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Now we are going to take an in-depth look at an entry-level power supply from Akasa, Essential Power 350 W (model number AK-P350G BK). Is this a good unit? Let’s see.
By the way, we’ve already reviewed another entry-level model from Akasa, Paxpower 500 W (AK-P050FG7).
Akasa Essential Power 350 W is 5 ½” (140 mm) deep, using a 120 mm fan on its bottom. This unit does not feature a PFC circuit, as you can see by the presence of a 115 V/230 V switch in Figure 1, based on the outdated half-bridge topology.
No modular cabling system is provided and all cables have nylon protections that come from inside the power supply housing. All cables use 18 AWG wires, which is the correct gauge to be used.
The cables included are:
- Main motherboard cable with a 20/24-pin connector, 16 1/8” (41 cm) long.
- One cable with one ATX12V connector, 17” (43 cm) long.
- One cable with one six-pin connector for video cards, 17” (43 cm) long.
- One cable with two SATA power connectors, 16 ½” (42 cm) to the first connector, 5 ½” (140 mm) between connectors.
- Two cables with three standard peripheral power connectors and one floppy disk drive power connector each, 17” (43 cm) to the first connector, 5 ½” (140 mm) between connectors.
The problem with this configuration is clearly the presence of only two SATA connectors. Nowadays you will be using at least one SATA hard disk drive and one SATA optical drive, making it difficult to install them when you only have 5 ½” (140 mm) between the two SATA power connectors.
Now let’s take an in-depth look inside this power supply.
[nextpage title=”A Look Inside The Akasa Essential Power 350 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.
This page will be an overview, and then in the following pages we will discuss in detail the quality and ratings of the components used.
[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.
Even though this is power supply has two Y capacitors and one X capacitor more than the minimum required, it doesn’t feature MOV’s, which are in charge of removing spikes coming from the power grid.
In the next page we will have a more detailed discussion about the components used in the Akasa Essential Power 350 W.
[nextpage title=”Primary Analysis”]
On this page we will take an in-depth look at the primary stage of Akasa Essential Power 350 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses one GBU6J rectifying bridge, which supports up to 6 A at 100° C if a heatsink is used, which is not the case, or up to 6 A at 45° C, if a heatsink isn’t used. At 115 V this unit would be able to pull up to 690 W from the 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.
This unit is based on the obsolete half-bridge design, using two KSH13009H power NPN transistors on the switching section, each one capable of delivering up to 12 A at 25° C in continuous mode, or up to 24 A at 25° C in pulse mode. Unfortunately the manufacturer does not provide the current limits at 100&de
The switching transistors are controlled by an AZ7500 PWM controller, which is physically located on the secondary from the power supply.
The two electrolytic capacitors from the voltage doubler are from Fhy and labeled at 85° C.
Now let’s take a look at the secondary of this power supply.
[nextpage title=”Secondary Analysis”]
This power supply has three 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. Since on power supplies based on half-bridge topology the duty cycle is of 50%, we just need to add the total maximum current of all diodes connected to the specific line in question.
The +12 V output is produced by one F20C20C rectifier, which supports up to 20 A (10 A per internal diode at 125° C, 1.30 V maximum voltage drop, which is ridiculously high – meaning low efficiency), giving us a maximum theoretical current of 20 A or 240 W for the +12 V output. It is important to note that this rectifier isn’t from the Schottky type but from the Fast type, which presents lower efficiency.
The +5 V output is produced by one S20D45C Schottky rectifier, which supports up to 20 A (10 A per internal diode at 125° C, 0.65 V maximum voltage drop), giving us a maximum theoretical current of 20 A or 100 W for the +5 V output.
The +3.3 V output is produced by another S20D45C Schottky rectifier, giving us a maximum theoretical current of 20 A or 66 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.
The outputs are monitored by a discrete circuit based on an AZ339 integrated circuit (which has four voltage comparators inside) instead of using a ready-made monitoring integrated circuit.
The electrolytic capacitors from the secondary are from a company called BH.
[nextpage title=”Power Distribution”]
In Figure 14, you can see the power supply label containing all the power specs.
As you can see, according to the label this unit has two +12 V rails. This information, however, isn’t true. Unfortunately lots of manufacturers print fake information on the product labels. Inside the unit all +12 V wires are connected to exactly the same place on the printed circuit board. There are no shunts (current sensors) and no over current protection (OCP) circuit inside this power supply, therefore making it impossible for this unit to have more than one rail. Click here to understand more about this subject.
Now let’s see if this power supply can really deliver 350 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 how the reviewed unit behaved 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 power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (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. On 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 this test they were connected to the single +12 V rail provided by this unit (+12VB input was connected to the ATX12V connector and all other connectors were installed on the +12VA input).
|Input||Test 1||Test 2||Test 3||Test 4||Test 5|
|+12VA||2 A (24 W)||4.5 A (54 W)||7 A (84 W)||9 A (108 W)||11.5 A (138 W)|
|+12VB||2 A (24 W)||4.5 A (54 W)||7 A (84 W)||9 A (108 W)||11.5 A (138 W)|
|+5V||1 A (5 W)||2 A (10 W)||4 A (20 W)||6 A (30 W)||8 A (40 W)|
|+3.3 V||1 A (5 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||66.4 W||133.0 W||207.2 W||271.2 W||345.4 W|
|% Max Load||19.0%||38.0%||59.2%||77.5%||98.7%|
|Room Temp.||44.5° C||44.1° C||44.3° C||45.5° C||47.6° C|
|PSU Temp.||52.7° C||51.7° C||51.5° C||52.5° C||55.5° C|
|Voltage Regulation||Pass||Pass||Pass||Pass||Fail on +12VB|
|Ripple and Noise||Pass||Pass||Pass||Pass||Pass|
|AC Power||95.4 W||176.8 W||272.2 W||363.1 W||484.0 W|
|AC Voltage||116.5 V||155.9 V||114.7 V||113.5 V||111.6 V|
Akasa Essential Power 350 W can really deliver its labeled power at high temperatures. However, power isn’t everything.
Efficiency was always below 80%, varying between 69.3% and 76.1%.
During test five we saw a voltage below the minimum allowed: +12VB input from our load tester was at +11.34 V, when the minimum allowed is +11.40 V. All other voltages were within specs during all tests.
Noise and ripple, although below the maximum allowed, were higher than we’d like to see during test five. Below you can see the results for test five. The maximum allowed is 120 mV on +12 V and 50 mV on +5 V and +3.3 V. All these numbers are peak-to-peak figures.
Let’s see if we can pull more than 350 W from this unit.
[nextpage title=”Overload Tests”]
Below you can see the maximum we could pull from this unit. If we tried to pull one extra amp from any output noise levels would increase too much. During this test noise level at +12 V outputs was touching the allowed limit at 112 mV. During this test the +12VB input from our load tester was at +11.37 V, when the minimum allowed is +11.40 V.
|+12V1||13 A (156 W)|
|+12V2||13 A (156 W)|
|+5V||10 A (50 W)|
|+3.3 V||8 A (26.4 W)|
|+5VSB||2 A (10 W)|
|-12 V||0.5 A (6 W)|
|% Max Load||112.7%|
|Room Temp.||44.4° C|
|PSU Temp.||50.6° C|
|AC Power||572.0 W|
|AC Voltage||111.1 V|
[nextpage title=”Main Specifications”]
Akasa Essential Power 350 W power supply specs include:
- ATX12V 2.2
- Nominal labeled power: 350 W.
- Measured maximum power: 394.5 W at 44.4° C.
- Labeled efficiency: Information not available.
- Measured efficiency: Between 69.6% and 76.1% at 115 V (nominal, see complete results for actual voltage).
- Active PFC: No.
- Modular Cabling System: No.
- Motherboard Power Connectors: One 20/24-pin connector and one ATX12V connector.
- Video Card Power Connectors: One six-pin connector.
- SATA Power Connectors: Two in one cable.
- Peripheral Power Connectors: Six in two cables.
- Floppy Disk Drive Power Connectors: Two in two cables.
- Protections: over voltage (OVP), over current (OCP) and short-circuit (SCP).
- Warranty: Information not available.
- Real Manufacturer: XHY Power
- More Information: https://www.akasa.com.tw
- Average price in the US: This product is not sold in the USA.
Akasa Essential Power 350 W is capable to deliver its labeled power at high temperatures. But as we always like to point out, maximum power isn’t everything. This unit presents lousy efficiency and therefore we can’t recommend it.
Even if it could present efficiency a little bit higher, it would still be a problematic product, because it only comes with two SATA power cables installed on the same cable, and nowadays even a very basic PC comes with one SATA hard disk drive and one SATA optical drive, making it difficult to install them when you only have 5 ½” (140 mm) between the two SATA power connectors.
Not to mention that at 350 W the voltage at the +12 V line was below than the minimum required, meaning that this product can cause you trouble if you operate it at its full labeled power.