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Re: Gear advice on solar panels?

Hi Sabine

I have a Mobile Solar Chargers 6W Compact USB 5V/1A folding solar panel charger. My initial review is here

I've used it on the Challenge - and it worked OK - but I've not decided whether to take it this year. My solar panel can't easily be attached to my pack when I am walking, so I can only use it in the morning and evening or when I stop for a break. The quality of sunlight at the start and end of the day is not always good enough to get a fast charge. A 30 minute lunchbreak on a sunny day will add about 5 to 8% of charge to my phone.

The solar panel was excellent last May when I was working on a Bothy and could leave the panel pointing at the sun for a couple of hours during the sunniest part of the day.

I'd been advised that the UK was not the best place to use a solar charger but my experience has been relatively positive. You just need to make good use of the sun when it is high in the sky.

If I was going to be away from a mains power supply for more than a few days I would definitely take my solar panel. However, this year I think I should be able to plug my phone in every couple of days so I'll probably just take a 10,000mAh power pack.

I hope that helps.

Re: Gear advice on solar panels?

Thank you very much for your answers!
I am really getting into this serial vs parallel wiring and crystalline vs oragnic cell thing at the moment. It is kind of fun. :grinning:

Re: Gear advice on solar panels?

Hi Sabine,

If you're considering wiring solar panels in parallel (to obtain higher current) I'd strongly suggest you wire a (schottky) diode in series with each solar panel.
Give me a shout if you need clarification or help with this.

If you're going to wire the panels is series (to obtain a higher voltage) no such diodes are needed.

Have a read of this:



Re: Gear advice on solar panels?

Hi Sabine,

Your post made me curious so I've done some testing!

Charged my phone (Samsung Galaxy S10e) from the mains and then only recharged thereafter from a 10,000mAh USB battery pack. After exhausting the battery pack and running the phone down to 15% charge remaining, the time from the initial mains charge was ..........12 days. The pack charged the phone approximately 2.5 times.

So I reckon I'll be fine for the 15 or so days of the Challenge with just a few judicious top-ups at cafes and camp sites.

Worth noting,

- the phone was used normally during the day for phone calls and texts. WiFi, Bluetooth and mobile data were on during the day.
- moderate power saving was used (no always-on display, CPU speed reduced to 70%).
- put in to flight mode overnight.

I would get more savings with increased use of flight mode whilst walking, with just occasional use of the GPS for a map fix and a quick check for messages on summits and near major roads.

Hope this helps.


Re: Gear advice on solar panels?

Hi Andy,

thank you for the test. 12 days is a very long time indeed.

I will be in the middle of nowhere coming summer for about 3,5 weeks and electricity is not guaranteed during town-stops.
And since I rely on my phone for GPS (of course I will have some paper maps, but there is only limited quality available), music / podcasts, the camera (most important!) and phoning home from time to time, it is important to me to have an independent charging option.
I bought a panel a few days ago and will test it a lot before deciding if it is reliable enough. :smile:

Re: Gear advice on solar panels?

you’ve inspired me to look up power saving on my new iPhone - it appears that there are 18 power-saving steps to take. I may need an extra day of leave before the challenge to adjust my phone.

Like you, I carry a 10000 mAh battery pack - I’ve started a test this morning to see if I can equal your 12 days under normal conditions.

On the Challenge, I turn off all the apps and keep it in flight mode except for phone check-ins - my previous phone was the iPhone SE which has a small screen and was extremely economical. I suspect the Xs will be more power hungry.

Re: Gear advice on solar panels?

Hi Graham,

Yep, there are lots of measures that can be taken to save power - I should better the 12 days with more use of flight mode.

These phones are designed to be fast, bright and pleasant to use, all at the expense of battery life, so we need to take as much non-essential function out as possible.

It's an interesting challenge in itself!