DIY UPS project.

[Mevuxatrox]

Hello everyone!

I have a problem that's been on my mind for a while now and i haven't been able to
find a reliable solution to my needs so far. Thus, i have decided to ask for help on
various forums to see if there is anyone with the skill and experience who could provide
solid instructions or advice on how to achieve what needs to be achieved.
(I apologize in advance for my limited english skills, I am not a native speaker.)

To make things a bit easier, let's say hypothetically that i need to build a miniature
bomb shelter (I'm not building a bomb shelter but we can all blissfully pretend i will).
In this construction, i need to have a fan and 4 lightbulbs connected to some sort of
UPS unit, battery bank, inverter or something which will be able to provide power
for a minimum of 2 hours straight in case of a power shortage.
People will be living in the bombshelter so risk of fire or release of harmful gases
has to be minimized.

The fan will be running at 40W, 220/230 Volt, 0.21A.
The lights will be 4 x 8W CFL bulbs.

My hopes are to be able to build an arrangement like this on a tight budget as possible
while having it run safely with minimized risk of fire or release of hazardous gases etc.
So i presume an offline setup would be the best?
My plan was to get an old UPS unit and daisychaining external hobby/motorcycle batteries
to lengthen the back-up runtime to a minimum of 2 hours.
So far what i think i have figured out is that deep cycle discharge batteries (gelcells?)
would be the best since they release no gases (unless i've misinterpreted this info).
What worries me is how to get the right Voltage and amps to run both fan and lights
without blowing eiher to smithereens.
If i use an old UPS unit, what VA and W should i have to which batteries?
How would this be built/assembled/connected?
In total, power consumption in case of a power shortage will probably not exceed 100W.
What kind of UPS could i get away with using which would be compatible with this
output with a daisychained battery stack?
Is there anything else which would be a better option?
Since this isn't about computers, the switch to back-up power probably doesn't have to
be immediate so ms's are probably of less importance unless it could fry the electronics
in the fan or lights.
Has anyone built something similar and what are your experiences?

I would be very thankful if i could get any advice.

 

[JimB]

The fan will be running at 40W, 220/230 Volt, 0.21A.
The lights will be 4 x 8W CFL bulbs.

Why not use 12v fans and LED lights, run them directly from the battery, and have a battery charger powered from the mains when mains supply is available?

JimB

 

[Mevuxatrox]

The CFL's could probably be switched out to LED's but the fan needs to be able to move air through ductings and be able to cope with airpressure resistance.
So the fan will be difficult to replace for a weaker one.

 

[Nigel Goodwin]

The CFL's could probably be switched out to LED's but the fan needs to be able to move air through ductings and be able to cope with airpressure resistance.
So the fan will be difficult to replace for a weaker one.

LED's are a far better choice for the lighting, as they are about twice as efficient as CCFL (I've replaced ALL lights in my home now with LED ones) - they also come on at full brightness instantly, and are a better colour.

No one suggested a 'weaker' fan - just a 12V fan - a 40W 12V fan is just as powerful as a 40W 230V one.

Far better to run stuff directly from a battery, so you're not losing energy in conversions.

 

[Les Jones]

You may find that the mains fans will not run from the waveform that most cheap inverters (And the inverters used in UPS's) give out. You may need an inverter with sine wave output which will be more expensive. Jim not suggest using a "weeker" (Lower power one.) It should be possible to find a 12 volt fan with suitable ratings. You can get 12 volt CFL bulbs but LED lighting would take less power.

Les.

 

[ClydeCrashKop]

You can get radiator cooling fans at an auto junk yard. They move a lot of air. You can use all the 12 volt deep cycle batteries you want. Just keep then outside of your living area and run cables inside.

 

[Tony Stewart]

DC fans are far more efficient than AC fans. So choose DC fans such as car heater blowers, or radiator coolers and 12V battery with 16V with small PV panel and 14.2 V switch to activate load to prevent overcharge such that load matches or exceeds PV power, so it will never overcharge and then shuts off automatically when clouds come and then can be manually control for emergency use, maintenance free for shelf life of battery. (10yr if cool)

16V PV panels are current sources that have optimal power transfer at 70~80% no load voltage. e.g. 50W panel, 50W fan, 5W 12V LEDs with current limiter. A 50W or 4A car fan would equivalent to a 100W AC fan. approx.

 

[Mevuxatrox]

Thank you very much for all replies so far!
I've been skimming amazon and found these which might be of use:

Bulbs:
https://www.amazon.co.uk/dp/B00Z9S2XGM
https://www.amazon.co.uk/dp/B00Z9QVG0S

Fan:
**broken link removed**

So if i want these connected to a battery setup and then to the 220v wallsocket (and to activate only incase the power fails) How is it done?
The fan has quite high Amp compared to other similarly sized fans so it should be able to take off a finger or two or pull air through a
carbon filter without blowing up?

 

[Tony Stewart]

both look unsuitable for a car battery being charged at 14.2 but ok for a PC PSU 12V
Also High current doesn't mean high pressure into a carbon filter. It just means high RPM and high current and high CFM with no filter load.

re-read my suggestions and use car accessories... fans and LEDs and battery

 

[Mevuxatrox]

I am having a hard time finding a radiator fan not exceeding 8" x 8" (200x200mm) which could be connected to a 4" (100mm) ducting.
Preferably it'd be 4" diam overall and be fitted inside the ducting.
Since i don't really know what kind of LED's you mean, i'd need a mix of red and blue alt. 5000k light spectrum.
There will be no possibilities to connect the devices to any solarpanels, it's wallsocket or nothing. :\

 

[Tony Stewart]

@Mevuctrox
Your new requirements, can be met with most interior heater blowers . Audi's use dual small fans on radiators.

Cars use all kinds of LED's now and StripLeds made for automotive may not very efficient with series R's to permit 9~14.5V operation, but will work. Or you can choose festoon style halogen 12V bulbs used in older cars.

R & B does not equal 5000'K ( sounds more like a grow-op)

Use a PC 12V PSU then with car battery kept at 50% SoC ( 0=11.5, 100%=12.5) which may be more than adequate for you, then you can use all the 12.0V accessories you desire. USe a polyfuse to battery properly rated for both source and load.

 

[ClydeCrashKop]

http://www.westmarine.com/buy/jabsco--12v-marine-blowers--P012_362_001_506
You can get them cheaper on eBay

Johnson Pump 4" In-Line Blower 240 Cfm 12V

You may also see Attwood brand = Poor Quality.

 

[tcmtech]

If it was my project and system efficiency and size was not a critical concern I would simply take a common UPS unit or power inverter that is rated for more wattage/VA than the combined load and use a battery that is sufficiently sized to give you atleast 2X your planned run time.

Most UPS units under 500 - 600 watts/VA use a single 12 volt battery and are very easy to modify to use a much larger external battery to increase their run time. I've done it to many of them over the years.

The only major concern with extending their run time is to be aware that in their stock form when running at or near their full rated power they are designed to have the battery go dead about the same time the unit is reaching its overheat point. Given that if you size them so that the maximum continuous load is less than 50% of their rating overheating should not be much of a problem.

Going by that I would recommend starting with a common 400 - 500 watt/VA UPS unit and a good 12 volt 75 - 100 AH deep cycle battery. No point to over complicate it any further if it's not absolutely necessary.