500w inverter

m8

No idea how to work this out but I was just wondering how long would a fully charged leisure battery run a 15w this LED TV through a 500w inverter?

also could you run a sat receiver as well?

niloc1951

m8 wrote: »

No idea how to work this out but I was just wondering how long would a fully charged leisure battery run a 15w this LED TV through a 500w inverter?

also could you run a sat receiver as well?

All inverters have an efficiency in how they work, the bigger the inverter the more power they use themselves to do the job.
Best advice is to choose the smallest inverter to do the job required, for an 15w tv AND say a sky box which is about 35w a 75w inverter would be more than enough, I would save the 500w for bigger loads.
The length of time a battery will last depends on how big it is and how good a condition it is in, but 15w from a 75w inverter would only be a very small current draw, certainly less than 2 amps per hour (about the same as two halogen internal lights)

m8

niloc1951 wrote: »

All inverters have an efficiency in how they work, the bigger the inverter the more power they use themselves to do the job.
Best advice is to choose the smallest inverter to do the job required, for an 15w tv AND say a sky box which is about 35w a 75w inverter would be more than enough, I would save the 500w for bigger loads.
The length of time a battery will last depends on how big it is and how good a condition it is in, but 15w from a 75w inverter would only be a very small current draw, certainly less than 2 amps per hour (about the same as two halogen internal lights)

Problem is this inverter is already built into my camper but it's good to know it will do the job.

niloc1951

m8 wrote: »

Problem is this inverter is already built into my camper but it's good to know it will do the job.

Running such a large inverter for such a small load is very inefficient use of the battery. The inverter itself will probably consume more power that the tv and sky box.

FWIW I would get one of THESE for the TV & Box (use a double adapter), it will also have many uses elsewhere too.

*Kol*

m8 wrote: »

No idea how to work this out but I was just wondering how long would a fully charged leisure battery run a 15w this LED TV through a 500w inverter?

also could you run a sat receiver as well?

Did you check if that TV uses a 12V transformer? If it does it could be run straight off the battery.

Get a 12volt tv.

Just to run that invertor you're using;
500 watts @ 12v = 41.67amps
P(ower)/V(olts) = I (current)

2 and a half hours on a 100ah battery
factor in the 20% power loss due to the invertor; 2 hours
with the invertor cut off at battery depletion to 25% charge; 1 and a half hours. You may get more as these are maximum values but not very long.

Some invertors have adjustable output to reduced inefficency at low loading but these are usually around the >1500w mark.

Recommended guideline for a 500w invertor is at least 220ah.
Rapid depletion of your batterys will damage them.

The tv itself only uses 0.7amp

If the tv has a transformer you could see if a variable 12v transformer is compatible.
something like this
http://www.maplin.co.uk/120w-laptop-car-adaptor-44736
It will say on the transformer what the output voltage and current is.
You need to match the voltage (meter it! there is margin for error in cheap electronics) and slightly exceed the current.

niloc1951

Sir Liamalot wrote: »

Get a 12volt tv.

Just to run that invertor you're using;
500 watts @ 12v = 41.67amps
P(ower)/V(olts) = I (current)

2 and a half hours on a 100ah battery
factor in the 20% power loss due to the invertor; 2 hours
with the invertor cut off at battery depletion to 25% charge; 1 and a half hours. You may get more as these are maximum values but not very long..............................

:eek::eek::eek::eek::eek:

What you say is sort of correct only if drawing the full load of 500w.

If only drawing say 18w @220v the draw from the battery will be 18w divided by 12v = 1.5 ah, plus the insufficiency of the inverter

Remember the wattage is the power requirement of an appliance, the number of Amps/Hours (ah) it uses is determined by the voltage at which the power is supplied over one hour of running.
Therefore looking at an appliance which requires say 24 watts.
If this power is supplied at 12 volts it will consume 2 amps from the source of supply (a 12 volt battery) in one hour
If the power is supplied at 230 volts it will consume 0.1 amps from the source of supply (a mains connection) in one hour

Looking at the example of running a typical 800 watt toaster via an inverter from a 12 volt source of supply.
To estimate the impact it will have on your battery you can forget about the fact that there is an inverter in the equation changing the voltage , simply divide the 800 watts by 12 (the voltage of the power source, the battery) which will give a figure of 66.66 ah put simple the toaster will take 66.66 amps out of your battery if used for an hour, or for example an 2,200 watt electric kettle will take 183 amps over an hour.

So, going back to a 15 watt tv, it will have only a small impact on the battery whether it's fed with 12v direct or 230v via an inverter. it's just that the inverter itself will also use some power to change the voltage.


An inverter in the equation adds in its own power requirement due to its own efferts to do the conversion, the more expensive ones are more efficient than cheap ones so they 'knobble' less of your precious battery reserves.
Also bigger inverters can be more power hungry themselves as the have heavier kit which usually include cooling fans to handle the bigger loads.

In summery, if possible try power light load stuff (tv's, laptops, chargers etc.) without using a mains inverter, but if the only option is 230v use the smallest inverter which will do the job without being overloaded.

kelbal

Hi. I'm in the same boat. I want to run my TV and Sat box off the leisure battery
The sat box says 'max 20w' on the back.
The TV has a transformer, like a laptop. Says "Input: 100-240v @1.8A. Output: 12v @ 5A"
So what way would the TV draw less from the battery, using the transformer and connecting to an inverter - or connecting the Tv direct to the 12v port? (Would have to get a new cable for this).
I guess I have 2 solutions:

(1) Connect a 150w inverter (that enough?) to the 12v port. Stick a double adapter on it, and connect the TV (with transformer) and Sat box

(2) Get a 12v 'cigarette' splitter, one connection goes straight to the TV. The other goes via a small inverter to the sat box, an inverter like this....

http://www.ebay.ie/itm/Ring-MP75-12v-Car-power-socket-240v-AC-UK-plug-75-Watt-Mini-Inverter-RINV75-/290655637854?pt=UK_MobilePhones_MobilePhoneAccessories_MobilePhoneChargers&hash=item43ac6d115e#ht_2433wt_1037

Which solution sounds best? Sorry for rambling on, would really appreciate the advice

paddyp

kelbal wrote: »

Hi. I'm in the same boat. I want to run my TV and Sat box off the leisure battery
The sat box says 'max 20w' on the back.
The TV has a transformer, like a laptop. Says "Input: 100-240v @1.8A. Output: 12v @ 5A"
So what way would the TV draw less from the battery, using the transformer and connecting to an inverter - or connecting the Tv direct to the 12v port? (Would have to get a new cable for this).
I guess I have 2 solutions:

(1) Connect a 150w inverter (that enough?) to the 12v port. Stick a double adapter on it, and connect the TV (with transformer) and Sat box

(2) Get a 12v 'cigarette' splitter, one connection goes straight to the TV. The other goes via a small inverter to the sat box, an inverter like this....

http://www.ebay.ie/itm/Ring-MP75-12v-Car-power-socket-240v-AC-UK-plug-75-Watt-Mini-Inverter-RINV75-/290655637854?pt=UK_MobilePhones_MobilePhoneAccessories_MobilePhoneChargers&hash=item43ac6d115e#ht_2433wt_1037

Which solution sounds best? Sorry for rambling on, would really appreciate the advice

First of all that ring 75w inverter is rated 75w for two minutes, the continuous rating is 50w so its too small.

TV adapter can provide 60W (12V x 5A) probably has an efficiency of between 70 and 90% so could draw 67W-85W from the inverter. Satellite box could draw 22w-28w. so worst case you're probably talking 113W so a 150w inverter. It may draw much less overall measuring.

Of course its more efficient to power the TV direct from the battery because you don't have the losses in the inverter and power adapter probably of the order of 20%-60%. The TV may not like the high voltages present when the engine is running though although I'd be surprised if there was a problem. There a bigger chance that the tv power adapter won't like the vaguely sinusoidal harmonic and noise ridden signal from the cheapie inverter.

kelbal

paddyp wrote: »

First of all that ring 75w inverter is rated 75w for two minutes, the continuous rating is 50w so its too small.

TV adapter can provide 60W (12V x 5A) probably has an efficiency of between 70 and 90% so could draw 67W-85W from the inverter. Satellite box could draw 22w-28w. so worst case you're probably talking 113W so a 150w inverter. It may draw much less overall measuring.

Of course its more efficient to power the TV direct from the battery because you don't have the losses in the inverter and power adapter probably of the order of 20%-60%. The TV may not like the high voltages present when the engine is running though although I'd be surprised if there was a problem. There a bigger chance that the tv power adapter won't like the vaguely sinusoidal harmonic and noise ridden signal from the cheapie inverter.

Thanks Paddyp.
Think what I might try is to split the 12v port with this...
http://www.aldi.ie/ie/html/offers/special_buys3_21797.htm

Then do a direct connection to the TV with this....
http://www.ebay.ie/itm/12V-LED-and-LCD-TV-cigarette-lighter-adapter-lead-/150804844522?pt=UK_Sound_Vision_Other&hash=item231cab4fea#ht_1175wt_1270

And connect that other 75w inverter thing to another 12v port for the sat box which need 20-28w.
That sound ok?!!

paddyp

kelbal wrote: »

Thanks Paddyp.
Think what I might try is to split the 12v port with this...
http://www.aldi.ie/ie/html/offers/special_buys3_21797.htm

Then do a direct connection to the TV with this....
http://www.ebay.ie/itm/12V-LED-and-LCD-TV-cigarette-lighter-adapter-lead-/150804844522?pt=UK_Sound_Vision_Other&hash=item231cab4fea#ht_1175wt_1270

And connect that other 75w inverter thing to another 12v port for the sat box which need 20-28w.
That sound ok?!!

That aldi splitter is only rated 5A.

kelbal

paddyp wrote: »

That aldi splitter is only rated 5A.

where do you see that in the ad?
Can I get one thats higher rated? How would I know I'm getting the right one?

thanks