First off, thank you all for all of the wonderful input! Secondly, i went back and re-calc'd the load. It's actually 2.1 amps @ 24vdc (not 5 amps as i previously stated).
What are the formulas (or websites) folks are using when sizing out solar systems? Thank You, Mike > On Nov 20, 2013, at 7:18, Eric Flanery <eflan...@fsr.com> wrote: > > A couple more thoughts... > > 5a/24v load on 600w of panel... That puts you at 5 hours of full sun, per > day, just to cover the load. Unless you are close to the equator, that > doesn't leave much for increasing the charge on the batteries. If you go even > a few days without full sun, it will take quite some time for the batteries > to recover. > > If you do go ahead and add more panels, and switch to a mppt controller, I'd > wire those in series as well, to 72v or 96v nominal. Most mppt controllers > can handle 150v, but you don't want to get too close to that, as panel output > can easily exceed their nominal rating. There are now mppts that can handle > 600v, but I have no experience with those. > > Regarding tracking arrays, I wouldn't consider them unless space is at a huge > premium, and the site is easily accessible for repair. You will almost > certainly get a better bang for your buck by spending the money on additional > panels, rather than trackers. > > --Eric > > -----Original Message----- > From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On > Behalf Of Robert > Sent: Tuesday, November 19, 2013 10:57 PM > To: WISPA General List > Subject: Re: [WISPA] Solat panels: series or parallel? > > Eric has the idea spot on, I'll follow up with what a lot of > off-gridders around here in N. Nevada had tutored me on. That is the > losses and controlling them. Number one with a bullet is loss from > throwing electrons down wires.. You know it from poe losses and it's a > 100 times worse in solar applications. The biggest gain through using > serial panels is in reduction of current loss through the wires between > the panels and to the charge controller. You would have to have > monster wires to be as efficient as 3 amps down reasonably sized wires > at 120 volts as 15 amps at 24. And as you go from the charge > controller to the batteries and you eat away your 5 amps ( at 24 Volts? > That is Big ) you still have 10 amps between the controller and your > batteries. Get Very Large Cables, as large as the controller will > accept. MPPT controllers are the ticket unless you have tracking > arrays, in which case the guys here go back to pwm for better results. > I haven't figured out why, they just show me the numbers that show it. > MPPT controllers running in serial also have the advantage that you > can mix and match your panels without losing the output of your large > panels into the small ones.. > > Lastly we angle our panels in the winter to the lowest sun angles as > that is when the transit is shortest and the need the greatest. > > Robert > >> On 11/19/2013 09:18 PM, Eric Flanery wrote: >> I'd replace the controller with a mppt model, wire the panels in series >> (to 48v nominal), and leave the battery bank at 24v. >> >> Decoupling the panel voltage from the charging voltage let's you start >> charging a bit earlier, and keep charging a bit longer; plus mppt is a >> bit more efficient than pwm. >> >> Most importantly, it let's you double your panels (which is your best >> bet overall), without having to increase the gauge of your wiring. >> >> --Eric >> >> >> Sent from my Samsung Galaxy Note(r) 3 >> >> >> -------- Original message -------- >> From: Mike Lyon >> Date:11/19/2013 8:29 PM (GMT-08:00) >> To: WISPA General List >> Subject: Re: [WISPA] Solat panels: series or parallel? >> >> And it has about a 5 amp load... >> >> >> >>> On Nov 19, 2013, at 20:23, Gary Garrett <ggarr...@nidaho.net> wrote: >>> >>> You probably need more Sun, or less load. >>> It sounds like you have it wired correctly. >>> The panels should tilt south about the same angle as your Lattitude. >>> Up here on the canadian border we are at 48 degrees lattitude so the >>> panels tilt about 45 degrees. >>> In the summer they lay flat. >>> >>> Gary >>> >>> >>> >>>> On 11/19/2013 7:43 PM, Mike Lyon wrote: >>>> So i'm trying to figure out what i need more of, voltage or current? >>>> >>>> I have 2x, 300 watt, 24vdc panels. I currently have them wired in >>>> parallel to a Morningstar SS20L-24 which in turn is hooked up to 4 >>>> banks of 2x 12vdc deep cycle batteries (for a 24vdc system). I plan on >>>> replacing these batteries soon with UB4Ds or something similiar. >>>> >>>> What would be best to keep these beasts charged? The solar panels >>>> wired in series or parallel? >>>> >>>> Thanks, >>>> Mike >>>> _______________________________________________ >>>> Wireless mailing list >>>> Wireless@wispa.org >>>> http://lists.wispa.org/mailman/listinfo/wireless >>> >>> _______________________________________________ >>> Wireless mailing list >>> Wireless@wispa.org >>> http://lists.wispa.org/mailman/listinfo/wireless >> _______________________________________________ >> Wireless mailing list >> Wireless@wispa.org >> http://lists.wispa.org/mailman/listinfo/wireless >> >> >> _______________________________________________ >> Wireless mailing list >> Wireless@wispa.org >> http://lists.wispa.org/mailman/listinfo/wireless > _______________________________________________ > Wireless mailing list > Wireless@wispa.org > http://lists.wispa.org/mailman/listinfo/wireless > _______________________________________________ > Wireless mailing list > Wireless@wispa.org > http://lists.wispa.org/mailman/listinfo/wireless _______________________________________________ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
