The cheapest upgrades, ranked

If you have limited money, spend it in this order — ranked by return per dollar, not by how good it looks.

1. CO alarm. Highest value purchase in off-grid life, full stop. Nothing else matters if you don't wake up.

2. LED lighting. You're not adding capacity, you're removing demand. Cheaper than every alternative.

3. Roof vent fan. Moves enough air to make AC unnecessary on a lot of days, for a fraction of the draw. Best comfort-per-watt in any rig.

4. Insulation and window covers. Every BTU you don't lose is heating or cooling you don't generate.

5. Battery monitor / shunt. Turns your system from a guess into an instrument. Pays for itself the first time it shows you a phantom load.

6. Potable water hose. Stops you leaching garden-hose chemicals into your drinking water at every fill.

7. Proper fuses and correctly-sized wire. Not optional, and cheap relative to what it prevents.

8. Mylar bags and oxygen absorbers. Turns cheap bulk rice and beans into a 25-year reserve.

Notice what's not on this list: more panels, more batteries, a bigger inverter. Those come after you've stopped wasting what you already have.