advice on my choices

[Buzz]

Samlex sa-300-124 pure sine wave inverter 24 vdc 300 watts
Would this be a better choice?

[SunEagle]

Samlex inverters are supposed to be a good products but I have no first hand experience with them.

[SunEagle]

I read that a 24 volt system is more efficient than a 12 volt system. and that the mppt controller is a better choice for reducing loss from the panels and controlling voltages. I just want a relatively simple system that is efficient and does what I need it to do.

I am not sure if a 24v system is more efficient than a 12 volt system but it allows you to run smaller DC wires due to lower currents.

Any time you use an MPPT CC you will get more out of your solar panels then using an PWM type. So an MPPT is more efficient.

[ewarnerusa]

MY OPINION,
Since you've offered up ditching the big 24V inverter for something smaller, I would recommend a 12V one and forget about trying to have 24V anything. As mentioned, there is an advantage in using 24V because you can achieve the same wattage at half the current required at 12V. This is a big deal when you're accommodating the potentially hundreds of 12V DC amps required to crank out >1500 watts out of an inverter. But if you're talking about a small inverter like <600 watts peak rating, then you're only dealing with around 60 amps max at 12V which you can accommodate with 2 gauge or maybe even 4 gauge wiring if the wire length is kept super short. That isn't going to break the bank by any means. Whatever inverter you go with, keeping the DC power supply wiring short needs to be a priority along with using fat enough wiring. On the AC output side the wire length and gauge aren't as big of a deal because it is 120V with low amperage.

You already have 3x12V batteries that you could run in parallel for >300 ah capacity, but there are balancing issues associated with batteries in parallel especially if they are used. 2x6V golf cart batteries in series is a very common RV setup that gets you >200 ah capacity at 12V and true deep cycle batteries. Costco sells 6V GC batteries at something like $85 each. 2x6V would match up well with a small inverter and your 200 watts of solar, although the solar wattage will be on the light side for getting a good daily recharge.

[Buzz]

Thanks for all the input. Definitely some things to consider