television power usage

[cessac]

Can anyone help me work out how much power my tv is using . I have a 120 hr leisure battery , which was showing fully charged , we watched for just under 2 hours & a message came up saying the Voltage was low . We turned the tv off , fine , but there was no problem with lights etc . SOOOOOOOO why does my tv get stressed when everything else is fine ?
plate on the back says " consommuation DC12v 36 W .But is it more if I use the built in DVD player ?

Cheers Tony

 

[Two on Tour]

DC12v 36 W = 3amps, so I would be more inclined to look to your leisure battery being on the way out maybe.

 

[Shrimp]

Yes DVD takes more.
If we are a bit short of Solar we use the Firestick more as it takes less than our Dome (dish).

 

[monzer]

Is the message coming up on the TV screen? Could be voltage drop. How far is your TV from your power source?

I have that problem with my TV. It's ok during the day with solar going in but at night there is too much voltage drop and the TV will cut off if it falls below 11v.

Annoying but I haven't got round to running a bigger cable in to sort the problem.

 

[Hoovie]

Can anyone help me work out how much power my tv is using . I have a 120 hr leisure battery , which was showing fully charged , we watched for just under 2 hours & a message came up saying the Voltage was low . We turned the tv off , fine , but there was no problem with lights etc . SOOOOOOOO why does my tv get stressed when everything else is fine ?
plate on the back says " consommuation DC12v 36 W .But is it more if I use the built in DVD player ?

Cheers Tony

36W on 12V would equate to a current draw of 3A. Not a great deal for a TV (my TV takes 5A when running for example).
The quoted consumption should really be the maximum, so including the DVD.
2 hours at 3A is 6AH. so just 5% out of your fully charged battery. Other loads such as lights, etc will be taking power, but if the battery started off full and two hours later couldn't support the TV, that points to an problem.

You said "showing fully charged"? How? if you are going by a series of LEDs on a control panel, they don't really show anything. Voltmeter slightly better, but can still be very misleading if you have a charger on or there is a load.
On the face of it, you may have a problem with a poor battery, but you could have inadvertantly made an assumption (due to the bad power indictors fitted in most Motorhomes) about the battery charge state. I would get the battery fully charged by plugging into a hookup for at least 24 hours, then disconnect, run the TV as you did before and see what happens. And when it reports Low Voltage, check the battery voltage at that point and make some notes of the run times, voltages, etc. to help pinpoint.
What you don't want to do is just replace the battery and find it made no difference.

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[Richard n Ann]

Our new TV uses 1.6 amps including inverter losses. It's an LG 24" 2021 model

 

[Rapido925M]

Did you also have heating on? There can be quite a current draw when the fan kicks in.

Gordon

 

[cessac]

36W on 12V would equate to a current draw of 3A. Not a great deal for a TV (my TV takes 5A when running for example).
The quoted consumption should really be the maximum, so including the DVD.
2 hours at 3A is 6AH. so just 5% out of your fully charged battery. Other loads such as lights, etc will be taking power, but if the battery started off full and two hours later couldn't support the TV, that points to an problem.

You said "showing fully charged"? How? if you are going by a series of LEDs on a control panel, they don't really show anything. Voltmeter slightly better, but can still be very misleading if you have a charger on or there is a load.
On the face of it, you may have a problem with a poor battery, but you could have inadvertantly made an assumption (due to the bad power indictors fitted in most Motorhomes) about the battery charge state. I would get the battery fully charged by plugging into a hookup for at least 24 hours, then disconnect, run the TV as you did before and see what happens. And when it reports Low Voltage, check the battery voltage at that point and make some notes of the run times, voltages, etc. to help pinpoint.
What you don't want to do is just replace the battery and find it made no difference.

Thanks for the info . The battery is only just under 2 years old , so it should be good , so i will try putting it on charge for 24 hours and see what happens.
Just as an aside , if the panel & a volt meter do not give a good indication of charge status , what does ?

 

[cessac]

Did you also have heating on? There can be quite a current draw when the fan kicks in.

Gordon

No just the tv & a light

 

[Two on Tour]

, if the panel & a volt meter do not give a good indication of charge status , what does ?

A battery monitor that uses a shunt to measure the charging and discharging of your battery so it can calculate and give you an accurate state of charge of your battery.

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[cessac]

Thanks. The battery is now on charge. I'll try it again tomorrow.

 

[Spriddler]

Thanks for the info . The battery is only just under 2 years old , so it should be good , so i will try putting it on charge for 24 hours and see what happens.
Just as an aside , if the panel & a volt meter do not give a good indication of charge status , what does ?

A voltmeter will usually be more accurate/specific than a panel indicator for voltage. Both will only tell you the current voltage of the battery, not its capacity. To check the capacity you need to do a timed discharge test with a known load (amps) which in effect is what you will be doing by running the T.V. from a fully charged battery. In theory you could run a 3amp load such as your T.V. for around 40 hours from your 120 A/h battery. However, in reality you will only get full voltage for around 50% of the rated capacity of a lead/acid battery so you'll get around 20 not 40 hours from your 120 A/h battery.
After charging the battery you need to leave it disconnected for an hour or two to allow the residual charging voltage to fade.

 

[denisejoe]

Also only read the voltage at night when solar has no input or disconnect the battery

 

[lunarman]

Did the message come up after you had used the remote control? Our TV gives that message when the battery in the control needs changing.

 

[donkey]

Did the message come up after you had used the remote control? Our TV gives that message when the battery in the control needs changing.

Good point.

Geoff

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[cessac]

Did the message come up after you had used the remote control? Our TV gives that message when the battery in the control needs changing.

So does mine , but , no I wasn't using it at the time

 

[Stealaway]

Can anyone help me work out how much power my tv is using . I have a 120 hr leisure battery , which was showing fully charged , we watched for just under 2 hours & a message came up saying the Voltage was low . We turned the tv off , fine , but there was no problem with lights etc . SOOOOOOOO why does my tv get stressed when everything else is fine ?
plate on the back says " consommuation DC12v 36 W .But is it more if I use the built in DVD player ?

Cheers Tony

You must be sure the battery is fully charged at 12.7V before you settle down to watch TV.
Once the voltage at the battery drops to 12V on the gauge you should turn it off or you could cause permanent damage to it.

 

[cessac]

A battery monitor that uses a shunt to measure the charging and discharging of your battery so it can calculate and give you an accurate state of charge of your battery.

I have looked into battery monitors (with a shunt ) & it appears to be a bit of a minefield .As I am not an electrical engineer , I find it difficult to sort out what will do the job properly , and what is just puff to hide the fact that the thing will not do the job . If anyone can point me in the right direction I will be obliged.

 

[peterc10]

Try the Victron BMV range. We have had a BMV700 for 7 years and it has kept us informed about the amps in and out and the state of the batteries. The display is small and sometimes difficult to read. Just attached a Bluetooth dongle so I can see a lot more information on the app on my phone. The BMV700 used to be the cheapest in the range, but now they do a smart shunt which has no display at all and instead uses Bluetooth to let you read all the information on your phone,

 

[Hoovie]

I have looked into battery monitors (with a shunt ) & it appears to be a bit of a minefield .As I am not an electrical engineer , I find it difficult to sort out what will do the job properly , and what is just puff to hide the fact that the thing will not do the job . If anyone can point me in the right direction I will be obliged.

Best Options (IMO):
Victron Smartshunt: 'Headless' (no display) Monitor. Got Bluetooth. Needs phone app to see info. If you are into your Apps, that is a good option
Victron BMV-700: Display but no phone app. If you like to look at a physical display, that is a good choice
Victron BMV-712: You can think of it as a BMV-712 AND a Smartshunt. you have a display, you have a phone app, so maximum choice.
There is a bit more differences than what I have said above, but these are the key things you need to know.
You can add dongles to add Bluetooth, but better to forget that and get the right one to start with rather than adapt if you are buying from new.

Other decent options:
NASA Marine BM1 and BM2 - bigger displays. not as good as the Victrons but similar price.
Alii Monitor (do a search) - nice clear display. probably the cheapest decent monitor available. not as good as the Victrons but significantly cheaper (and will work on all battery types).

My recommendation is the BMV-712. Most expensive yes, but most flexible and worth the extra.

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[Stealaway]

I have looked into battery monitors (with a shunt ) & it appears to be a bit of a minefield .As I am not an electrical engineer , I find it difficult to sort out what will do the job properly , and what is just puff to hide the fact that the thing will not do the job . If anyone can point me in the right direction I will be obliged.

I don't think you need these monitors. You won't have any control over what charge you get into the batteries per day.

You only need a voltmeter to see how much you have taken out of them.
Just get what you can that day. If its not enough then you need more solar or drive further, ideally with a B2B fitted.
If that's still not enough you will need more/bigger batteries

 

[Hoovie]

I don't think you need these monitors. You won't have any control over what charge you get into the batteries per day.

You only need a voltmeter to see how much you have taken out of them.
Just get what you can that day. If its not enough then you need more solar or drive further, ideally with a B2B fitted.
If that's still not enough you will need more/bigger batteries

A voltmeter will not tell you how much you have taken out the battery. It will tell you the voltage of the battery. nothing more, nothing less.

The voltage of the battery is not an indication of the charge level of a battery in any way unless the battery has been left disconnected off charge AND off load.
If you base the battery status off the voltage, as soon as you plug a battery charger in, your battery will suddenly be fully charged. Amazing. And wrong.

Sorry, but the advice about the voltmeter given is a nonsense.

 

[Two on Tour]

I don't think you need these monitors. You won't have any control over what charge you get into the batteries per day.

You only need a voltmeter to see how much you have taken out of them.
Just get what you can that day. If its not enough then you need more solar or drive further, ideally with a B2B fitted.
If that's still not enough you will need more/bigger batteries

Do I take it that you think that the fuel gauge on your van is a waste of time as well.

 

[Terry]

You simply need a new battery

 

[Richard n Ann]

Even the charge level won't tell you the remaining capacity

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[Hoovie]

You simply need a new battery

It's less than 2 years old. If there is an underlying reason why he needs a new battery whuch he doesn't address he will be going through batteries like no ones business!

 

[Hoovie]

Even the charge level won't tell you the remaining capacity

If you install AND SETUP an SOC monitor correctly, you will have a very good idea of the batteries capacity.

 

[Stealaway]

Do I take it that you think that the fuel gauge on your van is a waste of time as well.

Definitely not ---- but it's not telling me how much is going in.
Only when it's coming out

 

[Two on Tour]

Definitely not ---- but it's not telling me how much is going in.
Only when it's coming out

Rubbish, get a new fuel gauge.

 

[Stealaway]

A voltmeter will not tell you how much you have taken out the battery. It will tell you the voltage of the battery. nothing more, nothing less.

The voltage of the battery is not an indication of the charge level of a battery in any way unless the battery has been left disconnected off charge AND off load.
If you base the battery status off the voltage, as soon as you plug a battery charger in, your battery will suddenly be fully charged. Amazing. And wrong.

Sorry, but the advice about the voltmeter given is a nonsense.

I told him to monitor the voltage while he's watching the telly and to watch it while it goes down.
Just tell me how the fancy expensive monitoring measures battery condition?

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