UPS with 12V DC output?

C

cpbotha

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Since it's load-shedding season again, I'm looking around for solutions to keep just my TP-LINK TD-W8970 ADSL modem + wifi router up and running during the outages, so that various laptops and tablets can connect. (one hopes that one's ISP has power redundancy...)

The TP-LINK has a 12V 1.5A power supply. I would prefer not going through the UPS's inverter from its 12V DC battery up to 220V and down to 12V again to feed the router. Does anyone know of any UPS models, available in SA, that also expose 12V DC outputs, so that I could connect my router directly to that?

Thanks for any tips!
 
I just wire a multiplug into the the UPS and run my stuff of that. A 600va one lasts a couple of hours like that.
 
I just keep a charged car battery at hand.

I may be down for a few minutes while I connect, but hey, it is a cheap solution.
 
Electric said:
Interesting.
I didn't take efficiency into account.
Click to expand...

Yip...220V from Eskom -> UPS down to 12V to charge -> back up to 220V for UPS output -> back down to 12V on router transformer.
 
Jab said:
12V Battery with battery charger. Connect directly to battery
Click to expand...

Be careful of this because charging voltage is higher than 12VDC, normally around 14VDC, without a DC-DC converter you could fry the router.
 
Thanks everyone!

I ended up going down to the Incredible Connection here in Somerset Mall and taking their last Meissner 700VA UPS (for R699). My ADSL modem / wifi router is now happily running from that, with laptops and tablets all happily online. (I know I should be braaiing instead, but there are still many days of load-shed-induced braais, and I needed this setup urgently for my work the coming weeks)

I have not yet connected up any of my machines to the UPS to monitor its consumption. However, it has a 12V battery with 7Ah, and my modem/router consumes a maximum of 12V at 1.5A (that's what its supply is rated at), so even with the losses of the inverter and the transformer, we should be able to bridge the 2.5 hour load-shedding windows.

I am still interested to hear of people with working DC-only setups, as I think these are more efficient.
 
Last edited:
cpbotha said:
Thanks everyone!

I ended up going down to the Incredible Connection here in Somerset Mall and taking their last Meissner 700VA UPS. My ADSL modem / wifi router is now happily running from that, with laptops and tablets all happily online. (I know I should be braaiing instead, but there are still many days of load-shed-induced braais, and I needed this setup urgently for my work the coming weeks)

I am still interested to hear of people with working DC-only setups, as I think this is the more efficient.
Click to expand...

How much?
 
cpbotha said:
T
I am still interested to hear of people with working DC-only setups, as I think these are more efficient.
Click to expand...

They are more efficient. What exactly are you interested in ? I posted a link to a DC solution earlier.
 
Hi

I'm hoping to resurrect the thread, as it's in fashion again this week...
I tried a few cheap UPS devices, but the modem ends up running for only +/- 25 min - that inverter must be terribly inefficient...

I looked at the link from eddief1, but where would mere mortals like me (restricted to Kalahari and Takealot) procure such a device?
 
I run a mikrotik and adsl router from a 650kva UPS (small cheap proline) and it lasted me well through a 2hour 15minute load-shed. Looking at the graphs I had for it at one point, it should be able to take me easily through a 4-5hour outage. Those 2 devices pull so little, that the UPS easily last, with it's inefficiencies and all.

Not sure how you guys get it to last only 25 min, mine lasts 20minutes if I have a PC on it yeah sure, but only DSL router + mikrotik and use it with a MacBookPro that can last 9h on it's own battery, I am good.
 
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