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Inverter & Leisure Battery Problem.



 
 
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  #1 (permalink)  
Old September 26th 09, 07:54 PM posted to uk.rec.caravanning
Dave[_15_]
external usenet poster
 
Posts: 8
Default Inverter & Leisure Battery Problem.

Hi and thanks for reading this. I have two inverters, 150W & 350W and use
an 85aH Leisure battery. The load is a notebook computer and small fretsaw.
Both are rated at 240v MAX 1amp each. Im getting a maximum of 2 hours use
before the battery goes down. Its the same whichever inverter I am using.
Is this usage usual ? Some years ago I used a standard car battery with a
television running at more than 2 amps (240v) and got well over 5-6 hours
use. Sometimes over 8 hours. What can I realistically expect from an
inverter and leisure battery ? Or is it back to the generator ?
Thanks in anticipation
Dave


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  #2 (permalink)  
Old September 26th 09, 08:33 PM posted to uk.rec.caravanning
METWO
external usenet poster
 
Posts: 56
Default Inverter & Leisure Battery Problem.

"Dave" wrote in message
...
Hi and thanks for reading this. I have two inverters, 150W & 350W and use
an 85aH Leisure battery. The load is a notebook computer and small
fretsaw. Both are rated at 240v MAX 1amp each. Im getting a maximum of 2
hours use before the battery goes down. Its the same whichever inverter I
am using. Is this usage usual ? Some years ago I used a standard car
battery with a television running at more than 2 amps (240v) and got well
over 5-6 hours use. Sometimes over 8 hours. What can I realistically
expect from an inverter and leisure battery ? Or is it back to the
generator ?
Thanks in anticipation
Dave


Don't forget Inverters are not very efficient but 2 hrs is a bit low, but is
the
battery ok, and fully charged up?

metwo

  #3 (permalink)  
Old September 26th 09, 08:56 PM posted to uk.rec.caravanning
hugh
external usenet poster
 
Posts: 1,616
Default Inverter & Leisure Battery Problem.

In message , Dave
writes
Hi and thanks for reading this. I have two inverters, 150W & 350W and use
an 85aH Leisure battery. The load is a notebook computer and small fretsaw.
Both are rated at 240v MAX 1amp each. Im getting a maximum of 2 hours use
before the battery goes down. Its the same whichever inverter I am using.
Is this usage usual ? Some years ago I used a standard car battery with a
television running at more than 2 amps (240v) and got well over 5-6 hours
use. Sometimes over 8 hours. What can I realistically expect from an
inverter and leisure battery ? Or is it back to the generator ?
Thanks in anticipation
Dave


1 amp at 240v is the equivalent of 20 amps at 12v plus of course the
inefficiency of the inverter if my maths is correct.
--
hugh
It may be more complicated but is it better?

  #4 (permalink)  
Old September 26th 09, 09:26 PM posted to uk.rec.caravanning
Dave[_15_]
external usenet poster
 
Posts: 8
Default Inverter & Leisure Battery Problem.


"METWO" wrote in message
...
"Dave" wrote in message
...
Hi and thanks for reading this. I have two inverters, 150W & 350W and
use an 85aH Leisure battery. The load is a notebook computer and small
fretsaw. Both are rated at 240v MAX 1amp each. Im getting a maximum of 2
hours use before the battery goes down. Its the same whichever inverter I
am using. Is this usage usual ? Some years ago I used a standard car
battery with a television running at more than 2 amps (240v) and got well
over 5-6 hours use. Sometimes over 8 hours. What can I realistically
expect from an inverter and leisure battery ? Or is it back to the
generator ?
Thanks in anticipation
Dave


Don't forget Inverters are not very efficient but 2 hrs is a bit low, but
is the
battery ok, and fully charged up?

metwo

Well the battery is brand new and has been charged 3 times both at 'low
charge' and 'high charge' levels. It's the same whichever charge level is
in use. It's just that talking to some caravanners I get the impression
that they use a leisure battery for all their power at night with lights,
TV's and computers for at least 4-5 hours.
Dave


  #5 (permalink)  
Old September 26th 09, 09:35 PM posted to uk.rec.caravanning
Dave[_15_]
external usenet poster
 
Posts: 8
Default Inverter & Leisure Battery Problem.


"hugh" ] wrote in message
...
In message , Dave
writes
Hi and thanks for reading this. I have two inverters, 150W & 350W and use
an 85aH Leisure battery. The load is a notebook computer and small
fretsaw.
Both are rated at 240v MAX 1amp each. Im getting a maximum of 2 hours use
before the battery goes down. Its the same whichever inverter I am using.
Is this usage usual ? Some years ago I used a standard car battery with
a
television running at more than 2 amps (240v) and got well over 5-6 hours
use. Sometimes over 8 hours. What can I realistically expect from an
inverter and leisure battery ? Or is it back to the generator ?
Thanks in anticipation
Dave


1 amp at 240v is the equivalent of 20 amps at 12v plus of course the
inefficiency of the inverter if my maths is correct.
--

I am aware that inverters have only about 80% efficiency. However my
smaller inverter is only 150 watt.
Using the formula Volts x Amps = Watts where Watts is 150 and Volts is 240
the current used would be about 0.75 Amp. Is my maths wrong ? Even if my
inverter is supplying 300 Watts and efficiency at 80% there is still a big
difference between what I think I should be getting and what I am getting.
Maybe someone out there can tell me where I am going wrong.
Dave


  #6 (permalink)  
Old September 26th 09, 10:20 PM posted to uk.rec.caravanning
John Bridge
external usenet poster
 
Posts: 12
Default Inverter & Leisure Battery Problem.


"Dave" wrote in message
...

"hugh" ] wrote in message
...
In message , Dave
writes
Hi and thanks for reading this. I have two inverters, 150W & 350W and
use
an 85aH Leisure battery. The load is a notebook computer and small
fretsaw.
Both are rated at 240v MAX 1amp each. Im getting a maximum of 2 hours
use
before the battery goes down. Its the same whichever inverter I am using.
Is this usage usual ? Some years ago I used a standard car battery with
a
television running at more than 2 amps (240v) and got well over 5-6 hours
use. Sometimes over 8 hours. What can I realistically expect from an
inverter and leisure battery ? Or is it back to the generator ?
Thanks in anticipation
Dave


1 amp at 240v is the equivalent of 20 amps at 12v plus of course the
inefficiency of the inverter if my maths is correct.
--

I am aware that inverters have only about 80% efficiency. However my
smaller inverter is only 150 watt.
Using the formula Volts x Amps = Watts where Watts is 150 and Volts is
240 the current used would be about 0.75 Amp. Is my maths wrong ? Even
if my inverter is supplying 300 Watts and efficiency at 80% there is still
a big difference between what I think I should be getting and what I am
getting. Maybe someone out there can tell me where I am going wrong.
Dave

An invertor uses 1amp for every 10 watts it produces from a 12volt input so
your 150 watt invertor will use 15 amps to give it's maximum output of 150
watts, likewise your 300 watt would consume 30 watts at it's maximum output.
If your notebook does take 1 amp at 240 volt then it is using 240 watt, I
doubt that the notebook would need that much power. Are you extending the
leads that feed the 12 volts to the invertor as these need to be as short as
possible and fairly thick to carry the amps at 12 volt.



__________ Information from ESET Smart Security, version of virus signature database 4460 (20090926) __________

The message was checked by ESET Smart Security.

http://www.eset.com




  #7 (permalink)  
Old September 26th 09, 10:26 PM posted to uk.rec.caravanning
DieSea
external usenet poster
 
Posts: 508
Default Inverter & Leisure Battery Problem.


"Dave" wrote in message
...

"METWO" wrote in message
...
"Dave" wrote in message
...
Hi and thanks for reading this. I have two inverters, 150W & 350W and use an
85aH Leisure battery. The load is a notebook computer and small fretsaw. Both
are rated at 240v MAX 1amp each. Im getting a maximum of 2 hours use before
the battery goes down. Its the same whichever inverter I am using. Is this
usage usual ? Some years ago I used a standard car battery with a television
running at more than 2 amps (240v) and got well over 5-6 hours use. Sometimes
over 8 hours. What can I realistically expect from an inverter and leisure
battery ? Or is it back to the generator ?
Thanks in anticipation
Dave


Don't forget Inverters are not very efficient but 2 hrs is a bit low, but is
the
battery ok, and fully charged up?

metwo

Well the battery is brand new and has been charged 3 times both at 'low charge'
and 'high charge' levels. It's the same whichever charge level is in use. It's
just that talking to some caravanners I get the impression that they use a
leisure battery for all their power at night with lights, TV's and computers for
at least 4-5 hours.
Dave


Could the lights be operating on 12v

And

I'm now running an ASUS netbook for the van

Roughly 7 hours when fully charged

There is a 12v / 24v cigar lighter unit that will run and charge the box

Recon the 3G dongle is a waste of brass ( and that's being polite )

The Voda dongle works but's not much better

DieSea


  #8 (permalink)  
Old September 27th 09, 06:53 AM posted to uk.rec.caravanning
Woody[_3_]
external usenet poster
 
Posts: 146
Default Inverter & Leisure Battery Problem.

"John Bridge" wrote in message
...

"Dave" wrote in message
...

"hugh" ] wrote in message
...
In message , Dave
writes
Hi and thanks for reading this. I have two inverters, 150W &
350W and use
an 85aH Leisure battery. The load is a notebook computer and
small fretsaw.
Both are rated at 240v MAX 1amp each. Im getting a maximum
of 2 hours use
before the battery goes down. Its the same whichever inverter
I am using.
Is this usage usual ? Some years ago I used a standard car
battery with a
television running at more than 2 amps (240v) and got well
over 5-6 hours
use. Sometimes over 8 hours. What can I realistically expect
from an
inverter and leisure battery ? Or is it back to the
generator ?
Thanks in anticipation
Dave


1 amp at 240v is the equivalent of 20 amps at 12v plus of
course the inefficiency of the inverter if my maths is
correct.
--

I am aware that inverters have only about 80% efficiency.
However my smaller inverter is only 150 watt.
Using the formula Volts x Amps = Watts where Watts is 150 and
Volts is 240 the current used would be about 0.75 Amp. Is my
maths wrong ? Even if my inverter is supplying 300 Watts and
efficiency at 80% there is still a big difference between what
I think I should be getting and what I am getting. Maybe
someone out there can tell me where I am going wrong.
Dave

An invertor uses 1amp for every 10 watts it produces from a
12volt input so your 150 watt invertor will use 15 amps to give
it's maximum output of 150 watts, likewise your 300 watt would
consume 30 watts at it's maximum output. If your notebook does
take 1 amp at 240 volt then it is using 240 watt, I doubt that
the notebook would need that much power. Are you extending the
leads that feed the 12 volts to the invertor as these need to
be as short as possible and fairly thick to carry the amps at
12 volt.



The invertors may be rated 150 and 300W, but the power consumed
will only be that of the item connected to them less efficiences,
not 150/300 all the time.


--
Woody

harrogate three at ntlworld dot com


  #9 (permalink)  
Old September 27th 09, 08:54 AM posted to uk.rec.caravanning
Dave[_15_]
external usenet poster
 
Posts: 8
Default Inverter & Leisure Battery Problem.


"DieSea" wrote in message
...

"Dave" wrote in message
...

"METWO" wrote in message
...
"Dave" wrote in message
...
Hi and thanks for reading this. I have two inverters, 150W & 350W and
use an 85aH Leisure battery. The load is a notebook computer and small
fretsaw. Both are rated at 240v MAX 1amp each. Im getting a maximum of
2 hours use before the battery goes down. Its the same whichever
inverter I am using. Is this usage usual ? Some years ago I used a
standard car battery with a television running at more than 2 amps
(240v) and got well over 5-6 hours use. Sometimes over 8 hours. What
can I realistically expect from an inverter and leisure battery ? Or
is it back to the generator ?
Thanks in anticipation
Dave


Don't forget Inverters are not very efficient but 2 hrs is a bit low,
but is the
battery ok, and fully charged up?

metwo

Well the battery is brand new and has been charged 3 times both at 'low
charge' and 'high charge' levels. It's the same whichever charge level
is in use. It's just that talking to some caravanners I get the
impression that they use a leisure battery for all their power at night
with lights, TV's and computers for at least 4-5 hours.
Dave


Could the lights be operating on 12v

And

I'm now running an ASUS netbook for the van

Roughly 7 hours when fully charged

There is a 12v / 24v cigar lighter unit that will run and charge the box

Recon the 3G dongle is a waste of brass ( and that's being polite )

The Voda dongle works but's not much better

DieSea

Yes many do but I have spoken to some who certainly run off mains inverter.
Dave


  #10 (permalink)  
Old September 27th 09, 09:01 AM posted to uk.rec.caravanning
Dave[_15_]
external usenet poster
 
Posts: 8
Default Inverter & Leisure Battery Problem.


"DieSea" wrote in message
...

"Dave" wrote in message
...

"METWO" wrote in message
...
"Dave" wrote in message
...
Hi and thanks for reading this. I have two inverters, 150W & 350W and
use an 85aH Leisure battery. The load is a notebook computer and small
fretsaw. Both are rated at 240v MAX 1amp each. Im getting a maximum of
2 hours use before the battery goes down. Its the same whichever
inverter I am using. Is this usage usual ? Some years ago I used a
standard car battery with a television running at more than 2 amps
(240v) and got well over 5-6 hours use. Sometimes over 8 hours. What
can I realistically expect from an inverter and leisure battery ? Or
is it back to the generator ?
Thanks in anticipation
Dave


Don't forget Inverters are not very efficient but 2 hrs is a bit low,
but is the
battery ok, and fully charged up?

metwo

Well the battery is brand new and has been charged 3 times both at 'low
charge' and 'high charge' levels. It's the same whichever charge level
is in use. It's just that talking to some caravanners I get the
impression that they use a leisure battery for all their power at night
with lights, TV's and computers for at least 4-5 hours.
Dave


Could the lights be operating on 12v

And

I'm now running an ASUS netbook for the van

Roughly 7 hours when fully charged

There is a 12v / 24v cigar lighter unit that will run and charge the box

Recon the 3G dongle is a waste of brass ( and that's being polite )

The Voda dongle works but's not much better

DieSea

Just to clarify I am running an (ageing) Dell which says on the power supply
230V @ 1A and a fretsaw which is the same. I was taling to a guy in the
summer who runs a PC and printer using a 3kW (Yep) inverter and he reckons
on getting 'several days use'. He uses his for business around 8 hours a
day. I know people tell porky's but the general opinion of people I have
talked to is that I am not getting long enoug. I though it might be the
charger unit. Is there any way of giving these batteries a test such as
putting a (say 1A) load on and seeing just how long it does last. Would
such a test tell me anything anyway ?
Dave


 



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