Can I use a UPS just as a battery pack?

gterr

Hi there,


I've been given an old APC ES700 UPS. I want to use it as a surge protector and emergency battery back-up for my router (BT Home Hub). I downloaded a user manual and see that the device is really intended to be attached to a computer and configured to power down the computer safely in the event of an outage.


Can I use it just as a surge protector and as a power pack, with power to the master socket maintained for as long as the battery has charge? If there's nothing attached to the unit's data port is this how it will behave anyway, or do I need to configure it so that the master socket is 'always on'?


Thanks for your time.

Nilrem

It can be used for that fine, all the data port does is send a message to the software on the PC to tell it it's status and to shut down (it does things like tell the PC the status of the battery and whether it's running on battery or mains power).

I know various people who use similar set ups to keep their internet or cordless phones working during power cuts (often with a cheap/low power one for those, and a higher capacity/newer one for their computer if they're in an area that gets a lot of cuts).

IIRC UPS's act as better surge protectors than the standard ones you get as part of a normal extension type lead.

paddyrg

UPS aren't designed to run for a long time - they're designed (generally) to keep the server running long enough to either get onto backup/generator power or shut down gracefully. This might be just 30 mins

tronator

paddyrg wrote: »

UPS aren't designed to run for a long time - they're designed (generally) to keep the server running long enough to either get onto backup/generator power or shut down gracefully. This might be just 30 mins

It all depends on what the capacity of is and what you connect to it. You would expect a 500VA UPS last about 50 hours if you connect a router with 10W to it. A UPS is not designed to last a certain time as such, they last until they're empty.

mttylad

I asked Mr Google this, he said that if you look at Amazon reviews there is someone else who says that for a low current draw it sometimes fails to work correctly when the power fails.

If your router is backed by a UPS, what about the other devices connected to it? are the PC's all laptops? desktop PC's will need a UPS too.

paddyrg

tronator wrote: »

It all depends on what the capacity of is and what you connect to it. You would expect a 500VA UPS last about 50 hours if you connect a router with 10W to it. A UPS is not designed to last a certain time as such, they last until they're empty.

Yes indeed, in the sense that they're batteries strapped to inverters and will drive whatever load their rates for for as long as they can. Different units will handle tiny loads with greater or lesser efficiency for sure, and the hysteresis of going via an inverter to a transformer and back to DC isn't ideal.

tronator

mttylad wrote: »

I asked Mr Google this, he said that if you look at Amazon reviews there is someone else who says that for a low current draw it sometimes fails to work correctly when the power fails.

Never heard of this. I will try this out tomorrow.

mttylad wrote: »

If your router is backed by a UPS, what about the other devices connected to it? are the PC's all laptops? desktop PC's will need a UPS too.

mobile phones and tablets?

Strider590

I use a small UPS for my router and phone, I removed the pathetic 4.5Ah battery and replaced it with a 7.5Ah battery connected externally.

I used to have an old Smart UPS 700 for my PC+laptop, but these old beasts have a known battery overcharging fault, that can result in masses of black smoke filling the room after around 3 years of use.

virgo17

Strider590 wrote: »

I use a small UPS for my router and phone, I removed the pathetic 4.5Ah battery and replaced it with a 7.5Ah battery connected externally.

Can I ask you which small UPS you use for this please? I have a similar need. Thanks.

Strider590

virgo17 wrote: »

Can I ask you which small UPS you use for this please? I have a similar need. Thanks.

Off the top of my head it's an APC ES350. Used to !!!! me right off until I took it apart and replaced the buzzer with an LED

Theoretically there's no limitation to battery capacity, there's no reason (for example) why one couldn't connect a 60Ah car battery to one of these, as long as the battery itself was kept in a very well ventilated location (car batteries tend to "gas" when charging).

kwikbreaks

First make sure it's working. IME the batteries in a UPS don't last forever and replacing them is often uneconomic.