Ryobi RP4900 USB Power Source Review
The Ryobi RP-series power supplies are designed with efficiency in mind, but they’re not just about energy consumption. They’re also great at delivering high performance without breaking the bank.
These units come in two different models: one with a single 12V rail and another model with four 6V rails. Each model comes standard with a 90W DC output and up to 500mA of current draw from each rail (1A total). You’ll need to purchase additional cables or adapters if you want to use other types of power sources such as solar panels, batteries, etc.
We’ve been using these units for several months now and have found them to be reliable and efficient enough for our needs. They’re small enough that we don’t feel like we’re carrying around too much extra weight when we travel, which is always nice.
And they’re inexpensive enough that we can afford to buy new ones whenever we run out of juice.
So how do they stack up against their competition?
Let’s take a look!
Rail Power: The Good, the Bad, and the Ugly
Before we talk too much about the actual quality of these power supplies, let’s go over what you need to know about them. When most people think about a battery-like device, they think about how many “volts” and “amps” it can produce.
So a 12V, 15Amp battery is better than a 6V, 10Amp battery right?
Well, not exactly.
The amperage (amps) tells you how much current (how many electrons) can be delivered at once. The voltage (volts) tells you how many electrons you have available to deliver over time.
Think of it like a faucet: the voltage is constantly flowing (like water pressure), and the amps are how much water (electrons) comes out at once. It’s the amps that matter when it comes to quick, high-power draws, and it’s the volts that matter when it comes to long, sustained delivery.
Most power supplies have anywhere from one to four “rails” which are essentially separate paths that electrons can travel through the device. The standard is to have one rail with the “full voltage” of the power supply (called a “12V” rail, even if the actual output is closer to 11.5V), and then one or more lower-voltage rails (typically around 7.5V).
Rail split for the standard model power supply (top) vs a modified model power supply (bottom)
For most people, the standard model is more than enough to power all of their electronics for their entire life. But things get a little…interesting when you start to use a lot of high-power draw electronics at once.
While most power supplies can easily handle your laptop, it gets harder if you also have a gaming desktop plugged in and a couple of large screens and other power-hungry devices. To fix this, some power supplies will “derail” excess amps from one rail over to another rail.
So if you’re pulling 10 amps from the 12V rail, and you have enough “pressure” (volts), the supply can send 2-4 amps to a lower-voltage rail so that nothing trips and burns out. This is called “over-volting.”
The major downside to this system is that it’s not very efficient. It’s essentially wasting energy to move the power from one rail to another.
That’s why most high-end power supplies have multiple, dedicated rails with their own independent voltages. They don’t share any of the load between them.
But what about amperage? Can’t you just add more rails to increase the total amperage available?
Well, you certainly can, but it starts to become very inefficient very quickly. It’s much better to have a few high-powered rails rather than a bunch of lower-powered rails, so most manufacturers don’t do it.
Now that we’ve covered the basics, let’s get into our reviews!
The Best of the Standard Models: EVGA SuperNOVA 750 G3
EVGA is a brand that’s known for making quality power supplies at a reasonable price, and the G3 is no different. With its “Gold” certification and outstanding reviews from every major tech publication, you really can’t go wrong here.
The G3 is a fully modular model, so you only use the cables you need, helping to keep your case looking clean and preventing unnecessary wear and tear on the cables (as they’re not getting moved around as much).
The G3 also comes with a 5-year warranty, so if anything happens within that time you can get it replaced for free. That’s almost unheard of in the industry!
While the G3 is one of the cheaper units on this list, that doesn’t mean it skimps on quality. It features a full set of Japanese capacitors rated at a strong capacity, ensuring that it won’t crap out on you.
In addition, it comes with all the safety protections you could ask for, including OCP (over current protection), OVP (over voltage protection), UVP (under voltage protection), and OTP (over temperature protection).
The G3 is a great PSU that will keep up with even the most power-hungry system.
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