How do I know my solar power bank is charging by solar

By October 20, 2017

Those people like us, who have purchased a solar power, know that solar power bank isn’t a power bank which is only charged by solar as normal power bank charged by electricity. Sellers write this sentence in the introduction that please do not take solar as primary recharge source, as the charging speed will subject to sunlight intensity and panel conversion rate, which may take a long time to recharge. Therefore, solar power bank is charged by electricity source primarily. And the solar source acts as a very useful ancillary function in an emergency while outdoor. For the low conversion rate compared to USB charge, how do I know my solar power bank is charging by solar? Best Solar Charger for iPhone X


The way to know my solar power bank is charging by solar

LED Indicator

The easiest way to know your solar power bank is charging by the solar source is read from the indicators. I did a research on Amazon. And find out there are several ways of indication when the power bank is charging by solar:

1. The fourth LED indicator turns green indicating its charging via the solar panel. e.g.  OUTXE Savage 20000mAh Rugged Solar Charger 4A Dual Input (Type C and USB) $55.99

2. The one green light means it’s receiving light and is slowly charging. If you put it in dark places, it will turn off. e.g. Dizaul 5000mAh Portable Solar Power Bank.

3. The red LED indicator turns on indicating it’s recharging via the solar panel. e.g. RAVPower 15000mAh Portable Solar Power Bank

4. The green light on when charging by solar, blue light on when USB charging. e.g. Ayyie 10000mAh Solar Power Bank.

5. If the indicator lights are flashing (blue lights), it means it is receiving light and charging.It will turn off under a weak light environment or when the charger is totally out of charge. e.g. Ruipu 24000mah Portable Solar Power Bank


On some solar power bank’s Amazon product page, I can’t find any information about the indicators’ change while charging by solar source. It’s better to check the instruction of your solar power bank. If you find nothing or make sure the indicator is broken, please read Experimental Measurement below.

Experimental Measurement (Can’t read from indicators)

If the solar power bank you bought doesn’t have an indicator showing solar charge or it is broken, you should do an experiment to measure the power change when charging by solar source. And this measurement can even roughly measure how many mAh it has been charged by solar.

1. Fully charge your solar power bank by USB charging.

2. Discharged the power pack from a full charge down to just the point the 4th LED light began to blink out, meaning the unit still had about a 75% charge. (We suppose that the power bank we use has four LED indicators.)

3. Left it out in direct mid-day sun for 3 hours, after which the 4th blue led was solidly on again due to the solar charging.

4. Plugged it into your phone and let it charge up until that 4th light on the battery pack again just started to go out.

5. Check how many power increase on your phone.

6. Calculate the power increase of your phone. For example, your phone’s power capacity is 2915mAh. The power increase of your phone is 20%. 2915mAh*20%=583mAh

7. Now you know your solar power bank can be charged by solar source. And even know how many mAh.

If you have better methods, please leave a comment below and share with us. Solar Charger Q & A: How do solar charger work in the winter?

Read More:

Best Portable Solar Panels for Camping

How to Select a Solar Charger

Comments (2)




  1. What if it just has a green light and digital numbers for battery %?

  2. I have bought a solar power bank but without it’s cable. Can I use any cable to use it with the recharger ?