Akasa Essential Power 300 W Power Supply Review

[nextpage title=”Introduction”]

Although it is an entry-level power supply, the Akasa Essential Power 300 W (AK-PD030FG) comes with active PFC circuit, automatic voltage selection, and 80 Plus standard certification. Funny enough, this unit isn’t listed at Akasa’s website.

This power supply is manufactured by a company called Sirfa, which is a different manufacturer from the Essential Power 350 W from the same manufacturer.

Figure 1: Akasa Essential Power 300 W power supply

Figure 2: Akasa Essential Power 300 W power supply

The Akasa Essential Power 300 W is 5 ½” (14 cm) deep, using a 120-mm sleeve bearing fan on its bottom (Globe Fan S1202512L). As mentioned, this unit has active PFC, as you can see by the absence of a 115 V/230 V switch in Figure 1, being based on the outdated half-bridge topology.

No modular cabling system is provided and cables don’t have a nylon protection. The cables included are:

• Main motherboard cable with a 20/24-pin connector, 16.9” (43 cm) long
• One cable with one ATX12V connector, 17.3” (44 cm) long
• One cable with three SATA power connectors, 17.3” (44 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two standard peripheral power connectors, 16.9” (43 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with three standard peripheral power connectors and one floppy disk drive power connector, 16.9” (43 cm) to the first connector, 5.9” (15 cm) between connectors

On the good side, all cables use 18 AWG wires, which is the minimum recommended gauge. On the other hand, the cable configuration and reduced number of connectors and lack of a video card power connector clearly shows that we are dealing with an entry-level product. Although this unit has three SATA power connectors, you may have trouble installing a SATA hard drive and a SATA optical drive, depending on the distance between them inside your case.

Figure 3: Cables

Let’s now take an in-depth look inside this power supply.

[nextpage title=”A Look Inside The Akasa Essential Power 300 W”]

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our Anatomy of Switching Power Supplies tutorial to understand how a power supply works and to compare this power supply to others.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used. Internally the Akasa Essential Power 300 W is completely different from the 350 W model.

Figure 4: Top view

Figure 5: Front quarter view

Figure 6: Rear quarter view

Figure 7: Printed circuit board

[nextpage title=”Transient Filtering Stage”]

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

The transient filtering stage of the Akasa Essential Power 300 W is impeccable, coming with all required components plus two extra X capacitors and two extra Y capacitors. This is rare to see in an entry-level power supply. Kudos to Akasa.

Figure 8: Transient filtering stage (part 1)

Figure 9: Transient filtering stage (part 2)

In the next page we will have a more detailed discussion about the components used in the Akasa Essential Power 300 W.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of the Akasa Essential Power 300 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU605 rectifying bridge, which supports up to 6 A at 100° C if a heatsink is used, which fortunately is the case. Therefore, this unit would be able to pull up to 690 W from a 115 V power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 552 W without burning itself out. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Figure 10: Rectifying bridge

The active PFC circuit uses only one transistor, an SPW16N50C3, capable of delivering up to 16 A at 25° C or up to 10 A at 100° C (note the difference temperature makes) in continuous mode, or up to 48 A in pulse mode at 25° C. This transistor presents a 280 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistor will waste less power and the power supply will achieve higher efficiency.

Figure 11: Active PFC transistor and diode

The electrolytic capacitor in charge of filtering the output of the active PFC circuit is manufactured by Teapo and labeled at 105° C.

The Akasa Essential Power 300 W uses the two-transistor forward configuration, using two 2SK4106 MOSFETs, each one supporting up to 12 A at 25° C in continuous mode (unfortunately the manufacturer doesn’t say the limit at 100° C) or up to 48 A at 25° C in pulse mode, with an RDS(on) of 400 mΩ.

Figure 12: Switching transistors

The primary is controlled by a CM6805 active PFC/PWM combo controller.

Figure 13: Active PFC/PWM controller

Let’s now take a look at the secondary from this power supply.

[nextpage title=”Secondary Analysis”]

This power supply has five Schottky rectifiers on its secondary heatsink.

The maximum theoretical current each line can deliver is given by the formula I / (1 – D) where D is the duty cycle used and I is the maximum current supported by the rectifying diode. As an exercise, we can assume a duty cycle of 30%.

The +12 V output uses two MBR30L60CT Schottky rectifiers connected in parallel, each one supporting up to 30 A (15 A per internal diode at 120° C, 0.80 V maximum voltage drop), giving us a maximum theoretical current of 43 A or 514 W for the +12 V output.

The +5 V output uses one MBR3045PT Schottky rectifier, which supports up to 30 A (15 A per internal diode at 105° C, 0.76 V maximum voltage drop), giving us a maximum theoretical current of 21 A or 107 W for the +5 V output.

The +3.3 V output uses two PFR30L45CT Schottky rectifiers connected in parallel, each one supporting up to 30 A (15 A per internal diode at 110° C, 0.52 V maximum voltage drop), giving us a maximum theoretical current of 43 A or 141 W for the +3.3 V output.

All these numbers are theoretical. The real amount of current/power each output can deliver is limited by other components, especially by the coils used on each output.

Figure 14: +12 V, +5 V and +3.3 V rectifiers

The outputs are monitored by an HY-510N integrated circuit, which supports only over voltage (OVP) and under voltage (UVP) protections.

Figure 15: Monitoring circuit

[nextpage title=”Power Distribution”]

On Figure 16 you can see this power supply label containing all its power specs.

Figure 16: Power supply label

As you can see, according to the label this unit has two +12 V rails, but this is a lie. Even though the +12 V wires on the ATX12V cable use a different color (yellow with green stripe), inside the unit all +12 V wires are connected to the same spot on the printed circuit board, plus this unit doesn’t have over current protection, which is required for building multi-rail power supplies (click here to understand). Therefore, this unit has a single-rail design.

Let’s now see if this power supply can really deliver 300 W.

[nextpage title=”Load Tests”]

We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology.

First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During our tests, the +12VA and +12VB input were connected to the power supply single +12 V rail (the ATX12V connector was installed on the +12VB input of our load tester).

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	2 A (24 W)	4 A (48 W)	6 A (72 W)	7.5 A (90 W)	9.25 A (111 W)
+12VB	1.5 A (18 W)	3.75 A (45 W)	5.5 A (66 W)	7 A (84 W)	9 A (108 W)
+5V	1 A (5 W)< /td>	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1 A (5 W)	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)
-12 V	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)
Total	62.1 W	122.3 W	184.6 W	240.1 W	303.7 W
% Max Load	20.7%	40.8%	61.5%	80.0%	101.2%
Room Temp.	44.0° C	43.1° C	44.6° C	44.8° C	45.7° C
PSU Temp.	47.9° C	46.9° C	46.4° C	46.6° C	48.5° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	75.3 W	143.2 W	216.1 W	284.5 W	366.8 W
Efficiency	82.5%	85.4%	85.4%	84.4%	82.8%
AC Voltage	114.6 V	113.9 V	113.6 V	113.0 V	112.2 V
Final Result	Pass	Pass	Pass	Pass	Pass

The Akasa Essential Power 300 W passed our tests with flying colors, being able to deliver its labeled wattage at high temperatures.

Efficiency was excellent, between 82.8% and 85.4%. This is outstanding for an entry-level power supply. In fact, the manufacturer could have got the 80 Plus Bronze certification with this unit (it has the standard 80 Plus certification).

Voltage regulation was superb, with all voltages within 3% of their nominal values, including the -12 V output. The ATX12V specification allows voltages to be up to 5% from their nominal values (10% for the -12 V output). Therefore this power supply presents all voltages closer to their nominal values than necessary all the time.

Noise and ripple levels were very low. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for the +12 V and -12 V outputs, and 50 mV for the +5 V, +3.3 V, and +5VSB outputs. All values are peak-to-peak figures.

Figure 17: +12VA input from load tester during test five at 303.7 W (34.6 mV)

Figure 18: +12VB input from load tester during test five at 303.7 W (37.6 mV)

Figure 19: +5V rail during test five at 303.7 W (18.2 mV)

Figure 20: +3.3 V rail during test five at 303.7 W (14.8 mV)

Let’s see how much more power we could pull from this unit.

[nextpage title=”Overload Tests”]

Below you can see the maximum we could pull from this power supply. We couldn’t pull more than that because the power supply shut down, showing that its protections are working just fine. Efficiency was still above 80%, which is great.

Input	Overload Test
+12VA	12 A (144 W)
+12VB	12 A (144 W)
+5V	10 A (50 W)
+3.3 V	10 A (33 W)
+5VSB	2 A (10 W)
-12 V	0.5 A (6 W)
Total	388.6W
% Max Load	129.5%
Room Temp.	45.2° C
PSU Temp.	48.9° C
AC Power	484.2 W
Efficiency	80.3%
AC Voltage	110.2 V
Power Factor	0.991

[nextpage title=”Main Specifications”]

The main specifications for the Akasa Essential Power 300 W include:

• Standards: ATX12V 2.2
• Nominal labeled power: 300 W
• Measured maximum power: 388.6 W at 45.2° C
• Labeled efficiency: NA, standard 80 Plus certification
• Measured efficiency: Between 82.5% and 85.4% at 115 V (nominal, see complete results for actual voltage)
• Active PFC: Yes
• Modular Cabling System: No
• Motherboard Power Connectors: One 20/24-pin connector and one ATX12V connector
• Video Card Power Connectors: None
• SATA Power Connectors: Three on one cable
• Peripheral Power Connectors: Five on two cables
• Floppy Disk Drive Power Connectors: One
• Protections (as listed by the manufacturer): NA
• Are the above protections really available? Over voltage (OVP), under voltage (UVP), and short-circuit (SCP) protections present, over power protection (OPP) seems to be active
• Warranty: NA
• Real Manufacturer: Sirfa
• More Information: NA
• Average price in the US: We couldn’t find this model being sold in the US market on the day we published this review

[nextpage title=”Conclusions”]

Don’t let appearances deceive you. The Akasa Essential Power 300 W (AK-PD030FG) looks like one of those “generic” low-end power supplies, but it isn’t one of them. It is a superior entry-level power supply, with very high efficiency (up to 85.4%), exceptional voltage regulation, very low noise and ripple levels, and we could pull 380 W from it with efficiency still above 80%. The only “problem” with this power supply is that it has a reduced number of connectors, but that is somewhat expected on a 300 W unit. If you are looking for one of the best entry-level power supplies, the Akasa Essential Power 300 W is for you, provided you can find it in your country.

It is a rare occasion to find a pearl in the sea of lousy entry-level power supplies.