Re: Typical last mile battery runtime (protecting against power cuts)

[Mark Tinka <mark@tinka.africa>]

On 2/4/23 08:11, William Herrin wrote:

> Not for more than a decade now, at least not in the U.S. When you're
> up to whole-house generator prices everyone expects electric start.
> Half the portables have electric start. Most lawnmowers have electric
> start. Once you have that, the cost to make the switch automatic
> instead of manual is trivial. And the mass-produced consumer-grade
> switches are quite reliable.

Fair point, but it is not uncommon (YMMV) for backup solutions to not be 
whole-home, and this includes generators. I have not lived in the U.S. 
on any meaningfully extended basis, so I can't speak to the degree to 
which folk that install backup power choose their cost/value matrix. But 
in many other places I've lived, especially where the power is 
frequently out, splitting the house loads into different panels a 
generator or small solar/battery system can support is commonplace; 
mainly for convenience but also to reduce the chances of a fire or 
electrical shock from having to run wires ad hoc.

The same would also apply to renewables, especially where budget is 
limited and folk can't afford to backup the entire home.

This is often cheaper than investing in large backup solutions, while 
still providing some degree of convenience to power what one would 
consider critical items, whatever that means to them.

I've been helping quite a number of folk wire small inverters with 
limited power and backup battery time into DB boards that feed only 
lights and plugs to specifically drive wi-fi, TV, an IP phone and a 
fridge. The inverters and accompanying battery aren't terribly expensive 
here (US$500 - US$800 for a Lead Acid system, and up to US$1,400 for a 
Li-Ion one), and labour in Africa is dirt cheap (less than US$100 for an 
installation), so it's budget-friendly, and keeps basics going. One 
could even charge a laptop.

In general, the main things folk will not backup are electric stoves, 
electric ovens, electric water heaters, electric space heaters and air 
conditioners. Obviously, in places with winter periods, serious plans 
have to be made to avoid death from cold.

Mark.