โI do not want to buy a $500 controller that controls both power sources (solar and charger) electronically, but can spend under $50 for something to make it all work togetherโ
Good MPPT solar controllers are way under $500. Try $199. https://www.windynation.com/Charge-Controllers/Windy-Nation/WindyNation-TrakMax-MPPT-40A-Solar-Charge-Controller-12-or-24-Volts-for-Sealed-AGM-Gel-and-Lithium-Batteries-with-Opt/-/3403?p=YzE9MTc=
Did you mean a controller that handles solar and 110?
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad