What size solar panel do I need?

Malicious · Post by **Malicious** » Mon Apr 13, 2009 6:15 pm

What size (watts) solar panel do I need to charge 3 deep cycle batteries at BM daily?

dragonfly Jafe · Post by **dragonfly Jafe** » Mon Apr 13, 2009 6:29 pm

sigh...(bohica)

...since you have specified no draw, ie-what you are powering, one can only assume the batteries will remain charged (more or less, with a ~5% loss in stored power each month unless you trickle charge them)

How many amp-hours will you be using each day?

amp hours per day = (hours used each day) X (amps)

amps = watts / volts

so, how many watts are all of the devices that you want to power at once? If any of this is sound, assume 50% rated full load of the sound system (or if you want a margin, use the full rated power).

once you have all the watts added up, divide by 12 (assuming it is all 12v powered). That is your amps.

each deep cycle battery has 100-180 amp-hours of storage. As a rule-of-thumb do not use more than 50% of your capacity to prolong life. that means your three batteries have 150-270 useful amp-hours.

charging should occur at a slower rate than use, and the max. charge rate is about 1/10 the batteries capacity, so plan on 5+ hours of charging each day if you use them hard...

good luck!

ps - a search on eplaya for 12v would also turn up lots...

Sail Man · Post by **Sail Man** » Tue Apr 14, 2009 10:10 am

Here, check these guys out....

http://www.ae-zone.org/

Malicious · Post by **Malicious** » Wed Apr 15, 2009 9:32 am

The formula will help me figure it all out, thank you! The link to the AE zone is great also.
Basically what I am trying to do is power my gas powered mutant vehicle's stereo and lighting without a genie on board as I have done previously. There are 2 strings of 50 W rope lights and a 100 W stereo. I am going with EL wire for the rest of the lighting. I've just started thinking about solar so I needed that formula to figure it all out! I'm new to this so thanks for the help!

Captain Goddammit · Post by **Captain Goddammit** » Wed Apr 15, 2009 1:34 pm

Oh hell, don't do that!
If you have a gas powered mutant vehicle it'll be cheaper, easier, and better to use alternators!
You can get GM CS130 alternators super cheap at wrecking yards, from late '80s to mid '90s small GM cars and trucks... these are great, put out 100 amps at speed but more importantly at BM, they make lots of current at idle.
You can run two in parallel - I do on my Land Yacht mutant vehicle and running through a cheap, inefficient inverter it holds an 1100 watt 120VAC load at idle speed without discharging the batteries.
You can swap the serpentine belt style pulleys for regular v-belt pulleys easily.

Post by **Elderberry** » Wed Apr 15, 2009 2:18 pm

I sure wish I were more mechanically inclined.

JK

What size solar panel do I need?

What size solar panel do I need?

Thank you for your suggestions