I’ve been researching ways to stay online during power outages. After all, my productivity is dependent on having a computer to work on, and having fast, reliable Internet access.
To accomplish this off-grid goal, I would need energy storage in the form of batteries. However, batteries provide direct current (DC) voltage, and the PC power supply runs off of 120 volt power in the United States of America. To power the computer off of a battery, I would need to convert 12 volts DC to 120 volts alternating current (AC).
After researching a number of DC-to-AC power inverters, I finally decided to try out the Kriëger 1500W inverter. This inverter runs off of a 12 volt source, however you can also get inverters that support 24 volts or 48 volt signals.
Pure Sine Wave vs. Modified Sine Wave Inverters
Before we get into the specifics of the Kriëger inverter, let’s talk about two common types of sine waves for AC currents.
When you’re considering a DC-to-AC inverter, you’ll want to pay close attention to the sine wave output. There are a couple of common types of power inverters: modified sine wave and pure sine wave.
The pure sine wave inverters match the smooth alternating-current power that you get from your house mains. On the other hand, the modified sine wave inverters have a boxy-looking sine wave. If you want to measure and visualize the actual output from any electrical system, you would need to purchase an oscilliscope.
The biggest benefit of modified sine wave inverters is that they cost less than pure sine wave inverters. For example, consider the Renogy 1000W pure sine wave inverter at $185 USD.
In contrast, a modified sine wave inverter with 1100W of output costs only $85 USD. That’s less than half of what the pure sine wave inverter cost! This is the inverter that I’m reviewing in this article.
Some devices will not work with modified sine wave AC power. I have heard that power tools don’t like modified sine wave, but I am hesitant to test any of my expensive equipment on this theory. Thankfully, computer equipment seems to work just fine with modified sine wave.
Devices and Energy Loads
When you’re planning any kind of electrical setup, you’ll need to consider the devices that you are planning to run.
My custom-built desktop computer has a 500W power supply. Using a watt meter, I determined that under peak load, with both the CPU and GPU running at 100% utilization, power consumption is around 480 watts. The CPU I installed is an AMD Ryzen 3900X, whereas the GPU is an NVIDIA GeForce RTX 2080. Both of those products can chew through quite a bit of power, and generate a lot of heat!
The monitor I’m using with my desktop computer is the Dell P2715Q 4k LCD. Using a watt meter, I discovered that this monitor draws 47.5 watts @ 120 volts.
With a combined wattage of ~550, I should easily be able to run my desktop computer off of the 1500W Kriëger inverter.
Aside from my desktop workstation, I also needed to be able to run networking equipment off of the inverter. My Ubiquiti EdgeRouter X only consumes about 5 watts, and my TP-Link access point uses a similarly-sized power supply. Considering these are very low-energy devices, relative to a computer, I didn’t bother gathering specific measurements.
Of course, charging a phone during a power outage is always handy as well. I plan to use this inverter to retain access to the internet via phone, during a power outage. Phone charging ranges between 5 and 20 watts, so not very much throughput either. This is mainly because phone batteries are very small.
Inverter Build Quality
A stationary inverter won’t suffer much physical abuse over time. It’s still good to make sure you have a well-built device.
The chassis of the Kriëger inverter looks strikingly similar to the case of the Energizer inverter. I’m wondering if Energizer has simply rebranded the Kriëger unit, or vice versa. Either way, it has a sturdy metal body, along with yellow plastic pieces on the front and back. The silver, metal feet are also quite strong, and will be great for mounting the device to almost any surface.
The buttons on the front of the inverter are kind of flimsy, but not terrible. Below the buttons, there are a couple of USB ports. The ports themselves don’t move around, and are mounted well.
On the back of the unit, you have a couple of terminals to connect to your battery. I like the distance between the terminals, and they also include a couple beefy nuts to connect the installation kit (below).
In case you’re wondering, these terminal nuts are 14mm. You’ll probably want an adjustable wrench or a 14mm socket to tighten these down. Just be sure not to wrench too hard on them, as they flex and could break the circuit board inside.
Fan Noise (or lack thereof)
There is a temperature-controlled cooling fan at the back of the unit, near the battery terminals. During my testing with a high-end desktop computer, the fan never came on. The unit itself was totally silent throughout my tests.
The only noise that I heard was the buzzing generated by AC-to-DC power supplies that were connected to the inverter. This happens because of the modified sine wave coming from the unit, instead of pure sine wave.
I would imagine that a higher energy load, such as a refrigerator, would trigger the fan to come on. You could also try running a small space heater, rated at 1000 to 1500 watts, off of it.
Depending on where you mount the device, you might not even hear the fan kick on. For an RV installation, you might want to mount this inverter in a utility cupboard. For a semi-permanent home installation, you could bolt the inverter to a board in a basement or crawl space.
Included Installation Kit
The inverter included an installation kit, consisting of some large, 2 AWG wire and a 150 amp ANL-style fuse. The fuse holder is really nice quality, and made of clear plastic. If you accidentally blow your fuse, you’ll easily be able to see the fuse status with any disassembly. Replacing this fuse is incredibly easy, since it just bolts onto the terminals.
The 2 AWG wires aren’t very long, at about 3 feet. However, I would most likely keep the inverter close my battery bank anyway. Sometimes less is more! I would point out that the connectors on each of the wires is strongly crimped down. Heat-shrink tubing protects the connector from accidental contact with other metals.
If you need replacement 150 amp ANL-style fuses, you get get a 3-pack for a modest $10.
Real-World Battery Lifetime Test
I decided to discharge my 12v / 35ah battery using just my desktop computer as a load. That means I didn’t have my monitor, or any other peripherals plugged in. However, keep in mind that I do have some USB devices attached to the computer: mouse, keyboard, video capture device, XLR audio interface, external hard drive.
According to the Kriëger inverter, my desktop system would hover around 115-130 watts of power consumption during normal use. For example, while I am writing this post in my web browser, I’m seeing about 128 watts reported.
I started running my desktop system off of battery power at 2:09 PM Pacific Time. The voltage reported by the inverter was 12.7 volts under load initially. After running the computer for a few minutes, it dropped down to about 12.4 volts. Now it’s 2:49 PM Pacific Time, and after a full 40 minutes of the desktop computer running, the voltage is sitting at 12.2 volts.
Using a multimeter, I tested the voltage at the battery terminals, and received 12.0 volts. Hence, it seems that the Kriëger inverter may be incorrectly reporting the actual input voltage. If someone can explain this voltage discrepancy, please feel free to leave a comment on this article.
After lasting about 2.25 hours, the battery voltage finally dropped far enough that the inverter shutdown. I believe this was 11.7 volts, but I forgot to write down the exact measurement.
Overall, the Kriëger 1500W inverter is an excellent product. The build quality is outstanding!
My reservations mainly revolve around the USB ports, and some issues I had charging my Pixel 4 XL. As long as you have an AC USB charger handy, this unit works very well.
Because this is a modified sine wave inverter, you will probably experience some buzzing from your power supplies. Hence, this means I can’t use this inverter full-time on my desktop computer. I need an inverter that’s totally silent, if I were to use it as a full-time battery backup solution.
If you don’t need 1500W to power your small devices, consider the less expensive 1100W unit instead.
While the company does offer 3000W and 4000W variations on this product, I would highly recommend staying away from them. At 12 volts, you will probably burn up your wires if you try to push 250 amps (12v * 3000 watts) or more. This is a fire hazard, and in my opinion, these products shouldn’t even exist. At the very maximum, I’d say 2000 watts at 12 volts (167 amps) would be worth considering, for safety reasons.
If you need higher energy output, consider going with a 24v or 48v battery bank and inverter instead.
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