Both do the same, the LiPo Rider Pro just has everything on board. The 1n4001 diode used in the second instructable is used to prevent battery discharging though the solar panel at night, prevents reverse current through the solar panel when the usb charging (powering the lipo charger through usb) is used, and prevents the solar panel from affecting the charger when both light and usb charging is used. The LiPo rider has the same type of protection.
I want to series the solar panel up and have voltage regulator that can regulate it.
You're not going to be using the LM317 as a voltage regulator in this case. It will solely act as a current regulator, also known as a constant current source. (CCS).
How does the lm317t react when my solar panel hit shade and current goes under 200mah.
I would expect it to simply pass the current it gets as input in this condition, up to the point where the regulator doesn't get enough current to operate, which will happen somewhere under 10 mA. At that point, you'll get a large voltage drop across the LM317-as-CCS, and current through the regulator will drop off sharply. (There may be some residual leakage.)
I hesitate to guess whether this voltage drop will present as a cliff or a ramp.
It's not hard to test it and find out, though, and you have the equipment, which I do not. (I have LM317s on hand, but no bare solar panels.)
What voltage should I put on my voltage regulator that i will connect to lm317t
You shouldn't need a voltage regulator.
Think of the LM317 in this circuit as a rubber band between the voltage source and the sink. That is, between the series-connected solar cells and the NiMH battery. When the source voltage rises due to higher insolation, the voltage drop across the LM317 will increase accordingly, soaking up the difference between the battery voltage and the solar array voltage. As the battery charges, its terminal voltage will increase, decreasing the voltage across the LM317.
What current should be held constant to charge 7.2v 2000mah nimh?
You should set the LM317 for 200 mA or less, to avoid exceeding an 0.1C charge rate, which is the fastest you should charge a NiMH battery if you do not include safe methods of early charge termination, such as -ΔV detection and overtemp detection.
Best Answer
What you need to do is to buy both step up and step down converters. During the day, you use a step down converter to charge battery from your 5V solar panel. When you need to charge your phone, you use the step up converter to convert 3.7V up to 5V.
There are couple issues you need to watch out. First, you need to find proper step down converter. Most step down converters are regulator (fixed output). They are OK, but not ideal because the voltage of battery changes after ages and you have no control of how much power goes in battery. It may cause damage of the battery and inefficient charge. Then, when you buy your step up converter, making sure they are capable of 2 amp. You don't need to measure the current since you have a fixed load (basic physics 101, fix voltage and fixed load gives you fixed current) Also, using AA battery not gonna fly because they output power of them are too low and the capacity of them is very small. You need something having output power 10 to 15W (3.7V with 3A at least).
There are also other aspects I didn't cover. You need to do a lot more research.