Residential UPS systems?

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slc410

Electrician
Location
Madison wi
Occupation
Electrician
Wondering if anyone could give me any information on a battery backup system for a residential application.
Im putting an addition on a small hunting cabin which is powered solely on a generator. What I would like to know is if there is anyone with any information to correctly and safely intall a battery backup system to just power a light and a couple receptacles when the generator poops.
 

__dan

Banned
It likely will not work

It likely will not work

It likely will not work.

The small residential UPS's only allow enough battery runtime for an orderly shutdown of the computer. Two lamps draw about the same as a PC. You can expect about ten minutes of runtime on a new battery, decreasing to 1 sec runtime as the battery ages (5 yr max).

You would be much better served with a small array of rechargeable flashlights with spare batteries. Look at the Milwaukee and Bosch lithium ion types that take the same battery as the power tools. Expensive but you get what you pay for.

Charge the batteries when the generator runs, pump a full tank of water, wash clothes, and then shut the generator off.

If you're doing any work up, spend the money for a 36 volt Bosch combo kit or the same in the Milwaukee 28 volt, flashlight, drill, circ saw, and sawzall.
 
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hurk27

Senior Member
Wondering if anyone could give me any information on a battery backup system for a residential application.
Im putting an addition on a small hunting cabin which is powered solely on a generator. What I would like to know is if there is anyone with any information to correctly and safely intall a battery backup system to just power a light and a couple receptacles when the generator poops.

generally the batteries, most UPS systems are not design to be cycled all the time, and wont last long, but not being sure what you mean about "when the generator poops"

If your talking about when it runs out of gas, then I think you could get by with a moderate sized UPS, such as a 750 to 1600 VA APC UPS unit depending upon the load, but if your talking quit frequently and long periods, then I would opt for using an inverter, and 2 or 3 deep cycle marine type batteries, which could be hooked to a vehicle to be recharged in a pinch.

Also using CFL lamps will give much more light and not draw as much from either a UPS or a inverter.
Keep in mind with either one, if it has a modified sine wave (square wave) output, some motor loads wont like it, my small hammer drill runs about half speed on a square wave output. for the cost if you want to go the inverter way, locate a surplus RV/camper power system, most were a full sine wave output, and even have auto transfer when shore power was cut, I have a RV unit made by Tripp-Let that is 3600 watts, and can run quit a bit, I used it in my work van for a long time with 6 deep cycle batteries an it would last me the whole day on the job. but if you plan to just use it for lights and a few electronics, then a square wave inverter would work just fine, my little 150 watt, unit, that plugs in to a cigarett lighter, will power 9 100 watt equivlant CFLs, and run off my van battery almost all day.
A long time ago, I tried to use a APC UPS system, 1600 watt unit, but it didn't provide power for very long and the Ni-Cads didn't last very long.

Most places like Sam's club, Wall Mart, carry both, UPS and inverters, but they are low grade and have a modified sine wave output. almost all truck stops carry a large line of inverters, I have seen some up to 4kva but again you get what you pay for, and you dont get into good inverters until you get into companies like Trip-Let, but you will pay more.
 

JFletcher

Senior Member
Location
Williamsburg, VA
My concern with hardwiring outlets/lighting to a UPS running solely on generator power would be possibly damaging the UPS when the genset runs out of gas.

Most if not all smaller UPSs have outlets on them, and for a light you could simply use a drop light with a fluorescent bulb.

Generator aside, powering any real load with a UPS is either going to be a short-lived or very expensive affair. What did you (they) plan on plugging into the outlets?
 

slc410

Electrician
Location
Madison wi
Occupation
Electrician
what I think I need is a small battery bank setup with just an inverter but Im not sure of what type of disco I should put in or where. I guess I shouldnt have said a UPS system which opens up a whole bunch of technological cans of worms.
 

hurk27

Senior Member
what I think I need is a small battery bank setup with just an inverter but Im not sure of what type of disco I should put in or where. I guess I shouldnt have said a UPS system which opens up a whole bunch of technological cans of worms.


One that will handle the load?

but what about transfer, you cant have the inverter on when the generator is on?

small transfer switches don't cost to much.
 

wireguru

Senior Member
xantrex and others make inverter/chargers for this purpose. Use one of these with a big stack of AGM batteries and youre good to go.

I would not use a normal ups in this application.
 

dbuckley

Senior Member
Agreed; essentially this is an off-grid installation, so a standard set of off-grid components without the solar cells is what is needed. A computer UPS (particularly of the toy variety) would not work at all well in this application.
 
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