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240v versus 12v


Swendy666

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We have given up our life living on a marina, the decision wasn’t to hard as during the lockdown I had to work from home and the signal in the Mariana was woeful at best! 
This has now changed our view of living on a Marina! 
We haven’t missed a thing, in fact we’ve enjoyed our boat life more.

We run 8 140amp batteries fed by solar plus 2 alternaters and everything we need to live a good Life on the cut. We have a washing machine two fridge freezers and 65ft to play in.

ok so now you know our set up here’s the question!

We also have sky tv and a 43’’ tv.

The skybox and everything else can be left on indefinitely and the batteries charge is around 78 when we go to bed and 67 when we get up.

We have now realised as the nights draw in that the tv uses stupid amounts of power.

We are changing this for a 32’’ 12v 

Does anyone know if a 240v skybox can plug in and work in a 12v tv?

Edited by Swendy666
Wrong title
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Are you running the engine everyday or do you have a built in generator? and how much solar?  I suspect its going to get a bit difficult in the winter.

You might need to start working on this now.

Can't help with your question though, don't have a TV ?

 

...............Dave

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Hi

we don’t have a problem with power, we run the engine in a morning for hot water and at night for same.

we have a 3 k inverter and a 1k iron if the missus does a hot wash it’s while the boat runs for the water to warm up. 
the batteries only reduce if the telly is on late in the night. If they get to 54% the internal generator kicks in, not good if you’re moored close to someone.

All I need to do is change the tv but will the 240v skybox run with a 12v tv

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Yes it should work its only hdmi between them.

We turn our TV and sat box off at the socket when not in use, it takes longer to boot up but it saves a reasonable amount of electricity, we do this in the house as well as the boat. Occasionally we do leave the sat box on overnight when we are recording a late program but other than that its all off.

Might be worth considering a change of regime rather than a change of TV.

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Cheers for that

Hopefully it should be ok to buy the tv now.

Not sure I understand the change of regime?

We are full time live aboard so it’s hard to change that

 

Edited by Swendy666
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For long battery life - if the 78, 67, and 54% are readings on one of the common battery monitors then just be aware that in most boaters hands they the percentage charged and other readings derived from it will be ever larger and larger lies as time goes on so it encourages you to damage your batteries. The voltage and charging current scales will be accurate so its better to use rested voltage to infer state of charge and tail current to know when they are fully charged. You can also use Amp hours used measured from a fully charged battery to estimate the present battery capacity. with that info you can recalibrate the monitor when amps indicates fully charged so the lies are far smaller for a while. Also read and understand the manual and then reset it to take a tail current of about 1% as fully charged rather than the more usual default of 4%

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Just to clarify the point being made, lead acid batteries need to be fully charged regularly otherwise they lose capacity rapidly. It’s not clear from your posts but it does sound as though you are using your batteries in a perpetual state of part-charged. If so, this will end in tears with knackered batteries in short order.

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We have Sky Q and a 240V 32" TV. It is the sky box that takes the stupid amount of power rather than the TV.

Changing to a 12v TV will not change the power the tv takes....maybe a bit less for a smaller tv but are the 12v ones older and therefore less efficient?

From the numbers you quote it doesn't sound like you have a meter that measures current out. Having one of these can help decide on what kit to leave on. Our Sky box takes 6A when the green light is on and around 2.5A on standby increasing to 3.5A if recording on standby. Make sure you turn it off from the mains late at night or put it on a timer if you are recording late at night.

The Sky box is a very heavy power user.

of course it will work with a 12v TV as long as the TV has an HMDI input....and if it doesn't then it will be very inefficient on power, so get. 240V one....far cheaper.

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I agree with Tony above. If you are cycling between 67% and 87% full on your meter, you will wreck your 8 batteries by Christmas. They must be taken to full ......at least twice per week (some say more, some say less). You have a large amount of capacity but that will decrease as they get knackered by not charging to full and with the large capacity you won't notice. Running the engine a few hours a day is not going to put back in the 100 odd Ahrs you will be taking out....guesstimate based on your 11% SoC usage ...and the skybox etc.. You will need at least 3 hours per day.

Go back to Tony's post and understand how to tell the batteries are full. Never rely on the % the gauge tells you. 

3 minutes ago, Murflynn said:

at 12v or 240v ?

Sorry. The draw on my 12v batteries is 6A from the sky box via the inverter so if it's on from 5pm to 11pm then the batteries are depleted by 36 Ahrs. It's not the Telly that is destroying the OPs batteries, it's the Sky box! Leave it on standby for the other 18 hours of the day and you are up to well over 50-60Ahrs. 

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Lots of info: about your current drain - but nothing about a charge controller

With that amount of batteries (very good have a brownie) methinks you need some form of battery management system??

 

I'm sure others migh agreed ane mebe with some suggestions.

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51 minutes ago, Tony Brooks said:

I think they have a battery monitor because to looks to me as if they are quoting percentage charged with a precision that is not possible if using rested voltage.

Umm - I meant a charge controller - Sterling w.h.y, to do all the equalising stuff that a normal alternator doesn't do. In addition if he has two alternators for the domestics (? or did I misinterpret that) then he needs blocking diodes etc to make his charging more efficient. Wit nearly 1000 Ah of battery capacity - they should not be going that discharged overnight.

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1 hour ago, OldGoat said:

Umm - I meant a charge controller - Sterling w.h.y, to do all the equalising stuff that a normal alternator doesn't do. In addition if he has two alternators for the domestics (? or did I misinterpret that) then he needs blocking diodes etc to make his charging more efficient. Wit nearly 1000 Ah of battery capacity - they should not be going that discharged overnight.

I think he is saying it is going from 78% down to 67% each night which if the values were true would be 150Ahrs ish based on 1000Ahr capacity - so that sounds in the right ball park for what might be being used. The problem is he is not going up to 100% at all so his batteries will already be sulphating and that is why he is seeing the drop in SoC getting worse with the TV.

Peeps just dont realise how much power a sky box uses.

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15 hours ago, Loddon said:

what I mean by change of regime  is if you turn the tv etc off at the 13amp plug when not in use you wil save battery power.

 

 

I thought you meant he has not adapted to off grid.

No one has commented on running down batteries to "54%" [of what].

I guestimate I have about 600amp hour storage, I have three new 135ah, 2 old110ah  leisure AGM and a starter battery, I have 550watt new solar and input is not matching output this week even though I gave the engine a good three hour blast two days ago. I will get two hours of sun tomorrow, and probably leave if the batteries are not "full". I am in the forest so not getting fullmax solar.

I turned fridge off and will take the opportunity to remove any ice build and clean it first thing. Sorry to rabbit on, but I am trying to explain my idea of off grid living.

EDIT/UPDATE

Sorry only read to post #6

Edited by LadyG
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8 hours ago, LadyG said:

 

No one has commented on running down batteries to "54%" [of what].

 

why would we?  there is a convention that is understood by most. 

the only issue is whether this is a figure displayed by some not-so-smart monitor or whether it is a figure derived from accurate and controlled measurement of the battery voltage at rest.

this has been covered several times in this thread.

if you can't be bothered to read past #6 then why bother to respond at all?   :banghead:

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5 minutes ago, Swendy666 said:

By Cheers for that

Hopefully it should be ok to buy the tv now.

Not sure I understand the change of regime?

We are full time live aboard so it’s hard to change that

Charging regime. 
 

Have a read of this:

 

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Ok I don’t think I’ve made myself fully clear.

The batteries are at full charge every day.

 

So full in fact that the solar stops sending charge to them.

 

We can go to bed at night and due to it being dark we do take some out of the Batteries.

 

If we have the big 43’’ tv on for more than 6 hours at night the generator will kick in and fully charge the batteries.

 

As I said, the batteries are at full charge most of the time.

 

I have now rang sky and they have confirmed that the 240v box will work with a 12v tv

 

We have now ordered a Cello 32’’ 12v and the bigger 240v can go and meet its maker.

 

thanks for all the advice given 

 

I think most comments were about the state of my batteries, these have never been a problem due to 3 x 300amp solars

extra capacity alternators and a Generator back up.

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20 minutes ago, Swendy666 said:

Ok I don’t think I’ve made myself fully clear.

The batteries are at full charge every day.

 

So full in fact that the solar stops sending charge to them.

 

We can go to bed at night and due to it being dark we do take some out of the Batteries.

 

If we have the big 43’’ tv on for more than 6 hours at night the generator will kick in and fully charge the batteries.

 

As I said, the batteries are at full charge most of the time.

 

I have now rang sky and they have confirmed that the 240v box will work with a 12v tv

 

We have now ordered a Cello 32’’ 12v and the bigger 240v can go and meet its maker.

 

thanks for all the advice given 

 

I think most comments were about the state of my batteries, these have never been a problem due to 3 x 300amp solars

extra capacity alternators and a Generator back up.

Fair enough, but the reported reduction in state of charge from such a big bank of batteries means either they didn’t start off fully charged, or they have lost a lot of the original capacity. Not the former, it now seems.

 

However if you are taking the state of charge from the solar controller, that figure is pretty meaningless so maybe the batteries are fine after all.

 

As has been mentioned, it is probably the sky box that is taking most of the power, rather than the TV, but no doubt the smaller TV will use a bit less.

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