Make your computer UPS last for hours instead of mintues

Step 8 A word of caution

I learned this the hard way.. it cost me a UPS, and nearly a fire.

The transformer in these UPS's are cheap. They are not designed to be run at 100% capacity for extended periods of time (such as what you will be capable of using this size battery) When I ran my UPS's at 300 watts for more than 30 minutes, the transformer melted through the case. When I pulled out my infrared thermometer it read nearly 400 degrees F!!

I had to redesign my system. I chose two UPS's that were rated at 600 watts each, but used 24 volts (2 twelve volt batteries in series). Under my new setup, I have over four hours of backup capacity as I have two car batteries.

Comments

[gagan9897175966]

hey ben did u connected two UPS's to a single battery. I am worried about the charing of the battery cos i was told that UPS cannot charge a Car battery. do u have any charging issues in this instructables. i am waiting for ur reply.
also i have 3 PCs two with CRTs and one with 15inchs TFT how much power do i need for the whole, i am currently using 2 USPs, 1 550 VA and other is 500 Va with which i am using one to power Just monitors and others to power TFT and 3 CPS. and its working fine. (I think) i am fed up of the backup its less that 5 minutes.
please guide me.
Thanks
Gagan
India

[ben.mcfadden]

I have been using this system for 2 years now and it works great. The two UPS's do charge the batteries, although it does take a full week to get out of the "quick" charge and into the trickle charge. If you need to charge it faster, use a car-battery charger after an extended outage. Having two UPS's has shown no adverse affects. If anything, it just charges the batteries faster.

To determine how much power you need, I recommend using the Kill-A-Watt meter (http://www.thinkgeek.com/gadgets/travelpower/7657/) to determine how much power each item draws. Be sure to measure VA, as that's what most UPS's are rated in, although Watts are useful too.

Remember, if you are going to make your UPS system last for more than the time a stock battery will last, be sure you are putting less than 50% of their rated capacity on each UPS.

[gagan9897175966]

Thanks Pal

[gagan9897175966]

nothing will happen dear friends. what do u think about almost everyone in the world is using inverter systems (dont forget with battries) inside there homes or in the basements of there homes. what will u think about it.

[drzcyy]

hydrogen or oxygen is not toxic by themself, besides the explosive nature when combined. However, charging and discharging lead-acid batteries indoors will release microscopic sulphuric acid droplets due to bubbling (or gassing) of the acid in the cells (try leaving a piece of paper over the battery for sometime, the paper will turn color over the ventilation holes!).This has been known to cause damage to lungs, as well as oxidation of metal parts in the vicinity. The way to overcome this is to cover the ventilation holes of the cells with steel/iron (but not stainless steel ok) wool used for cleaning pots and pans in the kitchen.The wool will be oxidised first, rendering the released sulphuric acid harmless.

[ben.mcfadden]

Wouldn't air current solve this problem? Like, perhaps, and air conditioner? I'm in Arizona, so the unit is on pretty much 24/7. I don't think you could get much more air circulation.

[BretteJaro]

The main problem you will find is the batteries will be damaged pretty quickly (6-12 months) because the float voltage of the SLA batteries is higher than that of the flooded cell batteries. You will need to keep a close eye on the electrolyte level because it will drop pretty quickly. Another byproduct is higher standby power consumption because the UPS will keep trying to charge the batteries, but in reality, will just be disassociating the water, or gassing.

[fred_dot_u]

If you have to add water to a flooded lead acid battery, always use distilled water. Anything else will contain minerals or contaminants and reduce the life of the battery substantially!

[loki0347]

Actually I've seen a single car battery have it's excess hydrogen explode from the sparks thrown off by detaching a charger under load...

[bubba007]

Play it safe:
Remember charging a car battery indoors can release harmful (toxic) gas fumes. Be careful where you put the batteries

[ReCreate]

it releases hydrogen and oxygen,which is what is already in the air,Along with CO2 of course

[ben.mcfadden]

True, but if the hydrogen builds up, as is possible, it could be an explosive danger.

[ReCreate]

i don't think it will produce enough hydrogen to ...cause an explosion

[ben.mcfadden]

Theoretically, you're absolutely right. But I'm not going to take the blame if something goes wrong. :-)

[Spokehedz]

Hydrogen is lighter than 'Air' so it will float up and out of the way of the hot things.

Oxygen is only explosive in high concentrations, which is to say it has to be very pure to do so. Chances are, it is not going to have the correct mix for it to be combustible at any level that you could create with just 2 batteries.

Combined with the fact that it only produces these gases when it is charging and not discharging....... You should be pretty safe. Just don't keep it all contained in a super enclosed space and you should be fine.

[ReCreate]

go ahead,sue me if you die of an explosion...did i say that?

[ReCreate]

just as long as you don't have lead acid battery bank of ten batteries or so,then the bet is off!

[scook]

Haha, I'm pretty sure they have about 25 Lead Acid batteries for power in the television series "The Colony" .

[ReCreate]

if it is outdoors, Then the problem is solved...