Using battery power to go off the City's power grid

sns - no doubt parts quality is important especially the inverter. The cheaper ones can't maintain a consistent voltage under load and the sine wave begins to breakdown. Obviously, avoid those. There are some excellent online reviews since these new lithium ion portables are big amongst the camper/RV crowd. 

Mine is newer unit, lithium ion, mid price range of these.

@sns 

What battery system did you use? Perhaps not as good as what  @sbayne is showing here? 
 

This is most interesting to me.  I am building a new home and think something like this would be better than time and money spent on direct AC lines and power conditioners. 

Mine is rockpals 300W, around $500. Certainly mine is lower wattage, less expensive, but are you paying for better parts quality, inverter with higher watt versions of same basic design. I presume these all built in China, same factory or factories, similar parts quality.

So, I opened mine up, certainly not what is considered audiophile parts quality, just mass produced, common household electronics quality. I was thinking about modding with better wire, outlets, even then still left with cheapo circuit boards, inverter.

I very much doubt I was over loading inverter, rounding off transients. The most wattage draw I ever saw was 55w.

I presume Stromtanks priced in accordance with the quality of parts contained within. I do believe there is great potential with battery power supplies, I just don't think one can get by cheaply here. Presumably more of these devices will come to market in coming years, hopefully some will be audiophile quality.

Check out the hobotech reviews on YouTube. All inverters are not the same.  Rockpals has gotten some fairly bad reviews for inverter noise and voltage stability, sorry.  Bluetti and Ecoflow make quality units but they cost more.  Mine was $1,800.