Association Forum - LCD TV Power Consumption?

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

LCD TV Power Consumption?

New Topic

Topic Locked

Printer Friendly

Author

Topic

Steve Blackburn
Master Marine Consultant

Member Avatar

Canada
1091 Posts

Initially Posted - 01/13/2008 : 17:58:25

Following the thread "winter projects" I thought the LCD TV topic would be best served on it's own thread. I want to buy a 15" or 19" LCD/DVD combo(whichever fits best) for my 250WB. However I'm concerned about power consumption.

I have 2 deep cycle batteries connected in parallel that I keep charged up during winter at 2 amps with a good marine smart charger. During summer they charge through a 15W 1.2 amps solar panel undisturbed from Monday to Friday (we gets lot's of sunshine)
#1: Wal-Mart Everystart DeepCyle Marine 875amps crank (model 29HDP-6)
#2: Tumlin Deepcyle (no amp indication or other numbers, was suprised).

There were earlier discussions that using a power inverter will drain more amps since the power inverter by itself takes about 3.5 amps just to run. Was also said that a 12V LCD TV will take about .5 to 1 amp (without the need to use a power inverter).

So I went on the West Marine site and see that they sell the Skyworth brand. I also found this [url="http://www.roadtrucker.com/12-volt-lcd-tv-dvd-widescreen/skyworth-12-volt-lcd-tv-dvd-player.htm"]trucking web site [/url] that list the following power consumption figures:

15" 50 Watts (4.2 Amps max)
19" 70 Watts (5.8 Amps at 12-Volts)

How many amp hours will my batteries provide considering I only want to take 20% and leave 80% charge?

How many amps do these TV's take anyways? I have to admit that I am confused now since the power consumption figures do not match up with what Sean mentioned in his post.

Can anyone shed light on the subject?

Steve Blackburn, Calgary, AB
C250WB - 1999 - Hull 396

Edited by - Steve Blackburn on 01/13/2008 18:02:08

dmpilc
Master Marine Consultant

Members Avatar

USA
4593 Posts

Response Posted - 01/13/2008 : 18:54:26

One of the reasons I go sailing is to get away from the TV! Granted, i haven't done any long overnighters yet.

Edited by - on

GaryB
Master Marine Consultant

Members Avatar

USA
4304 Posts

Response Posted - 01/13/2008 : 19:17:30

Steve,

Watts divided by Volts will give you the Amps.

50 watts/120 volts = 0.417 amps
70 watts/120 volts = 0.583 amps

50 watts/12 volts = 4.17 amps
70 watts/12 volts - 5.83 amps

The trucking ad is correct.

Sean was probably calculating his numbers based on running the unit on the inverter at 120 volts.

GaryB
'89 SR/WK #5862
Kemah,TX

Edited by - GaryB on 01/13/2008 19:19:30

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 01/13/2008 : 20:15:44

Steve... Cranking amps don't come into play in your calculations--that's the max amount the battery can generate over 30 seconds without dropping below some specified voltage--for starting a big engine. You need to know your Amp Hours (AH), which for a Group 24 is somewhere around 100--higher for a Group 27. Then you can divide the draw from the TV into some percentage of the total AH for the batteries (in parallel).

Edited by - on

OLarryR
Master Marine Consultant

Members Avatar

USA
3463 Posts

Response Posted - 01/13/2008 : 22:44:24

On a side note regarding the solar panel. Do you have a controller with a digital readout as to just how much amps it really is producing ?

My experience with a 1.2 amp max solar panel and with a digital readout from the controller was that ideally...if the panel was exactly perpendicular to the sun it then would get the amp rating of the panel - 1.2 amps/hour. However, it is in practice much lower than that because the sun is not always perpendicular to the panel and many times it never is during the whole day, week, etc. My mount on the stern rail allows me to adjust the panel on a slope toward the sun but even doing that it is not 100% perpendicular. In the summer, I usually keep the panel horizontal and then slope it for the winter months. On a daily basis, the solar panel puts out between .4 - .8 amps/hour for the afternoon hours.

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 01/14/2008 : 00:29:25

OLarry: I do have a controller with the solar panel (so the batteries don't overcharge) but it doesn't have a digital read out. However I did test with my electrical meter and got about 1 amp out of it even though late in the afternoon (not directly into sunlight). But I'm not expecting this to be the norm.

Dave: What is weird is that one of my batteries just say DEEP CYCLE (Tumlin) and the other doesn't mention AH or Group.

DavidP: I agree with you, my wife and I quickly end up shutting down the music while we sail. We quite enjoy the silence. But for the kids who are confined in the cabin for 2-4 or more hours it can be a long ride, hence the TV. I'm hoping to get them more active in the process and hope the investment in the TV will be the worst I have ever done. Not easy being a family man trying to please everyone.

Gary: Thanks for that, I learned something today! I imagine there would be some loss of efficiency going through an inverter since it does heat up but following the laws of physics where no energy can be created or destroyed I wonder why an inverter alone would consume as much as 3.5 amps just sitting there.

To quote Sean "I think the walmart tv is 45 watts ac.
I cant check what the tv is drawing with out the inverter because I have a dc meter.
so when I turn the inverter on it shows 3 amp draw then I can turn the tv on it shows a total of 3.5 to a 4 amp draw". This would mean that 45/12 = 3.75 amps from the TV alone. So if he gets a total of a 4 amp draw with TV and inverter that would mean the inverter is consuming an overhead of 4 minus 3.75 about .25 amps. That would make more sense to me, but he does say that when he turns on the inverter alone it draws 3 amps. Sean can you comment on these numbers? I guess you have a digital readout of amp consumption between your batteries and inverter?

Edited by - Steve Blackburn on 01/14/2008 00:49:06

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 01/14/2008 : 09:13:25

Steve: Figure 100 AH for rough estimates (if the batteries are fairly new and in good condition--electrolyte never drops in any cells).

When you plug those little converters (the opposite of an inverter) for your cell phone, laptop, camera, etc. into the wall, they draw roughly the same amount of AC whether your device is turned on or not, and generate heat. I suspect the inverter is similar--it probably is "inverting" whether its output is being consumed or not, and generating heat. You'll want to make sure you can disconnect it or switch it off. Some inverters have an automatic "stand-by" mode for when no power is being drawn from them. However... another thing... See how your reading changes when you plug the TV in--when most TVs are "off", they're not really "OFF"--it's just in a sort of hibernation mode with the main power gobbler, the screen, turned off. So if your inverter has a standby mode, it might never be active with the TV plugged in.

Edited by - Dave Bristle on 01/14/2008 09:22:22

ilnadi
Captain

Members Avatar

452 Posts

Response Posted - 01/14/2008 : 11:40:47

Couple of observations

1. an inverter drawing 3.5A at idle sounds high, I would expect .5 to 1.5A, but it's in the ballpark. The simpler the inverter (modified sine, no AC load switching, etc) the less the idle draw.

2. Everything I've read is against using two dissimilar batteries in parallel (if you truly load them in parallel). They will discharge at different rates and try to charge each other.

3. Yes the inverter, TV etc will all draw power when off. If you want true no-current, you have to switch the 12V off at the panel. Of course depending on your TV you may lose all your channel memory.

4. The newer wall converters are "switching supply"s, meaning they will draw very little current when not loaded. EU regulations spreading out as it is cheaper to produce only one device.

5. As to why you seem to be running the TV with only .25A, I assume the inverter likes a load so works a lot more efficiently at small to medium loads. An AC-to-DC converter can generate a voltage and hold it with very little current but a DC-to-AC converter cannot really produce a sine (even modified) with no current draw. If your current draw is truly 3.75 and 4A (this depends on your meter, the inverter is probably drawing current unevenly and not every meter can really average that) then you should notice that the inverter runs cooler when the TV is on.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 01/14/2008 : 14:36:02

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by ilnadi
 Couple of observations

1. an inverter drawing 3.5A at idle sounds high, I would expect .5 to 1.5A, but it's in the ballpark. The simpler the inverter (modified sine, no AC load switching, etc) the less the idle draw.

2. Everything I've read is against using two dissimilar batteries in parallel (if you truly load them in parallel). They will discharge at different rates and try to charge each other...<hr height="1" noshade id="quote"></blockquote id="quote">If his "idle" is with the TV plugged in and turned "off", that means the inverter is probably not really idle--it's outputting to the TV's low-power circuit.

I agree on the batteries... Even batteries that are identical when new eventually aren't any more. That points back to a thread on isolators and other devices. My approach is a 1-All-2-Off switch--I start and charge on All, use 1 or 2 when the engine isn't running (keeping the other in reserve), and switch to Off when not on the boat.

Edited by - on

Nautiduck
Master Marine Consultant

Members Avatar

USA
3704 Posts

Response Posted - 01/14/2008 : 16:42:20

I like to keep things simple. Our boats do not need a seperate battery to start the outboard. No need for multiple banks. I bought two new AGM batteries and connected them in parallel. AGMs are the best for the kind of loads a sailboat needs. If I were you I would buy a 12V TV and forgo all of the inverter stuff.

Edited by - Nautiduck on 01/14/2008 16:42:48

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 01/14/2008 : 19:00:59

Yes 12V TV is the way to go. The 15" rated at 4.2 amps should provide about 23 hours on a 100AH battery. From my understanding 100 AH is the time the battery goes from a full charge to 10.5V (empty). For the moment I'll leave both my batteries as is and when they deteriorate I will go with 2 similar AGM's like Randy suggested. I would expect no more than 8 hours of TV watching during a single week-end meaning that I will draw 8 * 4.2 amps = 34 AH. With two 100AH batteries (200 AH) that is 17%. Leaves plenty of amps for the occasional radio, instruments and lights.

Is my assumption correct when stating that a 100AH battery will output 100 usable amp hours before attaining 75-80% of its charge which I that point I shouldn't draw anymore power?

Edited by - on

Nautiduck
Master Marine Consultant

Members Avatar

USA
3704 Posts

Response Posted - 01/14/2008 : 20:59:46

From a web site:

Amp Hours

The Amp Hour rating tells you how much amperage is available when discharged evenly over a 20 hour period. The amp hour rating is cumulative, so in order to know how many constant amps the battery will output for 20 hours, you have to divide the amp hour rating by 20. Example: If a battery has an amp hour rating of 75, dividing by 20 = 3.75. Such a battery can carry a 3.75 amp load for 20 hours before dropping to 10.5 volts. (10.5 volts is the fully discharged level, at which point the battery needs to be recharged.) A battery with an amp hour rating of 55 will carry a 2.75 amp load for 20 hours before dropping to 10.5 volts.

Reserve Minutes

Reserve minutes is the number of minutes a battery will carry a 25 amp load before dropping to 10.5 volts. (10.5 volts is the fully discharged level, at which point the battery needs to be recharged.)

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 01/14/2008 : 21:05:46

Excellent. So 1 battery should suffice for 8 hours of TV watching.

What will I be watching you ask? Other people sailing their boats while we are attached to the dock. LOL just kidding.

Edited by - on

johnsonp
Admiral

Members Avatar

USA
606 Posts

Response Posted - 01/14/2008 : 21:06:17

Steve
These are the questions that I would ask myself or think about first.

How many hours running TV before your battery system needs charging.

How many hours do you need to recharge your battery system ?

How do you want to recharge your battery system ?
Solar panel............................amps/hour
Existing engine with alternator.........amps/hour
110volt shore power battery charger....amps/hour
Ac/DC Honda generator.................amps/hour
I wouldn't use more than 4 batteries whatever size or type.

For my personal requirements and useage I use a Honda generator since my 2002 TV is 110v and I have an existing inverter.
Next year I will upgrade to a 15" 12 volt LCD TV with the new tuner and the 110 volt charger option.

paulj

Edited by - on

Steve Blackburn
Master Marine Consultant

Members Avatar

Canada
1091 Posts

Response Posted - 01/14/2008 : 21:12:20

Solar panel is 1.2 amps at peak performance. I actually forgot that my Honda 9.9 will charge my batteries. From a web site I see 2 Amps at 1000 RPM and an amazing 12 amps at only 3000. Is that right?

How many RPMs/amps at idle?

Edited by - Steve Blackburn on 01/14/2008 21:12:55

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 01/14/2008 : 21:54:32

1000 is roughly idle speed. I think those numbers are correct--12 amps is the listed maximum, but I've heard it reaches that at well below max RPMs. (3000 probably pushes you above 5 knots.) I suspect it's one reason (along with the lower pitch prop) the new Hondas have somewhat worse fuel economy than the older generation.

Edited by - Dave Bristle on 01/14/2008 21:56:28

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 01/15/2008 : 07:56:46

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Blackburn
 DavidP: I agree with you, my wife and I quickly end up shutting down the music while we sail. We quite enjoy the silence. But for the kids who are confined in the cabin for 2-4 or more hours it can be a long ride, hence the TV. I'm hoping to get them more active in the process and hope the investment in the TV will be the worst I have ever done. Not easy being a family man trying to please everyone.<hr height="1" noshade id="quote"></blockquote id="quote">

You might want to rethink that TV. Those boats in my marina with TV's are also the boats that don't leave the dock.

As someone whose been sailing since my kids were in diapers, I know very well of the need to keep the kids occupied. We've found that books are an excellent way to fend off boredom and rarely do my kids, one now a senior in HS, come down to the boat without a book in hand. The bonus of books, I don't have to listen to the drone of a TV for hours on end.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 01/15/2008 : 08:45:58

How 'bout one (or two) of these--built-in rechargable battery with 12V and AC adaptors. Just add earbuds.

[url="http://www.radioshack.com/product/index.jsp?parentPage=search&summary=summary&cp=&productId=2855063&accessories=accessories&kw=portable+tv&techSpecs=techSpecs¤tTab=summary&custRatings=custRatings&sr=1&features=features&origkw=portable+tv&support=support&tab=techSpecs"]Handheld TV[/url]

Edited by - Dave Bristle on 01/15/2008 08:46:47

Nautiduck
Master Marine Consultant

Members Avatar

USA
3704 Posts

Response Posted - 01/15/2008 : 15:48:54

One thing that I have considered is a portable DVD player. They can be had for a couple hundred $ and would be good for DVD movies, etc. They are portable so would be simpler than a TV setup and before cruising the kids could select a movie or two to bring along.

Where we sail, and cruise, there are not tv stations readily available so watching DVDs would make more sense for us.

Edited by - on

roberoo
Navigator

Members Avatar

USA
182 Posts

Response Posted - 01/16/2008 : 20:38:44

Laptop......I have one setup for DVD and Wifi. Kept my 22yr old going nd now the 13 year old.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.