Small UPS for DSL Modem + WiFi Router


#1

While I have a Deutsche Power DH Series 2KVA UPS, I need a seprate, small UPS that could be used to provide backup supply duirng scheduled power outages (aka "loadshedding") to the following equipment: i) DSL modem, ii) WiFi Router. I might occaisionally connect a mobile phone charger, too. In all, I don't think that I would be drawing more than 15 to 20W power. These days, our area suffers from three outages of two hours each (i.e. a total of six hours) with a gap of three hours in-between.

A quick survey reveals that the smallest UPS is rated for 500VA load. I need a small, dedicated UPS. Is there any such product -- or solution -- available in Karachi or Islamabad?


#2

mercury ups or similar brands with built in battery for 1 hour PC backup would easily be able to work your setup for 2 hours minimum.

available from wherever PC are sold in your area.


#3

[quote=“farhan_ds, post:2, topic:21667”]

mercury ups or similar brands with built in battery for 1 hour PC backup would easily be able to work your setup for 2 hours minimum.

available from wherever PC are sold in your area.

[/quote]

farhan_ds, thank you for your quick reply. As mentioned in my original post, the smallest UPS available in the market is usually rated 500VA. I am looking for something smaller, say 100VA. The idea is to have a smaller UPS that is low on power load, and, as a result, high on electrical efficiency.


#4

Use 12V 7Ah dry battery with 13.8 Volt Charger and take desired outputs by using 78xx regulators or LM 317T you can get backup time of minimum 10 Hrs with DSL Modem (12 /9VDC and Mobile Charging (5VDC).

Note: Little know how about electronics required for assembling above arrangement, but after using you will be happy. for more safety LVD(Low voltage disconnect) may additionally used to prevent deep drain of battery(below 10.5VDC) if unattended longer shutdown of utility(more than 10 Hrs)


#5

[quote=“rizwansadiq, post:4, topic:21667”]

Use 12V 7Ah dry battery with 13.8 Volt Charger and take desired outputs by using 78xx regulators or LM 317T you can get backup time of minimum 10 Hrs with DSL Modem (12 /9VDC and Mobile Charging (5VDC).

Note: Little know how about electronics required for assembling above arrangement, but after using you will be happy. for more safety LVD(Low voltage disconnect) may additionally used to prevent deep drain of battery(below 10.5VDC) if unattended longer shutdown of utility(more than 10 Hrs)

[/quote]

rizwansadiq, this is indeed a very good solution. My soldering skills are bit rusted, but I still have a soldering iron in the attic. May even have a 7805 lying around from my college days. I guess that I can do it, but will need more than a description -- a schematic will be quite helpful :)

As far as I understand, the above solution may not have automatic switching to battery power (when there is no electricity), and automatic battery charging (when the electricity is back). How complicated will it be if an (automatic) UPS with 12V, 7Ah battery is built?


#6

For schematic use LM350 datasheet from google.

No changeover required just directly connect with battery using rectifier diode your devices will not face any interruption during utility failure.

However if you feel difficult in assembling use old laptop charger 20VDC connected with PWM solar charge controller as a battery charger (low cost) with low voltage disconnect and use them.


#7

^simpler but slightly costly ..the laptop charger method is your easiest solution...


#8

rizwansadiq and farhan_ds, thank you to both of you. The idea of using some old laptop charger is cool. Will give it a try.


#9

Please dont use laptop charger (20VDC) directly to charge battery, it will damage battery, use it with Solar charge controller input and get desired output 13.8V for battery.


#10

[quote=“rizwansadiq, post:9, topic:21667”]

Please dont use laptop charger (20VDC) directly to charge battery, it will damage battery, use it with Solar charge controller input and get desired output 13.8V for battery.

[/quote]

@rizwansadiq are you from chakwal? your name reminds me of someone I know :)


#11

@nasirjavaid yes I am from Chakwal, and remember you


#12

hahaha... great... nawazish :)


#13

320 va in apc is also available in market.


#14

[quote=“APC_UPS, post:13, topic:21667”]

320 va in apc is also available in market.

[/quote]

Is there any APC ups which output 12 volts DC ?


#15

All 500 va and 650 va are 12 V DC UPS .................


#16

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#17

[quote=“APC_UPS, post:15, topic:21667”]

All 500 va and 650 va are 12 V DC UPS .................

[/quote]

Oh no I'm not talking about battery ........

I was taking about OUTPUT I was looking for an imported UPS which provides 12 V output to directly power small appliances ......


#18

Thn kindly say 12v ac ... Cuz dc means battery volt ...


#19

All appliances cums wid their respective adapter ..,, ups ll give u 220 volt ac n their adapter r charger does the rest ...

Wot do u want 12 v ac btw ?


#20

[quote=“APC_UPS, post:18, topic:21667”]

Thn kindly say 12v ac ... Cuz dc means battery volt ...

[/quote]

[quote="APC_UPS, post:19, topic:21667"]

All appliances cums wid their respective adapter ..,, ups ll give u 220 volt ac n their adapter r charger does the rest ...

Wot do u want 12 v ac btw ?

[/quote]

My dear uncle APC_UPS please read my first comment again "carefully"

Is there any APC ups which output 12 volts DC ?

I'm looking for a UPS with a DC output for DC load ............. for example solar panel charge controllers have 12 volt DC output like this