Battery capacity/electronic load tester 150w 200v 20A from amazon

[Dimitri]

Hello,
Does anyone know how to use this load tester? It has a heater fan with a coarse and fine knob and it connects to your 12v solar battery. The instructions that come with it are useless. Ive watched 2-3 youtube videos but it is not clear from any of this what exactly it does and how to use it. I paid 49.99 from Amazon for it. Please can someone help!
thanks,
Dimitri

 

[Mattb4]

You will need to post the model.

Just as a general thing battery load testers will apply a certain amount amperage load and check the voltage drop. If your battery can not sustain a proper voltage under load it is bad.

There are load testers that test the batteries capability to carry a load that corresponds to battery capacity. Say you have a 100ah battery. That is usually a 20 hour rating. So 100ah/20h=5a This type loads the battery at amps you select and you time how long it goes.

 

[Dimitri]

The model of the tester is “makerhawk electronic load tester usb load tester 150w 200v 20a resistor adjustable constant current battery capacity tester module intelligent discharge resistance power tester” thats the exact model listing on amazon. It costs $49.99.
the battery I need to test is the solar battery sold by harbor freight rated at 12volts at 35ah. How do I set this tester to check the battery?
thanks,
Dimitri

 

[Mattb4]

Glancing at it on Amazon you would hook the battery to the leads like the last picture on the Amazon link. Set your amperage at the level you want to discharge at (in your case 35ah) you could set it for 10a (120w-140w approximately) and wait for around 3.5 hours for full discharge. If it discharges quicker than that you know the batteries capacity is less than rated.

 

[wiseacre]

Will covers it in this video:

 

[Dimitri]

Glancing at it on Amazon you would hook the battery to the leads like the last picture on the Amazon link. Set your amperage at the level you want to discharge at (in your case 35ah) you could set it for 10a (120w-140w approximately) and wait for around 3.5 hours for full discharge. If it discharges quicker than that you know the batteries capacity is less than rated.

Thank you. I get it now. Ill set it for 10a and time it for 3.5 hours and see if it discharges quicker then that or not. Harbor freight tech support told me that the lowest voltage the battery can be discharged to is 9.3 volts. Does that make sense? Ill set the tester so it doesnt drop below that number. Thanks

 

[RCinFLA]

Hello,
Does anyone know how to use this load tester? It has a heater fan with a coarse and fine knob and it connects to your 12v solar battery. The instructions that come with it are useless. Ive watched 2-3 youtube videos but it is not clear from any of this what exactly it does and how to use it. I paid 49.99 from Amazon for it. Please can someone help!
thanks,
Dimitri

Most of the adjustable knob units do not have remote voltage sensing (4 wire terminals). Cell sense voltage goes through high current wires. This is fine if all you are testing is 18650 cells at low currents.

I highly suggest you find a load tester that has separate cell voltage sensing port lines that allows voltage remotely read directly from cell terminals. At high current loading it is difficult not to have significant voltage drop on load carrying wires.
DL24P tester has remote voltage sensing.

 

[Dimitri]

So I tested my battery using this makerhawk load tester. The battery is the harbor freight 12 volt 35ah one. Their tech support people told me that the cutoff discharge voltage for this battery is 9.3 v. I set the low voltage cutoff on the makerhawk for this. I then set it to draw 10A perhour for
3 1/2 hours To test the battery. After 2 hours and 53 minutes it reached the 9.3v low voltage and the test stopped! These are the values on the makerhawk at that time: 28.73Ah, 329.21Wh, 2:53:26T.
Do these values seem satisfactory about this battery? What Do people think?

thanks,
Dimitri

 

[Mattb4]

Seems about right (perhaps just a bit low but I do not know the starting conditions for your test and the age of the battery). Remember that if you discharge at a higher amperage than battery 20 hour rate you will not get as much from it. Most batteries amp-hr are based on 20 hour discharge some are less like 10 hour. So your battery at 35ah divided by 20h = 1.75a

 

[RCinFLA]

So I tested my battery using this makerhawk load tester. The battery is the harbor freight 12 volt 35ah one. Their tech support people told me that the cutoff discharge voltage for this battery is 9.3 v. I set the low voltage cutoff on the makerhawk for this. I then set it to draw 10A perhour for
3 1/2 hours To test the battery. After 2 hours and 53 minutes it reached the 9.3v low voltage and the test stopped! These are the values on the makerhawk at that time: 28.73Ah, 329.21Wh, 2:53:26T.
Do these values seem satisfactory about this battery? What Do people think?

thanks,
Dimitri

Depends on your wiring loss. Compare voltage at tester terminals (or what tester reads out) to voltage reading by DVM directly on battery terminals at 10 amps load. (need battery to reach load current equilibrium which takes 1 to 3 minutes from start of load current)

This is why it is better to have a load tester that has remote voltage sensing that can be connected directly to battery terminals.