$.80 solar panels

[EldIr]

A while back, maybe months, maybe last year, someone posted a link to solar panels for 80 cents per watt. I've tried searching but can't find it. I've also looked around eBay and Amazon and can't find anything even close to $1 a watt. Anyone have a link?

[Gulfcoast]

My Xantrex digital 400-watt inverter uses 0.25 Amp on standby... thats 3 watts. I can't find another one that uses less, or I'd buy it. smile

[EldIr]

BFL13 wrote:
No way is that 3 amps with a 300w inverter. Something else must be going on there.

Eg using the 1000w inverter and a 120v CFL lamp I get a 2 amp draw showing on the Trimetric, vs a 3 amp draw with no inverter and one 12v two bulb lamp. The CFL lights up the whole place in comparison with the 12v lamp. ( I don't have the newer, better LEDs for the 12v lamps)

I won't be back to the cabin until the week after next due to work. I'll recheck the inverter manual and test the draw with my Fluke but I'd swear the manual said the inverter draws about 30w. It does have a cooling fan that runs any time it's on regardless of load and I know some of those aren't very efficient. It is quite old from before pure-sine inverters became all the rage. (back then, even the cheap modified-sine were still expensive not like the 30 dollar ones at the auto parts stores now.)

[westend]

Newer pure sine inverters up to 1000w output use around .5 amps or less when not powering a load. Nearly all are better than 94% efficient.

You'll have to make the decision whether having all 12V appliances is better than a mix of 12V and 120V items but I'm guessing that you are going to have some of each. That means an inverter is going to be in use, anyway. FWIW, I think the difference in standby load between a Samlex 600W and a Xantrex 1000W is less than 250 MA, maybe less.

[BFL13]

No way is that 3 amps with a 300w inverter. Something else must be going on there.

Eg using the 1000w inverter and a 120v CFL lamp I get a 2 amp draw showing on the Trimetric, vs a 3 amp draw with no inverter and one 12v two bulb lamp. The CFL lights up the whole place in comparison with the 12v lamp. ( I don't have the newer, better LEDs for the 12v lamps)

[EldIr]

I think a couple of you are misunderstanding my efficiency question. It's not about comparing 12v to 120v loads. It's about the inefficiency of the inverter itself. The inverter uses some of the power coming from the batteries just to run the inverter. If you're running 12v loads, you're not wasting the power the inverter itself uses. I think our 300w pure sine inverter draws about 3amps all by itself independent of what it's outputting.

Also starting to look at hydro as an option as we're right on a river. Need to do more math as the initial purchase is higher than solar, but running 24/7 the power over time may end up costing less.

[BFL13]

We had a thread here not long ago where were looking at possible "remote" power supplies for an RV where the RV had no battery in it. All you need is to plug the 120v shore cord into an inverter in the power supply.

The RV converter makes any 12v needed, but of course it costs extra amps (about 6a being a typical amount, so in an hour that's an extra 6 AH to get from the solar later on.

A cabin does not need any 12v stuff, just 120v, so you could park a 48v golf car (or your truck with batteries in the bed) outside with a 48v inverter strapped to those batteries and put solar on the roof of the golf car.

If the cabin is in the shade, move the golf car out into the sun--it doesn't matter so much how long your 120v line is to the cabin.

We park our RV for long periods in the one place and use it as a sort of cabin, so I keep looking at this, but can't escape the RV's 12v stuff totally (so far! 🙂 ) A real cabin saves you from that.

Anyway it is another approach to the problem to give a thought to.

[mena661]

EldIr wrote:
I'd be curious to know if the inefficiency of using a 12v controller is really more wasteful than running an inverter.

I find that it depends on the device. My Vizio 26" LED LCD TV draws less power running through an inverter than any same sized, and even smaller, 12V TV I've ever seen. It seems that efficient 120V devices draw less power than most 12V only devices but I haven't done really in depth research to prove this. My Vizio TV and a Bluray player I once found drew way less than any 12V comparable device I've seen. I'm assuming that if I looked further into this, I'll find more.

[Canadian_Rainbi]

EldIr wrote:

BFL13 wrote:
There is a saving in solar where the controller only has to step down to 24v instead of 12v to run things. So a 24v inverter on a 24v battery bank supplying 120v has that advantage. Going to 48v even greater. You lose that when you choose 12v systems that need the controller to step down to 12v.

It would be interesting to compare the savings using 12v direct rather than bricks taking in 120v from inverter with the solar savings from only having to step it down to 24 or 48v.

The Rv is tied to 12v by the fridge and furnace control boards needing 12v even though they run on propane. Otherwise, you could do everything with 120v.

A cabin can have 120v for res fridge and heaters, so no more 12v.

All appliances are propane. Heat is wood and propane. It would be interesting to do the math, but that's too much for my head right now. Even our 300w inverter wastes battery and when we step up to 1000w, it will waste more. That's why we like to run things on 12v. I'd be curious to know if the inefficiency of using a 12v controller is really more wasteful than running an inverter.

24 volt panels will work happily with 12 volt batteries but of course you need an MPPT controller. When connecting the controller you connect the the batteries first, this tells the controller that it needs a 12V output and will convert the incoming voltage to suit 12 volt batteries. It does the same thing with 12V panels, making sure that the battery voltage doesn't exceed say 15 volts. Using 24V panels and an MPPT controller will allow lower gauge wire (cheaper) and/or lower losses and the panels are cheaper too. An MPPT controller will usually put more amps into the batteries as well. In a cabin, that is what I would do.

[EldIr]

BFL13 wrote:
There is a saving in solar where the controller only has to step down to 24v instead of 12v to run things. So a 24v inverter on a 24v battery bank supplying 120v has that advantage. Going to 48v even greater. You lose that when you choose 12v systems that need the controller to step down to 12v.

It would be interesting to compare the savings using 12v direct rather than bricks taking in 120v from inverter with the solar savings from only having to step it down to 24 or 48v.

The Rv is tied to 12v by the fridge and furnace control boards needing 12v even though they run on propane. Otherwise, you could do everything with 120v.

A cabin can have 120v for res fridge and heaters, so no more 12v.

All appliances are propane. Heat is wood and propane. It would be interesting to do the math, but that's too much for my head right now. Even our 300w inverter wastes battery and when we step up to 1000w, it will waste more. That's why we like to run things on 12v. I'd be curious to know if the inefficiency of using a 12v controller is really more wasteful than running an inverter.

[BFL13]

There is a saving in solar where the controller only has to step down to 24v instead of 12v to run things. So a 24v inverter on a 24v battery bank supplying 120v has that advantage. Going to 48v even greater. You lose that when you choose 12v systems that need the controller to step down to 12v.

It would be interesting to compare the savings using 12v direct rather than bricks taking in 120v from inverter with the solar savings from only having to step it down to 24 or 48v.

The Rv is tied to 12v by the fridge and furnace control boards needing 12v even though they run on propane. Otherwise, you could do everything with 120v.

A cabin can have 120v for res fridge and heaters, so no more 12v.

[time2roll]

I bought my primary equipment at solarblvd. I am fairly close so one of the guys delivered 3 large panels, controller, MC4 cable in their own truck for $50. Basically just gas money but no worries with common freight shipping damages.

[EldIr]

BFL13 wrote:
A cabin could be with no 12v systems like an RV has, freeing you to go to higher voltage battery bank and inverter to then make 120v for lights, fridge, etc It seems higher voltage panels are generally cheaper per watt.

Our existing cabin has, and the new one will also have, a 12v system. We use it to run a car stereo, some lights, charge cell phones, power a cell phone booster amp, etc without the need to have the inverter running (which uses battery power itself). We may have even more 12v in the new cabin like a stereo in each bedroom, out on the deck, more lights, etc.

[Tom_M1]

I purchased an 80 watt panel from Solar Blvd. last year. Shipping cost was reasonable and panel arrived promptly and in good shape.

Sun Electronics has about the best prices but shipping costs where quite high when I checked last year.

[steveexplorer]

I am still researching prices for larger 24v panels, but here is some of what I am finding:

** earthspowerstore.com 1. Kyocera KD315GX-LPB 315 Watts Black $375 2. Suniva Optimus OPT305-72-4-100 305w $340 3. Canadian Solar CS6X-295P 295w $280

** king-solarman.com 1. TOPOINT 300w JTM300 Poly $225 .75/w 2. Canadian Solar 300W Mono CS6P-300M $240 .80/w 3. Canadian Solar 305W Mono CS6P-305M $240 .80/w 4. Canadian Solar 295w Poly CS6X-295P $221 .75/w

** www.qualitytolast.com 1. ReneSola JC305M-24/Ab 305W $255 .84/watt

** solarblvd.com 1. LG/Solar Cynergy 270 W 24 Volt MONO X NeoN LG270 Solar Panel .75/w

BTW, one site had panels at .57/w but I do not remember which one! The panel was smaller than I was looking for so I did not write it down.


Do you have experience or info regarding dealing with these companies?

[westend]

Solar Blvd offerings