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UK Caravanning (uk.rec.caravanning) A forum for the discussion of caravanning undertaken by residents of the United Kingdom, whether in the UK or abroad. It encourages the interchange of views on the merits of models of caravan, makes of tow car, accessories, caravan sites, caravan clubs, and other related topics. The term caravan is to include trailer vans, motor caravans and trailer tents.

Inverter



 
 
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  #1 (permalink)  
Old July 26th 11, 11:31 AM posted to uk.rec.caravanning
ForeverArsenal
external usenet poster
 
Posts: 61
Default Inverter

Hi.
Hope someone can help me help someone else.

Have a friend (oap) who is going to a non hook up
site in Scotland in 2 weeks time.

Asked me the following but not clever enough to help
him with the answer.

Has 75 AH battery and wants to connect a 12volt to 300 watt inverter
to it to run his TV/FREEVIEW box.

He has worked out the wattage of the two items to be approx
50 watts drain.
So can anyone work out how many hrs the battery would
last before needing to be re-charged please.

Also would he be better off getting a smaller inverter,say 200 watts?.

Baz.
--
The more people I meet.
The more I love my dog.


Ads
  #2 (permalink)  
Old July 26th 11, 01:52 PM posted to uk.rec.caravanning
Long tall ugly
external usenet poster
 
Posts: 158
Default Inverter

On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.

Have a friend (oap) who is going to a non hook up
site in Scotland in 2 weeks time.

Asked me the following but not clever enough to help
him with the answer.

Has 75 AH battery and wants to connect a 12volt to 300 watt inverter
to it to run his TV/FREEVIEW box.

He has worked out the wattage of the two items to be approx
50 watts drain.
So can anyone work out how many hrs the battery would
last before needing to be re-charged please.

Also would he be better off getting a smaller inverter,say 200 watts?.

Baz.



As far as I recolect...

Watts= amp X volt therefore 50/12 = 4.17amps

75/4.17 = 17.98 hours.(this is a mathmatical solution which , in
reality , has little bearing on the REAL situation

BUT....

Battery must be in A1 condition AND as the battery runs low so will
the voltage and therefor not able to run TV/freeview after a certain
threshold + other lights etc in van.

may be able for 10 hours say.....

John

what doeseverybody else think
  #3 (permalink)  
Old July 26th 11, 02:02 PM posted to uk.rec.caravanning
bill lord
external usenet poster
 
Posts: 2,533
Default Inverter

On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.

Have a friend (oap) who is going to a non hook up
site in Scotland in 2 weeks time.

Asked me the following but not clever enough to help
him with the answer.

Has 75 AH battery and wants to connect a 12volt to 300 watt inverter
to it to run his TV/FREEVIEW box.

He has worked out the wattage of the two items to be approx
50 watts drain.
So can anyone work out how many hrs the battery would
last before needing to be re-charged please.

Also would he be better off getting a smaller inverter,say 200 watts?.

Baz.


he would be better off finding a TV that will run off 12v directly.
Many modern flat screen tv's have a separate power supply which is
usually 12v, so if he has a look he might well find that with a little
work to sort the correct lead out he can connect it directly.

I find that using a 110amp battery in summer for all normal caravan
functions plus a couple of hours TV direct each night that I can
manage at least 4 days and frequently longe,r but I do not like
cmpletely draining the battery, before I need to recharge. However
using an inverter to run the TV would probably cut this down to no
more than 3 days. as an aside I have never had a lot of success using
an inverter to run 240v devices from my inverter, it is fine for
charging batteries but does not seem to do a good job on anything
else.
Bill Lord
I've taken a vow of poverty To annoy me send money

e-mail messages to bill dot lord at tunshill dot co dot uk
( Get rid of the spaces and use symbols for the hyphen at and dots )
  #4 (permalink)  
Old July 26th 11, 07:11 PM posted to uk.rec.caravanning
ForeverArsenal
external usenet poster
 
Posts: 61
Default Inverter


"Long tall ugly" wrote in message
...
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.


Hi John.

Many thanks for the reply.I have printer your reply
and will give to my friend.


Baz.


As far as I recolect...
Watts= amp X volt therefore 50/12 = 4.17amps

75/4.17 = 17.98 hours.(this is a mathmatical solution which , in
reality , has little bearing on the REAL situation

BUT....

Battery must be in A1 condition AND as the battery runs low so will
the voltage and therefor not able to run TV/freeview after a certain
threshold + other lights etc in van.

may be able for 10 hours say.....

John

what doeseverybody else think



  #5 (permalink)  
Old July 26th 11, 07:16 PM posted to uk.rec.caravanning
ForeverArsenal
external usenet poster
 
Posts: 61
Default Inverter


"bill lord" wrote in message
...
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:


he would be better off finding a TV that will run off 12v directly.
Many modern flat screen tv's have a separate power supply which is
usually 12v, so if he has a look he might well find that with a little
work to sort the correct lead out he can connect it directly.


Hi Bill, thanks for the reply.
Thinks this is a one time visit to non hook up site as
he only goes away approx 3 times a year and normally
goes on hook up so don't think he would want to change tv.

Thanks for imput.
Baz


  #6 (permalink)  
Old July 27th 11, 09:02 AM posted to uk.rec.caravanning
Roger Mills[_2_]
external usenet poster
 
Posts: 38
Default Inverter

On 26/07/2011 14:52, Long tall ugly wrote:
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.

Have a friend (oap) who is going to a non hook up
site in Scotland in 2 weeks time.

Asked me the following but not clever enough to help
him with the answer.

Has 75 AH battery and wants to connect a 12volt to 300 watt inverter
to it to run his TV/FREEVIEW box.

He has worked out the wattage of the two items to be approx
50 watts drain.
So can anyone work out how many hrs the battery would
last before needing to be re-charged please.

Also would he be better off getting a smaller inverter,say 200 watts?.

Baz.



As far as I recolect...

Watts= amp X volt therefore 50/12 = 4.17amps

75/4.17 = 17.98 hours.(this is a mathmatical solution which , in
reality , has little bearing on the REAL situation

BUT....

Battery must be in A1 condition AND as the battery runs low so will
the voltage and therefor not able to run TV/freeview after a certain
threshold + other lights etc in van.

may be able for 10 hours say.....

John

what doeseverybody else think


That sounds reasonable. But you also have to consider *other* demands on
the battery (lights, water pump, toilet flush, etc.) which will use some
of the capacity and leave less for the TV and Freeview box.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.
  #7 (permalink)  
Old July 27th 11, 10:30 AM posted to uk.rec.caravanning
bill lord
external usenet poster
 
Posts: 2,533
Default Inverter

On Tue, 26 Jul 2011 20:16:48 +0100, "ForeverArsenal"
wrote:


"bill lord" wrote in message
.. .
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:


he would be better off finding a TV that will run off 12v directly.
Many modern flat screen tv's have a separate power supply which is
usually 12v, so if he has a look he might well find that with a little
work to sort the correct lead out he can connect it directly.


Hi Bill, thanks for the reply.
Thinks this is a one time visit to non hook up site as
he only goes away approx 3 times a year and normally
goes on hook up so don't think he would want to change tv.

Thanks for imput.
Baz


With a 75amp battery and using an inverter to power a televison for
three hours or so a night I would not expect to manage more than a day
without having to charge the battery, The voltage would drop too
rapidly to power the inverter.

Bill Lord
I've taken a vow of poverty To annoy me send money

e-mail messages to bill dot lord at tunshill dot co dot uk
( Get rid of the spaces and use symbols for the hyphen at and dots )
  #8 (permalink)  
Old July 27th 11, 01:22 PM posted to uk.rec.caravanning
hugh
external usenet poster
 
Posts: 1,616
Default Inverter

In message ,
ForeverArsenal writes

"Long tall ugly" wrote in message
.. .
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.


Hi John.

Many thanks for the reply.I have printer your reply
and will give to my friend.


Baz.


As far as I recolect...
Watts= amp X volt therefore 50/12 = 4.17amps

75/4.17 = 17.98 hours.(this is a mathmatical solution which , in
reality , has little bearing on the REAL situation

BUT....

Battery must be in A1 condition AND as the battery runs low so will
the voltage and therefor not able to run TV/freeview after a certain
threshold + other lights etc in van.

may be able for 10 hours say.....

John

what doeseverybody else think



The TV and box will have a wattage rating on them, so the total gives
the power output from the inverter. However inverters are about 80%
efficient (IIRC) so the actual draw from the battery will be greater.
The total power rating of the inverter is otherwise not important as it
will only supply the power required at its output.

I think 10 hours is maybe a bit optimistic but the only way to find out
is suck it and see - preferably not on a dark winter's night - as
batteries do vary according to age and usage.
Would recommend that he carries a spare battery and arranges a suitable
carrying and charging facility in the boot of his car.
--
hugh
  #9 (permalink)  
Old July 27th 11, 01:27 PM posted to uk.rec.caravanning
hugh
external usenet poster
 
Posts: 1,616
Default Inverter

In message , bill lord
writes
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.

Have a friend (oap) who is going to a non hook up
site in Scotland in 2 weeks time.

Asked me the following but not clever enough to help
him with the answer.

Has 75 AH battery and wants to connect a 12volt to 300 watt inverter
to it to run his TV/FREEVIEW box.

He has worked out the wattage of the two items to be approx
50 watts drain.
So can anyone work out how many hrs the battery would
last before needing to be re-charged please.

Also would he be better off getting a smaller inverter,say 200 watts?.

Baz.


he would be better off finding a TV that will run off 12v directly.
Many modern flat screen tv's have a separate power supply which is
usually 12v, so if he has a look he might well find that with a little
work to sort the correct lead out he can connect it directly.

Been lots of discussion/arguments on this in the past on using a normal
domestic TV in this way so I don't intend to re-open this particular
debate
I find that using a 110amp battery in summer for all normal caravan
functions plus a couple of hours TV direct each night that I can
manage at least 4 days and frequently longe,r but I do not like
cmpletely draining the battery, before I need to recharge. However
using an inverter to run the TV would probably cut this down to no
more than 3 days. as an aside I have never had a lot of success using
an inverter to run 240v devices from my inverter, it is fine for
charging batteries but does not seem to do a good job on anything
else.

Depends on the quality of the inverter and how close to a sine wave the
output is.


--
hugh
  #10 (permalink)  
Old July 27th 11, 02:28 PM posted to uk.rec.caravanning
bill lord
external usenet poster
 
Posts: 2,533
Default Inverter

On Wed, 27 Jul 2011 14:27:23 +0100, hugh ] wrote:

In message , bill lord
writes
On Tue, 26 Jul 2011 12:31:30 +0100, "ForeverArsenal"
wrote:

Hi.
Hope someone can help me help someone else.

Have a friend (oap) who is going to a non hook up
site in Scotland in 2 weeks time.

Asked me the following but not clever enough to help
him with the answer.

Has 75 AH battery and wants to connect a 12volt to 300 watt inverter
to it to run his TV/FREEVIEW box.

He has worked out the wattage of the two items to be approx
50 watts drain.
So can anyone work out how many hrs the battery would
last before needing to be re-charged please.

Also would he be better off getting a smaller inverter,say 200 watts?.

Baz.


he would be better off finding a TV that will run off 12v directly.
Many modern flat screen tv's have a separate power supply which is
usually 12v, so if he has a look he might well find that with a little
work to sort the correct lead out he can connect it directly.

Been lots of discussion/arguments on this in the past on using a normal
domestic TV in this way so I don't intend to re-open this particular
debate


You just did. :-) It works for me

I find that using a 110amp battery in summer for all normal caravan
functions plus a couple of hours TV direct each night that I can
manage at least 4 days and frequently longe,r but I do not like
cmpletely draining the battery, before I need to recharge. However
using an inverter to run the TV would probably cut this down to no
more than 3 days. as an aside I have never had a lot of success using
an inverter to run 240v devices from my inverter, it is fine for
charging batteries but does not seem to do a good job on anything
else.

Depends on the quality of the inverter and how close to a sine wave the
output is.


I would agree however the vast majority of reasonably affordable
inverters are not particularly close to a sine wave which is the
problem that the OP is likely to face. In general the best advice
would be to try it before you go and see just how long the battery
coupled to the inverter running a TV works.
Bill Lord
I've taken a vow of poverty To annoy me send money

e-mail messages to bill dot lord at tunshill dot co dot uk
( Get rid of the spaces and use symbols for the hyphen at and dots )
 



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