Questions on Solar and Deep Cycle Charging and MORE!

[River Song]

I could guess but I would rather ask the experts! Since I know a lot of you have experimented with the use of Deep Cycle batteries to power varying things on and off playa, used solar possibly to charge said deep cycles, you are the best possible group of people in the world I can think if to ask about this.

So, I have a project in mind for my vehicle. And by that I mean, I'm turning my 2006 Pathfinder into my ultimate camping vehicle. But I'm not just camping in it... its becoming my home for a while. I'm going to go with a roof top camping system with it. But what I'm wanting to do electronically is where things get interesting. So I have a the thumpin sound system which is a must for me as music is my life. I will be putting in a deep cycle specifically to run my sound system (deck 1.5-2 amp, 2 sub 12in, 500w amp, 300w amp, 4 6in door speakers, 2 6x9's) and rbg light strips. Now i also will have a small 12v fridge and a freezer I would like to power in my vehicle. I've looked into solar panels for this and would like to put in a system that can be charged with solar when I'm sitting still. My question is... approximately how many deep cycle batteries would you recommend? What type of power inverter? Do you have specific things you've tried and liked? Do you have definitely do not do that suggestions? How many and what type of solar panels would you suggest? I would like to have the option for using a laptop need be. Possibly for future add ons as per need. Remember this isn't just for the Burn... I'm seriously considering this becoming my new living space. Let me here what you guys think! I'm excited to try this. Open to your suggestions!

[Token]

Surface area of your roof will pretty much dictate the capacity and capability of your solar setup.

The rest is just figuring out some basic arithmetic.

[some seeing eye]

Welcome to ePlaya! Can you go over to the Greater Station and say your city?

ePlaya has better search via google, oddly. So if you do https://www.google.com/search?q=site%3A ... ar+battery

or site:eplaya.burningman.org search-terms

you can get a start.

Many burners have experience solving your use case. Audio loads would benefit from measuring with a meter because they quote inflated Watts.

[River Song]

Thank you. Posted my little ditty on Greeters too. I have done some research... still not search about exactly what I'm doing. I know what I want just not sure how to make it happen!

[XPTom]

here is some solar math tips for beginners.

Panel wattage isn't what it seems. The 100W rating of my first panel translated to 5+ amps at 18ish volts. Your basic economical PWM charge controller simply protects the battery and passes 5+ amps to the battery at an average 14ish volts..... minus a few percent of cable and battery loss and figure on 60+ useable Watts. More expensive MPPT controllers convert the 5+amp/18 volts to 7+amps/14V and you can figure your 100W panel to be 90+ watts. …..(or eventually become fluent in "Amp Hours")

Hours in a Solar Day vary greatly with panel alignment. Dunno if you re talking about rooftop camping tent or panels. I tilted my freestanding panel 30+ degrees and pointed it toward the sunrise(stand on 7:30 and aim near the man.) 3+ amps within minutes of sunrise and the full 5+ amps well within an hour. Adjust the azimuth a few times day and you have 12++ prime charging hours. After I got crowded in I laid the panel flat on top of my vehicle and took a big hit. Low sun angles reduce morning and evening output and dust on the panel cut into the afternoon output. If you're laying them flat on your roof figure AmpHours on a 9 hour day or less..

Battery charge time is on a curve also. Basic lead acid batteries can reach 70% charge in 7 our so hours, and another 7 to top off. A true deep cycle that you're asking about is even slower to top off. Simple math showed my 70AH battery to be adequate, but it never got to the finish line before sunset. Theory says a 100AH battery with 70% charge is equal to a 70AH that is 100% charged, but reality is one of those charges faster......err in favor more AmpHours when doing solar charging math.

Pad all ratings 30 or more percent. Don't hook up 18 amps of panel to a 20 amp charge controller in the Black Rock heat.... ditto A/C inverters...

[some seeing eye]

I always recommend high quality monocrystalline panels. That is especially true for small areas and low demand as Mr Token notes. There are various websites that rate panel reliability for solar. You will find brand new project leftovers for sale at local solar installers and Craigs. There is a rumor that "wholesale solar" websites can benchmark prices. Given the increase in efficiency, new may be more economical than overpriced used panels.

It sounds like you might want a mostly 12V load system. If you look around the DIY audio sites, you may find class-D amplifiers with built in DSP systems. With a little work, you can do your crossover and even tune equalization with the DSP. Keep in mind that the vehicle 12V system, when the engine is running, is extremely noisy electrically and electronics need filtering protection from that to prevent being destroyed.

You can save a huge amount of battery drain by using wireless headphones while parked instead of free space speakers. Obviously headphones while driving are illegal.

You will get better use of your panels, as Mr XPT notes, by being able to adjust the angle to horizon and compass by site and hour.

Thanks for posting to our Greeters. You will find solar DIY groups in Oly, SEA and PDX, as well as other burners to meet. Solar RV is a useful search term as well. At the event, stop by the Alternative Energy Zone [AEZ] village. You will find plenty of experienced solar DIYers. You can also research "burning man mailing lists." The AEZ has one.

[Token]

Before you get too giddy on this dream, you really need to downsize your expectations.

First, your vehicle has very limited surface area on the roof. ~ 2 square meters. That limits you to about 300W of panels, maybe more if you are rich and can afford panels with 23% efficiency.

Second, as XPT mentioned, unless you can have the panels align either automatically (ooh, expensive) or manually (ooh, are you really gonna dote over panel alignment five times a day?) you are looking at marginal charging hours. Maybe 8 hours per day?

Then you got your fridge n freezer that need power 24 hours per day so your panels need to store all that juice in the above 8 charging hours ...

So if your fridge n freezer consume 100W per hour on average, you’re at capacity already.

So, measure the power draw of your fridge n freezer. Know for sure what it is over a 24 hour period before you do anything else.

[RudolphDiesel]

I tried operating a fridge on solar, and I even had a rack that oriented the panels towards the sun. With 200-300W panels that is a no go.

So, if you want to have a fridge you have two ways to solve that:

A) use a RV fridge and operate it on solar only for the electronics. Those sip very little power, but the cooling comes from a propane container. A single 20lbs propane container is sufficient for the week if you’d don’t use the propane for anything else.

B) run a generator

We are going to use a propane operated fridge