(Part 2) Reddit mentions: The best electrical timers

I bought this, and it's been great since the beginning of July. Wish I got one years sooner. It was manual, water resistant, 15A rated with a low profile plug (since my weather outlet is hinged), and no mounting required.

https://www.amazon.com/gp/product/B0779LVSB5/

Or this + this.

Yes

Plenty of different styles too

https://www.amazon.com/Spiral-Liquid-Motion-1-Unit-Assorted/dp/B004USLSCW/ref=pd_lpo_vtph_79_tr_t_2/139-0396739-1996950?_encoding=UTF8&psc=1&refRID=VH24DVAJ9CMMXD0T7H98

From scratch: 12v to 3.3v DC to DC converter, Arduino, mosfet, isolated relay, RTC.

From amazon: https://www.amazon.ca/Digital-Automotive-Display-Support-Vehicle/dp/B01MZ8DIOM/ref=sr_1_8?keywords=relay+timer&qid=1567360644&s=gateway&sr=8-8

Programmable Plug in Thermostats Heating Temperature Controller Switch -US https://www.amazon.ca/dp/B07VXN1L1R/ref=cm_sw_r_cp_apa_i_12FWDbAN3C70B

I mean, you want a thermostat, right? Just buy a thermostat, no need to do such complex workaround when you can just buy it premade for $26.

I know you posted this to /r/arduino, but you didn't explicitly say you wanted this to be a micro-controlled project. Also it appears that your scope is very small.

Forgive me if I'm wrong, but maybe you should look into a pre-built timer, such as a reliable: Altronix 6062 Timer

Buy one of these: https://smile.amazon.com/SUPERNIGHT-Switching-Universal-Regulated-Transformer/dp/B01LATMSGS/ref=sr_1_3?crid=2P5ENVT2763JH&keywords=120v+to+12v+dc+power+supply&qid=1564685533&s=gateway&sprefix=120v+to+12%2Caps%2C198&sr=8-3

Hook it up to one of these: https://smile.amazon.com/SHINESTAR-Converter-Cooling-10V-60V-Adjustable/dp/B07RRZR1WY/ref=sr_1_5?keywords=1500w+dc+dc+converter&qid=1564685429&s=gateway&sr=8-5

Use a timer to turn them off (a few hours later): https://smile.amazon.com/Fosmon-C-10707US-Mechanical-Resistance-Grounded/dp/B0779LVSB5/ref=sr_1_7?keywords=outlet+timer&qid=1564685576&s=gateway&sr=8-7

Just be sure to make your connection to battery first, then plug in the timer. Since voltage and current are adjustable, you could set it up for a quick heavy current charge or set it for low slow trickle charge. Either way, the timer can be set for just a few hours.

I use one of these setups for "quick" charging my 20s14p battery. I also have a stack of 7 HP server power supplies wired in series for a 84v @ 36a "fast" charger. I also carry a very small 84v @ 1.6a trickle charger in my backpack for emergency or long distance top offs.

Yea, I put it off a while too. It was kind of a pain thinking of the dementions for the corner pieces so all 3 sides could fit a filter.

As for the switch. Just came in and put it on today. Prime Outdoor Electronic Timer with 2 Grounded Plugs and Remote Control https://www.amazon.com/dp/B01N7V4I64/ref=cm_sw_r_cp_apap_YTsvoJaYAlZDA