I've been looking at a backup water system for my house to provide water from my shallow well in case the electricity goes out. I had been thinking about a 12V pumping system, but then after mulling over how to get the water where I wanted it, it seemed to me easier to just provide backup to the 120V mains by putting what I want to keep running (pump, fridge, freezer) on a separate branch with a transfer switch to automatically switch over if mains goes out. The battery or battery bank would be charged by solar with an additional trickle charger from mains. I'm looking at the Windy Nation 2-100 Watt panel kit with P20L controller. https://www.windynation.com/Polycry...er-Inverter-for-12-Volt-Battery-Systems/-/362 https://www.windynation.com/cm/Complete_Solar_Kit_Manual_R2.1.pdf and https://www.windynation.com/cm/P20L Controller Manual_R1.pdf and B&D charger https://www.amazon.com/BLACK-DECKER-BM3B-Automatic-Maintainer/dp/B0051D3MP6/ref=sr_1_8 I have a 100Ah battery and plan to get a 1500W pure sine wave inverter (I guess with the WindyNation kit). The controller will shut off solar charging above 13.8V and load below 12V (both settable). After the load is turned off, it will restart if the battery voltage reaches 12.6 (also settable). The controller takes 6 wires--two from the panels, two to the load, and two to/from the battery. I plan to inject mains trickle charging at the battery terminals, using the B&D trickle charger with a 7.5-amp MBR745G Schottky diode. With these components, especially the controller and transfer switch, it seems to me that these parts are "self-leveling". My question regarding the WindyNation kit is, is it suitable to inject the B&D (or other) trickle charger at the battery terminal posts? Code: .___________. .____________. .____________. | | ~15V | | ~13V | | | 200W, 12V |-------| P20L |------| Inverter | | Solar | | Controller | | | | Panel |-------| |------| | | | 0V | | 0V | | '-----------' '------------' '------------' | | | 120VAC Load .___________. | | .____________. .____________. | | ~13V8 | | | | | | | B & D |----------o | | Transfer | 120VAC | Pump | | Charger | | | | Switch |---------| Fridge | | +Diode |----------|------o | | | Freezer | | | 0V | | | | | | '-----------' | | '------------' '------------' | | | 120VAC .____________. .____________. | | | | | Battery | | | | 100Ah | | Mains | | | | | | | | | '------------' '------------' (Upon reflection, I would upgrade to 3000W inverter, 10 AWG wire, and bigger/more batteries.)