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solar panels and battery shopping
#1
arizona wind and solar
https://www.solar-electric.com/solarland...panel.html
battery is around $200 have amg,gel and lead acid


renogy
https://www.renogy.com/renogy-100-watt-1...lar-panel/
https://www.renogy.com/renogy-eclipse-10...lar-panel/
have gel,amg battery $200

renogy doesnt have lead acid but has free shipping


if you were going to get a couple solar panels and a 100 ah battery from one of these companies,which would it be?
"not of the body"
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#2
Do we have to pick from those options? 100w Renogy panels are about $110 on amazon, and were recently less than $100 at home depot.
---
frater/jason - FT 2018.  Retired/boondocking 2020.  
159" Promaster, 570w:220Ah, 35gal fresh
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#3
I have had customers order the Renogy batteries and pay for the expedited shipping they got them the next day.

There are a lot of great things out there today.

If someone wanted to build a solid system, (with limited funds) where would you go and what would you buy? Stearnwake, any suggestions?
Compared to parenting, Cat herding is less complicated
[-] The following 1 user says Thank You to GotSmart for this post:
  • heron (12-22-2017)
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#4
Yes, please, SW!
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#5
We got panels from Home Depot but need the rest of the stuff.
I'm not lost. I'm exploring.
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#6
I've not been shopping nor keeping up with solar panel nor solar controller offerings for a long while, so it would be irresponsible of me to make product recommendations, and I do not like doing so unless I have actually used or tested a product myself.

But The features i recommend on solar controllers are easy enough, adjusable absorption voltage and float voltage and adjustabe absorption voltage duration. Whether PWM or MPPT.

The loud touting of MPPT increased harvest, over PWM controllers elsewhere on the net when 12v nominal rated panels are employed, can be considered grossly overexaggerated by those who do not really understand what is going on. If going to 24v Nominal residential panels then MPPT is necessary.

Far too many solar controllers left on stock settings, on batteries deeply daily cycled, will not hold absorption voltage nearly long enough, which leads to prematurely sulfated batteries needing to replaced well before that should have been necessary. Those who think premature float voltage will have enough time to top up the battery in the remaining daylight, are trying to anthropomorphise batteries, thinking the float stage is nice and smooth and gentle. The battery wants to be truly fully charged, before the next discharge begins. When daily deeply cycling batteries, seek and hold absorption voltage until a hydrometer says the battery is full, or with an AGM, an Ammeter reveals current into the battery to have tapered to 0.5% of battery capacity, or less. 100 amp hourAGM battery, hold it at 14.4 to 14.7v until amps taper to 0.5 or less.

A solar controller which can allow the user to bump absorption voltage duratin from 2 to 4 hours will likely double their battery longevity if they are cycling their batteries 365 times a year, but a hydrometer will dictate how long absorption voltage needs to be held. Excessive absorption voltage duration is not desirable either.

Avoid Gel batteries if alternator charging is going to be employed. Too many amps caused by uncontrollable vehicle voltage can instantly cause voids in the gelled electrolyte forever reducing capacity.

Gel batteries are good and can be superior in certain applications but not in most RV usage.

Fit as much solar as you can on the roof. It will extend battery life and give the warm and fuzzies that many choose to seek through lots of unnecessary and excessive battery capacity.

Premature dropping to float voltage from absorption is the main killer of a huge percentage of deeply cyled lead acid batteries.

Gel batteries are Lead Acid batteries, So are AGM.

Differentiate regular sloshy batteries by calling them wet, or flooded batteries.

Also there are sealed flooded batteries whose caps are not easily removed nor water added.

Avoid these for cycling duties. They are best used and intended as starting batteries, and if accidentally deeply cycled, need higher voltages applied until amps taper to near zero before they can be considered fully charged.

I have heard that some retailers are slapping marine labels on these maintenance free sealed flooded batteries. Avoid these batteries for anything but as starting batteries on a vehicle that has nothing to do with having a bed inside.
[-] The following 4 users say Thank You to sternwake for this post:
  • Gunny (12-22-2017), Putts (12-23-2017), TWIH (12-23-2017), Scott7022 (12-23-2017)
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#7
Next question, say you only have a marine battery, group 27-29 for your starter. Say you want to charge it some off solar and you get a 30 watt glass panel to place on your dash. Then you confirm that your ciggie plug on the dash is always hot. Is it ok to just directly plug the panel into the car outlet without the cheapo pwm controller?  A particular 30 watt panel says: 
  • Maximum power (Pmax): 30W

  • Voltage at Pmax (Vmp):17.4V

  • Current at Pmax (Imp): 1.74A

  • Open-circuit voltage (Voc):21.6V

  • Short-circuit current (Isc): 1.93A

    so 17.4 watts and 1.74 amps.  Is that really going to bother a large marine battery to not have the voltage regulated? I know the cheap pwm controllers are $10-20 but they waste a lot of power, and the 30 watt panel doesn’t have that much output to begin with. Plus being on the dash makes it weaker yet. What say thou?
"Life is short, smile while you still have teeth."
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#8
Any panel that's going to do you any real good is going to need a controller so it doesn't overcharge the battery.  And, as you seem to already know, putting a panel on your dash, under your windshield, drastically reduces the output.

As far as I can tell, small panels, on your dash, and plugged in through your cigarette lighter, are designed to serve as trickle chargers to keep your starter battery good while you leave your vehicle parked in a long term lot at an airport for a month or two, to make sure it starts when you fly home.  I don't think they produce enough power to be useful to us, unless you're just trying to keep a cell phone charged or something REALLY minimal like that.
Regards

John


I don't like to make advance plans.  It causes the word PREMEDITATED get thrown around in the courtroom!
I'm NOT crazy!  My mother had me tested! Cool
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#9
So in general, even if the panel is small and not likely to really over-voltage the battery (like the example above), it’s better to use a cheap pwm and accept the losses, correct?
"Life is short, smile while you still have teeth."
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#10
(12-25-2017, 03:53 PM)TWIH Wrote: So in general, even if the panel is small and not likely to really over-voltage the battery (like the example above), it’s better to use a cheap pwm and accept the losses, correct?

I would defer to Stern or GotSmart on that, but my take is that any panel that will fit on your dash probably isn't worth having, for our purposes.  Any panel big enough to be worthwhile WILL need a controller.
Regards

John


I don't like to make advance plans.  It causes the word PREMEDITATED get thrown around in the courtroom!
I'm NOT crazy!  My mother had me tested! Cool
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