BFG ES-800 Power Supply Review
By Gabriel Torres on June 26, 2009
ES-800 (also known as BFGR800WESPSU) is a power supply using a different internal design called “frequency conversion,” with BFG claiming it provides higher efficiency even under very low loads. Is that so? Let’s check this out.
BFG ES-800 is manufactured by a company called Andyson, being the first power supply we’ve tested built by this manufacturer.
ES-800 is small for an 800 W unit, being 6 1/2” (16.5 cm) deep, using a 138-mm fan (which actually measures 130-mm) on its bottom and featuring active PFC, of course. It does not have a modular cabling system.
All cables are protected by a nylon sleeving that comes from inside the power supply housing, measuring 19 19/64” (49 cm) between the housing and the first connector on the cable, and 5 ½” (140 mm) between connectors, on cables with more than one connector. All wires are 18 AWG, which is the correct gauge to be used.
The cables included are:
This power supply has four power connectors for video cards, allowing you to install up to two very high-end cards in SLI or CrossFire mode, since each card from this class uses two power connectors. So no direct support for three-way SLI is provided. These four connectors are available in two cables, and we particularly don’t like this configuration. For better performance each connector should use an individual cable. The reason why is that when the power supply is fully loaded voltage on the connectors tend to drop when they share the same cable.
Now let’s take an in-depth look inside this power supply.
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.
The interior of BFG ES-800 looks like a mad scientist’s erotic dream: lots of circuits cramped in a very small form factor. On ES-800 the standby (+5VSB) power supply is built in a completely separated printed circuit board.
Another thing we immediately noticed was the presence of only Japanese capacitors. The primary uses capacitors from Panasonic (Matsushita, the black one), from Hitachi (the blue one) and from Chemi-Con (the brown ones), while all capacitors from secondary are from Chemi-Con.
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 power supply has two X capacitors and two Y capacitors more than the required, it doesn’t have a MOV, which is a sin on a supposedly high-end product. On the other hand, the coils have a fair better construction than the ones usually used on the power supplies we review.
On this page we will take an in-depth look at the primary stage of BFG ES-800. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses one GBU1510 rectifying bridge in its primary, supporting up to 15 A at 100° C if a heatsink is used (which is the case), so in theory, you would be able to pull up to 1,725 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 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.
Two SPW32N50C3 power MOSFETs are used on the active PFC circuit, each one capable of delivering up to 32 A at 25° C or 20 A at 100° C in continuous mode (note the difference temperature makes) or up to 96 A at 25° C in pulse mode. These transistors have a RDS(on) of 0.11 ohms. RDS(on) is the resistance of the transistor when it is turned on. We are starting to add this information as the lower the RDS(on) is, less power is wasted when the transistor is working, i.e., the higher efficiency will be, at least in theory.
This power supply uses two electrolytic capacitors to filter the output from the active PFC circuit. The use of more than one capacitor here has absolute nothing to do with the “quality” of the power supply, as laypersons may assume (including people without the proper background in electronics doing power supply reviews around the web). Instead of using one big capacitor, manufacturers may choose to use two or more smaller components that will give the same total capacitance, in order to better accommodate space on the printed circuit board, as two or more capacitors with small capacitance are physically smaller than one capacitor with the same total capacitance. BFG ES-800 uses one 560 µF x 450 V capacitor (the black one from Panasonic/Matsushita, labeled at 85° C) connected in parallel to one 180 µF x 450 V capacitor (the blue one from Hitachi, labeled at 105° C); this is equivalent of one 740 µF x 450 V capacitor.
As mentioned all capacitors used on this power supply are Japanese, which do not leak. It would be nice to see all capacitors labeled at 105° C, but as mentioned one of them is labeled at 85° C. All other capacitors used on ES-800 are labeled at 105° C.
In the switching section, two STW25NM50B power MOSFET transistors are used on configuration called half-bridge series ressonant, which uses a big coil in series between the output of the transistors and the transformer. Each transistor supports up to 22 A at 25° C or 14 A at 100° C (note the difference temperature makes) or 88 A in pulse mode at 25° C, presenting an RDS(on) maximum of 0.140 ohms.
Now let’s take a look at the secondary of this power supply.
The design used on the secondary from ES-800 is similar to the one used by some other power supplies we reviewed recently, like Corsair HX850W and Seasonic M12D 750 W. The main transformer is directly connected to a bank of eight SBR4045CT Schottky Rectifiers in charge of producing the +12 V output. Each one of these rectifiers can deliver up to 40 A (20 A per internal diode at 110° C with a typical voltage drop of 0.47 V. We are now indicating the voltage drop, as this spec has direct impact on efficiency. Voltage drop is a small amount of voltage that is wasted by the diode when it is conducted. The lower this number, the lower the waste and thus the higher efficiency is. This bank has a maximum theoretical current of 228.6 A (20 A x 8 / 0.70). This theoretical limit is for the whole secondary, as the +5 V and +3.3 V are produced from +12 V.
The +5 V and +3.3 V outputs are produced from the +12 V output using two NTB125N2RG MOSFET transistors each. Each MOSFET is capable of delivering up to 95 A at 25° C in continuous mode and a maximum RDS(on) of only 0.0062 ohms (6.2 mΩ), promising to provide high efficiency.
This power supply uses a PS232S monitoring integrated circuit, which is in charge of the power supply protections. Unfortunately there is no information about this circuit on the manufacturer’s website.
Electrolytic capacitors from the secondary are also Japanese, from Chemi-Con and labeled at 105° C.
In Figure 17, you can see the power supply label containing all the power specs.
This power supply has four virtual rails, distributed like this:
This distribution is just perfect.Now let’s see if this power supply can really deliver 800 W.
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 +12V1 and +12V2 inputs listed below are the two +12 V independent inputs from our load tester and during all tests +12V1 input was connected to the power supply +12V1 and +12V3 rails and +12V2 input was connected to the power supply +12V2 rail.
5.5 A (66 W)
12 A (144 W)
18 A (216 W)
25 A (300 W)
33 A (396 W)
5.5 A (66 W)
11 A (132 W)
17 A (204 W)
22 A (264 W)
25 A (300 W)
2 A (10 W)
4 A (20 W)
6 A (30 W)
8 A (40 W)
10 A (50 W)
2 A (6.6 W)
4 A (13.2 W)
6 A (19.8 W)
8 A (26.4 W)
10 A (33 W)
1 A (5 W)
1.5 A (7.5 W)
2 A (10 W)
2.5 A (12.5 W)
3 A (15 W)
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)
% Max Load
Ripple and Noise
Failed on -12 V
Failed on +5VSB
Failed on +5VSB
Failed on +5 V, +3.3 V and +5VSB
BFG ES-800 presents a high efficiency between 84% and 85% if you pull up to 60% of its labeled capacity (i.e., up to 480 W). Pulling 80% from its maximum wattage efficiency dropped to 82.4%, still above 80%. At full load, however, efficiency dropped to 79.1%. Important to notice that we tested this power supply with our new GWInstek precision power meter.
The main problem with this power supply is noise and ripple. The first sample we got presented noise levels outside specs from test two on, with -12 V at 195 mV during test one but at 50 mV or below on other tests. For example, the +5 V output presented a noise level between 67.2 mV and 121 mV, depending on the load and +3.3 V output presented noise level between 64.4 mV and 133 mV, also depending on the load. The maximum allowed for these two outputs is 50 mV (all values are peak-to-peak). The standby output (+5VSB) was also out of range from test three on (between 64 mV and 96.8 mV).
We got in touch with BFG and they said they were aware of the problem and it would affect only the first batch of ES-800, models with serial number starting with 0804. They sent us a second sample, which would supposedly have this problem fixed, serial number starting with 0835. The results above are from this second “fixed” sample.
This second sample fixed the noise problem at +3.3 V and +5 V, at least partially. We only saw it out of range during test number five, where noise level at +3.3 V was at 68.4 mV and at +5 V was at 61.4 mV. During test four noise on these two outputs was at 48.4 mV and 45.2 mV, almost touching the maximum allowed. On the other hand, with the second sample we saw exactly the same problem with the -12 V output during test one (172 mV noise level) and +5VSB during tests three through five (between 64.2 mV and 115.4 mV).
ES-800 can really deliver 800 W at 50° C, but as we always mention, power isn’t everything.
Now let’s see if we could pull more than 800 W from this unit.
Before overloading power supplies we always test first if the over current protection (OCP) circuit is active and at what level it is configured.
We configured our load tester to pull 33 A from the power supply +12V2 rail. The unit didn’t shut down, meaning that either over current protection (OCP) was disabled or configured at a value above that.
We always try to overload power supplies maintaining them working inside ATX specs. Since ES-800 was already working out of the proper range when delivering 800 W, we decided not to overload it.
BFG ES-800 power supply specs include:
BFG ES-800 isn’t the best product available on the market, but it is also not the worse. If you decide to buy this product, you need to make sure that your serial number starts with 0835 or greater, otherwise you will have a huge electrical noise problem. Also, if you decide to buy it, you must register within 30 days of buying it, otherwise you will lose the lifetime warranty provided by BFG and get only a louse 1-year warranty.
If you have a unit with production batch lower than 0835 (most likely 0804), contact BFG and ask them to replace your unit, because your model is completely flawed.
But even the “fixed” version of this power supply presents high noise levels when delivering 800 W. This shows how having only Japanese capacitors may mean nothing.
BFG ES-800 presents a high efficiency between 84% and 85% if you pull up to 60% of its labeled capacity (i.e., up to 480 W). Pulling 80% from its maximum wattage efficiency dropped to 82.4%, still above 80%. At full load, however, efficiency dropped to 79.1%.
Having so many “ifs” and costing USD 190, we can’t recommend this power supply, even though if you bought one from the right batch you should not face more problems, as most people won’t pull even close to 800 W. Currently there are several other better options on the market (e.g., Corsair HX850W costs the same thing, doesn’t have the same issues and presents a far higher efficiency).