Generators

[Ned]

I'm anticipating a lot more blackouts in the future and am thinking of getting myself a small generator, big enough to run a fridge, air con, TV, and a few lights. A shower heater too.

Has anyone out there installed one lately? I was wondering what size I'd need and how much it'd cost me.

Thanks

[phibunmike]

Look at the labelling on each of the items you listed and note the power requirement - e.g. my fridge says 170W, my TV (a smallish LCD one) is 25W (but a conventional one would be much more). Add to this your light bulbs, e.g 100W, 60W (incandescent) or 7W, 11W (low energy).

Whatever your total add a safety margin and that will give your generator requirement. Make sure your generator has a sine wave output.

[SiamOne]

Its the aircon that will determine the size. Add the water heater and 20%

that should do it!

[Crossy]

Good advice so far, a little clarification.

Your appliances will be marked in Watts (W). Generators are rated in VoltAmperes (VA). Now I know you were taught that Watts = Volts x Amps but for AC supplies that's not quite true, there is a nastly little thing called Power Factor, PF is always less than 1. With a PF of 1 VA=W.

Assume a PF of about 0.8. So add up all your Watts, add 20-30% and get the next bigger genset.

BUT

Gereating electicity to heat water is rather inefficient (read expensive), consider getting a gas water heater it may prove cheaper in the long run.

Consider getting a diesel genset (rather than gasoline/petrol), cheaper fuel and many will run on vegetable oils.

[monty]

If you have a slightly bigger budget, an industrial UPS might be an option!

I have a 3500VA fully automatic charger/inverter, coupled to a 400 amp / 48 volt battery pack.

Advantages:

* works completely automatic, keeps the battery's charged, and when the power blacks out it switches to inverter mode in 30 msec. Your PC doesn't even notice, the lights don't even flicker...

* Output is pure sine, so no problems with expensive electronics.

* Filters out any spikes in the power supply, so no damaged electronics anymore.

* No maintenance apart from filling up the batteries with distilled water twice a year.

* Completely noiseless.

* Peak power of 7000VA will make sure the fridges compressor can start up...

* No smelly fuel around, no oil changes,...

Disadvantages:

* Limited back-up time, my set provides juice for 3 hours at full power, 6 at half power.

* not suited for high powered stuff, such as water heaters, washing mashines or aircon units

* High initial cost (mine was 120.000 Baht)

* Consumption of around 1kWh/day for keeping the batteries topped up (= around 100 Baht/month)

* Needs a well ventilated place to put the batteries

Considering a decent, quit 3.5kva genset, with electric starter costs aroud 50.000 Baht, the extra money was well spent in my personal opinion.

Mainly, when the power blacks out, I don't have to go find my flashlight, then run to the generator room to start the generator (wouldn't you know, the battery just died let's pull-start ) and then throw over the transfer switch...

[ArtfulD]

I'm anticipating a lot more blackouts in the future and am thinking of getting myself a small generator, big enough to run a fridge, air con, TV, and a few lights. A shower heater too.

Has anyone out there installed one lately? I was wondering what size I'd need and how much it'd cost me.

Thanks

<{POST_SNAPBACK}>

Fridges dont use much power over time, their really efficient at staying cool if you dont open/close the doors a lot. But Air con and shower heater will just eat energy, as mentionned above get the rating of each of the appliances you use, and work out how many will be switched on at any one time....e.g. can you turn off aircon when you use the shower?

Check these links:

http://www.oru.com/energyandsafety/energye...genergyuse.html

http://www.absak.com/design/load.html (check out the load calculation pdf form at bottom of page)

[Thetyim]

I don't know how big your aircon or appliances are but I think you are going to need a 10KW genny.

Your aircon and shower will probably need 7.5 KW

[Ned]

Thanks for the replies everyone. Plenty of info there to think about.

[mobile69]

Consider getting a diesel genset (rather than gasoline/petrol), cheaper fuel and many will run on vegetable oils.

<{POST_SNAPBACK}>

Does anyone know of the availability of lpg generators in Thailand? Surely they would be cheaper to run & you don't have petrol being stored & hardly ever used, if the generator is only a backup.

[lopburi3]

I wonder why you believe there will be a lot more blackouts in the future? There sure haven't been many past/present in my experience (but understand your location may be different). Even when a transformer blows it has never been off for more than an hour or so. The longest here in Bangkok was about 6 hours when they replaced the main HV feed lines into mooban. As said you will probably require 10kw generator and changover panel (and hope you don't forget to turn off anything extra).

I would not advise a gas water heater as they can be a real danger if not vented well.