Solar Power Quest

[tvoneicken]

That mysolarbackup is an 1800W inverter (probably a crappy cheap one), a 90W solar panel, and an unspecified battery. The advertisement is very deceptive, although I don't believe there's anything factually incorrect. "Amazing power" is very relative...
If you want such a system, probably better to assemble it from quality components you can actually rely on in an emergency...

[blkmagikca]

Let's not lose sight of what is to be accomplished. Firstly, over time the technology gets better. Thus the 75-watt panels that were installed on my rig in 2003 are now surpassed by panels that have much more output. (When I walked through Costco in Vegas last month, they were selling 200 watt panels for about $600.) Similarly, the inverters are getting better and more powerful. With this improvement in technology, there is always going to be a vendor of questionable scruples who will offer a system that uses cheap components with a questionable installation.

As well, once you have a solar charging system installed, are you going to get caught up in the race for more wattage? Or for a bigger inverter? What the previous owner of my rig installed in 2003 was pretty much the top of the line then - he paid then about $4,000 (panels, controller, inverter & AGM batteries).

The system I have does what I need it to - I don't watch TV for hours at night - my requirements are simple: enough power to run my CPAP machine all night, provide lights (all are LED), power my fresh water pump and power my computer connectivity (laptop, router, aircard & Wilson cellular amplifier) during daytime hours when I'm boondocking.

Granted I've seen mindboggling solar arrays on big 5th wheels and motorhomes out in Quartzsite, but they have lots of real estate on their roofs AND flat roofs so that they can install huge tilting solar arrays. These guys also have lots of slideouts and more "toys" in their rigs - all these differences lead up to bizarre maintenance issues. I had a '94 LY diesel pusher with a large flat roof (which was a source of multiple leaks) and I experienced the high costs of repairs and maintenance. I had suffered as well form that insidious disease known as "two-footitis" - (lets get a slightly larger rig). This past summer I came to the realization that the KISS principle was the sane approach - keep it simple stupid - no slides and avoid the unnecessary.

In summary, make sure what you get is good quality, competently installed and meets your requirements -- then lean back and enjoy.

[lewster]

Just for informational purposes, you really can't compare panels by wattage alone.The open circuit voltage is extremely important, and one that many seeking 'bargain panels' or 'lowest cost per watt' often neglect.

Look for panels that have high open circuit voltage and similar voltages at the maximum power point. As an example, AM Solar has their panels built for higher outputs or 'hotter' voltages. Their Voc (open circuit voltages) range from 17.7-21.2VDC and their Vmpp (maximum power point voltages) range from 18.5-22.2VDC.

When connected to a quality solar charge controller with maximum power point tracking, these hotter panels turn this excess voltage into more charging amps seen at the batteries. This effect is called 'boost', and a properly designed and installed system can see up to 30% boost at the batteries over what is seen at the panel output before the controller.

ALL PANELS ARE NOT CREATED EQUAL!!!

[ROBERT CROSS]

blackmajik,

..well said, spend your $ on what you want.

My rationalization, when I get the Solar Urge.... I go outside, sit down in the SHADE, start the generator and grab a brew 'til it passes.

Bob

[UAPachyderm]

Originally Posted by robert cross

blackmajik,

..well said, spend your $ on what you want.

My rationalization, when i get the solar urge.... I go outside, sit down in the shade, start the generator and grab a brew 'til it passes.

bob

pbr?

[ROBERT CROSS]

pbr.....nope



Bob

[masseyfarm]

Bob: You are a lucky man if it only takes one brew to do the job.
Usually the more I drink, the easier I see the project, and the braver man I am.
(and thats with Canadian content)
Dave

Originally Posted by ROBERT CROSS

blackmajik,

..well said, spend your $ on what you want.

My rationalization, when I get the Solar Urge.... I go outside, sit down in the SHADE, start the generator and grab a brew 'til it passes.

Bob

[ROBERT CROSS]

Originally Posted by masseyfarm

Bob: You are a lucky man if it only takes one brew to do the job.
Usually the more I drink, the easier I see the project, and the braver man I am.
(and thats with Canadian content)

Dave

Actually Dave it took a sex pac and seven hrs to do both battery door frames.

Bob

[UAPachyderm]

Originally Posted by ROBERT CROSS

pbr.....nope

Bob

You do know that PBR has the same amount of alcohol for much less money? LOL ... Sorry, I couldn't resist!

Just giving you a hard time! Actually, your beverage looks inviting. Nice job on the battery door as well!

[spenfolder]

Originally Posted by ROBERT CROSS

pbr.....nope

That's one nice look'n battery cover Bob. Of course, I realize that image may be distorted by the "brew" in front!

Stan

[ROBERT CROSS]

Before being HB adjusted....


Bob


hi-jack over

[barts]

We're taking the Airstream out this weekend... and we'll have all the LED light, CPAP power and water pump we need, and likely finish the weekend w/ 100% charge in the batteries because of the solar panels.

The two solar panels and controller, cabling, instructions, etc. cost a bit more than a small Honda generator (I installed them myself) ... but I never have to buy, carry or smell gasoline, or worry about locking up the generator or listening to it run. During the day, when we're away hiking or sight seeing, the solar panels are charging up the batteries, and there will be plenty of power for charging cameras, laptops, etc. as needed when we return in the evening. I don't have to think about it - it just happens automagically. Vacation time .

- Bart

[slowmover]

Auto-magically, very good!

[DreamStreamr]

I like Lew's and other's advice to buy from very good supply/service company who has been helping folks like us for a long time. Cheap stuff is very rarely a bargain and often becomes doggone expensive.

Four years ago we installed two 125w Sharp panels (wired in series 24v to use the Airstream's section of pre-wire) to a MPPT charge controller.

Two weeks we completed a nifty panel tilt conversion and really like it. You can read about it here. We can tilt either panel up from the trailer's roof edge, they each pivot at the roof's center line. Not perfect, would be nice if could tilt both the same direction -- but still the panels are filling the batteries up to float charge level before lunch time every day -- no worries.

We're just completing conversion from two U2200 6v golf cart batteries to four GC2 6v golf cart batteries. A week so far on solar only and the difference in battery capacity is just amazing, seems like more than just 2X.

Sure wish I had done this a few years ago!

[lewster]

Jim,

Nice job on the tilt bars. Just for informational purposes, AM Solar has had a proprietary panel mounting and tilt system for many years. We use 3M VHB tape for attacking the panel's feet to the roof (especially effective on Airstream's metal roof) and have 2 lengths of tilt bars that work seamlessly with the mounting foot system.

In fact, AM Solar sells many sets of mounting feet to folks that have purchased SOB panels!

[Gene]

Has anyone done objective tests of the gain in charging from tilting panels? What is the cost of the tilt kits?

I suppose I could jack up one end of the trailer but the fridge wouldn't like it.

Gene

[lewster]

You can find AM Solar's tilt bars here: Tilt Bar Set - 15.5" | for Solar Panels

[slowmover]

Gene, bragging rights accrue to gimbal-mount, multi-axis degree of tracking accuracy. E-bay occasionally has Polaris, Minuteman or Titan celestial navigation units for retrofit.

[Gene]

I was just curious about costs and efficiency. I don't feel a great need to add anything, but I seem to find something new to do every year. This year it is a new floor and making a new dinette table. A TV in the bedroom has crossed my mind, but I am trying to repress that thought.

Gene

[BrandonJenna]

Mr. & Mrs. S,
Thanks for posting a link to HandyBob's site. I have been reading it all morning and was hoping I can ask a question to everyone with more knowledge and experience than myself.

If I have two of these batteries running in series:

http://www.optimatrays.com/optima_pd...34M_082104.pdf

and a two panel, 190 watt solar system with this ZS-30A Digital 3 stage PWM charge controller:

Solar Charge Controllers | Zamp Solar

Can I bump the little switch seen to the left of the display screen to the 14.7 volt setting based on the above pdf of my batteries specs and HandyBob's comments:

"Get the battery manufacturer’s charging specifications and pay strict attention to them. The charger manufacturers are nearly all not setting their equipment up for the voltage that the battery manufacturers specify. The difference between 14.4 & 14.8 volts is not 3%. That difference is nearly 20% of the charging range (12.2 to 14.8 volts). That 20% makes a huge difference in how full the battery gets before the charger shuts off. You can eventually get the batteries full by charging at 14.4 volts, but it takes hours, not minutes. We have related industries that are not talking to each other and the outcome is that the majority of RV’s are running around with weak batteries."

The RV Battery Charging Puzzle « HandyBob's Blog

Thanks,

-Brandon