Computer UPS for an inverter/charger/12V supply

[EZ]

I just picked up a free computer Uninteruptible Power Supply. It has 4 outlets for AC power and a new battery. The battery is only 12AH but I ran it anyway and it kept a small AC fan running for 4 hours. I was semi-impressed. I am thinking that I could just tap into it with another 12V battery in parallel and have a charger, inverter and DC power all rolled into one.

Ed

[Micro469]

I just picked up a free computer Uninteruptible Power Supply. It has 4 outlets for AC power and a new battery. The battery is only 12AH but I ran it anyway and it kept a small AC fan running for 4 hours. I was semi-impressed. I am thinking that I could just tap into it with another 12V battery in parallel and have a charger, inverter and DC power all rolled into one.

Ed

Ok, I got one of those but the battery is shot. The a new battery will cost me about $125.00 and still debating..... Maybe an auto battery can be substituted if used for outdoor applications (Like in a tear, not a house). Would be very interested to hear other's ideas and comments also

[Micro469]

Hey anybody... Got any ideas if this would work? would really like to hear feedback... Even negative feedback... It's all good.

[Ken A Hood]

Hey anybody... Got any ideas if this would work? would really like to hear feedback... Even negative feedback... It's all good.

Have you looked at one of these? POWERBOX

I've got one, and used it a couple time to boost my car. I'm going to plug something in to see how long it will run [a light, radio etc]. And it can be recharged while your driving. Mine is a few years old, and doesn't have the built-in compressor, but that's also a nice feature

[Kevin A]

I just picked up a free computer Uninteruptible Power Supply. It has 4 outlets for AC power and a new battery. The battery is only 12AH but I ran it anyway and it kept a small AC fan running for 4 hours. I was semi-impressed. I am thinking that I could just tap into it with another 12V battery in parallel and have a charger, inverter and DC power all rolled into one.

Ed

Ok, I got one of those but the battery is shot. The a new battery will cost me about $125.00 and still debating..... Maybe an auto battery can be substituted if used for outdoor applications (Like in a tear, not a house). Would be very interested to hear other's ideas and comments also

John,
I really don't have an answer whether it would work or not. It has a 110 volt input and 110 volt output, So I'm going to go out on a limb here and "assume" that the battery itself is 110 volt output (having not opened a UPS up, I have no clue of the battery output voltage). If this is the case, it's probably not a good idea to substitute an automotive battery for the one built in.

[Leon]

The batteries in them are at a lower voltage and use a switching supply to step up to the 110 AC. Most UPS are not designed to run for more time at the rated output than what their internal battery will supply. You're better off with an inverter designed for longer run times.

[GeorgeTelford]

Hi

A UPS is an invertor and a small battery and a charger

when mains on the charger keeps battery charged and provides mains, if mains fails then the battery invertor provides power until the battery runs out.

Typically these are for short term emergencies so the battery capacity is not great.

to make this useful you would need to increase the battery size.

using a normal battery will work, beware that the charger in the UPS will take ages to charge a big battery, I would use a deltran to charge the bigger battery.

Can be easily made to work, proceed very carefully if you decide to do it. For me it would be like falling off a log, I know what each part is and which part is likely to bite you, but remember electricity is dangerous.

[Chuck Craven]

The problem is, they are designed for use on computers.
If the power goes off, when the computer is running, it gives the operator time to save there data and shut down the box.
The battery in the UPS is not the same as a deep cycle battery.
It is designed to be flout charged most of its life. If the battery is discharged it may not recharge up. If the battery is replaced with a deep cycle battery the charger will not be able to fully charge the battery in a short time. Once charged the flout charger in it will most likely over charge and damage the battery. Next the inverter will not start by its self. It needs to be powered up by the AC to start the inverter. Then when the AC power is removed does it then takes over the AC output.
The output power of UPS’s is only a few hundred watts. If over loaded the UPS will burn up. Use it with your computer is the best use for it.
Chuck

[Shiro]

I tried to use a UPS to power Xmas lights on my sidecar rig. I bought one at a computer junk yard. It didn't work. There was no way to turn it on. It was not designed as battery per se, but rather a back up for something powered by 110 volt AC. The only way that it would go on was if there was 110 AC that was interrupted. So you couldn't turn it unless you already had 110 AC on and then stopped the 110. No good for my use. That feature may have been unique to that UPS. I ended up returning it

Powered the lights on the sidecar with a couple of D batteries

[GeorgeTelford]

Hi Chuck

It needs to be powered up by the AC to start the inverter. Then when the AC power is removed does it then takes over the AC output.

I have just tried an old UPS torefresh my memory, once charged I disconnected all mains input power and switched it off. I then plugged a TV in and switched the UPS on, the TV worked no problem, so I can only assume that some must be made differently.

If over loaded the UPwill burn up.[/S quote]

No it wont, it will just powered down like any other overloaded Invertor

Most UPS are over 400 Watt Plus ( the one I just tested is 1000w cont 1400w peak and they are very good invertors.

Once charged the flout charger in it will most likely over charge and damage the battery.

No it wont, I already mentioned the charging, low level float charging is not going to damage a good battery.

[Chuck Craven]

Hump you must have a rear bird, my personal UPS is 500 watt and will not start on its own. Have 4) 300 watt units at work and a 2000 watt sever UPS and they will not start on there one also. But I am sure some one makes ones that will start with out ac power. Is the one you have a UPS or a EPS (emergency power source)?

Chuck

[Chuck Craven]

Oh! The new UPS’s have shutdown circuitry if you try to over load them but the old ones do not. If the power goes out with the units overloaded the switcher supply will smoke. I have had several do just that. Smoke and burnt control board. Not repairable!

Chuck

[GeorgeTelford]

Hi Chuck

In the history of invertors, I have never ever come across one that smoked, they have either cut out or blown fuses, right back to the early days. But I wonder is it that UPS gather dust?

I have however checked out 2 other UPS's this afternnoon and as you say neither would start without mains being present first, so I stand corrected there the one I took camping that did not need power to start was a Microdowell B Box UPS

[Chuck Craven]

Some had liquid NI-Cad batteries and charge a lot different than lead acid does. It’s hard to tell the batteries apart. We have 400 servers and routers. We now have just one big UPS as an inter-stage to the Generator back up. No those units were made in China back in the mid 90’s and have gone to the crusher years ago.
Chuck

[bg]

I've been around UPS's longer than most, so I'll share my thoughts.

Most small units (less than 300 va) are only designed to run until a power failure, then send a signal to shut off the computer(s) and then shut themselves off. Meaning little to no internal cooling, if an 'extra capacity' battery is added, it's quite likely it'll burn itself up before its able to take advantage of the added capacity. I do have a small UPS that has survived for 8 hours run time during an outage, but it supplys power to networking equipment and does have internal cooling.

There are some larger units out there designed to support extra battery packs, but most are far outside the price range of our uses.

Personally, if it were me, I would invest in a large deep cycle, a good charger, and use as many 12v things as possible. Would probably be cheaper in the long run.