Typical last mile battery runtime (protecting against power cuts)

Sat Feb 4 21:36:00 UTC 2023

----- On Feb 3, 2023, at 9:05 PM, Mark Tinka mark at tinka.africa wrote:

> On 2/3/23 21:11, Sabri Berisha wrote:

Hi Mark,

>> Living in an area served by PG&E, I've had my share of power cuts. At home
>> I have a 600va UPS that protects my cable modem, RPI router, and POE switch
>> which serves 2 APs. That lasts about 30 minutes, which gives me enough time
>> to fire up my generator.
> 
> I'd assume it doesn't take you that long to fire up the genie, if you
> are home when the power goes out :-).

Yes, there have been times where I wasn't at home. 

> Out of interest, depending on how long you've had the UPS, how many
> times have you changed the battery?

All the "small" ones, I bought in 2019, they still work fine. I have one larger
UPS for my homelab in my garage that I've had since 2014; I changed the
batteries in that last year.

>> Tip of the day: I also have a 1000va UPS that protects my garage door opener.
>> This makes it a lot easier to a. get a car out if needed, and b. get my
>> generator out of the garage.
> 
> In South Africa, garage door motors historically come standard with a
> 12V 7Ah Lead Acid battery. What most people don't realize is that within
> 1.5 to 2 years, those batteries are dead, and since there was power most
> of the time, they never noticed, until the power went out and the
> battery did not have sufficient energy to drive the motor.

Those must be different from ours, because we don't have that...

>> So far, my current ISP (Spectrum cable) has had 0 outages as a result of
>> power loss. Which is pretty impressive, given the instability of the grid
>> in this area.
> 
> Not bad.

Pretty impressive. How do they do that in SA? 

Thanks,

Sabri