UKC

I've been looking at what's available in the way of cheap solar phone chargers for camping trips...

Amazon has stuff like:
http://www.amazon.co.uk/EZOPower-Capacity-6000mAh-Portable-External/dp/B009...
and
http://www.amazon.co.uk/Portable-Solar-Battery-Charger-1350mAh/dp/B00378SRD...

but the solar panels look rather undersized - e.g. the one with a 6000mAh integrated battery claims the solar panel delivers 100mA @ 5v (so about 0.5W); assuming the battery is the usual 3.7v li-ion it would work out at 22.2Wh, so about 44 days of full sun to fully charge! The 1350mAh one is more reasonable - 1350mAh @ 3.7v is 5Wh, the solar panel delivers 80mAh @ 5.5v (= 0.44W), so 11 hours, but still seems a bit excessive.

There are lots of cheap chinese USB chargers on ebay with very suspicious specs (e.g. 30,000mAh ones with 1.5W solar panels for under 15 quid) and with no brand names mentioned.

So, does anyone have any experience with these things? Are they worthwhile or do they produce so little power that it isn't worth it? And how trustworthy are the cheapy chinese devices on ebay?

In reply to Steve Hill:

I've used the Solar Monkey and found it to be very good.

I have a spare with some corporate branding on it. Brand new - can be yours for £22.50 posted. Have a google and let me know if you're interested.

In reply to rj_townsend:

Buy a proper solar charger with a large solar panel. Otherwise it's a waste of time and money.

Go for atleast 5W if you are not in a sunny place and want to charge your smartphone. If you want to charge something consuming more power, you want a bigger one.

If you are not using too much power, just go for a large external battery.

be aware of cheap chinese external batteries. There have been cases of people ordering a cheap one from china, with a old laptop battery inside and little sandbags...

In reply to tjin:

Still better than this USB Memory Stick! http://i.imgur.com/HICt8hB.jpg



I usually have 1-2 extra batteries for the smartphone I use and it's fine. My Samsung S3 had 60% of battery after 9 days walk in Cairngorms. The key point is to turn your phone off and turn it on only when needed.

If you want a phone for receiving calls, go for something like Nokia 100. Its battery is supposed to last 35 days.

In reply to Steve Hill:

Two threads on solar chargers - what are the odds?

Forget the small cheapies - I had a Pico for a while, and the only way I could tell it was on was the little orange light. My (old, pre-smart) phone certainly never charged properly on it.

Equally, the figures quoted for these tiny models are unattainable in the field, and seem often to be more theoretical than derived from hard experimental data in any case. Add in the lack of sunlight in the UK, and you've got an expensive paperweight. That won't hold down paper.

I have a goal zero 7w panel with the Guide 10 plus charger, and it'll happily do camera batteries and most phones directly from the panel (I believe there are some issues with really whizzy phones), and ALL phones and small tablets if you charge the battery pack and then use that to charge the device.

There are smaller - and cheaper - devices on the market, but they don't work in the field. It's not that goal zero are so great, but that other gear is often totally cr@p. You absolutely get what you pay for, and below a certain level you get nothing at all for your money, so it's a false economy.

Martin

In reply to Steve Hill:

I'll vote for the power monkeys if you're definitely looking for something like this.

I managed to "borrow" one a couple of years ago and you can charge them off the mains as a mini power-pack, giving approx 1 and a half phone charges (I forget the model I have though) and the little solar flap charges the power pack to about 60-70% in midday sun, in maybe a couple of hours??? enough pretty much for a full charge.

They might be a bit better now and other similar brands are probably just as good, but I've never used them...