I ordered 5 units of "1-8S Lipo/Li-ion/Fe Battery Voltage 2IN1 Tester Low Voltage Buzzer Alarm" from The HS (Hong Kong) co., LTD store on AliExpress.com.
Tested them with 8S 18650 cells at 4.09-4.10V. All units defective.
Read ~3.07V for one of the first cells , 6.06-6.15V for cell 7. (All cells are 4.09-4.10V). Other voltages also incorrect.
I did an accuracy comparison of both these products with a multimeter. Here are voltage readings from a partially discharged Li-Ion 8S1P pack:
Cell BVM-8S AOK-BL8S Multimeter
1 3.906 3.93 3.91
2 3.831 3.83 3.84
3 3.809 3.81 3.81
4 3.861 3.84 3.86
5 3.822 3.83 3.82
6 3.784 3.80 3.78
7 3.952 3.93 3.95
8 3.902 3.88 3.90
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Tested them with 8S 18650 cells at 4.09-4.10V. All units defective.
Read ~3.07V for one of the first cells , 6.06-6.15V for cell 7. (All cells are 4.09-4.10V). Other voltages also incorrect.
Update 170422: Ordered two more units from another vendor, labelled AOK-BL8S, and they work fine. Also now have a very nice, more elaborate unit, the BVM-8S, that has a color backlit LCD display. Cost is about $10, but it has over and under voltage alarms and delta voltage alarm as well. And, since it is from China, I know some of you are just dying to know if it is provisioned with a lanyard. Yes, it comes with one!
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I did an accuracy comparison of both these products with a multimeter. Here are voltage readings from a partially discharged Li-Ion 8S1P pack:
Cell BVM-8S AOK-BL8S Multimeter
1 3.906 3.93 3.91
2 3.831 3.83 3.84
3 3.809 3.81 3.81
4 3.861 3.84 3.86
5 3.822 3.83 3.82
6 3.784 3.80 3.78
7 3.952 3.93 3.95
8 3.902 3.88 3.90
