Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

dg

"dg" wrote in message
om...
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

dg

You can run low power things off an adapter, but don't expect to run battery
operated drills and the like.

mrcheerful

In article ,
dg wrote:
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

If the unit is designed to run off a mains power supply, then you could
use (eg) a car battery and a 12V to 230V invertor. I do it this way when
"in the field" and need to do things like charge mobile phone, cameras,
Laptop, etc.

Eg. See

http://www.tlc-direct.co.uk/Main_Ind...ers/index.html

I have the basic 150W model. Seems to work fine for my needs.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

It could - IF it's just designed to power the unit.

Is it this simple or would I need some electronics to regulate to
output voltage?

Regulating voltage isn't a problem, but if the units also charge their
(internal, rechargable) batteries then you must be carefull how you
regulate it. NiCd rechargables have different requirements to NiMH for
example. Some devices do have internal regulators and aren't so fussy
though, but it's hard to tell which does and which doesn't, and unless
you are absolutely sure, it's best to not try.

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

I've found it easier to use the invertor, then just plug the devices
standard mains adapters into the invertor to run/charge them.

Gordon

dg wrote:

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

For devices that have a DC in socket, it is pretty straight forward.
Make up an external pack with a flylead a suitable connector on the end.

Most devices that expect to run from an external DC power source will
have a regulator in them anyway since the external "wall wart" type
power bricks are typically unregulated.

If the device expects mains in only then an inverter may work, but
chances are it will work out bigger and heavier than just taking a few
sets of replacement batteries.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 28 Aug 2004 08:15:06 -0700, dg wrote:

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

In principle yes but you'll probably find that every single one of
your devices has a different input voltage requirement, some may not
be a multiple of the (nominal) 1.2v and have quite strict limits. You
need to go through the manuals of each device to find what they will
live off from the "DC" input.

Parts available from Maplin, Rapid, CPC, RS, Farnell etc.

--
Cheers
Dave. pam is missing e-mail

In an earlier contribution to this discussion,
dg wrote:

Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

dg

It *can* be done, but bear in mind that there are a lot of size variations
in these little concentric plugs which feed the appliances - so one size
definitely *doesn't* fit all. Add to that the range of voltages required and
polarity differences (some have +ve on the outside and some on the
inside!) - and you need to design a pretty flexible bit of kit!

I think I would go with the car battery plus inverter suggestion, in order
to provide "mains" to the original adapter. You're then sure of the right
fit, and the right voltage and polarity.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

mrcheerful . wrote:

"dg" wrote in message
om...
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

You can run low power things off an adapter, but don't expect to run battery
operated drills and the like.

There are adaptors and adaptors.
Some will run things like battery drills, but are of course comparatively
expensive.

In message , Set Square
writes
In an earlier contribution to this discussion,
dg wrote:


It *can* be done, but bear in mind that there are a lot of size variations
in these little concentric plugs which feed the appliances - so one size
definitely *doesn't* fit all. Add to that the range of voltages required and
polarity differences (some have +ve on the outside and some on the
inside!) - and you need to design a pretty flexible bit of kit!

CPC do an excellent little power supply which comes complete with 8 or
16 connectors which plug into another connector either way around to
give you about every possible permutation

That's that problem solved for the OP'r
--
geoff

(dg) wrote in message . com...
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?


Right. Get voltage right, and polarity. Also put a fuse on the nicads,
as they can deliver firestarting amounts of current if the connector
touches what it shouldnt.

Regards, NT

On Sat, 28 Aug 2004 22:46:26 GMT, raden wrote:

CPC do an excellent little power supply which comes complete with 8
or 16 connectors which plug into another connector either way around
to give you about every possible permutation

That's that problem solved for the OP'r

Until he takes the device from a device needing 12v tip +ve to a
device needing 3v tip -ve without remembering to change the connector
round...

--
Cheers
Dave. pam is missing e-mail

In an earlier contribution to this discussion,
raden wrote:

In message , Set Square
writes
In an earlier contribution to this discussion,
dg wrote:


It *can* be done, but bear in mind that there are a lot of size
variations in these little concentric plugs which feed the
appliances - so one size definitely *doesn't* fit all. Add to that
the range of voltages required and polarity differences (some have
+ve on the outside and some on the
inside!) - and you need to design a pretty flexible bit of kit!

CPC do an excellent little power supply which comes complete with 8 or
16 connectors which plug into another connector either way around to
give you about every possible permutation

That's that problem solved for the OP'r

But does that require a mains input? AIUI, OP wants it to run off a 12v
battery.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

In article ,
dg wrote:
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

Certainly possible.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Assuming the voltage is correct, then yes. If size isn't a problem, one of
those car starter packs that are complete with charger would be a very
cheap source of 12 volts - much cheaper than building one.

Is it this simple or would I need some electronics to regulate to
output voltage?

It would depend on the individual item. Some have internal regulation,
some have this in the supplied wall wart.

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

You could build in internal regulators for all the voltages you need -
although you'd have to start out with somewhat higher a voltage than the
highest you require. IC regulators are cheap and require few external
components.

--
*I went to school to become a wit, only got halfway through.

Dave Plowman London SW
To e-mail, change noise into sound.

In message om, Dave
Liquorice writes
On Sat, 28 Aug 2004 22:46:26 GMT, raden wrote:

CPC do an excellent little power supply which comes complete with 8
or 16 connectors which plug into another connector either way around
to give you about every possible permutation

That's that problem solved for the OP'r

Until he takes the device from a device needing 12v tip +ve to a
device needing 3v tip -ve without remembering to change the connector
round...

Ah, the human interface problem

If he does this, he has nobody to blame but himself

--
geoff

In message , Set Square
writes
In an earlier contribution to this discussion,
raden wrote:

In message , Set Square
writes
In an earlier contribution to this discussion,
dg wrote:


It *can* be done, but bear in mind that there are a lot of size
variations in these little concentric plugs which feed the
appliances - so one size definitely *doesn't* fit all. Add to that
the range of voltages required and polarity differences (some have
+ve on the outside and some on the
inside!) - and you need to design a pretty flexible bit of kit!

CPC do an excellent little power supply which comes complete with 8 or
16 connectors which plug into another connector either way around to
give you about every possible permutation

That's that problem solved for the OP'r

But does that require a mains input? AIUI, OP wants it to run off a 12v
battery.

I was pointing him to a source of connectors - I was expecting that he
was useful enough to be able to use a pair of cutters on the lead

--
geoff

In article ,
says...
In article ,
dg wrote:
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

If the unit is designed to run off a mains power supply, then you could
use (eg) a car battery and a 12V to 230V invertor. I do it this way when
"in the field" and need to do things like charge mobile phone, cameras,
Laptop, etc.

Eg. See

http://www.tlc-direct.co.uk/Main_Ind...ers/index.html
snip

Thats an interesting site. I would be utterly at sea in this area but
two things seem interesting.

Firstly they sell a compact USA 110v to UK240v transformer
http://www.tlc-direct.co.uk/Main_Ind...ter/index.html

There are various ratings (100va,300va,500va,) available. Would any of
these be suitable to run things like hair dryers, curling tongs etc.
(For SWMBO, who moans when across the pond that none of her collection
of feminine tools work over there)

And secondly are the ratings on their 12v to 240v inverters a reliable
way of determing their suitability for a particular task. I have in mind
running a microwave on a boat.

As an addendum to this last would 24v to 240v be any different to 12v to
240v ? (The boat has a bank of 12v batteries for the domestics)

What sort of draw would an 800w microwave have on a 12v battery ?



--
Paul Mc Cann

In article ,
Paul Mc Cann wrote:
What sort of draw would an 800w microwave have on a 12v battery ?


Assuming 100% efficiency of the invertor, some 67 amps. But invertors
aren't 100% efficient, so you could add perhaps 20% to that.

A 1000 watt invertor will cost serious money.

--
*A woman drove me to drink and I didn't have the decency to thank her

Dave Plowman London SW
To e-mail, change noise into sound.

raden wrote in message ...
In message , Set Square
writes
In an earlier contribution to this discussion,
raden wrote:

In message , Set Square
writes
In an earlier contribution to this discussion,
dg wrote:


It *can* be done, but bear in mind that there are a lot of size
variations in these little concentric plugs which feed the
appliances - so one size definitely *doesn't* fit all. Add to that
the range of voltages required and polarity differences (some have
+ve on the outside and some on the
inside!) - and you need to design a pretty flexible bit of kit!

CPC do an excellent little power supply which comes complete with 8 or
16 connectors which plug into another connector either way around to
give you about every possible permutation

That's that problem solved for the OP'r

But does that require a mains input? AIUI, OP wants it to run off a 12v
battery.

I was pointing him to a source of connectors - I was expecting that he
was useful enough to be able to use a pair of cutters on the lead

LOL. I looked on their site and noted a multi purpose LiOn battery
pack for £250 !! I thought you meant this.

dg

(Gordon Henderson) wrote in message ...
In article ,
dg wrote:
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

If the unit is designed to run off a mains power supply, then you could
use (eg) a car battery and a 12V to 230V invertor. I do it this way when
"in the field" and need to do things like charge mobile phone, cameras,
Laptop, etc.

Eg. See

http://www.tlc-direct.co.uk/Main_Ind...ers/index.html

I have the basic 150W model. Seems to work fine for my needs.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

It could - IF it's just designed to power the unit.

Is it this simple or would I need some electronics to regulate to
output voltage?

Regulating voltage isn't a problem, but if the units also charge their
(internal, rechargable) batteries then you must be carefull how you
regulate it. NiCd rechargables have different requirements to NiMH for
example. Some devices do have internal regulators and aren't so fussy
though, but it's hard to tell which does and which doesn't, and unless
you are absolutely sure, it's best to not try.

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

I've found it easier to use the invertor, then just plug the devices
standard mains adapters into the invertor to run/charge them.

Gordon

On the subject of inverters, isn't it very inefficient to convert 12v
to 240 v, and then back to say 12v for the appliance?

If say, I wanted to power a laptop this way (mains transformer = 12v
and 4.16A) how long could I expect the car battery to last? Would it
just be better to get a 12v cigar adaptor - or would the current drain
to the car battery be the same either way?

dg

(dg) wrote in message . com...
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

I presume that mains adapters just output the necessary voltage and
current to power the unit, so If I made up a pack consisting of a
number of 1.2v NiCads to acheive the correct output voltage and use
and a standard connector, then this could power the unit?

Is it this simple or would I need some electronics to regulate to
output voltage?

If its not just a case of batteries, box and a connecting lead, any
pointers to suppliers of the necessary kit would be appreciated.

dg

Thanks for all the replies.

I used to have a battery belt for a video camera ( from the days when
they used to be power hungry!), and I was thinking that something
similar would be useful for some of the devices I carry around today.

Something like a few high capacity D cells may be more portable than a
bigger square pack.

An extended runtime 7.4v battery for a TabletPC I have to use for
extended site visits is nearly £100, so I thought why can't I just use
a pack of normal batteries - not quite as glamorous but probably would
keep me going all day.

That got me thinking about the other devices and equipment etc I have
to frequently carry and recharge.

One query regarding amperage - if I did make up a battery pack to
replace the mains adapter, is it the appliance that draws the current
or is it the pack that supplies the current?
ie if the pack supplied say 'x' volts at 5000ma, but the appliance
stated that it used 'x' volts at 4000ma, would this cause a problem or
just mean it would run for longer?

Sorry if thats a bit OT DIY.

dg

dg wrote:

An extended runtime 7.4v battery for a TabletPC I have to use for
extended site visits is nearly £100, so I thought why can't I just use
a pack of normal batteries - not quite as glamorous but probably would
keep me going all day.

You could - although remember the current drain on a tablet PC may be
quite high. Hence running costs on ordinary "dry" (i.e. non
rechargeable) batteries could be high. Some decent (i.e. 4Ah or better)
D cell NiCds or NiMh cells may work out cheaper.

One query regarding amperage - if I did make up a battery pack to
replace the mains adapter, is it the appliance that draws the current
or is it the pack that supplies the current?

Generally the appliance will dictate what current it requires. The
supply simply needs to be able to supply enough.

ie if the pack supplied say 'x' volts at 5000ma, but the appliance
stated that it used 'x' volts at 4000ma, would this cause a problem or
just mean it would run for longer?

No problem - and it will run longer. Batteries are usually given a
capacity rating in either Amp Hours (Ah) or Milli-Amp Hours (mAh). So a
2Ah cell could in theory supply 2A for 1 hour before being exhausted. It
could also do 1 amp for two hours, or perhaps 4 amp for 30 mins.

Sorry if thats a bit OT DIY.

Not OT really...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
dg wrote:
(Gordon Henderson) wrote in message ...

I've found it easier to use the invertor, then just plug the devices
standard mains adapters into the invertor to run/charge them.

Gordon

On the subject of inverters, isn't it very inefficient to convert 12v
to 240 v, and then back to say 12v for the appliance?

If say, I wanted to power a laptop this way (mains transformer = 12v
and 4.16A) how long could I expect the car battery to last? Would it
just be better to get a 12v cigar adaptor - or would the current drain
to the car battery be the same either way?

No, it's not that efficient, but it's convenient - especially if the
appicance requires a regulated external power source to charge internal
batteries. If the appliance comes with a 12V lighter-socket adapter,
then by all means use that instead, but it might be cheaper to use the
invertor than buy lighter-adapters for every bit of kit you want to power.

They aren't that innefficient either, and the one I have claims to switch
off if the voltage drops to below 11V, but I've never been able to run
anything that long to find out.

For battery calculations, you need to know the rated AmpHour capacity. But
note that they are usually stated at a particular amp rating. Eg. a typical
car battery might be 40 Amp Hours at 10 Amps. That means it will last
for 4 hours (down to some set voltage, maybe 10V, I don't know, would
have to check spec.) at a current drain of 10 amps, but it wouldn't last
one hour at 40 amps (usually a lot less!)

So drawing 5 amps, you might expect it to last 8 hours. Most car batteris
will have their rating printed on the labels.

Gordon

In article ,
Paul Mc Cann wrote:
In article ,
says...
In article ,
dg wrote:
Faced with a number of battery operated portable items I wondered if
it was possible to make a battery pack that would plug into the units'
mains adapter socket, to power the item.

If the unit is designed to run off a mains power supply, then you could
use (eg) a car battery and a 12V to 230V invertor. I do it this way when
"in the field" and need to do things like charge mobile phone, cameras,
Laptop, etc.

Eg. See

http://www.tlc-direct.co.uk/Main_Ind...ers/index.html
snip

Thats an interesting site. I would be utterly at sea in this area but
two things seem interesting.

Firstly they sell a compact USA 110v to UK240v transformer
http://www.tlc-direct.co.uk/Main_Ind...ter/index.html

There are various ratings (100va,300va,500va,) available. Would any of
these be suitable to run things like hair dryers, curling tongs etc.
(For SWMBO, who moans when across the pond that none of her collection
of feminine tools work over there)

Sure - one minor difference is the supply hertz - it's 50 here and 60 in
the US. Make sure the transofrmers are capable of handling this. You also
might have a problems with motors too - they'll run a bit faster on 60Hz.

Another problem is weight. A hairdryer might be up to 1KW (or more for
some of the fancier ones these days) A transformer to handle that is
f'ing heavy. I don't fancy putting that into my luggage...

And secondly are the ratings on their 12v to 240v inverters a reliable
way of determing their suitability for a particular task. I have in mind
running a microwave on a boat.

I do a lot of scuba diving, and a lot of the boats these days are moving
away from having gas (cookers) on-board to electrics. There are some nice
12/24V electric boilers and even microwave ovens avalable these days. You
are probably looking at at least a 1KVA model to power a cat. D microwave
though, and these aren't cheap!

Gas is convenient, but LPG is heavier than air, so you have to be totally
paranoid about using it on a boat...

As an addendum to this last would 24v to 240v be any different to 12v to
240v ? (The boat has a bank of 12v batteries for the domestics)

Not really - as long as you bought an invertor with the appropriate
input rating.

What sort of draw would an 800w microwave have on a 12v battery ?

P = I * V, or I = P / V

So 800/12 is 67. This isn't perfect for AC and inductive loads, but but
it's good enough for a rough ball-park.

You are looking at a BIG battery bank and alternator run off the main
engines to keep them charged. (And HEAVY cable to connect them all
together!)

Gordon

Gordon Henderson wrote:

What sort of draw would an 800w microwave have on a 12v battery ?

P = I * V, or I = P / V

So 800/12 is 67. This isn't perfect for AC and inductive loads, but
but it's good enough for a rough ball-park.

Except that 800 W is the _output_ of the magnetron in the microwave oven
and you haven't allowed for efficiency of same in your calculation. The
efficiency's probably about 70% so the input power is going to be
getting on for 1.2 kW. At 100% inverter efficiency that would require
87 A from your battery (at 13.8 V, by the way, not 12 V, if it's on
charge). With a practical inverter efficiency of say 85%, your poor
battery's going have to deliver over 100 A! Forget it and use a primus
stove instead :-)

--
Andy

On 29 Aug 2004 14:19:15 -0700, dg wrote:

If say, I wanted to power a laptop this way (mains transformer = 12v
and 4.16A) how long could I expect the car battery to last?

Quite a long time 12 hrs maybe longer but I doubt that a car battery
would survive this sort of treatment for very long. They are designed
for short high current use and immediate recharge. Not for long slow
discharge to almost nothing.

(Mr Plowman will be along shortly saying his car battery based UPS is
fine thank you very much...)

You should be using a "leisure" battery for deep discharge use. These
are designed to provide all their charged over a period of time and
then be recharged.

--
Cheers
Dave. pam is missing e-mail

In message om, Dave
Liquorice writes
On 29 Aug 2004 14:19:15 -0700, dg wrote:

If say, I wanted to power a laptop this way (mains transformer = 12v
and 4.16A) how long could I expect the car battery to last?

Quite a long time 12 hrs maybe longer but I doubt that a car battery
would survive this sort of treatment for very long. They are designed
for short high current use and immediate recharge. Not for long slow
discharge to almost nothing.

Most laptops run of a higher voltage, e.g. looking at my laptop PSU,
it's 19.6V output


--
geoff

In article om,
Dave Liquorice wrote:
If say, I wanted to power a laptop this way (mains transformer = 12v
and 4.16A) how long could I expect the car battery to last?

Quite a long time 12 hrs maybe longer but I doubt that a car battery
would survive this sort of treatment for very long. They are designed
for short high current use and immediate recharge. Not for long slow
discharge to almost nothing.

(Mr Plowman will be along shortly saying his car battery based UPS is
fine thank you very much...)

Err, no, Mr Liquorice. (gawd we're a polite lot). It's not a UPS as such -
merely an emergency backup for the central heating if we should ever have
a power cut. And it uses my spare car battery, which I wouldn't run
anywhere near flat - if it were a prolonged power cut I'd swap them over
in plenty time.

You should be using a "leisure" battery for deep discharge use. These
are designed to provide all their charged over a period of time and
then be recharged.

If you can be sure you'll not anywhere near fully discharge a car type, it
might just be the cheaper option, given the difference in cost.

--
*I must always remember that I'm unique, just like everyone else. *

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 31 Aug 2004 00:06:50 +0100, Dave Plowman (News) wrote:

(Mr Plowman will be along shortly saying his car battery based UPS
is fine thank you very much...)

Err, no, Mr Liquorice. (gawd we're a polite lot).

It's a "style" thing. B-) I'm sure you've seen me use it before...

It's not a UPS as such - merely an emergency backup for the central
heating if we should ever have a power cut.

Sounds like a UPS to me, thought it had a relay or two to
automatically change over and drop out on low batt volts.

--
Cheers
Dave. pam is missing e-mail

In article om,
Dave Liquorice wrote:
On Tue, 31 Aug 2004 00:06:50 +0100, Dave Plowman (News) wrote:

(Mr Plowman will be along shortly saying his car battery based UPS
is fine thank you very much...)

Err, no, Mr Liquorice. (gawd we're a polite lot).

It's a "style" thing. B-) I'm sure you've seen me use it before...

It's not a UPS as such - merely an emergency backup for the central
heating if we should ever have a power cut.

Sounds like a UPS to me, thought it had a relay or two to
automatically change over and drop out on low batt volts.

I have several UPSs at home and I can run the CH and cooker off them
if required. Very handy things UPSs are.. (Although they are normally
connected to my computer systems, but I know what I'd rather have during
an extended power cut!)

Gordon

In article om,
Dave Liquorice wrote:
It's not a UPS as such - merely an emergency backup for the central
heating if we should ever have a power cut.

Sounds like a UPS to me, thought it had a relay or two to
automatically change over and drop out on low batt volts.

Putting it that way, then yes it is a UPS. Mind you, a UPS has to have the
battery connected to work, and I don't keep the 'spare' in the same room.
;-)

--
*I started out with nothing, and I still have most of it.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Gordon Henderson wrote:
I have several UPSs at home and I can run the CH and cooker off them
if required. Very handy things UPSs are.. (Although they are normally
connected to my computer systems, but I know what I'd rather have during
an extended power cut!)

You can run a cooker off a UPS? Good grief...

--
*If a pig loses its voice, is it disgruntled? *

Dave Plowman London SW
To e-mail, change noise into sound.

On Wed, 01 Sep 2004 09:25:50 +0100, Dave Plowman (News) wrote:

You can run a cooker off a UPS? Good grief...

Well my small APC one will chuck out 700W but not for long about 3 or
4 mins from it's internal 7A/hr batteries. 1.5kVA UPSs aren't that
much more expensive, the limitation is the energy storage, I've
somtimes thought about getting a couple of good sized leisure
batteries for my UPS just to up the runtime, it's calculation of
runtime will be up it but I could live with that.

--
Cheers
Dave. pam is missing e-mail

In article ,
Dave Plowman (News) wrote:
In article ,
Gordon Henderson wrote:
I have several UPSs at home and I can run the CH and cooker off them
if required. Very handy things UPSs are.. (Although they are normally
connected to my computer systems, but I know what I'd rather have during
an extended power cut!)

You can run a cooker off a UPS? Good grief...

It's a gas fired range cooker thing. It has a fan blower thingy to make
it hot quick. (not a fan oven)

Gordon

In article om,
Dave Liquorice wrote:
On Wed, 01 Sep 2004 09:25:50 +0100, Dave Plowman (News) wrote:

You can run a cooker off a UPS? Good grief...

Well my small APC one will chuck out 700W but not for long about 3 or
4 mins from it's internal 7A/hr batteries. 1.5kVA UPSs aren't that
much more expensive, the limitation is the energy storage, I've
somtimes thought about getting a couple of good sized leisure
batteries for my UPS just to up the runtime, it's calculation of
runtime will be up it but I could live with that.

I've used and installed various UPSs over the years (in my IT capacity)
and the general rule seems to be that on a standard unit you'll get 15
miuntes at half load. It's more or less linear at less loads than that
(eg. 30 miuntes at 1/4 load) but more than half load it's non-linear. Down
to 5 or 6 minutes at full load. This seems to be a reasonable general
rules I've seen with different makes (although I prefer APC ones)

Of-course the extended range ones offer more run-time, but ...

Gordon