Reddit mentions of ZMYGOLON 300A Battery Power Disconnect Battery Switch Rotary Isolator Kill ON Off Switch for Car Van Truck Boat

I don't think i see your logic regarding your alternator's charging capabilities.

So here is a quick mental check: A 40 Amp DC-DC charger or a 40A isolator will pull 40 Amps regardless if your alternator was a 1000 Amp alternator. Alternators have the ability to change their output capabilities depending on the load. A 150 Amp alternator isn't looking to dump 150 amps all the time, think about your starter battery: if you were constantly dumping 100 amps into that battery you would damage it.

Other than that your parts look good!

A couple pointers... With the Renogy controller the remote meter is pretty much a must on most models, the MT-50 i think is the name. Also how are you mounting the panels? Renogy's Z-brackets are a great solution.

Finally i would strongly recommend (3) heavy duty switches for the following: 1) Loads 2) Solar 3) Battery. The logic here is that whenever you power on/off your system there should be a sequence. Never allow solar energy to enter your controller without the battery connected so that the power can be dumped somewhere. A load switch is also useful if you ever have a short you can switch all your loads off quickly. A switch that is impossible to accidentally flip is the correct solution here, like this one: https://www.amazon.com/gp/product/B07QTYH995/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

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Feel free to ask anymore questions!

This is the switch I got. I didn't really think about weathering, maybe I ought to get one with a more beefy housing.

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https://www.amazon.com/gp/product/B07QTYH995/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&psc=1