Re: Cascading UPSs

On 1/7/2025 4:27 AM, Sylvia Else wrote:

Some UPS designs cannot be turned on[*] without a battery in them, even when supplied with mains power, because they cannot energise the relay that enables the mains connection.

I managed to stumble on one of these, today.  An older APC Smart-UPS
(with only LED indicators).  No battery.  Plugged it in and no signs
of life.
[Of course, it's possible that it was just broken -- after all, these
ARE "scrapped" units so no telling why it was scrapped]
Regardless, of little use to me without that capability so back to
the scrap pile it went.  We'll see what turns up tomorrow... (and
I should remember to bring a VOM to check for salvageable batteries)

Sylvia.
 [*] They can stay on, just not be turned on.