Sometimes small systems are plenty

[HiTech]

Friday my wife suddenly got the urge to camp. Immediately.

All the TT has is the original Group 24 battery, 5w solar to maintain it and a 700w/1500w inverter I've never even run under significant load. I didn't really need the system to do a lot since at 103 degrees in full sun we will be absolutely doing full hook ups.

Fired up the fridge at 8 am on propane. Pupmed the over chlorainated full water tank almost dry to be ready for use. Ran the compressor from home on the inverter to air up all 4 tires and headed to work.

At noon the freezer and fridge were cold so she loaded but did not even run the fan as the camper still held the cool from overnight.

1:05 PM we headed out for Fredericksburg and wine country.

The current set up is barely above factory, but the battery was brimming with charge and the inverter did everything we would have wanted except for the AC.

I actually think it is the ability to use the microwave that will finally push me to get the Deka AGMs put in the TT. Putting them in will mean i pit in the solar charger to maintain them without cooking the, dry or leaving the discharged. Other than the microwave though, there is just no burning need for us at the moment.

Now if I went crazy and got enough batteries and inverter to run the AC for an hour 15 times a year, that would he a horse of a different color.

😉

Jim (sipping a nice glass of 2010 Brennan Dark Horse)

[mena661]

I don't think the Samsung BD-E5700 uses HQV. BTW, my main TV is still a 2005 Samsung 720p 55" DLP. My other 3 TV's (23", 26" and 47") are LCDs with two being LED LCDs (26 and 47). Eventually I will replace the DLP but not sure yet with what. Plasma is not a consideration though.

Almot wrote:
BR is not terribly important in RV. The screen is not big enough to see the difference from SD DVD or even a compressed digital file on laptop. Though laptop at twice smaller screen would draw same power as DVD + 26TV.

I don't have a regular DVD player and since BR players can play DVD's there's no point in buying a DVD player.

[eric1514]

Almot wrote:
BR is not terribly important in RV. The screen is not big enough to see the difference from SD DVD or even a compressed digital file on laptop. Though laptop at twice smaller screen would draw same power as DVD + 26TV.

It's important to me in so far as any movie I purchase (rarely) will be Blu-ray. I don't buy the sets that come with multiple discs in every format.

You're right about the screen size stuff.

Eric

[KJINTF]

Looks like we are a bit off topic discussing Blue Ray and High resolution TV's

pnichols
Curious if that CRT projection TV is a true HDTV or not - not many CRT TV's were designed with anything more than ED resolution. Sounds as if you have some interest and experience with picture display technology have you looked at the OLED HDTV's? Technology that emits light as compared to passing it through thus requiring an additional backlight(LED or CCFL) develops a far superior picture. Deeper blacks, higher contrast, better off angle viewing, etc. Today the affordable solution is the Plasma however it draws lots more power than the LED/LCD does. LED / LCD is the proper technology for the RV market and IMHO for the high end home environment the affordable technology is Plasma but OLED is coming on strong.

I managed 35 years as a broadcast engineer / Product manager

PS - If that CRT system is the high end Sony three tube with 9" liquid cooled CRT's I have several spare tubes if interested

[Almot]

BR is not terribly important in RV. The screen is not big enough to see the difference from SD DVD or even a compressed digital file on laptop. Though laptop at twice smaller screen would draw same power as DVD + 26TV.

[pnichols]

Mena,

That BD-E5700 is very low power for standard/Blu-Ray DVD playback in an RV - it looks to be about twice the width of my tiny little Nagnavox 8 watter, but that's no problem. Thanks at lot for the link!

I'd like to know what video engine they're using for the upconversion of lower resolution DVDs. My older Samsung home system's Blu-Ray DVD players uses HQV technology - which is superb and specifically why I bought it. With it at home I can hardly tell the difference between Blu-Ray discs and upconverted standard DVD discs on our 58 inch screen. On a 26 inch screen in an RV you could not see the difference between full resolution progressive Blu-Ray DVD playback and standard DVD upconverted progressive playback with the HQV engine.

However as I mentioned earlier in a post, deep black levels that result from high contrast ratios is also very important ... with many LCD and LED TVs falling way short in this area. That's why my home system still employs three high resolution red/green/blue CRTs - which are legendary for their accurate reproduction of the black levels in images.

[mena661]

PN, good luck with that search. 🙂 I have yet to see a low draw TV with a built-in low draw BR player. My standalone cheap Bluray player draws 25W. There may be some players that draw less watts.

EDIT: This one, Samsung BD-E5700, only draws 12.6W while running according to specs.

[full_mosey]

I deliberately chose a Vizio 19" VM190XVT because it had the 12V brick. The reason was that I could use the 12V plug at the Antenna connection.

It stands to reason that there will be less battery draw when I avoid the two conversions that would be needed if it was run from AC.

KAW shows the brick using 16.2W and 33.3VA at .47PF. That says to me 1.6A or less on 12V.

With an inverter I would use 3.3A plus inverter losses for the battery draw. 1.6-A is much better than 3.3+A.

HTH;
John

[pnichols]

Mena,

Now ... for the ultimate upgrade challenge that is perplexing me.

Find a state-of-the-art low power draw 26 inch LED TV (with superb image characteristics) that ALSO has a built-in Blu-Ray DVD player with low power draw ... so that you have one video screen appliance that does it all.

It's a pain having to mess with both a DVD player and a separate TV in order to watch movies from your collection when boondocking in the rain. 😞

(I have an ultra-low power draw - 8 watts - DVD player for the RV but it means setting up another appliance along with the TV, it's not a Blu-Ray player, and it has no brick so I have to use an inverter with it.)

[mena661]

My Vizio doesn't have a brick so I can't test that. Although given what Almot said, it probably wouldn't be that much better. Wasn't concerned with picture quality at all. I specifically looked for a TV with low draw. It was to replace the cheap crappy one that came with my "old" 5er. That TV drew a whopping 75W and it was also a 26" LCD. About my inverter, I never tested this myself so take it for what it's worth but efficiency is rated at 80-90%. In reality it's probably similar to that Powerstream converter. BTW, looked at those converters when I was considering going 24 or 48V. Was interested in a unit that could be run 24/7 without crapping out. Some DC-DC converters looked like they could only be run occasionally. The Powerstream's seem to be pretty beefy units. I find the inverter usage to be very convenient and less costly than running from 12V plugs. I have one 12V plug behind the passengers seat in my rig and it most likely is the too small wiring, not enough amps capacity type. Didn't feel a need to run thicker wires and higher capacity plugs all over the place. One inverter and three cables was all I needed for installation. And it's all neatly tucked out of sight. DW and I can plug into any outlet in the coach and get power. No need to run around telling people which outlets they can and can't use (this detracts from my camping enjoyment).

[pnichols]

Here's the actual DC-to-DC upconverter brick I would use with my LG 26 inch 720P HD TV so as to operate it directly from a 12 volt receptacle in my RV to eliminate use of the stock brick plus inverter - note that it's efficiency is listed as 88%:

http://www.powerstream.com/z/ED1010.pdf

By the way 88% efficiency is higher than most inverters, so in my case I'd use up less RV battery capacity to power my 26 inch TV from a 12 volt receptacle using the upconverter in the link above instead of using the brick that came with the TV and my existing inverter.

I'm not advocating elimination of use of inverters in RVs (so as to directly use 12 volt receptacles) for ultra low current-draw periodic appliance recharging applications such as iPhones, iPads, toothbrushs, shavers, etc. - just use direct 12 volts for as much as possible inside the RV otherwise. For instance, laptops and TVs are often used many hours when camping so - since modern laptops, LED TV's, etc., already use low voltage DC circuitry internally - why not take advantage of this to stop using inverters with them?

I use a DC-to-DC upconverter brick plugged into a 12 receptacle for my laptop all the time and for many hours in the RV ... so it would be very easy to do it with an LED TV, too.

[Almot]

I recall from the store that had specs of small DC-DC converters, up to 10A, the efficiency was not too impressive, ranging from 60% to 80%. So by all means, get a small inverter, lose 10% and plug in all those AC-DC "rectifiers" bricks. It is just too complicated to convert each one to its own VDC - TV, cell phone, cordless drill etc etc.

[pnichols]

Mena,

Now measure the draw with a DC-to-DC upconverter brick powering your TV instead of your 120V-AC-to-12V-DC stock brick plus inverter combination powering your TV - to see which draw on your RV battery bank is less between the two setups.

Then ... the gauntlet may really wind up being thrown down.

By the way, I notice that the dynamic contrast ratio of your Vizio is not specified. This is not the best situation in the video screen specifications world - it could lower than optimum ratios in the design with subsequent compromise in subtle image quality. My LG's dynamic contrast ratio is 3,000,000 (that's 3 million) to 1. TV's with dynamic contrast ratios this high may indeed get beat slightly on current draw by TV's with lesser contrast ratios. FWIW, high contrast ratios make for superb black levels for the best images, but only avid videophiles demand these kind of performance niceties.

[mena661]

PN, NOPE!!! I measured the draw myself, don't trust specs. Draw was 20-24W. It has an ambient light sensor. The only time it was 30W was for the first 1/2 second it was turned on. It quickly drops. My challenge still stands.

EDIT: I have a thread about this here somewhere. Can't find the thread but here's a quote from me on the testing, "Startup watts is 36.7 but quickly settled to 22.5W. It ran as low as 20.3W while watching a movie. This was with lights on but at night. A pitch black room got 20.2W. A fully lit room by sunlight raised the draw to between 26.7 to 27W. I bought it from Walmart online."

[HiTech]

My Visio draws less MSW AC power than its spec as well. Works really well from a small inverter.

Jim

[pnichols]

mena661 wrote:

I keep saying this but the 12V TV crowd never has a response. I have yet to see a 12V TV draw LESS power than my off the shelf, 26" Vizio. If there is a 12V 26" LED LCD that draws less than 2A DC, I'll STFU about it.

Hmmmmmm .... here's the specifications for the VIZIO E261VA (click the TECH SPECS tab):

http://store.vizio.com/e261va.html

.... and it looks like it's power consumption is 33.8 watts which - if an inverter in an RV powering it was 100% efficient - it would be drawing about 2.82 amps of 12 volt current. Since inverters aren't 100% efficient, this TV would probably draw in the neighborhood of 3.52 amps from an RV's battery for each hour the TV was running.

My 26 LED LG 720P HD TV draws about the same, but this question remains: If I power my LG with a another DC-to-DC converter brick that makes 12 volts into 24 volts (the internal DC voltage required for my TV's circuits is 24 volts) so that I can plug it directly into an RV's 12 volt receptacle - would the current draw on the RV's batteries be less or more than powering my TV via it's existing brick and through my PSW inverter? (I bought my LG TV specifically because it's brick could be unplugged from the back of the TV and replaced with a DC-to-DC converter brick for use in the RV directly from a 12 volt receptacle.)

A more basic question is: Are modern small PSW inverters more or less efficient than modern DC-to-DC upconverters?