wiki: Backup power

Another one for your welcome input.... an intro to the backup power options

There are lots of ways of providing '''Backup power'''. This article introduces the various options, with their main features. Some of these have their own articles that go into the option in more detail.

=3D=3DPower options=3D=3D =3D=3D=3DGenerator=3D=3D=3D

  • how to detemine power needed
  • noise
  • maintenance
  • cost
  • service life (often very short)
  • 2 strokes and starting reliability
  • listeroids
  • connecting to mains wiring

=3D=3D=3DTorch=3D=3D=3D

=3D=3D=3DGas lighting=3D=3D=3D Despite being historic technology, gas lighting has some advantages over electrical power. The main one is its long term reliability, which is hard to match using elecrical kit. Gas lights can be expected to work for decades without attention or failure.

Gas cylinders don't discharge in storage, so power is always there ready to go. This contrasts noticeably with rechargeable batteries, which are prone to either

  • being flat when wanted if not left on trickle charge
  • having limited life if left on trickle

Gas lights produce a lot of heat due to low efficieny, and with suitable care this can be used to cook or heat water. Even a small camping gas light will put out around 400w of heat, which is enough to cook on.

The high heat output means it should be put somewhere it cant be knocked over in use. Hanging from the ceilng is often practical.

Putting foil round half the globe produces nearly twice the level of forward light.

Cost per volume of gas varies widely for different cartridge types. High gas cost lights can be uneconomic purchases, even if cheaper initially.

=3D=3D=3DUPS=3D=3D=3D '''U'''ninterruptible '''P'''ower '''S'''upplies provide a mains feed that's not interrupted in the event of a power cut. The switchover to internal battery is instant.

Large whole building units are available, but nearly all UPSes sold are plug-in items intended to run one or a few low power appliances, typically a computer system.

To avoid disappointment, the required capacity of UPS should be calculated before purchase, otherwise its likely to fail to deliver the run time wanted. UPS capacity is rated in kWh (kilowatts x hours), so for example a 0.2kWh UPS could run a 100w (0.1kW) load for 2 hours.

UPSes are also rated by their max continuous power output. The load appliance(s) should not exceed this rating. Note its the load's VA that matters rather than watts. For some loads VA =3D watts, and for some their VA rating is greater than watt rating.

Finally UPSes are also rated by peak power output. Some appliances draw well above running power for a brief period at startup. It would be wrong to assume that if the UPS meets an appliance's run current it would also meet the startup current requirement.

=3D=3D=3DLaptop=3D=3D=3D A laptop is often a practical way to get computer time during power loss.

Where TV is wanted to sedate the kids, a laptop with a USB TV card can be cheaper than a UPS to run the main TV, and of rather more use.

Extra batteries can give more run time. As well as expensive Li-ion laptop batteries, laptops can be run off lead acids with higher capacity and lower cost per hour, or carbon iron batteries. Manufacturer's instructions should be followed in such cases.

=3D=3D=3DLead acid, charger, invertor=3D=3D=3D A good option for people that already have most or all of the parts. However the necessary bits and leads need to all be to hand when the power cut bhappens, and te battery must of course be charged and ready to go.

=3D=3D=3DCandles=3D=3D=3D Although basic, candles are a workable way to provide occasional lighting. =A31 buys a lot of tea lights.

Candles are associated with significant fire risk, so its only sensible to use some means to keep the candle safe in use. Wall sconces are effective, placing the candle high up out of reach, especially of young kids.

Always keeping candles and matches in the same place makes finding them in the dark easy.

=3D=3D=3DEmergency escape lights=3D=3D=3D Non-maintained lights will light up automatically when mains power fails. (Maintained units are designed for a slightly different job.)

Run time typically 1-3 hours, typical cost =A315-20.

Fluorescent units generally give more run time due to the much higher efficiency of fluorescent tubes.

=3D=3D=3DRechargeable torch=3D=3D=3D These are left permanently on trickle charge. Some can be set to come on automatically when power goes off. Available light output and run time vary.

Fluorescent torches generally give better run time, since the fluorescent tube is much more energy efficient than the filament bulb.

All share one defect, limited battery life, and will require re- celling after so many years. Cells with higher capacity can give longer run time if required.

=3D=3D=3DCarbon iron battery=3D=3D=3D The home made carbon iron battery can provide plenty of power at any chosen voltage during a power cut. These are stored dry, and water is added to activate them. Because of this, shelf life is indefinate.

Construction cost is trivial, they're easily replenished after use, and can be built to any size for any load requirement.

=3D=3D=3DLuminaire backup pack=3D=3D=3D Mains fluorescent lights are available with a battery backup pack built in which will light the tube when mains fails. Be aware that battery operation is usually at much reduced power. While popular in commercial premises, this is not one of the cheaper options for domestic use, expect to pay anywhere in the region of =A380 or so. They also arent generally styled for domestic use, but this issue is easily sidestepped with trough installation.

=3D=3D=3D12v battery & 12v lights=3D=3D=3D Fluorescent lights give several times the run time per light output than filament lamps. A practical option where mains power isn't needed.

Its possible to feed 12v wiring to every room, and add a relay that switches a 12v lighting system on when mains fails. This may be an attractive option when carrying out work that permits running new low voltage wires, such as major redecoration, rewiring, installing a wired network, etc.

Lead acid batteries require a few minutes of occasional maintenance to last well.

=3D=3D=3DNothing=3D=3D=3D A lot of people choose no back up power, and are quite happy to sit in quiet for once. It can be a nice break in a hectic life, and quite refreshing.

=3D=3DChoice=3D=3D The usual question that's posed when choosing is:

What do you want power for?

  • lighting
  • ch/hw
  • tv
  • computer
  • etc

What will that cost, and is it worth it?

Now, more realistically, what will do?

=3D=3DBusiness use=3D=3D When using backup power for commercial premises, its helpful to estimate how much business is lost in one power cut, and roughly what this value adds to over say a 10 year life of a power backup system. This quick calculation shows that UPSes are a no-brainer for many businesses.

Bear in mind that power cuts are in practice due to on-premises faults as well as supply outages, and that getting an electrician generally takes many hours.

=3D=3DConnecting to house electrical circuits=3D=3D Care should be used in doing this, as its quite possible to kill or injure a linesman if its not done right. Integrating the backup power source with the whole house wiring is more involved than most DIYers are willing to do. Running an extension lead from power to appliance is a simpler option.

=3D=3DSee Also=3D=3D

  • [[Special:Allpages|Wiki Contents]]
  • [[Special:Categories|Wiki Subject Categories]]

[[Category:Electrical]]

NT

Reply to
meow2222
Loading thread data ...

===Gas lighting=== Add that a small camping lantern will produce more light than a 60W incandesent light bulb for several hours when flat out. If longer run time or less light is required they can be turned down and give really long run times, 10 hours or more depending on cartridge size. The quality of the light is much better than electric as well.

Not convinced that is correct. My APC Smart UPS 700 is rated at a nominal

700W, ie it will deliver 700W but the runtime at that power level is at best 10 minutes.

Yes, I see that thar rating in the wiki is kWh but I've not seen that used as the headline rating of a UPS.

Ah, I'd swap these to around as the VA is more often quoted along with a runtime at various power levels rather than an overall kWh rating, certainly for smaller UPS units. Large industrial ones may well have their ratings quoted differently.

Add a warning that switching something on that takes a surge can trip the UPS protection circuit when running on battery power. That same appliance probably won't when the UPS is on mains power.

Add "shaker" torches. These you shake for a 30s or so to provide light for a few minutes. They work by having a magnet slide through a coil generating electricity that is stored in a capacitor. The light source is a white LED. The light is not winderful but enough to see by to find and startup up other back up systems. With built in power generation and or bulb to blow reliablity is high.

Interesting link to instructions?

Reply to
Dave Liquorice

Someone is very busy. Thanks for putting in the effort.

Suggestions:

Mention that the ADSL/cable modem and router(s) will need to be on the UPS - not just the computer system.

Various forms of glow stick/light can be very effective. Although relatively expensive, they are very safe and can be stored for long periods.

Simple glow-in-the-dark tabs/labels can help in locating door handles, light switches, etc.

Although not ideal on the safety front, Coleman-style petrol stoves and lamps are cheap to run on unleaded (or were until recently :-) ), and very effective. My choice for one-ring emergency cooking outdoors.

For many, use of some sort of amplifier and/or distribution device is necessary for their television reception. This too will need to be on UPS if it is to work. And, of course, the various set-top boxes (including the ridiculously hot running, power hungry Virgn media boxes).

Reply to
Rod

Useful to put DECT basestation on UPS too, but also keep a wired phone handy.

Reply to
Andy Burns

Most UPS' will have a rating in VA or KVA. This indicates the maximum load[1] rather than the run time. The Capacity of the batteries in Ah will be proportional to the run time. More professional units allow the run time to be increased with additional battery boxes. It is worth noting also that the internal inverter in the UPS will have some load anyway and hence there will be a maximum run time even without any load on the UPS. This can be as little as 20 mins on a small one.

[1] More significantly combined real and reactive load - so with much computer related kit (especially older stuff) you need to allow for the non unity power factor.

IME, they often do it the same way on bigger boxes.

Even if you don't trip the UPS, you may glitch the power for long enough to upset something else already powered. I deliberately put my big CRT monitor a separate UPS from anything else that might not appreciate being glitched.

(If you have a power cut while the computer is on, but the monitor is off, and you find you need to turn the monitor on to close down the system gracefully and get yourself out of whatever docs you left open. it can be quite annoying if the monitor switch on surge resets the computer! DAMHIK)

Reply to
John Rumm

If you want any decent runtime for a PC/monitor/xDSL etc you are going to have some hefty battery storage. Best to forget a PC other than a laptop when the power goes. Have one to enable clean automagic shut downs though.

Some DECTs have batteries, personally I'd have a wired phone always plugged in somewhere anyway.

Reply to
Dave Liquorice

Yep, handy to give to the kids in the pitch dark. Also have very long shelf life.

I bought some little tabs just for that purpose but No.1 Daughter removed the few I put on within hours. She was about 2 at the time though, they might stay there now.

Reply to
Dave Liquorice

Must admit, I had assumed laptop earlier.

Good point re DECT. And perhaps 'keep your mobile charged' should also be added to advice?

Reply to
Rod

As in don't rely on a charged mobile phone for communications? If your power is off there is a reasonable chance that the power to the local cell site is also off. Some have UPS back up for a hour or two, some autostart gensets but the vast majority don't.

A BT provided wired phone will work for a considerable time from the exchange batteries or genset. A cable company provided wired phone may not be so resilient.

Reply to
Dave Liquorice

Same as me I suspect BTDTGTTS. B-) In my case just an ordinary 15" CRT monitor not a big jobbie. I don't think LCD monitors have the big switch on surge of CRTs.

Reply to
Dave Liquorice

Agreed - not to rely on mobile. Just thought it was sensible to have that charged up *as well* as non-mobile working.

Reply to
Rod

Indeed. I still use proper phones with dials :-)

Reply to
Frank Erskine

Its the degauss on most CRTs that does it. My 23" aperture grill screen will glitch even my 1KVA UPS boxes...

Reply to
John Rumm

OK, version 2... and hopefully the last version.

And a brief note - there seems to have been a lot of confusion around UPSes, and since theres a fair bit to write about them I decided to move the ratings info to a prospective UPS article rather than within this one - it doesnt seem to belong here after all.

Oh, iron carbon batteries are here:

formatting link
NT

There are lots of ways of providing '''Backup power'''. This article introduces the various options, with their main features. Some of these have their own articles that go into the option in more detail.

=3D=3DPower options=3D=3D =3D=3D=3DGenerator=3D=3D=3D

  • how to detemine power needed
  • noise
  • maintenance
  • cost
  • service life (often very short)
  • 2 strokes and starting reliability
  • the Cult of the Listeroid
  • connecting to mains wiring

=3D=3D=3DTorch=3D=3D=3D [[Battery]] torches tend to turn out to have flat batteries. [[Nicad battery|Rechargeable batteries]] are worse in this respect, with quite high self discharge rates.

Wind-up and shake torches don't need batteries, so are more likely to work when they haven't been used in ages. They don't run long on a charge, but can be useful to see to get another power source running.

[[LED Lighting|LED]] torches give out less light and light of lower CRI, but run longer, are much less prone to bulb failure and are far more robust.

=3D=3D=3DGas lighting=3D=3D=3D Despite being historic technology, gas lighting has some advantages over electrical power. The main one is its long term reliability, which is hard to match using elecrical kit. Gas lights can be expected to work for decades without attention or failure.

Gas cylinders don't discharge in storage, so power is always there ready to go. This contrasts noticeably with rechargeable batteries, which are prone to either

  • being flat when wanted if not left on trickle charge
  • having limited life if left on trickle

A small camping lantern will produce more light than a 60W incandesent light bulb for several hours at maximum brightness. If longer run time or less light is required they can be turned down and give really long run times, 10 hours or more depending on cartridge size.

The quality of the light is quite good, and much better than the low CRI and high CCT types of electric lighting, such as LEDs and [[Fluorescent Lighting|cool white fluorescent tubes]].

Gas lights produce a lot of heat due to low efficiency, and with suitable care this can be used to cook or heat water. Even a small camping gas light will put out around 400w of heat, which is enough to cook on.

The high heat output means it should be put somewhere it can't be knocked over in use. Hanging from the ceiling is often practical.

Putting foil round half the globe produces nearly twice the level of forward light.

Cost per volume of gas varies widely for different cartridge types. High gas cost lights can be uneconomic purchases, even if cheaper initially.

=3D=3D=3DUPS=3D=3D=3D '''U'''ninterruptible '''P'''ower '''S'''upplies provide a mains feed that's not interrupted in the event of a power cut. The switchover to internal [[battery]] is instant.

Large whole building units are available, but nearly all UPSes sold are plug-in items intended to run one or a few low power appliances, typically a computer system. Small cheap units may only manage minutes of backup time.

To avoid disappointment, the required capacity of UPS should be calculated before purchase, otherwise its likely to fail to deliver the run time wanted.

=3D=3D=3DLaptop=3D=3D=3D A laptop is often a practical way to get computer time during power loss.

Where TV is wanted to sedate the kids, a laptop with a USB TV card can be cheaper than a UPS to run the main TV, and of rather more use.

Extra batteries can give more run time. As well as expensive Li-ion laptop batteries, laptops can be run off [[Lead acid battery|lead acids]] with higher capacity and lower cost per hour, or an [[iron carbon battery]]. Manufacturer's instructions should be followed in such cases.

=3D=3D=3D[[Lead acid battery]], charger, invertor=3D=3D=3D A good option for people that already have most or all of the parts. However the necessary bits and leads need to all be to hand when the power cut happens, and the battery must of course be charged and ready.

=3D=3D=3DCandles=3D=3D=3D Though basic, candles are a workable way to provide occasional lighting. =A31 buys a lot of tea lights, but not a lot of light level.

Candles are associated with significant fire risk, so its only sensible to use some means to keep the candle safe in use. Wall sconces are effective, placing the candle high up out of reach, especially of young kids.

Always keeping candles and matches in the same place makes finding them in the dark easy. Finding them in a new location can be a hopeless task in the dark.

=3D=3D=3D[[Emergency Lighting|Emergency escape lights]]=3D=3D=3D Non-maintained lights will light up automatically when mains power fails. (Maintained units are designed for a slightly different job.)

Run time typically 1-3 hours, typical cost =A315-20.

[[Fluorescent Lighting|Fluorescent]] units generally give more run time due to the much higher efficiency of fluorescent tubes.

=3D=3D=3DRechargeable torch=3D=3D=3D These are left permanently on trickle charge. Some can be set to come on automatically when power goes off. Available light output and run time vary.

Fluorescent torches generally give better run time, since the [[Fluorescent Lighting|fluorescent tube]] is much more energy efficient than the [[Filament Lamps|filament bulb]].

All share one defect, limited [[battery]] life, and will require [[Nicad battery|re-celling]] after so many years. Cells with higher capacity can give longer run time if required.

=3D=3D=3D[[Iron carbon battery]]=3D=3D=3D The home made iron carbon battery can provide plenty of power at any chosen voltage during a power cut. These are stored dry, and water is added to activate them. Because of this, shelf life is indefinate.

Construction cost is trivial, they're easily replenished after use, and can be built to any size for any load requirement. Very large batteries are quite constructable.

=3D=3D=3DLuminaire backup pack=3D=3D=3D Mains [[Fluorescent Lighting|fluorescent lights]] are available with a battery backup pack built in which will light the tube when mains fails. Be aware that battery operation is usually at much reduced power. While popular in commercial premises, this is not one of the cheaper options for domestic use, expect to pay anywhere in the region of =A380 or so. They also aren't generally styled for domestic use, but this issue is easily sidestepped with [[Fluorescent Lighting|trough installation]].

=3D=3D=3D12v battery & 12v lights=3D=3D=3D [[Fluorescent Lighting|Fluorescent lights]] give several times the run time per light output than [[filament Lamps]]. A practical option where mains voltage isn't needed.

Its possible to feed 12v wiring to every room, and add a relay that switches a 12v lighting system on when mains fails. This may be an attractive option when carrying out work that permits running new low voltage wires, such as major redecoration, rewiring, installing a wired network, etc. See [[Low Voltage Wiring]].

A [[Lead acid battery]] requires a few minutes of maintenance every couple of years to last well.

=3D=3D=3DGlowsticks=3D=3D=3D Low light output and high price, but long shelf life, completely safe to give to kids and keeps them amused.

Glow in the dark tabs can be added to door handles to help small children navigate the dark.

=3D=3D=3DParaffin lamp=3D=3D=3D Old fashioned pressurised paraffin lamps (Coleman, Petromax etc) are much cheaper to run than gas canister lamps, but a little knowledge & time is needed to get them started. They're also not the safest lighting option.

=3D=3D=3DNothing=3D=3D=3D Most people choose no back up power, and are quite happy to sit in quiet for once. It can be a nice break in a hectic life, and quite refreshing.

=3D=3DChoice=3D=3D The usual question that's posed when choosing is 'What do you want power for?'

  • lighting
  • ch/hw
  • tv
  • computer
  • freezer
  • cooking
  • etc

What will that cost, and is it worth it? Now, more realistically, what will do?

=3D=3DServices=3D=3D =3D=3D=3DCooking=3D=3D If power for cooking is needed, as well as the above options it can be provided by any of:

  • disposable charcoal BBQ tray
  • wood/coal fire
  • gas stove, either mains, bottled gas or camping canister type
  • paraffin stove
  • and maybe self heating instant meals

If considering these options, bear in mind that old fuel cookers such as paraffin types can sometimes produce significant CO, and will require proper ventilation or use outdoors.

=3D=3D=3DPhone=3D=3D=3D Wired phones connected direct to the line should continue to work in a power cut. Not all companies keep as much reserve run time at the exchange as BT.

Mobile phones may stop working as most nearby cell towers have no backup power source. A mobile with a flat battery will of course be dead - obvious, but sometimes overlooked.

Cordless phones stop working if the base unit doesn't have a built in [[Nicad battery|rechargeable battery]]. Those that do should continue to work for a fair time if the battery is serviceable.

=3D=3D=3DInternet=3D=3D=3D Dialuppers using a land line should have no problem for a while. Wireless mobile net access will suffer the same fate as mobile phones, and usually stop working.

Broadband services require power to the modem to work, otherwise net access stops. Any routers will also need power if you want them to work.

=3D=3D=3DTV=3D=3D=3D [[TV aerial]] systems that include an [[Aerial amplifier|amplifier]] will play dead during a power cut.

Set top boxes and anything else the aerial signal runs through will also want power providing, or won't co-operate. However its not hard to connect the [[Cable for TV aerials|aerial lead]] direct to the TV to just get the 5 main channels.

=3D=3D=3DComputers=3D=3D=3D Desktop systems and CRT monitors are both power hungry. Cheap plug-in power backups won't run these for long, and in some cases won't run them at all. Laptops are more practical.

Desktop systems with a CRT monitor on a UPS suffer a particular issue: if the monitor is off when power is lost, switching it on tends to glitch the backup power, which often resets the computer or shuts down the UPS. This is due to the high initial current consumption of the degauss circuit in nearly all CRT sets. Even a 1kVA UPS can be caught out by this in some cases.

CRT monitors can be modded to sidestep this problem by putting the degauss circuit on a switch, and normally leaving it off, but few would bother for domestic use.

=3D=3DBusiness use=3D=3D When using backup power for commercial premises, its helpful to estimate how much business is lost in one power cut, and roughly what this value adds to over say a 10 year life of a power backup system. A quick calculation shows that UPSes are a no-brainer for many businesses.

Bear in mind that power cuts are in practice due to [[Circuit faults| on-premises faults]] as well as supply outages, and that getting an electrician generally takes many hours.

=3D=3DConnecting to house electrical circuits=3D=3D Care should be used in doing this, as its quite possible to kill or injure a linesman if the right safeguards aren't in place. Integrating the backup power source with the whole house wiring is more involved than most DIYers are willing to do. Running an extension lead from power source to appliance is a simpler option.

=3D=3DWiring Design=3D=3D Its possible to choose what appliances you want to work in a power cut, and provide a separate circuit to run them, possibly with a UPS to keep the circuit alive for a while. Very few of us go that far, but some will wish to at design time.

=3D=3DSee Also=3D=3D

  • [[Special:Allpages|Wiki Contents]]
  • [[Special:Categories|Wiki Subject Categories]]
[[Category:Electrical]]
Reply to
meow2222

Number please, caller.

Reply to
Andy Hall

That was a handle not a dial...

Ask a youngster to make a phone call on a phone with a dial and they are stumped.

Reply to
Dave Liquorice

Reminds me of a story I heard when I was working for GPT, 15 years back. A telephone exchange engineer was out on a long-term assignment in India (IIRC) with his family, as often happened when a large network infrastructure was being installed.

His kids got chatting to some local kids, and were talking about the new phone technology daddy was installing.

"You'll be able to lookup someone's number, lift the receiver and dial anwhere in the world."

The Indian kid replied:

"We don't need to do that. We just pick the receiver up and ask to be connected".

Reply to
Andrew Gabriel

That's a lovely story.

On the theme of GPT, I can remember planning and making a visit to their site in Coventry. The address was New Century Park. It sounded impressive and high tech with a name like that. Until one got there. What they had omitted to mention was *which* century.

I suppose nowadays they have the three sausages on the roof.

Reply to
Andy Hall

Somewhat surprising that there is just one hit on the entire web for "Iron carbon battery". And that link is the interesting but confusing:

So does that count as a googlewhack?

Reply to
Rod

No - that's for phones _without_ dials.

:-)

Reply to
Frank Erskine

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.