I have built a solar charger by using a linear voltage regulator (LM7805) that outputs 5V from a solar panel which can deliver a maximum of 18V. It works fine, but the current is very low and there is a lot of heat coming out from the voltage regulator.
I read here and there that a better option for this would be to use a DC/DC converter (or buck converter) which, according to Wikipedia is a device that rises up the current while dropping the voltage.
Now, it would be great to have a constant 5V output like I do now, but I'm afraid that the oscillation in the current is not so good for charging a phone, but I base this on pure intuition, therefore I would like to hear an opinion on this.
- Will a buck converter have a large current interval as the sun goes behind the clouds?
- Can this interval be regulated?
- Is it harmful to have a large interval of current for charging a phone?
- What type of buck converter should one look at if one plans to buy a bigger solar panel in the future?