Yes, I really do "need" a 12V USB charging adaptor with a built-in voltmeter.
Driving my VW camper van around, I frequently swap the USB charger with a voltmeter. I'm always curious about how much current my alternator is putting out, and if my house batteries are charging up. I also worry that my kid may plug into the wrong 12V outlets and drain the starting battery. This charger lets me know what is going on as I charge. I NEED TO KNOW!
There are a few chargers with voltmeters, I picked this one as it has both 2.4A and 1A charging, the swivel lets me angle it so I can read it while driving, and the display is super easy to read/understand. When the engine is running the voltmeter tells you what current it sees at your 12V port, with the engine off it's reading the charge from the battery.
Thanks to help from our readers, I successfully put together and sized my house battery, solar panel and portable fridge to allow me uninterrupted cold storage, regardless how long I stay out. This voltmeter helps me manage the system. I'll write up a post what I ended up going with soon.
HAWEEL Rapid LED Dual USB Car Charger Adapter(5V/3.4A output) with LCD Screen Display via Amazon Read the rest
For $20 I really like this new Matone dual USB battery pack! I haven't found anything better at this price.
The Matone battery is a great combo. I've tried water and damage resistant batteries, and solar charging units -- but this is the Bartles and James of outdoor USB power banks.
At 10000 mAh advertised, I can get around 1 3/4ths full charges on my iPhone 6 with this battery. It seems a bit low, but is certainly enough juice for my needs. Keeping a cellphone running Waze going on an all day motorcycle trip. Charging with the solar panel is slow as there isn't a lot of surface area. I'd consider solar to be an emergency only kinda thing, and not to rely on it for regular charging.
This'll certainly be the battery I use for this Spring's road trips.
Matone® Portable 10000mAh Solar Battery Charger Shockproof, Dual USB output via Amazon Read the rest
Sometimes I just don't need to carry a big battery with me, but I know my 1 year old iPhone battery can't be trusted. If I want to be sure I can call a ride home, after a full day out and about, I bring Anker's lipstick battery with me.
While this little guy has enough capacity to completely recharge my iPhone 6, once, I find I tend to remember it in an emergency. I'll need to call a Lyft or Uber, and see that I'm sitting at a 4% battery cliff, where my phone loves to suddenly dive for zero. Charging this once and dropping it into my jacket pocket tends to get bail me out of trouble a couple times a month.
Anker PowerCore+ mini 3350mAh Lipstick-Sized Portable Charger (3rd Generation, Premium Aluminum Power Bank) via Amazon Read the rest