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Results tagged with ups
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user 3288
A UPS is an Uninterruptible Power Supply that provides backup power when the main power source is lost. Questions on repairing commercial ones are generally off topic.
3
votes
Accepted
How long will laptop run from UPS?
UPS Battery = 12V, 30 Ah.
UPS available energy = 12 x 30 x 0.8 = 278 Watt.hour
Laptop battery = 14.6V.
So N = 4 as 3.6 x 4 ~~ 14.6
Laptop battery capacity = 4Ah (on battery). … Laptop power use = Laptop battery energy / hours operaing
= 48/4.5 = 10.666 atts = say 11 Watts
UPS runtime - UPS energy/Laptop power
= 278 Wh/11 W ~= 25 hours
This is longer than a UPS will …
- 152k
0
votes
Diode rating for a UPS project with extra battery
I_diode mex >= Power_UPS / V_UPS >= 50A
An ultra-low Rdson MOSFET used as a diode gives the best results.
A MOSFET can provide Rson of < 1 milliOhm at 50A.
V drop < 0.05V.
MOSFET loss < 2.5W at 50A.
…
- 152k
0
votes
Accepted
Temporary (just 2-3 second) 5V Power Backup for Raspberry Pi
Capacitor:
The voltage on a 1 Farad capacitor will drop 1V in 1 second with 1A load.
So eg for 100 mA load and 3 seconds holdup for 1V drop you need
1F x 3s x 0.1A ~= 0.3F.
More mA or time or less …
- 152k
11
votes
Accepted
Can I connect a capacitor in parallels to power supply of a router
Yes, but ... .
A capacitor can help as you suggest but it may need more than that.
Restating Steven's formula - a Farad will supply one amp for one second with one volt of drop. So 10,000 uF ( = 0.01 …
- 152k
0
votes
UPS for ESP32 Microcontroller
The easiest approach is to use a capacitor that will power the system during the changeover period.
For capacitance C farad, time t seconds, current i amps and voltage drop V volt
C = t x i / V
…
- 152k
2
votes
Solar Charge Controller as "UPS"?
Designing a quality solar battery charging system CAM be as simple as connecting the right COTS components together - BUT knowing how to design to use the COTS parts can be a challenge in itself. Many …
- 152k
7
votes
Accepted
Fixing APC UPS buzzing noise
Applying EHT to far end is to be frowned on - you should not have any EHT in a UPS. … If it's confirmed that the cap's at fault, could I put in the 20uF 250V pedestal fan capacitor on the APC UPS board and expect it to have no detrimental effect on the UPS? …
- 152k
5
votes
Accepted
Effect of Battery charging with un equal batteries in parallel
During UPS operation you want the combined energy of all batteries (of course). …
- 152k