Typical battery run time of 12 volt TV

[wagoo]

I live almost exclusively on 12 volt power in my little cabin in the hills.
I have a Teac 19 inch LCD 12/240 TV that I have had a couple of warranty issues with,so have only used it occasionally. I don't power it from my deep cycle battery bank as they are getting a bit old and rarely exceed 12 volts, wheras the TV's sound cuts out at 12.2 volts. I do power the tv on various car/truck batteries that I keep charged up with my daily travels. The battery power consumption of this unit does seem a bit high compared to other equipment such as lighting, laptops etc.
I'm trying to get an idea of the typical run time of these or similar units out there and the size/capacity of battery they are powered with.
Thanks in advance for any advice offered.
Bill.

[DeanoH]

The 12 volt shop is advertising a 19" Teac combo TV which has a power consumption of 60 watts. This is pretty much the same as a car headlight. In round figures this is 5 Amps. So how long the TV goes for depends on the size of your battery and the length/dia of your 12 volt cable (voltage drop / power loss issues). Might be more efficient to run a small inverter if the distance between the battery and the TV is an issue. Also as you double the supply voltage in a given power cable you halve the current and QUARTER your power losses, but living in 12 volt land you probably know this. :)

From a theoretical viewpoint an N70 100 AH battery will last 20 hours but in practice probably half that taking voltage drop, TV low voltage cut out and not totally flattening the battery into consideration.

Deano :)

[drivesafe]

Hi Bill and if your batteries are flooded wet cell, whether sealed or open type, if you have an 80 ( or slightly larger ) watt solar panel, connect the solar panel directly to one battery and leave it there for a week or so of good sunlight.

At 12v, your batteries are either stuffed or are badly sulphated.

If they are sulphated, by using the solar panel, you might be able to cook much of the sulfation off and get the batteries back to a useable state.

They won’t be back to 100% but you could possibly get them from their currant 50% to over 80%.


Hi Deano and the ONLY way to improve voltage loss in a DC circuit without using more battery capacity is to increase the thickness of the cable.

While your suggestion of using an inverter will potentially increase the voltage at the TV it will dramatically increase the amount of current needed to run the TV, thus dramatically shortening the effective operating time of the TV.

[DeanoH]

...................................Hi Deano and the ONLY way to improve voltage loss in a DC circuit without using more battery capacity is to increase the thickness of the cable..................

Thanks, no argument here but can be an expensive exercise.:)
The point I was making, possibly not very well, was more about POWER loss in the distribution between the battery and the load (assuming the batterys are some distance from the TV). eg. say there's a 1 volt drop in the cable between the battery and the TV and assuming a 60 watt load with a nominal 12 volt supply then 5 amps will be drawn and 5 watts will be lost in the cable. Also the TV will shut down earlier due to low voltage cutout because of this loss.

If hypothetically the battery was 24 volts and the load was a 24 volt TV, if such an animal exists, then half the original amps would be drawn to supply the 60 watt load and as half the current in the same cable will result in half the voltage drop in the cable and as Power (loss in this case) = Current (in the cable) X Voltage (drop in the cable) the overall loss in the cable is 1/4 of what it was originally. :)

Which is why from a design point, 24 volt or 48 volt systems are more efficient than 12 volt systems, or smaller cheaper cables can be used for the same loss.


..............................While your suggestion of using an inverter will potentially increase the voltage at the TV it will dramatically increase the amount of current needed to run the TV, thus dramatically shortening the effective operating time of the TV.

The point I was making here, and again not specific enough, was to put the (small) inverter at the (presumably remote) battery and run a 240 volt lead to the TV. This would result in very low POWER loss between the supply and the TV. As long as the inverter loss was less than the transmission loss POWER would be saved. :)

Agree with your comments re battery sulphation by the way and potential rejuvenation using the panel(s).

Hope this clarifies ( not confuses) things. :D

Deano :)

[wagoo]

Thanks for the replies gents.
I place the single 12 volt battery as close as practicable to the TV set without it actually being inside the cabin. That is 3mtres of heavy house type wiring plus 2metres for the 12 volt lead supplied by Teac. I try to avoid using the invertor for TV, laptops etc due to increased power consumption compared to direct 12 volts, and the fact that it also cuts out completely when battery voltage drops to about 12.2 volts.
The run time in Deano's example seems about on par with what I'm averaging overal with the mixed range of batteries I'm using. With the garbage on offer with free to air television these days, a couple of hours per day is about all I can stand anyway.
Bill.

[DeanoH]

.............................. With the garbage on offer with free to air television these days, a couple of hours per day is about all I can stand anyway.
Bill.

You're not wrong here. I bought a brand new all singing dancing Sony TV at Christmas time, apart from watching the occasional movie it's probably on for an hour or two a week. Waste of money really, but the Blue Ray movies are nice. :)

Are your deep cycle batterys salvageable, ie. sulphated as opposed to completely knackered ?
Drivesafe's suggestion of using a panel to try and rejuvenate the cells is a good one. Electrolyte stratification can also be an issue.
Rapid charge / discharge is good for stiring up the electrolyte and breaking down lead sulphate build up on the plates and if the cells are knackered already there's nothing to lose. Need a good high current charger though and a bit difficult without mains power.

As a temporary solution you could cheat a bit, If you can stick another cell in the (deep cycle) battery, so 7 instead of 6, (easy to do with single cell batterys) and increase the charge voltage from the solar reg ( I assume that's how you charge it) you may be able to sneak another volt or so out of the battery. Not ideal but could tide you over.:)


Deano :)

[bee utey]

Get yourself a stationary exercise bike and run a small 12V generator off it. When you're tired it's time for bed anyway!:angel:

Or stick one of these on your slow combustion stove...

POWER GENERATION TEG - HIGH TEMP THERMOELECTRIC PELTIER | eBay (http://www.ebay.com.au/itm/POWER-GENERATION-TEG-HIGH-TEMP-THERMOELECTRIC-PELTIER-/310155795073?pt=LH_DefaultDomain_0&hash=item4836b9da81)

[wagoo]

Thanks again Deano. I don't really know how to test if the deep cycle battery bank is salvageable. They are sealed 6 volt 150AH units connected in series. There are two banks of 4 batteries each. I alternate between the two banks, one week on , one week off, because it takes too long to charge all 8 batteries together. I dont have solar panels.Probably just as well with the lousy weather we've had recently. I just charge them up with 2x 80amp alternators mounted on a deisel engine. The batteries have exposed terminals for each cell. that's 3 2volt cells per battery.How many cells would I need to borrow from the 'resting' bank if I were to try to cheat as you suggested to do with a 12 volt battery?
One other question. I run the power from the battery bank through the original 240 volt wiring in this transportable cabin. That is 5 light switches, and 6 mostly unused power points, and probably a mile of wiring inside the walls and ceiling.Would switching off the power point circuit breaker at the fuse box be likely to reduce battery drain in your opinion?
Bill.

[DeanoH]

Thanks Bill, the first thing to do is determine if the batterys are stuffed or nor. Pity they're sealed units. What brand and model number are they ? are they truly sealed units ? Presumably they are flooded cell lead acid batterys ?

Also what is the output voltage of the alternators and how are the two configured. ie. used individually or commoned output ? Older alternators may have an output of 13.2 volts whereas a more modern alternator may have an output of say 14.5 volt. This could be the difference in getting a 'good' charge into your battery(s).

As to sneaking an extra cell in the chain. At a nominal 2 volts per cell you could connect another 3 cell 6 volt battery in series with your existing battery and tap off the output at the connecting bar between the first and second cell, this would add another 2 volts to your battery giving it a nominal 14 volts which may be beneficial. This can be a temporary solution to a problem but becomes a bit tricky when charging the overall battery. Also the additional battery is then unevenly discharged which isn't good for it.

Plan a would be to see how many of the original batterys are salvagable and to configure them to charge correctly. :)
Don't really understand the bit about the 240 volt wiring in the cabin, but as a general rule it would be too light for 12 volt distribution. It may do for low wattage lights so you can see in the cabin but that's about all.

With 12 volt stuff there's no such thing as cable that's too thick.

Deano:)

[bee utey]

Have you got a multi meter handy? Run a set current (say 5 amps) for as many hours you need to reduce the voltage to telly cut-off, this gives you the remaining amp-hours available in your batteries. Then test each cell individually, any cell that is way under the others in voltage is likely stuffed.

BTW solar panels are probably cheaper than diesel fuel for charging once the sun comes back.

And if your batteries are stuffed look for second hand batteries that have been removed from commercial UPS systems, they are often good value and long lasting, so long as you don't regularly run them totally flat, eg:

12 volt deep cycle battery solar camping caravan fishing 4x4 truck campervan | eBay (http://www.ebay.com.au/itm/12-volt-deep-cycle-battery-solar-camping-caravan-fishing-4x4-truck-campervan-/150865561118?pt=AU_Electronics_Batteries_Chargers&hash=item232049c61e)

[wagoo]

Deano. My batteries are Yuasa Endurance EN160-S. actually 160 AH. They appear to be sealed, although there seems to be a plastic disc on top of each cell that may be a vent. I'd have to break a disc off to know for sure.
My alternators are configured as commoned output and earths. The highest readings I've seen at the batteries while charging is 13.9 volts.
For lighting I run direct 12volt 50watt Halogen down lights from the original 240 volt house wiring and switches. I tried $30 LED globes in them, but they died quickly.

BeeUtey. Whilst Solar panels may in the long term be more economical than my present setup,I believe they do require an invertor, and I've had little success with longevity of the lower priced 1000w invertors that my current pension affords me to purchase. Similarly with the Solar panels. Haven't checked for a couple of years, but the payback period (No government subsidy off the grid) was longer than I reckon I'll still be around.

Bill.

[bee utey]

50W halogens are sooo last century. What a way to drag down a battery!

The last two batches of 9W LED downlights I have purchased have all been 100% reliable. Their price, along with that of solar panels, has more than halved over each of the last two years. They are now so cheap that you buy them in boxes of 10 or 20. e.g.:

10x Mr16 12v Led Light Bulb 9w Downlight energy saving Warm White Dimmable CREE | eBay (http://www.ebay.com.au/itm/10x-Mr16-12v-Led-Light-Bulb-9w-Downlight-energy-saving-Warm-White-Dimmable-CREE-/160823837903?pt=AU_Lighting_Fans&hash=item2571d904cf)

6x 9W LED MR16 12V LED down lights spot ceiling globe lamp lighting bulb C/W | eBay (http://www.ebay.com.au/itm/6x-9W-LED-MR16-12V-LED-down-lights-spot-ceiling-globe-lamp-lighting-bulb-C-W-/280913700494?pt=AU_Lighting_Fans&hash=item4167c2e68e)

NEW - 95W Solar Panel Monocrystalline Module 12V ! | eBay (http://www.ebay.com.au/itm/NEW-95W-Solar-Panel-Monocrystalline-Module-12V-/280899031317?pt=AU_Solar&hash=item4166e31115)

Any solar panel needs a regulator to charge a battery bank, they are also not that dear. Unless you are getting your diesel for nothing a solar panel will be considerably cheaper to run.

[DeanoH]

G'day again Bill. Is it EN 160-S or EN 160-6 ? Yuasa's EN160-6 batterys are AGM (absorbed glass matt) type. This means that they do not contain a liquid electrolyte like a 'normal' Lead Acid Battery. The electrolyte is held in a sponge like material between the batterys plates, hence the name absorbed glass matt). Do NOT try and open up these cells, there is no point. Electrolyte can't be topped up and specific gravity cannot measured like a 'normal' flooded cell.

These batterys are designed to be used in a 'float' situation. This is where a power source,ie. generator, rectifier etc is connected across a battery with the load connected as well. What happens is the battery basically 'floats' with the power source supplying the power for the load. The battery in this situation provides filtering of the supply voltage and a backup should the mains fail. A typical example would be a UPS, (uninteruptable power supply), where such a battery supplys an inverter which supplys a load. No matter what happens to the supply there is always an output. Widely used in computer applications.


The optimal float voltage for a battery comprised of these cells (EN160-6) is 2.26 Volts/cell (@20 degrees C) or 13.56 volts for the battery and they have a design life of 10 years when used this way.

They are not designed to be used in a charge/discharge application. This would reduce the life of the battery and like all lead acid batterys the more and deeper they are discharged the shorter the life.:(

Assuming the batterys are OK they should be given a nice even charge at a 10 hour rate (for a 160 AH battery that's 16 amps for 10 hours) and see how they come up. Charging them any harder than this could damage the battery. If the sides of a battery are bowed outwards this is a sign that they have been 'overcharged' and are probably had it. They can be charged for longer at a lower rate but not advisable to charge at a higher rate. :)

Are your alternators identical ? I've never liked the idea of commoning alternator outputs as their voltages may vary. I'd be more inclined to have them wired separately so that I had two separate charging sources which would give me more flexability. You don't really need a 12 volt 160 Amp battery charger for these batterys. :eek:

I agree with 'bee utey' regarding the halogen lights. These are absolutely poisonous for power consumption, very inefficient and IMO get too hot for safety. They use up to 8 times the power as a LED for the same light output. As they draw more current (up to 8X) than a Led of the same light output the voltage drop in the cable feeding them is 8X as much as for a LED with the same output, so the power loss can be significant.
For lighting purposes you can dimension a much smaller (cheaper) system using LED's than you can using halogens.

I take your point regarding older LED lights and their 10,000 hours etc. life claims. The LED's might last that long but if the crappy driving electronics don't the light still doesn't work. One issue with LED lighting is supply voltage. When they say 12 volts, they mean 12 volts. If you're running 13.2 volts this can represent a 10% overvoltage and decrease LED life considerably. This used to be more of a problem with automotive type applications than domestic. The old style downlight transformers actually provide 11.7 volts (or there abouts) and are perfect for '12 volt' LED's. One transformer can feed multiple lamps.

The only problem I've found with modern LED lights (MR16's) is that they can generate a lot of electrical noise and in a low signal area completely swamp TV reception. I'd definitely recommend you get rid of the halogens and replace them with LED lights. Buy one or two of a particular type to see if they're OK and then do the rest. If you've got a bit of voltage drop between the battery and the LED light all well and good they run just as good on 10 or 11 volts anyway.:)
You can of course just wire in a small resistor in series with the LED holder if need be to drop the voltage a tad, or if you're lazy like me use 1N1001 diodes instead. Cheap as chips and good for 1/2 volt drop each regardless of current (up to their rated max). :D

LED lights have come along way in the last couple of years, prices have dropped significantly, quality improved and some actually come with built in 'dropping resistors' for automotive (read greater than 12volt) applications.

I've no idea what your power needs are but using LED lighting I calculated that a 120 watt panel, muli stage solar reg and a 120 AH battery would provide all the lighting power I needed for my 14 sq cottage.

Deano :)

[wagoo]

Thanks again Deano. You are correct, the batteries are 160 -6 , with 'valve regulated, sealed lead acid type rechargeable battery' printed on the side.
I think they are pretty much knackered because even when seperated into pairs they go flat fairly quickly. The sides of the batteries aren't swollen, but I have run them down as low as 11 volts many times over the past 3 years. Oh well, I got them for free so it's probably time I bought a couple of new ones.
I must have bought a dud pair of LED globes when I tried them as they barely lasted 100 hours, never mind 10,000. I don't run my downlights through a transformer, just direct 12 volts.The heat from the halogens isn;t a problem, as they are mounted around 100mm below the level of the colorbond steel ceilings. I take your point about the Halogens power consumption though. I had no idea it was so comparatively high. Would mixing LEDs and Halogens on the same wiring have caused the early demise of the LED's?
I do live in what is called a low signal area regards TV reception. I couldn't get reception with Analog TVs unless I mounted the antenna 10 metres higher than the cabin roof.
My household electrical power needs aren't really that great, as we are only a rung or two above camping out. Just a TV, 6 down lights, 2 laptops, and various battery chargers for Coleman gas hot water system, 2 mobiles and 2 'I' phones. Cooking, heating, refrigerator and hot water run on bottled gas.
Bill.

[DeanoH]

Hi Bill, I don't reckon mixing the LED's and halogens had anything to do with their failure. More likely crappy LED's or over voltaged to death.
Here's an example.

With the TV on for only a couple of hours a day (maybe a bit more during the Olympics) and with the laptops typically using say, 50 watts each, though that is a guess, say also for 2 hours a day and say an average of 4 of your halogen lights on for 4 hours a day and averaging your various chargers to collectively account for another 50 watts of consumption for 1 hour a day you have

TV @ 60 watts X 2 hours = 120 watt hours
Laptops @ 2 X 50watts X 2 hours = 200 watt hours
Halogen lights @ 4 X 50 watts X 4 hours = 800 watt hours
Misc chargers etc 50 watts X 1 hour = 50 watt hours

for a grand total of 1170 watt hours per day, call it 1200 watt hours to make it easy of which your halogen lights @ 800 watt hours account for 2/3 of your power usage. :eek:

If you replace the halogens with 9 watt LED's, and the ones I chose have 3X3 Epistar LED's, an output of approx. 500 Lux (similar to your halogens) and consume 4.8 watts of power each.

So with LED lights @ 4 X 4.8 watts X 4 hours = 76.8 watt hours, call it 80 watt hours. Your daily usage is now 120+200+80+50 = 450 watt hours which is just over half what it was previously using halogens. :D
Lighting power usage is now less than 1/6 of total power usage.

A 12 volt 100 AH N70 battery has a theoretical capacity of 12 X 100 = 1200 watt hours. So in the first example a fully charged N70 would hold enough charge to last one day, in the second example it would last nearly three days. Disclaimer. This is a guide for COMPARISON only to help you get a 'feel' for it.:)

Which is all well and good, but what it means is that a 'system' to provide your power needs would now be a lot smaller and CHEAPER. The saving in battery size alone would more than pay for the LED's I would think. :)

Have a look here

The 12 Volt Shop (http://www.12volt.com.au/)

I reckon Morningstar's SHS setup (for example) could be a simple, cheap solution for what you need.

Deano :)

[bee utey]

For the last 12 months I have six 12V 5W LED downlights in the kitchen running off my backup battery system, probably on for around 8-12 hours a day. No sign of dimming, and the voltage can be anywhere from 12 to 14 volts depending on the sun. My desk lamp is a 12V 9W LED and is on a lot. It barely gets warm inside its converted 240V lamp shade.

[wagoo]

Thank again for the advice Gents.
I think i would lean towards crappy LEDs rather than over voltaged to death, because the voltage drop back then, when I parked the generator/battery bank 30 metres from the cabin was significant, with insufficient voltage to run the TV when the batteries were giving a reading of 12.8 volts.
At $30.00 each for LED globes in those days I was a bit resistant to experiment any further,but on your advice i'll have another try.
Bill.

[superquag]

I recently bought an LED downlight set, LED globe and 240v power supply, for $70. Its a LUMEX brand, puts out 500+ lumens...which are nice, big, healthy LUMENS... and is 'natural' colour-temp. At present, it sits behind my monitor illuminating the corner-wall and ceiling...and the reflected light is sufficient to read by. (at the keyboard.)

The (single, not multiple LEDs) LED runs on 12 volt, and it is an expensive way to buy a top-quality LED... But the point I'm making is that good, effective LEDs are available.

The whole set-up is rated at 11 watts (240VAC) LED is around 6 to 8 watts

[wagoo]

The replacement of all my halogen downlight globes with 6 watt LEDs as advised, has massively reduced my weekly generator fuel costs. My deep cycle batteries are knackered anyway, so I just charge them once a week to about 12 volts and they run down to about 10.5 volts before I charge again (the lights are still bright at this voltage).
I travel at least 60km every day, and this is sufficient to keep the car style batteries charged to run the 2 laptops and TV. Even if battery life is reduced,replacements are only $20 each from Pick A Part self serve wreckers.
Bill.