12v Dish reciever or extra 75 watt solar panel?

[mightybooboo]

Sent: 6/18/2003

I currently have a 12 volt 13"color tv/vcr,and a 120 volt dish receiver. Don't know what the dish draws power wise (hopefully you do?). I would like to know how to get the best bang for the buck,buy an extra panel or a 12 volt dish reciever? We watch lots of satellite when available.Price is about the same at 350.00.Should I go all 12 volt for TV setup or invert the dish?Or even get a LCD TV?? Currently 150 watts of panels.Plan is 375 watts of panels eventually( 3 more panels) .We like to boondock. Help greatly appreciated,thanks
Solar BooBoo

AST #402 12 VOLT DISH NETWORK SATELLITE SYSTEM
SPECIFICATIONS: DIMENSIONS: 17" Wide x 10.75" Deep x 3.25" High         
Shipping Weight: 8 Pounds         
RCA System Navigator Menu         
Color On Screen Menu System         
Digital Video & Digital Stereo Output         
Complete with 18" Dish & LNB DC         
         
Draws Approximately 1 Amp @ 12 Volts DC         
         
$ 355.00 Plus Shipping         
         

AST #402
12 Volt Satellite System

For more Information, Please E-Mail: CMACM Technologies
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Oh,1 more thing,using the inverter for only 35 watts,would it perhaps be soooo awfully inefficient at that low power draw that the ONLY reasonable answer is the 12 volt dish which is very efficient.Its a 1000 watt continuous rated inverter. I'm thinking the inverter efficiency at that low rate must be horrendous,but I really don't know.
Thanks again,
Boo 

[melyash]

Sent: 6/23/2003

Boo, It seems to me, that waste not want not, if the 12V system meets your needs then get that unit. You would be far more efficient since the inverter is going to be so massively inefficient to begin with. You would be going 12V, with whatever loss in your power cables to the inverter, through the inverter, with it's attendant loss's of up to 15% and then into your Dish receiver. Seems like a lot of loss to me.

As for an extra panel, you can never have too much Solar, but you reach a point where your current batteries will not take any further juice without boiling. Just keep it in mind.

Matt

[mightybooboo]

Sent: 6/23/2003

Matt,thanks for comments. I'm trying to make a simple strategy for the solar for decision making that will fit all modes and i think i got it.Its "EFFICIENCY FIRST"
Think that would cover well in all solar decisions and save a lot of searching for answers.I may open up one of the dish receivers and see if its got a transformer in there,if so I'm gonna probe it with my volt meter. Wouldn't it be something if the thing is running on  12 volt internals???
Will let you all know what I find.
BooBoo

[Collyn down-under]

Sent: 6/23/2003

Boo

Agree re using 12 volts. Inverters are extremely inefficient on very light loads - your 35 watts is more likely to be at least 60 watts taking inverter losses into account.

Re too much solar capacity - as long as you have a good solar regulator there's no risk whatever of overcharging no matter how many modules you have - that's the main point of the regulator!.

Do note that batteries should gas a bit once past about 60% charge - and should use some water. If they do not need topping up very three months or so it's a sure sign they are being chronically undercharged.
Collyn down-under

[mightybooboo]

Sent: 6/23/2003

Collyn, also picked up some mineral oil the other day. I'm going to put it in the cheapo wally world battery and see what happens.Supposed to keep  big bubbles from forming,makes a lot of teeny bubbles that don't pop and splatter while charging and therefore keeps the terminals cleaner and less water loss.Kind of like the Thermoil (TM) brand battery thing.Have heard good reports from people who have done this(but only short term reports so far),only problem is to keep the oil off the plates as thats supposed to be a very bad thing.
BooBoo

[Collyn down-under]

Sent: 6/24/2003

Booboo
Have never tried the mineral oil technique - but it's been around for at least 100 years. It was used by telegraph technicians on the original telegraph line from Adelaide to Darwin (that runs right up the center of Australia) in the 1890s!. I'd be interested to hear from anyone who has long-term experience of doing this.
Collyn down-under

[Rick Shaw]

Sent: 6/25/2003

Boo,

So are you saying that the 12volt dish system takes a lot of power to use?  I have to explore options right now because I don't have a generator and my home dish system cannot be used  while boondocking.
Rick

[mightybooboo]

Sent: 6/24/2003

Rick, if the ad is true the 12volt dish system only draws 1 amp(or 12 watts), a minuscule amt.  Using the 120volt home dish(35 to 45 watts, depends on system.) would use a lot more power (3 times as much) If we were to use an inverter to power it from our own batteries  we would have the inverter conversion loss(possibly another 30 watts)  So now it looks like the 120 volt  would draw 60 watts.  Looks like the 12 volt dish uses only 1/5th the power of the home dish does when boondocking.

Collyn, would you please correct my numbers if I blew the math here again?In any event,the 12 volt is the most efficient.
I will go the 12volt dish as my next system upgrade.

BooBoo

[mightybooboo]

Sent: 6/24/2003

Soooo...To see what a Dish receiver uses power wise internally I opened up my Dish box and looked inside.There is what looks like a small transformer by the power cord.Its part of the circuit board.  I didn't probe it as to do so requires removing board from chassis.  Also it says on the box that the LNB runs on 13-18 volts (Now is that a promising clue or what??).  However I paid a bunch for this home receiver and don't want it going PHYTTT!!! and smoking away as I ignorantly probe along.Anyone here got the smarts to attack one of these receivers and see what the it really uses power wise inside the box?  Is it being knocked down from 120AC to 13volts or so DC?  Hmmmm...Let me search the web and see....
BooBoo

[Rick Shaw]

Sent: 6/25/2003

It appears that the 12volt dish system is the more efficient way to go.   I had two dishes.....one at home and one in the motorhome and just unhooked the box from the house.....it was a pain in the arse but sometimes you need 130 channels on the road.    If the 12volt system is about 350 dollars then it sounds like a bargain.
Rick

[mightybooboo]

Sent: 6/25/2003

Rick,yes it seems the consensus is 100% that the 12volt dish is the way to go.
Thanks everyone for all the help in figuring this out,its really appreciated!
Drinks are on me.
The Boo Crew+3 crabs(grandsons new pets),as if we need more

[Collyn down-under]

Sent: 6/25/2003

BooBoo

Your maths are impeccable! It's very likely the 120 volt unit is simply the 12 volt unit with a transformer (and rectifier) that converts the 120 volt back to 12 volts again. If so the reason it uses so much more energy is losses in that transformer.

If there is any cost advantage you could probably adapt the 120 volt unit by by-passing the transformer etc and running it off 12 volts dc. Best to find a friendly radio amateur - or someone who knows their way around electrics tho before you get in their with a soldering iron!

Otherwise - go for the 12 volt unit - otherwise you are converting 12 into 120 and back again to 12. Which does not make any sense at all (except it helps heat up the truck).
Collyn down-under.

[mightybooboo]

Sent: 8/26/2003

I tried to order the 12 volt dish setup,no reply from the company,so unless someone knows another source the 12 volt option is a no go.
BooBoo