INTP:
Guess that leads back to my other thread about dumb chargers- voltage potential automatically stops charging, so if input voltage matches battery voltage, there isn't any movement to quantify this 'keeps trying to charge' idea.
And even if so, isn't that a trickle charge that makes up for the constant slow self discharge of the battery?Oh, I didn't mention a battery. I have one of these bad boys and was duly assuaged by the store clerk that the SLI in the part number is an oops by their naming convention and not a naming used by Duracell- I.e., it's not an SLI battery.
It'll do just fine getting charged by my alternator. But I'm planning for days where I'm camping and not driving, and solar panels may come into consideration.
So previously, I asked what the harm is in having the alternator constantly 'try' charging the second battery while driving. The results seemed to indicate that there was no harm. When voltage matches, current is nil-ish.
So that'd be the case with a solar panel run through a boost/buck- if the converter was set to something like 14.7V, then once the battery is full, the converter isn't passing anything.
Right? or not right?
First, your alternator has a voltage regulator built into the alternator. Has been that way for quite a number of years. It senses the voltage on you battery before allowing the DC from the rectifiers to charge the battery. My truck has two 12 volt batteries charged by the alternator, so if your alternator can produce enough power to charge two batteries, you are good to go.
The problem with charging batteries from a solar panel without using a controller is when the panel power (voltageXcurrent) is not enough to drive the boost/buck converter, then what? Does it allow the battery to discharge?
Is there a set point on the boost/buck to cause it to stop trying?
Solar charge controllers are so cheap, I wonder why you are concerned? Also, years ago, there were ICs that controlled the whole solar charge process. Look into building something with one of them.
Paul