I have the one linked below and it’s sat in my living room window facing south since January and despite all the rave reviews the charging is basically in equilibrium with natural battery drainage.
https://www.blavor.com/cms/a/3.htmlDespite this being sat in my window for so long only once has the strength meter hit 4/4 lights, will see what it’s like the rest of this month and into May and as I’m doing the west highland way I have a decision to make risk this or take my big Anker block which is 500g but is tried tested and trusted, all my Apple accessories are Anker in my opinion they are the best.
The only one I’ve seen recommended for the uk due to the solar strength here is the Anker 24W but it’s heavy. Sorry can’t remember where I saw this recommendation it was on one of my rabbit hole excursions on google.
https://www.amazon.co.uk/dp/B08FJ12RTM/ref=cm_sw_em_r_mt_dp_FH8P8D4THGPRGMAP9EPCThis would be a consideration if it didn’t weigh 1.2kg and cost £70 my pack weight is low enough to accommodate it as a luxury item but for a few days not worth the expense or the weight.
Anker also do a 21W which isn’t quite as big but not recommended for uk weather but could be a consideration if you wanted to save some weight.
https://www.amazon.co.uk/dp/B012VL20GW/ref=cm_sw_em_r_mt_dp_F99A10FX86539NE5CSBVAccording to Amazon this is half the weight of the one above and £60 but I am no solar charging expert but isn’t powerful if that’s the right word for often cloudy uk conditions but may work well enough if it’s going to be sunny.
I am going to give my one at the top a real life 5 day test at some point and see if it works if it dies I am just going to take my huge 26800mah Anker block at 542g which I know will last me as it’s tried and trusted. I know Anker do newer blocks but this has 3 usb-a ports and I need 2 as opposed to the new one which has 1 usb-a and usb-c ports. As I’m using an Apple Watch and iPhone 8 I need the a ports.
I hope this helps as it’s an area I keep looking at as I’d like to be power self sufficient as I’m guessing that’s your aim.
This is just what I’ve found from my interweb searches on the topic please anyone feel free to correct anything I’ve said if it’s technically wrong I’m not a solar scientist the rest is just my opinion.