Think about how many devices you want to charge in the field: camera batteries, laptop, cell phone, tablet, GPS; the list may be long. And unless you’re an electrician, the varying voltage and power requirements can get confusing.
Here’s the good news: Many solar chargers have built-in circuitry to avoid damaging your product. One good rule of thumb to follow is recharge from a battery, not directly from your solar panel (check your specific panel for directions). Recharging from a battery is safer and has a constant output, and batteries often have different output options to match your device. I do recharge my small devices directly from my solar panels using a 12V cigarette car adapter, since the panels are designed for this use, but if I was charging my higher voltage laptop, I would use a battery that was charged by my solar panel. I’d rather not worry about fluctuating current as the sun goes in and out of clouds.
Another plus for batteries is that they store power. If you get one day of sunshine and four days of rain, you’ll be able to power your devices using your battery until the sun comes back out.
I’m already thinking of my next adventure. I’ll fly into Alaska’s vast Wrangell-St. Elias Range, set up a nice basecamp near a turquoise glacial lake, and photograph ice climbers and stunning landscapes. Two weeks without power! I’ll rely on my solar panels and batteries to keep me juiced up.