Reddit reviews 5A/9V LED Display Multi Tester Dual USB Output Current Detector for Phone Charger, Power Bank
We found 5 Reddit comments about 5A/9V LED Display Multi Tester Dual USB Output Current Detector for Phone Charger, Power Bank. Here are the top ones, ranked by their Reddit score.
Easy to Use: simply plug in and you will get dataEasy to Read: voltage and current displayed in different colorEasy to Carry: small, compact, only thumb length long
I don't have the equipment to do it. For cheap, I might pick up something like this and run the pi off of it. If it holds at a steady amperage draw, you could calculate it out.
Suppose its drawing 250ma constantly. Without the solar panel in the picture, a 5000mah battery theoretically gets you 20hrs of use. It's literally just how many milliamps are being used multiplied by how many hours to arrive at mah.
Others have already mentioned that it is either your total wattage, or a cable or device that is worn out and causing a bit of a short circuit.
What might be worthwhile to diagnose this is a simple USB volt/current meter. You plug that in the USB port, and the device plugs into that. You can see how much current it draws, and also if the output voltage of your port starts to sag.
Example: https://www.amazon.com/Display-Tester-Current-Detector-Charger/dp/B015F83X0U/
(Note: never used one myself, I just found you a random one on Amazon, no idea how well this particular item performs).
Only other option would be to get a USB amp meter to see how much power it's pulling.
https://www.amazon.com/Display-Tester-Current-Detector-Charger/dp/B015F83X0U/ref=sr_1_3?ie=UTF8&qid=1491509183&sr=8-3&keywords=usb+amp+meter
Should be good then. Like I said, should take 11 hours from dead. The only other possible limitation can be the cable. There are some cheap cables that can only pass through 1A, or even only 0.5A regardless if the wall port is 2A. It's a real thing (unfortunately) that not all cables are equal.
I have something similar to this USB Meter Tester and tested all of the cables that I own and threw out all of mine that weren't capable of 2A because I don't have time to wait around on poor performing cables.
> USB digital volt /amp meter from Amazon
Something like this?
https://www.amazon.com/Display-Tester-Current-Detector-Charger/dp/B015F83X0U/ref=pd_lpo_469_lp_img_3?ie=UTF8&refRID=WK80BEHH5GMWT04ED3WD