Electrical supply issues + work arounds

gwmss15

I live in Mahachai city in a massive condo complex of 42 eight story towers. Every time it rains or becomes windy the power will fail and then go on and off repeatedly for the next 30 to 60 mins. All very annoying and has created damage to my aircon system in my apartment. Which is used 7 days a week for 11 and half months a year.

From time to time (read a couple of times a month) on very hot 40 C afternoons the power may just suddenly fail and be off for hours.

On more regular occasions i.e once a week the power will go into a weird "half power" that only my laptop computers power can use. The aircon will not run on half power and the older light bulbs will be dim and the new white fluro lights will not operate nor the towers lift.

The other frustrating power issue is the voltage range of the power supply its too wide "95 volts (half power state) to 270 volts normal is 230 volts. the voltage can change from one hour to another.

This may not be a direct effect of power shortages or peak oil but id like some advice on how to mitigate this problem.

The biggest issue i face with this annoying power problem is the loss of power to the fridge.

Is there anyway of creating a cheap backup power supply for the fridge that can run for up to 18 hours?

The fridge is only 170 litres capacity single door. Not sure of power usage though.

Does anyone on here face similar power supply issues?

What are your recommendations for working around them?

Are theses power problems an indication of peak oil related power failures that get talked about on this site from time to time?

Ludi

Perhaps get a small fridge which can run on a battery?

http://stormprepare.com/Refrigeration.htm
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strider3700

start by measuring the power usage of your fridge over an 18 hour period using some form of watt meter ($30 or so). do this for awhile and get an average usage.

With that you can start designing a backup system. 18 hours of running an inefficient fridge requires a fair amount of power. The inverter probably won't be overly expensive maybe $100-$200 but it will require a decent battery bank. If money isn't the limiting factor space may be based on the description of your place.

It all starts with knowing that usage number however
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shame on us, doomed from the start
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gwmss15

Data from instructions that came with the fridge.

Uses 205.13 Units of power per year. 1 unit = 1 kilowatt hour.

Per hour 23.40 watts per hour.

therefore the total power used in 18 hours is 421.23 watts/hour or 0.421 KW/h.

I hope this data helps.

I have no idea how to use it to build a battery back up system.

As it runs on 230 volts AC power not 12 volt DC.

How much is a battery back up likely to cost?

The space to put it in would only be 1 foot by 2 foot by 2.5 foot and a second area for 8 inch by 3 foot by 3 foot.

strider3700

I can't take the time to do the math but roughly off the top of my head you are using about 2.5 amps to run the fridge spread over 18 hours

so 45ish amphours needed. since you don't want to drain a battery more then 50% (you'll damage it) you should look at roughly 100 amp hours in your battery bank. That is within the capability of a golfcart battery but you'll need at least 2 since I know of no 6 volt inverters.

A little hunting will show that golfcart batteries can be found for roughly $100 each pretty easily.

the 230 V inverter is not something I'm at all familiar with so no idea on price.

A slow charge of the two batteries can be handled by pretty much any car battery charger and is probably the cheapest way to go.

Having said all this the numbers sound way too low and I'm questioning my needed amp hours calculation.
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shame on us, doomed from the start
god have mercy on our dirty little hearts

SteinarN · Tar Sands Joined: Sep 20, 2007 Posts: 95 Location: Norway

pedalling_faster · Intermediate Crude Joined: Dec 10, 2005 Posts: 848

patience · Expert Joined: Jan 04, 2008 Posts: 1523

If I converted correctly, 170 litres = 6 cubic feet, which is a small fridge. (In the US a 15 cu, ft. fridge is common.) So, I think the power usage sounds correct.
I think SteinarN and strider3700 numbers are correct, so two golf cart 6 volt batteries in series to get 12 volts should be enough.

Since the US has a 120 volt standard, that is all I'm familiar with in inverters, but Europe and Britain, I think, use 220 volts, so maybe some of our posters from there will help with the inverter needed and who sells them.

The system goes like this: You buy the batteries and while your power system is running, a small "trickle charger" sold for auto and motorcycle batteries is hooked to the batteries to keep them at full charge. When the power goes off, the trickle charger is no longer working, but the batteries are full, so they can supply your fridge through an inverter that changes the 12 volts DC of the batteries into 220 volts for the fridge. An inverter is a small metal box of electronics that has 2 terminals to hook to the batteries with battery cables, and a suitable outlet for your appliance to plug into. An auto matic switchover to the battery/inverter power could be done, but it would be much simpler to do that manually when utility power fails.
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da23 · Heavy Crude Joined: Jun 06, 2006 Posts: 127