "A" leg and your bathroom lights were on the "B" leg on your main panel before Tesla showed up, when Tesla moves those circuits to a sub-panel, they might just put them both on the "A" leg. This means that your washing machine and your bathroom lights were previously not sharing a 120-volt feed from the power company, but they are now.
Newer LED bulbs are very sensitive to voltage fluctuations. The more efficient the bulb, the more likely it is to flicker with even a slight voltage change. Older LED bulbs had transformers in them that stepped the voltage down and which converted some of the energy to heat. They were pretty resilient to voltage fluctuations. But, the very newest bulbs appear to run directly on 120 volts. These bulbs are the most likely to experience flickering when there is even a slight voltage change. The flickering is most noticeable when the voltage fluctuates down and then back up (or up and then back down) nearly immediately.
Many devices in your home can generate momentary, but substantial energy draws that can cause the voltage to temporarily drop on the same circuit, and even on adjacent circuits on the same leg. The most common culprits I have found in my house are my LG washing machine (especially when it is on the agitate cycle), my laser printer, my Toto bidet toilet seat, and my electric space heaters.
When a large load kicks on the same circuit, this can cause a voltage drop. If the load is large enough, it can even cause a voltage drop on adjacent circuits on the same leg, though the drop will not be as large. When you're on grid power, additional power will rush in and raise the voltage back up quite quickly. If you're on Powerwall, it takes a bit longer.
And this is one of the reasons that we can experience flickering on newer, highly efficient LED bulbs once a Powerwall is installed. Even when you're on grid power, if Tesla moved a noisy device (like your LG washing machine or a laser printer) to the same **leg** as your highly efficient bathroom lights, then the bathroom lights may flicker when your washer is agitating or when your printer is printing. This can happen even when they are on different circuits. The problem can be worse when you're off-grid, but it can occur even when you're using grid power. The solution, if you care about it, is to move the circuits back to separate legs.
There can be other causes of flickering. When you're on Powerwall power and the powerwall is more than 97% charged, the powerwall starts out generating power at 66hz, and not 60 hz. It does this in order to tell your solar panels not to generate any power. It does this even if you don't have solar panels. This can cause some UPS devices to believe that the power is unreliable and to use the batteries instead of relying on the powerwall supplied power. You can call Tesla and ask them to change this to a lower frequency if you want. I changed mine to 62 hz. I have found that once the Powerwall gets below 98%, it reverts to 60 hertz. Some have reported that the Powerwall's initial tendency to produce a higher frequency power when its power level is above 97% can cause flickering, especially with older dimmer switches. I have found that certain older dimmer switches do have issues when off-grid, but didn't find that it made any difference whether the frequency was at 60hz or higher. Eventually, I just replaced the dimmer switch with a newer LED compatible switch and the problem went away.
There's also the possibility of a loose neutral (or a shared neutral) causing issues. When I first started experiencing problems, I used an Ideal 61-164 to check my house for loose neutrals and couldn't find any.
I did, however, find a shared neutral. Finding a shared neutral is a major PITA, but it is worth doing as it also causes massive EMF fields in your house (if you're worried about that sort of thing) and it can electrocute someone in very rare cases. The easiest way to find if you have a shared neutral is to shut off the main power at your main breaker, and then pull one neutral off the main panel at a time, and check that neutral for continuity against the neutral bus. If there is continuity, that neutral is tied to another neutral on the bus somewhere in your house (and it shouldn't be). Put that neutral back on the neutral bus, remove the next one, and check it. Once you find the neutrals that are shared, you have to hunt down where they are shared. It's usually in a breaker box that has multiple circuits (such as a gang of light switches that are served by different circuits).
I hope this helps someone else. If anyone else has any suggestions on addressing flickering, I welcome comments below.
I had two Powerwalls installed in early 2021 and since then have experienced quite a few flickering issues. Some happened even when I was on grid power, and some happen when I was timeshifting (powerwall supplying power with the grid up), and some only happen when I'm totally off-grid on powerwall only. I've gotten most of them resolved, but am still hunting down one of them. I wanted to share my experience and what I've learned so that it might help others who come along after me. Here's what I've learned:
Residential service in the USA is delivered as 240 volts at 60 hertz. The voltage is delivered on two 120-volt legs. For convenience, I'll call them the "A" leg and the "B" leg. In a typical electrical panel, each set of two breakers alternates between the A and B leg. In other words, the first two breakers are pulled off the A leg. The second two breakers are pulled off the B leg. And so on.
When Tesla installs your Powerwall (and Solar system), they move many (sometimes all) of your circuits to a sub-panel. When they do this, they pay no attention to which leg the circuits were on before. That is to say, if your LG washing machine was on the "A" leg and your bathroom lights were on the "B" leg on your main panel before Tesla showed up, when Tesla moves those circuits to a sub-panel, they might just put them both on the "A" leg. This means that your washing machine and your bathroom lights were previously not sharing a 120-volt feed from the power company, but they are now.
Newer LED bulbs are very sensitive to voltage fluctuations. The more efficient the bulb, the more likely it is to flicker with even a slight voltage change. Older LED bulbs had transformers in them that stepped the voltage down and which converted some of the energy to heat. They were pretty resilient to voltage fluctuations. But, the very newest bulbs appear to run directly on 120 volts. These bulbs are the most likely to experience flickering when there is even a slight voltage change. The flickering is most noticeable when the voltage fluctuates down and then back up (or up and then back down) nearly immediately.
Many devices in your home can generate momentary, but substantial energy draws that can cause the voltage to temporarily drop on the same circuit, and even on adjacent circuits on the same leg. The most common culprits I have found in my house are my LG washing machine (especially when it is on the agitate cycle), my laser printer, my Toto bidet toilet seat, and my electric space heaters.
When a large load kicks on the same circuit, this can cause a voltage drop. If the load is large enough, it can even cause a voltage drop on adjacent circuits on the same leg, though the drop will not be as large. When you're on grid power, additional power will rush in and raise the voltage back up quite quickly. If you're on Powerwall, it takes a bit longer.
And this is one of the reasons that we can experience flickering on newer, highly efficient LED bulbs once a Powerwall is installed. Even when you're on grid power, if Tesla moved a noisy device (like your LG washing machine or a laser printer) to the same **leg** as your highly efficient bathroom lights, then the bathroom lights may flicker when your washer is agitating or when your printer is printing. This can happen even when they are on different circuits. The problem can be worse when you're off-grid, but it can occur even when you're using grid power. The solution, if you care about it, is to move the circuits back to separate legs.
There can be other causes of flickering. When you're on Powerwall power and the powerwall is more than 97% charged, the powerwall starts out generating power at 66hz, and not 60 hz. It does this in order to tell your solar panels not to generate any power. It does this even if you don't have solar panels. This can cause some UPS devices to believe that the power is unreliable and to use the batteries instead of relying on the powerwall supplied power. You can call Tesla and ask them to change this to a lower frequency if you want. I changed mine to 62 hz. I have found that once the Powerwall gets below 98%, it reverts to 60 hertz. Some have reported that the Powerwall's initial tendency to produce a higher frequency power when its power level is above 97% can cause flickering, especially with older dimmer switches. I have found that certain older dimmer switches do have issues when off-grid, but didn't find that it made any difference whether the frequency was at 60hz or higher. Eventually, I just replaced the dimmer switch with a newer LED compatible switch and the problem went away.
There's also the possibility of a loose neutral (or a shared neutral) causing issues. When I first started experiencing problems, I used an Ideal 61-164 to check my house for loose neutrals and couldn't find any.
I did, however, find a shared neutral. Finding a shared neutral is a major PITA, but it is worth doing as it also causes massive EMF fields in your house (if you're worried about that sort of thing) and it can electrocute someone in very rare cases. The easiest way to find if you have a shared neutral is to shut off the main power at your main breaker, and then pull one neutral off the main panel at a time, and check that neutral for continuity against the neutral bus. If there is continuity, that neutral is tied to another neutral on the bus somewhere in your house (and it shouldn't be). Put that neutral back on the neutral bus, remove the next one, and check it. Once you find the neutrals that are shared, you have to hunt down where they are shared. It's usually in a breaker box that has multiple circuits (such as a gang of light switches that are served by different circuits).
I hope this helps someone else. If anyone else has any suggestions on addressing flickering, I welcome comments below.
