Keep It Simple Solar

[FosterWV]

There are some really nice Solar and Shore Power set ups on here, with fridges etc. As nice as these are they are over kill for my needs, and was wondering what type of panel and controller would you guys suggest for maintaining a house battery? I’d like to keep it budget friendly I’ve looked thru Amazon and there’s so many choices.

Power needs, small water pump, lights and fan that runs all night. After two days the battery drops below 11V

I was thinking a simple 100W panel.

Thoughts?

 

[tacomabill]

You might get away with only 50W panel. Renology has a calculator, but it does not include a lot of factors like time of year and latitude and is likely biased to overestimate size needed since they sell panels. My 100W panel powers a 35 watt 2 way fridge(no propane) and I do not have anything else that draws on my 75 aH battery. I can go between 2-3 days in summer time. My guess is your system draws fewer amps per day than mine.

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Renogy's Solar Power Calculator Tool can quickly help to estimate your solar power requirements, calculate the size and cost of an off-grid solar system needed.

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[dreadlocks]

What size in AH is the house bank? In my wanderings and many attempts at solar from minimal to full blown I've found 100W per 100AH FLA is the minimum, and 200W is the sweet spot.. assuming you have a 100AH Lead house battery, I'd say get a controller capable of at least 200W input (15A), and start off with a single ~100W panel, with the ability to add a 2nd one later if you need.

SmartSolar 100/15 installed near battery + Ridgid 100-120W or Suitcase 50Wx2 is a good, simple and robust setup..

 

[FosterWV]

Appreciate the help and info. I’d like to keep it simple a kit would probably be easiest. Wiring is not an issue it’s matching components and what panel to go with.

I believe it’s a 100ah battery. Also as much as I’d like to replace the cooler w a fridge I don’t see it in the budget. But I’d like to keep fans and lights (led) running w out worrying about it. Also have a power inverterI barely use.

Forgot to mention this is going on a small trailer that holds kayaks and camping gear so I should have plenty of room.

 

[dreadlocks]

there's nothing special about it, SmartSolar 100/15 will output up to 15A of power and can input up to 100V of Panels.. so fundamentally, any panel you hookup will work.. find one in the size/shape/budget you want, and plug it in.

Kits are for suckers, more money for more medocracy.. the key piece of kit is the charger/controller, and I already pointed you at one of the best on the market with features you dont yet realize you want..

 

[FosterWV]

Thoughts? $127

Only 100w capable so if I ever upgraded 200w I’d have to upgrade the controller, I understand and agree that thinking ahead just in case but honestly I don’t see me going over 100w


Renogy 100W 12V Monocrystalline Solar Starter Kit w/Wanderer 10A Charger Controller https://www.amazon.com/dp/B07QCXM7H6/ref=cm_sw_r_sms_c_api_i_OxKJEbYSQ7TZW

 

[FosterWV]

there's nothing special about it, SmartSolar 100/15 will output up to 15A of power and can input up to 100V of Panels.. so fundamentally, any panel you hookup will work.. find one in the size/shape/budget you want, and plug it in.

Kits are for suckers, more money for more medocracy.. the key piece of kit is the charger/controller, and I already pointed you at one of the best on the market with features you dont yet realize you want..

I looked up SmartSolar and they are $200+ plus a panel I’m not sure I understand what makes it different than the one in the Renogy Kit. I understand 10A vs 15A is it that big of a difference?

Thanks

 

[dreadlocks]

MPPT is worth the expense over PWM in my experience, and your honestly cant see your self ever going over 100W is because you have 0 experience right now.. out in the field, catching sunlight in ever changing locations is much easier said than done.. overcast, forest canopies, non-summer lighting.. all can reduce your output to a small fraction, so instead of 100W your seeing like 15W, and with 200W you could be seeing 30W, or you only get a few hours of direct light and need all the amps your battery will take, plus are you wanting to runt a FAN WHILE charging your bank? because if you have ANYTHING at all running, its going to reduce the charge your battery gets.. so this is alot more complicated than it seems, thus my simple formula earlier.. 100W is a bare minimum for that size bank, anything smaller is a waste of money and effort.

The SmartSolar controller I suggested is like $130, not $200+

 

[dreadlocks]

Power needs, small water pump, lights and fan that runs all night. After two days the battery drops below 11V

just FYI, this is not a light load like you think it is.. with a 100AH battery and just a fridge I can go 3 days before I dropped below 12V.. so your loads, are greatly in excess of those of us just running fridges.. sounds like you got about a 30AH+ a day diet, most fridges use about 15-20AH a day..

so your statement that 100W will be more than enough, is famous last words.. I think you should probably go straight to 240W with a pair of 120W panels, or a house panel if you want any hope to go off the grid indefinitely.

 

[FosterWV]

Dreadlocks appreciate the info I think I’m down to two questions

cable from panel to controller does length or gauge change efficiency? I’ve seen 10g and 12g also I was looking at 20’ would give me more opportunity to move it around compared to 10’

what’s the difference between MPPT vs PWM ?

Thanks

 

[FosterWV]

just FYI, this is not a light load like you think it is.. with a 100AH battery and just a fridge I can go 3 days before I dropped below 12V.. so your loads, are greatly in excess of those of us just running fridges.. sounds like you got about a 30AH+ a day diet, most fridges use about 15-20AH a day..

so your statement that 100W will be more than enough, is famous last words.. I think you should probably go straight to 240W with a pair of 120W panels, or a house panel if you want any hope to go off the grid indefinitely.

Last three years the battery hasn’t dropped below 10.5V in three days. The water pump is small and efficient (don’t remember the draw but did some homework before ordering) it’s also used sparingly, fan is the small and ran in the tent at night.

I’m certain 240W would be more than I want to deal with, two panels loading setting up etc is just more than I want to deal with, I want to keep it light simple and help maintain the battery

 

[dreadlocks]

With a 100AH battery, you really have 50AH usable if you desire the battery to last.. If you are discharging it below 50% you are damaging it, even so called "deep cycles".. a battery thats going to 11v, or 10.5v is not long for this world.. I suspect its gonna be dead by 100 cycles.

With lead batteries I cut off at 12V, which is 50%.. 10.5V is 0%, completely f'n dead and way past safe discharge levels.. lets do the math, 3 days your at 0%, so your at >30AH a day power usage.. you need a bigger bank, and more solar.. In comparison, an ARB 60qt fridge uses 15AH a day, and can go about 4 days before battery is 60% discharged... it could almost 8 days if I let it drain battery to 0% like you... you have pretty heavy power usage, much more than you realize.

 

[john61ct]

Yah kits suck IMO, same with most mass market retail $ online.

SmartSolar 75/15 should be ~$120 for what you get dirt cheap.

Up to say 280W just fine even 300W if you found a bargain, one panel is better than multiple per SC.

If you **know** 100W is all you need, check out 75/10 but likely not much cheaper.

Best source for panels is local, specialist shop or leftover from a commercial or house project, even scratch / dent rejects can be just fine.

Heavy framed glass for longevity, not "flexible" crap.

$1 per watt is a bargain to shoot for, lical pickup.

 

[FosterWV]

Yah kits suck IMO, same with most mass market retail $ online.

SmartSolar 75/15 should be ~$120 for what you get dirt cheap.

Up to say 280W just fine even 300W if you found a bargain, one panel is better than multiple per SC.

If you **know** 100W is all you need, check out 75/10 but likely not much cheaper.

Best source for panels is local, specialist shop or leftover from a commercial or house project, even scratch / dent rejects can be just fine.

Heavy framed glass for longevity, not "flexible" crap.

$1 per watt is a bargain to shoot for, lical pickup.

Did some homework on MPPT vs PWM and Dreadlocks was correct MPPT is worth the extra $

John I was just looking at the 75/15 (closest to my budget) and was trying to confirm it would handle a 100W panel and looks like it can handle 220W.
Hadn’t thought about looking at used panels etc I thought $100 for the Renogy wasn’t terrible.
100W panel is prob max I’d have room for size wise, two 100w take up a lot of space.

 

[john61ct]

looking at the 75/15 (closest to my budget) and was trying to confirm it would handle a 100W panel.

I said nothing about used panels.

Pro installers buy by the pallet full, only way to get good pricing on delivery of quality panels.

So leftovers of the install job get sold locally.

And as stated 75/15 handles lots more than 200W so of course lower is no problem, can add another later.