Posted by
Jim Brown-10 on
Aug 30, 2017; 3:55pm
URL: http://elecraft.85.s1.nabble.com/Wattage-Draw-K3S-100-vs-KPA500-KAT500-for-UPS-tp7633842p7633859.html
A UPS consists of a DC power supply that charges a battery, and a DC-AC
inverter to convert the battery voltage to 120VAC. Both operations can
be noisy. The DC power supply is probably a swtich mode, and the
inverter is a square wave generator that is shaped to resemble a sine wave.
Most UPS units operate in standby mode -- until power fails, the SMPS is
charging the battery, but the inverter is not operating, and the
equipment is connected to the power line. When power fails, the inverter
starts operating.
A FAR better way to provide UPS for radio gear is a 12V deep discharge
lead acid battery or 14.4V LiFePO4 that is float charged by a suitable
power supply. And as has been discussed several times, LiFePO4 batteries
have the major advantage that their operating voltage stays above 13V
for most of their discharge curve, while lead-acid batteries are below
12V for most of their discharge curve. This system is as quiet as the
power supply used to float-charge the battery.
With either battery type, care must be taken to not overcharge the battery.
73, Jim K9YC
On 8/30/2017 4:16 AM, MaverickNH wrote:
> I'm looking to switch in another UPS rated 2200VA/1320W, or 420W higher, for
> use with the KPA500/KAT500 I just acquired from another forum member.
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