BFG LS-450 Power Supply Review
Load Tests
Contents
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.
+12V1 and +12V2 are the two independent +12V inputs from our load tester and during our tests both were connected to the single +12 V provided by this power supply.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12V1 | 3 A (36 W) | 6.5 A (78 W) | 9.5 A (114 W) | 13 A (156 W) | 16 A (192 W) |
| +12V2 | 3 A (36 W) | 6.5 A (78 W) | 9.5 A (114 W) | 13 A (156 W) | 16 A (192 W) |
| +5V | 1 A (5 W) | 2 A (10 W) | 4 A (20 W) | 5 A (25 W) | 6 A (30 W) |
| +3.3 V | 1 A (3.3 W) | 2 A (6.6 W) | 4 A (13.2 W) | 5 A (16.5 W) | 6 A (19.8 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 | 89.5 W | 180.4 W | 269.2 W | 361.3 W | 440.5 W |
| % Max Load | 19.9% | 40.1% | 59.8% | 80.3% | 97.9% |
| Room Temp. | 47.9° C | 47.9° C | 48.4° C | 48.2° C | |
| PSU Temp. | 49.2° C | 48.7° C | 48.9° C | 50.3° C | 51.0° C |
| Voltage Stability | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 101 W | 201 W | 304 W | 418 W | 522 W |
| Efficiency | 88.6% | 89.8% | 88.6% | 86.4% | 84.4% |
| Final Result | Pass | Pass | Pass | Pass | Pass |
BFG LS-450 proved to be an excellent power supply. It could deliver its labeled power at 48.2° C with a very high efficiency, peaking 89.8% when delivering 40% of its labeled power (180 W). At full load efficiency was still very high, at 84.4%, which is outstanding.
The only problem we saw was voltage level at -12 V. This output has a higher 10% tolerance, so it can be anywhere between -13.2 V and -10.8 V. During test number one this output was at -10.81 V, touching this limit. During test two it was at -10.92 V, during test three it was at -11.00 V, during test four it was at -11.08 V and during test five it was at -11.16 V. All values were still inside the limits, but we’d prefer to see this output closer to the nominal -12 V.
Ripple and noise was another highlight from this product. Below you see the waveforms during test number five. Just to remember, the maximum allowed is 120 mV at +12 V and 50 mV at +5 V and +3.3 V. All values are peak-to-peak.
Figure 15: +12V1 rail with power supply delivering 440.5 W (67.6 mV).
Figure 16: +12V2 rail with power supply delivering 440.5 W (61.4 mV).
Figure 17: +5V rail with power supply delivering 440.5 W (24.4 mV).
Figure 18: +3.3 V rail with power supply delivering 440.5 W (21.8 mV).
Now let’s see if we could pull more than 450 W from this unit.