Im really glad my post was able to help.

I got my batteries from https://www.batterywholesale.com/ but I got three of these https://www.batterywholesale.com/collections/all-batteries/products/douglas-dg12-200-12v-200ah-sla-battery when they were on sale for $200. They had free delivery.

For batteries for your solar you want something that deep cycles...so for lead acid look for AGM (absorbent glass mat) or gel. Not a regular car battery. I mean it will "work" but youll wear it out pretty fast.... by wear it out I mean it takes less and less charge until finally it can hold almost no charge.

I think most marine batteries are deep cycle.

Theres some guys on here that have found some pretty sweet deals on lithium ion banks from China through aliexpress Lithium Ion is the gold standard but they are pricey.

And some guys have found some really stellar panels used on ebay.

Look at the amp hour rating of the battery and less on the cold cranking amps (cca) because youre more interested in how much power the battery can hold (amp hour) instead of how much it can discharge at once. (your deep cycle battery shouldnt even list cca because thats not its intended purpose).

Once you know how many amp hours you may need, double it. You dont ever want to discharge your deep cycle batteries more than halfway if you can help it.

Your 600 watt inverter may be enough. I dont know youre particular laptop model but most just use I think no more than 60 watts.

Watts = volts * amps so for battery size youd go through (60 =12 volts * amps) 5 amp/hours of battery charge every hour of laptop use (figure a little more because your inverter eats some of that but not too bad). If youre just looking for a few hours of use before going to bed at night....thats just 15 - 20 amp hours. Thats pretty affordable.

Also on the supply side your 2 100 watt panels (200 watt total) can make up to 16 amps, so if you got an hour of sunlight youd get 16 amp hours (theoretically, in practice much less). So for a ball park it kind of works out that for every hour of daylight is about 2 hours of laptop.

Your slow cooker may be more challenging. My insta pot (not a crock pot) uses 1000 watts its a 6qt model, but it can cook a roast in an hour. so for me thats 1000 watt hours. So IF you had a large enough inverter you would need 83 amp/hours in your batteries to power it...and it would take more than 5 hours of sunlight (with your panels). But your setup is really close. A smaller instapot, a larger inverter, and if you didnt need to run it everyday.... I think would work.

I tell you what I did on my tv and blu ray player that saves a good chunk of electricity. So your tv is DC, your battery is DC, but your tv and most electronics have a "brick" that converts the AC from the wall back into DC...but thats an unnecessary step for us because we're starting with DC, having to invert it to AC and now the tv is just converting it back. The difference is the voltage may be different. You can get a dc to dc converter. This is the one I used if you need to step up I think my tv is 19 volts DC. I used this one for the blu ray player which I was 5v so I needed to step down This saves me about 30% on their electricity. Of course they're wired in the bus now so they cant leave.

Sadly I dont know much about inverters. This is the one I bought This is a later model or something and isnt exactly like mine. Mine is the 2200w pure sine but it also had a solar controller for 20 amps and was only 290 instead of 380.

BUT Idont want to hype it up too much because its just a chinese inverter too. I had to make a hard choice at 2000w for something affordable and I chose affordable. I wanted something to power the ac at night (which it does) but I didnt want to spend a fortune until I was sure the ac unit I picked out could cool the bus, how comfortable, loud...etc. It was all unknowns so I needed something to sort of test the proof of concept.

Im positive theres a fire risk using it. I have it out where I can see it, its not mounted under cabinets or under the floor or anything. Like you Im looking a little to replace it with something more....american-made.

I would say that at 300 t0 500 watt I would steer clear of the ones that plug into the cigarrette lighter and get one thats wired to go right to your battery. Thinner wires get hot and not only is it dangerous, but they'll get hot enough to melt themselves apart and you can bet its going to be someplace you cant get to so youll have to rewire everything (if youre lucky and dont catch something on fire).

And I think youre smart for having a separate battery for your "house" and not just using the vehicles battery.

Good luck with your bus! Let me know if you have any questions or anything. Theres a ton of resources and I feel like more and more everyday. This is a good time to be working on your build I think!