Do Solar Power Banks Degrade with Time?

The days of getting easy dunks on solar energy are long over. Solar energy has come a long way and is efficient, clean, and incredibly versatile. Solar power banks allow for consistent charging of electronics even in the most isolated of locations. But do solar power banks degrade over time?

Solar power banks degrade over time, like any equipment that sees years of use. However, the rate of degrade is actually quite slow. Known as performance ratio, solar panel banks lose between 1-3% of their ability on year one before losing 0.5% to 1% a year thereafter.

This means in an absolute worst case scenario your solar power bank still stores at 88% of what it did brand new after a full 10 YEARS of use!

How many electronics or appliances do you have that can boast those levels of long-term effectiveness?

portable solar charger on phone

Solar panels will experience the same thing over a longer arc, but if they’re still working at 75% capacity in 30 years you’re doing more than okay.

How Much Energy Do Solar Banks Lose?

Quick Solar Power Bank Efficiency Over Time Table (Explained in-depth more below)

Year(s) of UseLikely Worst Case Solar EfficiencyAverage Solar EfficiencyOptimal Solar Efficiency

If only I could hope to be 78-89.5% of what I am now in 20 years 🙂

Solar banks will degrade over time, but you will find that most quality models are closer to the .5% per year mark. While this isn’t ideal, for anyone who deals with having to buy a new laptop battery or trying to keep an old one charged…that 0.5% to 1% mark sounds great.

They are still very functional. To the point where if you buy a reliable solar bank it will still work quite well when you go about looking for a new one.

IMPORTANT: This isn’t a guarantee that a solar bank will last 20 years, but it shows what you can expect based on current data if it does.

There are some brands that brag of showing even slower decline than the optimal numbers on the chart above. These are usually the highest rated solar power banks on the market, and the ones that are easy to research.

You know, company websites, long history of purchases, clearly NOT dropshipped out of a minimum wage warehouse somewhere.

If your too lazy to do the research, we’ve got your back. When it doubt start by looking at these:

All those links go up to date listings on so you can see what the current market is for the best (and most reliable) solar banks on the market. Not the most expensive.

Those are reliable names in the solar field and they are favorites of many users. You’re not going to be doing badly if you go with any of the three of these.

What Happens When Solar Panels & Batteries Both Denengrate?

Eagle-eyed readers, or those of you who have done at least some research up to this point, notice that some degree of efficiency happens over time with both solar panels as well as storage batteries.

This shouldn’t be surprising. Cars run down over time. Computers run down faster than any of us care for.

So what’s the average total efficiency drop when combining both solar panels and batteries?

The numbers aren’t sure yet. There haven’t been enough in-depth studies to show comparison charts or have a really good idea of what the potential issues are.

Then there are outliers. Instances where a solar battery has a sudden 20% efficiency drop…but then keeps on working. What do you do with that data?

It’s extremely rare but it has happened from time to time, especially with more “middling” brands.

What we do know:

The denegation rate between solar panels and batteries is probably similar. Because of this you can use the rough rule of thumb of doubling the above numbers to look at the grid, understanding that’s not completely accurate.

It’s also a rule of thumb that could become less accurate the further you go. There’s a point where on the graph it levels out a bit more.

I’m not a mathematician so I’m working with someone who is to try to make a graph that shows that flattening affect, but for now understand in the beginning it’s similar to that.

That’s not the case later. A solar bank and solar panel combination 20 years from now is not going to be running at 60% of original. It will flatten out before that point.

Also keep in mind:

  • Replacing a lower functioning solar panel with a better one changes those numbers
  • So does replacing an underperforming solar battery
  • Solar technology continues to advance by leaps and bounds which can alter numbers completely in the future

Solar power banks will slowly lose very small amounts of capacity over time, but they are still great tools.

If you’re worried about that slow steady decline then chances are you’re potentially losing out on dollars while worrying about pennies. While solar power banks lose small amounts of power of time, they are a fantastic tool that remain practically functional over the long-term.

So What Does This All Mean?

The verdict on solar power banks degrading is actually a very good one when you actually crunch the numbers. Although you won’t be at 100% functionality from the time you begin using it, the amount of loss is so nominal as to not be noticeable to most people.

At least not for many years.

If you notice issues beforehand check other things like the connections for loose wires, cleaning the solar panels of dust, dirt, or specks that could be blocking its efficiency, or other factors that might explain the potential issues.

Now you know. Even though solar banks do technically degrade over time, they are still surprisingly effective years or even decades later!


Hi, I'm Shane! I've always felt a passion for two worlds: one in technology and one for the great oudoors away from it. The amazing advances in solar power in my lifetime have really opened up the possibilities, and both my brother and I are deeply passionate about where solar power meets outdoor gear!

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