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Backup Generator and pure sine waves.

J

jackazulay

macrumors newbie
Original poster
Feb 18, 2021
4
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Hi, after recent weather events and power outages I’m finally going to be investing in a whole house backup generator. The generator I’m going to be getting is not an inverter type and does not have a pure or modified sine wave and so I have learned not be good for anything sensitive like charging my MBP16”. My question is, how much protection does the incredibly expensive and advanced usb-c power adaptor that came with the MacBook provide? And would it be best to invest in a second smaller dedicated generator just for sensitive electronics like laptops/ TVs etc? Or should I get a dedicated battery backup system of some kind? I did not realise until yesterday that ‘dirty power’ was even a thing!
TIA!
 
I think you may be mistaken about the power produced by a non-inverter generator. To my knowledge, all large generators produce a pure sine wave because they are an AC generator. Inverter generators produce DC that is then inverted to a modified or pure sine wave. They are popular because of lower fuel usage and quieter. While the power produced by a whole house generator is a pure sine wave, there can be voltage fluctuations so surge protection is recommended for sensitive circuits. I have a whole house generator but use a UPS for some equipment I want running continuously like my internet connection. It takes 5 minutes for my backup generator to take over when power fails.

While you’re doing the wiring for the transfer switch, consider adding a whole house surge suppressor if you don’t have one.
 
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I would get the dedicated battery backup, for multiple reasons.
1- Because there is a delay between the power outage and the whole house generator kicking in it will keep any peripherals attached to it running when the power goes out (such as hard drives).
2- It will provide surge protection for the generator switch over and any others that may occur from the grid or other equipment in you house.
3- It will help clean up the "dirty power" from your generator.

It may also be a good idea to get a power line conditioner.
 
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glenthompson said:
I think you may be mistaken about the power produced by a non-inverter generator. To my knowledge, all large generators produce a pure sine wave because they are an AC generator. Inverter generators produce DC that is then inverted to a modified or pure sine wave. They are popular because of lower fuel usage and quieter. While the power produced by a whole house generator is a pure sine wave, there can be voltage fluctuations so surge protection is recommended for sensitive circuits. I have a whole house generator but use a UPS for some equipment I want running continuously like my internet connection. It takes 5 minutes for my backup generator to take over when power fails.

While you’re doing the wiring for the transfer switch, consider adding a whole house surge suppressor if you don’t have one.
Click to expand...
glenthompson said:
I think you may be mistaken about the power produced by a non-inverter generator. To my knowledge, all large generators produce a pure sine wave because they are an AC generator. Inverter generators produce DC that is then inverted to a modified or pure sine wave. They are popular because of lower fuel usage and quieter. While the power produced by a whole house generator is a pure sine wave, there can be voltage fluctuations so surge protection is recommended for sensitive circuits. I have a whole house generator but use a UPS for some equipment I want running continuously like my internet connection. It takes 5 minutes for my backup generator to take over when power fails.

While you’re doing the wiring for the transfer switch, consider adding a whole house surge suppressor if you don’t have one.
Click to expand...
Ok so I could just plug the MacBook directly into the outlet on the generator itself? Or you’re saying once the 30a transfer is directing into my main panel then I can just plug in as usual into my house and not have to worry? How do you specifically have your UPS set up? Thanks
 
justashooter said:
I would get the dedicated battery backup, for multiple reasons.
1- Because there is a delay between the power outage and the whole house generator kicking in it will keep any peripherals attached to it running when the power goes out (such as hard drives).
2- It will provide surge protection for the generator switch over and any others that may occur from the grid or other equipment in you house.
3- It will help clean up the "dirty power" from your generator.

It may also be a good idea to get a power line conditioner.
Click to expand...
Thanks. I’m thinking about getting a Westinghouse iGen300s. Lithium ion backup pack with pure sine wave and Westinghouse says it should recharge a 13” MBP 12 times from a charge which is way more than I would need in a pinch as I could be recharging the unit itself directly off the main generator and or solar. Thinking it could run my router and Tv too for a few hours to stop my family from going crazy in the next outage.
 
When you said whole house I assumed you meant a stationary generator connected into your main panel via a transfer switch that would power all or most circuits in your house. I have a natural gas powered 12kw generator that can’t power everything so there are two panels, one for generator powered and one for circuits thar would be dead in a power failure. Things not covered by the generator are the dryer, dishwasher, and EV charger. Items items powered by the generator include main lights, refrigerator, furnace, and microwave. There are no outlets on the generator itself as it feeds directly into the transfer switch. If you’re thinking of using a large gasoline powered generator that you plug items into directly then that is a very different scenario.
 
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glenthompson said:
When you said whole house I assumed you meant a stationary generator connected into your main panel via a transfer switch that would power all or most circuits in your house. I have a natural gas powered 12kw generator that can’t power everything so there are two panels, one for generator powered and one for circuits thar would be dead in a power failure. Things not covered by the generator are the dryer, dishwasher, and EV charger. Items items powered by the generator include main lights, refrigerator, furnace, and microwave. There are no outlets on the generator itself as it feeds directly into the transfer switch. If you’re thinking of using a large gasoline powered generator that you plug items into directly then that is a very different scenario.
Click to expand...
Yes it’s a gasoline/propane duel fuel generator that is mobile but would be tied in to the main panel via a lockout
 
I would get a UPS, some portable USB battery packs, and a solar charger.

Here are some resources to get you started, if you're interested:

The 9 Best Solar Chargers of 2025

We tested 30 solar chargers to power our adventures, including brands like Jackery, GoalZero, BioLite, and more.
www.outdoorgearlab.com

The Best Power Banks for Laptops With USB-C

The Anker 747 PowerCore 26K is our favorite power bank for charging modern laptops as fast as possible while you’re on the go—no need to hunt for a power outlet.
www.nytimes.com

The Best Uninterruptible Power Supply (UPS)

We tested leading UPS models and found that the CyberPower CP900AVR is the best option to keep essential gear running for up to four hours during a blackout.
www.nytimes.com

Then you'll be protected when the power first goes out and you won't need to directly connect any expensive gear to the generator. Plus if an outage goes on for more than a few hours and there is clear weather, the solar charger can take care of your smaller devices (plus no fuel consumption!).
 
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jackazulay said:
Yes it’s a gasoline/propane duel fuel generator that is mobile but would be tied in to the main panel via a lockout
Click to expand...
In that case the generator will feed the main panel via the lockout. All you need to do in a outage is turn off any high power circuits that can turn on automatically like the AC. Laptops usually do fine in short outages since they have their own battery backup. Good surge suppressors or UPS on sensitive equipment are a must.
 
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i bought a Honda inverter generator to power tire warmers at a race track. Used it a bit but mostly sat in my garage for 10+ years. The chances of a power outage re occurring is nill. Americans suffer from paranoia and conspiracy theory.

Do not buy this junk, you will never use it.

-an inverter generator is the way to go. I dont know about the purity of a sine wave but it would be a good to keep the generator's output at 60.00 hz. A mechanical system will never be able to keep up. Also load fluctuations and power up and down instances are rough with the old style mechanical systems.
-Get a portable honda inverter generator you can carry. They are very lite and power full. Extend the unit's use to camping, home improvement projects and remote xmas lights. Buy the unit locally, not on the internet, so its engine is tuned for your area.

i do advocate buying a craigslist medium size portable heater that dosnt require electricity. Buy a few tanks of propane and cycle through the tanks on the patio gas grill. Again all this could sit in your garage for decades.
 
The key thing to look at with generators is Total Harmonic Distortion - THD. Aim for 3% or less. Generally inverter generators have the cleanest THD - conventional generators can reach 25% or higher THD.

Figure out what you must have functioning and the load to keep it going. Also figure out the voltage needs - 120V or 240V. Those have an impact on what's the best option for your needs.

For heating indoors, a kerosene heater and a couple sealed 5gal drums of kerosene will keep for many many years and be ready when you need it. Just be sure you have a way to light it. :D
 
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i bet a lot of people in Texas are glad they have generators. You never know when or what may take out your power or how long the outage may last. Wildfires, hurricanes, tornadoes, and traffic accidents can all take out power for awhile.
 
the storm and infrastructure failure is a once in a generation situation.
do not buy a generator
 
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