solar panels VS batteries

[droid_ca]

ok I 've been trying to understand the whole solar movement and I am wanting to know is it better to have more batteries so that you have a reserve supply of power or is it better to have more panels to meet the demands and have the batteries fully charged or is it better to have an equal amount of both?

[madjack]

...first, ya gotta get an accurate idea of the amount of power you are going to use...both as a max output at any one time and a max usage for a day...batteries to cover the max output at one time and panels to cover the max output for a whole day...in other words, you don't need 1000watts worth of panels to power a microwave for 5r10min, that is what the batteries are for...the panels are to replace what you have used from the battery over a days time..........
madjack

[Ratkity]

I think it depends on your needs. Don't expect solar to run your microwave, AC, electric space heater, blow dryer, i.e. anything that has high electrical requirement.

I have 1 battery (120A) deep cycle (generic). When it runs it's little life out, I will get a decent replacement. I also have one 85 watt solar panel that will recharge my battery usage by 9 am on a sunny day and noon on a cloudy or shaded area. My needs are few: cpap, fantastic fan, a couple lights, recharge phone and watch a little bit of a movie to relax before bed.

When I have full electric, I put up the chili pepper lights and plug in the electric kettle for hot water.. might even plug in a portable fan to blow away some of the bothersome gnats and bugs while I sit and read outside. All things I can live without when in a non-electric site.

Figure out what you can live with when without electric and then calculate your battery needs. Add solar as needed. Nothing wrong with getting a generator and running it to charge a battery during allotted times in a national park.

Hugs,
Ratkity

[droid_ca]

so what about times when it's say clouded over and all you want to do is stay insde read a book watch tv do you have enough battery storage so you can do that or do you have more panels to make up for the little amount of light?

[Ratkity]

so what about times when it's say clouded over and all you want to do is stay insde read a book watch tv do you have enough battery storage so you can do that or do you have more panels to make up for the little amount of light?

I had one camping trip where it rained all day and I read a lot inside, watched a movie, listened to the radio (runs on batteries), had lights on and ran the vent on low. Battery did just fine and had plenty for the next night for all the routine power draws. That was before I had the solar panel.

All the solar panel does is allow me to camp for more than 2 days in a row and keeps my battery topped off all the time, even when sitting by the house. Keeping the battery maintained without having to run an electrical cord through the basement window is a major plus!

Hugs,
Ratkity

[Cliffmeister2000]

Slight deviation from the intended topic, but...

I just had the house evaluated for solar. $30k for a 5kw system. Rebates and tax credits of $20k, leaving a net expense of $10k.

The reality of the situation:

I would need close to $30k up front as the credits don't come through until tax refund time.

Uncle Sam (who happens to be horribly broke) would be funding the credits using money they seem to be printing just as fast as the printer will print!

Even at $10k, it would take 7+ years to break even on the projuct.

Why did I post this here? Because, ladies and gentlemen, I think solar works perfectly well in a teardrop. This is pioneer ground, and teardroppers are, and always have been, of the pioneer spirit. Some day, when solar becomes realistic without Federal involvement, I plan on having it at home. For now, I am content with figuring out how to best use it in the tear.

[Shadow Catcher]

It is a balancing act. Our system is only partially installed (one of my next tasks). Compass Rose was designed with Boondocking in mind, with LED lights through out and a plug installed in the roof for the solar panel. My hope is that the system has enough reserve capacity to survive shady sites and bad weather. If I will be in an area where I want the AC or anticipate the weather or tree cover then the generator will go with us.

[bdosborn]

First thing you need is an inventory of the electrical devices in your trailer so you can come up with an amp-hr usage. Here's a link to a site that has a worksheet showing you how to figure your usage:

Solar Design Worksheet

Once you know that, there's two things you need to design for:

1. How many days do you want to go without sun?

This will allow you to pick a battery size. I can go 3 days with my maximum usage ( more if I turn the DVD player off).

2. Once you've picked your battery you can size your PV panel.

A quick rule of thumb is about 1 watt of PV for every amp-hr of battery capacity.

OR

You can go with a group 27 deep cycle battery and an 85 watt PV panel and trust us when we say you should be good for 3 days or so of cloudy days...


Bruce

[droid_ca]

bdosborn do you have any links for those batteries and panels

[mikeschn]

What ever Bruce says, goes! The wife has given me approval to build whatever I want solar wise...

I am still debating between two 30 watt panels hinged together, or one larger panel. But more importantly, the meters and controllers etc that Bruce recommends is what I want to try next.

Bruce,

a link to your folding dual 30 watt panels might help here...

Also, a link to your meter and controller might also help...

Mike...

[bdosborn]

Group 27 is the size of the battery. I would go to Costco or Sams Club for the battery. Look for one that is a true deep cycle, not a marine battery.

Here's a link to a discussion on a complete panel/controller package:

Panel Linky

Bruce

[bdosborn]

Mike,

Here's the portable 60 watt solar panel I put together. I got a chance to use it last weekend and the size is very handy. That's one thing to keep in mind: the best place to camp is in the shade buts its a terrible place for the solar panel. Portable panels solves that problem:

DIY Portable Solar Panel

I got great output by tracking the sun during the day.

Bruce

[mikeschn]

Thanks Bruce...



Mike...

[Pyrofish]

Try Batteries + if you have one near you for the battery. I picked up a Group 31 Deep Cycle 105 Ah for $100 there this weekend. Price seemed right to me

[Ratkity]

I contemplated the diy double 30 panel, but my unique body style of my reverse TD had a perfect spot for the 85W panel I settled on....



I also made a cloth covered foam cover to prevent road debris from nicking the panel:



So far, I've been very happy with it! It's only a month old and have used it 2x camping.

Hugs,
Ratkity