LEPA B650 Power Supply Review

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 this test, both inputs were connected to the power supply’s single +12 V rail. (The power supply’s EPS12V connector was installed on the +12VB input of the load tester.)

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	5 A (60 W)	10 A (120 W)	14.5 A (174 W)	19 A (228 W)	24.5 A (294 W)
+12VB	5 A (60 W)	10 A (120 W)	14 A (168 W)	19 A (228 W)	24 A (288 W)
+5 V	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 (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)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)	3 A (15 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	136.1 W	263.2 W	380.5 W	507.3 W	644.9 W
% Max Load	20.9%	40.5%	58.5%	78.0%	99.2%
Room Temp.	46.5° C	45.7° C	48.5° C	49.4° C	48.8° C
PSU Temp.	45.8° C	46.7° C	47.7° C	49.3° C	50.3° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	158.8 W	302.4 W	442.1 W	601.4 W	787.0 W
Efficiency	85.7%	87.0%	86.1%	84.4%	81.9%
AC Volt age	115.4 V	113.3 V	111.7 V	110.5 V	109.9 V
Power Factor	0.982	0.993	0.996	0.997	0.998
Final Result	Pass	Pass	Pass	Pass	Pass

In our tests, the LEPA B650 presented efficiency between 81.9% and 87.0%, matching the 80 Plus Bronze certification, which promises a minimum efficiency of 82% at light (i.e., 20%) and full loads, and 85% at typical (i.e., 50%) load.

All voltages were closer to their nominal values during all tests. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values. However, we’d prefer to see voltages within 3% of their nominal values to consider this unit “flawless,” which didn’t happen. See the table below.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	≤ 3%	≤ 3%	+11.63 V	+11.55 V	+11.49 V
+12VB	≤ 3%	≤ 3%	+11.63 V	+11.56 V	+11.50 V
+5 V	+5.18 V	+5.17 V	≤ 3%	≤ 3%	≤ 3%
+3.3 V	≤ 3%	≤ 3%	≤ 3%	≤ 3%	≤ 3%
+5VSB	≤ 3%	≤ 3%	≤ 3%	≤ 3%	≤ 3%
-12 V	-11.29 V	-11.38 V	-11.47 V	-11.53 V	-11.60 V

Let’s discuss the ripple and noise levels on the next page.