You're absolutely right Bob!
A charge controller is an often overlooked piece of the puzzle that may do not realize is a SUPER important part of the equation.
I guess for those who are not in the know, the following is "really" the essentials to charge devices in the field.
1. Solar panel ( either foldable or rollable)
2. Charge controller ( to regulate the power from the panel as it fluctuates)
3. Powerbank ( storage for the power produced from the solar panel )
If you do your homework and take the time to learn about solar, you will realize that still now there are now real lightweight options. Sure you can get some little 5 watt panel with a 5V USB outut, but.... will take atleast 8-10hrs to charge a few AA batteries, in full sunshine. OK if you are staying put everyday, but for on the move, you really need a panel ( or set up ) that will charge a smartphone, or tablet or AA /AAA's. Let's say you are out for a weekend. Your best bet is just to take a batterypack/powerbank/etc,etc. Usually they are a Lithium Ion battery pack. For the above mentioned devices I wuld say a 40 Watt hour ( Whr) pack would suffice. Let's say you are wanting to watch a movie a night, well that would serve your needs. But.... if you go out for a week or more, then you will obviously need to think of charging that powerbank ( big battery pack ). The problem is that for us UL'ers, the only options are the rollable or foldable panels from either Powerfilm or Global Solar. - That is, they are the thin film technology products, but the trade off from light weight and packability is tht they are inefficient. I learnt the hard way, I lived in the High Arctic for 10 years, and at times spent weeks out camping/hunting etc, and needed to power/charge a GPS/ Iridium sat phone/ AA's etc, I bought a Iowa Thin Film ( powerfilm ) panel and unless I had fll sunshine ( yes only in summer or late spring north of 60!!!), it wouldn't even recharge the sat phone.
I then looked into the options, and learned about charge controllers, watt hrs, amp hrs, etc etc. In my opinion I would recommend you go for slight overkill and get a system that is more powerful than what your calculations work out to. Just think of how many days of your trip that you have full sunshine and are in a campsite etc that affords full sunshine???!!!. If you want to say keep an ipad/tablet, and a smartphone, and lets say 2x AA's alive for a week - then go for the highest wattage monocrystalline panel you can afford ( they come as foldable panels). At least a 40 watt panel is the realistic size. then get a 2 amp charge controller, and look for a lithium battery pack ( there re a million on Ebay and alibaba) at around 50+ watt/hrs). For trip and usage of around let's say 4-5 days - you can most likely get away with just the battery pack.Powerenz ( US cottage company ) have many really good options ( albeit expensive). If you research, you will realize that most companies will buy their panels and battery packs/powerbanks ( apple is one of them!!!), from China, and Brand Name them with their own and charge you a huge markup, or you can go online and do your homework= learn about exactly what you need and buy a nice setup from Alibaba/Ebay for a reasonable price.
Solar is awesome. Unfortunetely brands like Goal Zero market their stuff as the best, but their gear is overpriced to the max, heavy and VERY impractical for all hikers bar car campers ( IMHO!).
Research, research, research. Learn how Photovoltaics work etc, then you will realize that you can get great free energy for an initial low cost, or you can be a sucker and believe some of the manufacturers that will sell you underpowered products and you will just walk away mad and disgruntled and think Solar is still a joke - which it isn't!.