Op Summary: I'm calling this a "summary" but it may not be the last word. I read the manual. Fortunately, it's in English, well written, and has lots of diagrams. My model is POWERTEK ECO SW Series, 1.5 KW. I didn't understand much of what I read but what I did read and possibly understand doesn't look good. (1) It says that the battery life is 3-5 years, so take the median, 4, and that's 48 months. Then it says that the battery is discharged/recharged every 4 to 6 months. LOL! What country is that? I think that's the (arbitrary) definition of "normal" use. So take the median, 5 months. Divide 48 by 5 and you get, rounding up, 10 discharge/recharge cycles. What the hell? I discharge/recharge once per week or more! So if I'm reading this right, my battery has reached EOL. (2) In Programming mode, the battery can be set to SLD (lead-acid) or to GEL. Gotta check that as I think my battery is gel. Not sure, (3) Per recommendations here, that I set the shut-off at 50% voltage, the only parameter I found that I think fits that is the one that says "Battery low voltage shutdown setting." Well, the default is 10.0 V which makes the advice here not possible to implement. Further, the range of values I can adjust to is 10.1 - 10.9 V. So the maximum shutdown voltage is 10.9 versus 10.0 V?? Does that really matter? And irrelevant if my battery is EOL. But I'm also preparing for next time. (3) It says that the inverter provides over-discharge protection. Really? So maybe I did have that protection but the battery is EOL. (4) Lastly, there are two different battery low voltage fault codes, neither of which have I gotten.