Instead of buying in an expensive MTTP-Charger I want to buy a cheap module only. You get these small 2A/40V Buck-converters at eBay for 2-3 USD or the bigger 10-12A /40V from 9-11 USD.
Setup: Solarmodul 18V - Step-Down-Modul -(Skotty-diode)+(Fuse) - Battery.
Fuse is a should have, I know.
But I wonder if you need the Skotty-diode? What happends to the Step-Down Buck-converter-
- when there is no SolarInput? Then you have the 12.6V from the battery at the moduls OUTPUT.
- when the Buck-input(Solar) is short-circut, what will happen to the modul? Take all ampers from the battery to do the shortcircuit? Will it burn?
Perhaps the easy answer would bee to test it out in real, it iss only 2 USD.