[Tom]

For my last 3 day trip I picked up a 15000 mAh battery bank from Costco to charge my phone and inReach. The packaging claimed it would charge an iPhone 14 Pro Max 4.5x. Strange math since the battery capacity of the iPhone 14 Pro Max is a little over 4300 mAh. Perhaps they intended to refer to a lower capacity iPhone. In any case, I only got 2 charges on my Pixel 7 Pro which has a 5000 mAh battery, and a slight top up on my inReach (which in hindsight I should have charged longer as it ran out of juice just before getting back to the trailhead - wouldn't have been good if I actually got into trouble). From what I've read these battery banks only offer 80% of stated capacity so seems about right. I decided for longer trips I definitely needed to look into a larger battery bank or solar options. A larger bank didn't seem like a very smart option from a weight perspective relative to picking up an ultralight solar panel. Apparently panels charge best when stationary, although many have success strapping them to their backpack connected to a small battery bank. I picked up this 4 oz panel as the reviews indicate it has a more advanced voltage regulator than the slightly lighter 3.5 oz option reviewed here. Just arrived today and so far I've tested it in the backyard with cloud cover and both my phone and tablet show charging, granted the battery percentage hasn't moved at all, but at least it hasn't drained power from either device. It doesn't seem like it needs to be reset when it loses sunlight so I'm assuming it will work attached to the back of the backpack unlike some panels which don't have an auto reset feature. Will be interesting to test on a sunny day. https://www.amazon.com/gp/aw/d/B09WD5FV41

Strange math... 15000 / 4300 = 4.5?

15000 mAh battery bank (11.5 oz)

5200 mAh battery bank (4.3 oz)

4.1 oz solar panel

[Cyclopath]

It's not that the capacity is less than stated, it's losses due to inefficiency, but it's six of one and half a dozen of the other. GPS is one of the more power hungry things most people take into the backcountry. I wound up carrying less battery weight when I moved from a hand hand Garmin to one of their watches that sips battery. Now I have a solar GPS watch, any amount of sunlight even on an overcast day slows the rate of drain to the point that it's just not an issue. Not having to deal with keeping a GPS charged means a 3 oz battery pack is plenty to keep my camera going for several days.

[Tom]

GPS has nothing to do with it. No way a 3 oz battery pack is going to keep my phone camera charged for more than half a day haha. Granted the Pixel and other android phones are far more power hungry than iPhones, but any sort of heavy duty image processing or video is going to really suck battery power on a phone. It's a double-edged sword in terms of the processing. If you are getting 3 days on 3 oz of battery I'm guessing you have a really old phone that isn't doing much photo processing, or not taking many pictures.

[neek]

How are you burning through battery that fast? My Pixel 7 Pro lasts 4 days in battery saving + airplane mode, even when using it as the primary camera. Agree moving GPS to a watch makes a huge difference if you're tracking, although a watch costs at least 10x more than a battery pack. Seems like to get much value from a solar charger you'd have to combine it with a battery pack as folks in the reviews are doing. Connecting it to the phone all day at best would be annoying, at worst break that flimsy USB-C port. 6W is barely anything and I bet you're lucky to get half that in typical conditions, and lose another 20% or so moving the charge between batteries. Unless on an expedition I'd just go with a bigger battery pack.

[Tom]

I shot quite a few sunrise and sunset pictures and more video than normal. That processing uses a lot of battery, especially the video and longer exposure photos. The phone is smart enough not to use GPS and other things so that's not really eating up a lot of battery power. When I was taking sunrise pictures I could see the battery percentage dropping, you don't get all that wiz bang photo processing for free. As far as the solar panel, from what I've read, it can charge a phone in just few hours at camp. The weight of the panel is less than the weight of my smallest battery pack (pictured). I'm guessing over the course of a day strapped to a backpack would easily charge that small battery pack. I would much rather bring the panel then a second small battery pack. Of course, I won't know until I actually test, but you can look at some of the reviews on Amazon from people that have actually used it and had pretty good success. As far as the USB port breaking, if you attach a small cord to it and never remove it from the USB port, I don't necessarily see it being a huge risk of failure. The idea is not to have it plugged into your phone, but rather keep a battery pack charged and then use the battery pack to top up whatever device you want.

[Randito]

FWIW: I went on a 1 week sea kayaking trip in BC recently. I had a 30,000 ma auxiliary battery and my wife had a 40,000 ma auxiliary battery. These kept her iPhone 12 pro and my Samsung S21+ charged up. Using airplane mode is very helpful in minimizing battery usage when you can't see cell towers nearby. Took about 24 pictures per day, my wife triple that.

Previous I tried using a large 15watt solar panel to recharge on a bike tour and found it ineffective, except during layover days.

[RumiDude]

I had a solar charger that did the reset thingy but discovered there was a lag time associated with the reset. Strapped to my pack that lag meant that there were significant lengths of time the panel was not charging and often when it was charging it was at significant reduced output due to less than optimal alignment with the sun. I gave up on trying to charge while on the move. Eventually I gave up on charging at stops and such because it was easier to just bring more battery capacity than bother with solar charging. YMMV I use my Samsung phone for navigation and photos, though I take significantly less photos with my phone than before, especially if I have my DSLR with me. Rumi

[Luc]

[zimmertr]

My Nitecore NB20000 has gotten me through multiple 1-2 week long trips and kept my phone, Fenix 6X watch, and InReach charged. I used a bank with a built in solar charger on my first trip and didn't find it worth the weight.

[Tom]

Those look like really nice ultralight battery banks. Strange the 20K version at 11.5 oz is more than twice the weight of the 10K version at 5.3 oz. Seems like a no brainer to buy the smaller units for versatility unless I'm missing something.

[zimmertr]

It's a fan favorite of the /r/ultralight crowd. I recall they mentioned it was more efficient to use two 10k banks as well. Lots of PCT hikers do so for redundancy. I went with one for simplicity. With respect to packweight, I'd probably reap much higher rewards by simply skipping a meal or two the week before the trip. Usually my InReach doesn't even need to be charged as I only use it to send tracking beacons every ten minutes. So I'll actually finish a long trip with battery remaining. My watch has a custom battery profile that automatically turns off the screen and disables everything but GPS and the heart rate monitor so it usually only needs to be charged once. I also usually put my phone in "Extreme Battery Saver" mode with a handful of allow-listed apps. But I take so many photos and videos I will end up having to charge it every three days or so.

[Tom]

Thanks, I might pick a couple of those up. I picked up this inexpensive 10,400 mAh bank on Amazon for grins as it claimed to be 6.6 oz which didn't seem that much heavier than the Nitecore 10K: https://www.amazon.com/Charmast-Portable-Charger-Charging-10400mAh/dp/B07JYYRT7T After putting it on the scale, it's more like 8 oz. Last night I charged my Pixel 7 Pro with it. The battery bank showed it had 90% charge and my phone was at 33%. This morning the phone was charged to 100% and the battery bank was down to 10%. Holy crap! So basically this so called 10,400 mAh bank can only charge my Pixel 7 Pro with a 5000 mAh hour battery once. I guess I'll pick up a Nitecore 10K to compare.

[Randito]

Some phones and battery banks don't have a "smart" charging configuration. So the phone will still draw power from the battery even though the battery has reached 100%. So leaving the phone connected to the battery overnight can waste a lot of energy. It's less convenient, but charging the phone while you are awake and only charging it to 90-95% is more efficient in terms of auxiliary battery utilization. I also turn my phone off when I'm in bed, this saves a small amount of power when everything is working well, but can save considerable power if I've inadvertently installed an app that burns up battery when it shouldn't.

[Tom]

Yeah, I don't think that's the issue. It's a Pixel 7 Pro so not dumb enough to keep charging past 100%. When I got the phone it wouldn't charge to 100% as it was conditioning the battery. It's a new phone as my other Pixel 7 Pro cracked on my last trip and it was about the same cost to buy a new phone and trade in the old one as it would be to get the screen replaced, not to mention the latter would no longer have the same waterproof rating. That said, I'm beginning to wonder if there's something wrong with the battery on the new phone. It sure seems to be drawing a lot of power. I still have my old phone as I haven't mailed it in for trade-in so will do a test tonight to see if it exhibits similar usage from the battery bank. More than likely though it's just a case of getting what you pay for with an inexpensive battery bank. I ended up picking up two of the NB1000 from longhorn tactical. No sales tax and they have a 20% off Labor Day coupon if you buy $100 or more so two batteries only set me back a little over $90. May likely end up being a better option than the solar panel, we will see.

[Chief Joseph]

My hiking partner Dylan says that the solar chargers aren’t worth their weight…I don’t really care, I don’t take that many photos.