Morning all,

Looking for a solar charger with built in battery for keeping GPS/phone charged over multi day bivi trips. Any recommendations? Would like to keep to a 50 quid budget if possible …

Any advice appreciated!

Got a Powermonkey for going sailing a while back, think they’re abour £50. Comes with attachments for loads of phones etc. and a normal USB connector. Can be charged from a socket (give it a full charge before you leave) or solar and I get about 1.5 charges of an iPhone with it. The solar charging can be a bit patchy in Scotland 🙂 but I expected that, so maybe have a backup plan incase it’s cloudy and raining the whole time. Have a look at the Mophie juice packs (depending on phone). It’s not solar, but would give you more capacity if you charged it before you left. Also, the solarstorm battery boxes come with a usb charger.
Battery Box
(out of stock there, but you get the idea)
Just take a bunch of charged 18650 batteries and they’ll keep you going too.

There’s a Kickstarter “solar paper” project.
May be a bit over your budget and not in your time frame. Weight weenie attractions…

isnt there a dyno hub that has a usb charge connector?

They’re not hard to make. I mounted this lot to a sheet or cardboard which folds to cover the panels then folds back over itself to stand up like an iPad cover.

You could use two of these in series and a low dropout 5v regulator+caps bodged onto a usb lead.

What exact devices are you using?

Over your budget, but the Goal Zero stuff works really well. In my experience the compact panel things from the likes of PowerTraveller etc just aren’t big enough for typical UK use.

Powermonkey worked ok for us when camping but filling the battery then charging from that, not direct from solar.

Unless it’s a very long trip away from civilisation there are big-capacity, fairly light battery banks that will do many changes before running out, and you don’t have to ensure you have panels pointing at the sun for long enough.

Awesome, thanks all, some good options here, I shall take a good look at them…

@gofasterstripes- devices are old motorolla phone as gps 3.7v 4000mAh battery, and a sony erricson xperia S 3.6v 1500mAh, so nothing too pokey..

Somewhat tempted by the DIY version…. I intend on taking a battery for my bike lights 7.4v 6600mAh, and I have a spare 12v Car usb charger. Could I hack the two together? Will 7.4v be enough to charge 2x 3.6v devices?

Forget the solar (esp in the UK) and get a battery that has a big charge. There’s been a couple of threads on here recently with good recommendations, but this is silly cheap right now:
http://www.amazon.co.uk/16000mAh-Portable-External-Technology-Motorola-Black/dp/B00D5T3QK4

Do you need the dedicated charger or will your normal phone/ iPod charger work?

I bought one of those that tootall linked to. Its a good bit of kit indeed.

Ooos missed that post eviljoe, BBL, pizza!

Right, if those devices charge over USB, then what you need is 5v DC out. The two panels in series give over 7v (roughly what you need to feed the regulator to get a stable 5v out) in any reasonable light, like somewhat overcast daytime. The limiting factor is the current. My hacked thing above will charge about 700mA at full chat(bright light, no clouds) so you’re looking at 3 hours for the Samsung and 6 hours for the Motorola (are you sure it’s 4000mA?!) Really it’s best used all day, I mean left plugged in to the phone.

That’s a lot of battery capacity there, and two devices means more power lost in the recharge. I would suggest you just use the one device, less lost energy.

I’m not quite sure what the other bits you wrote mean, but you can only charge lithium batteries with a charging circuit, charging the direct will ruin then. Let the phone do it.

Tbh, it’s going to be a real pain with all that gear, I’d been thinking you just meant 2x phones and that was it.

You could also use the panels to charge up the power bank, but each extra layer decreases the efficiency.

If you want, post back and I’ll see if I can help more, but IMHO u really need to simplify the setup, or go with the 16,000mAh bank, it’s a bit of a bargain… But when it’s flat it’s flat!