A Sanity Check, Please?

[GreyCoyote]

Old school engineer here. First time caller, long time listener.

I'm about to take my horse barn off the grid as a "dry run" prior to tackling a much larger PV system for my home (rural, south Texas, Houston-ish). I'm 100% DIY and want to learn small before making more spectacular mistakes. 

Background: The barn system will be supporting a shallow well, some basic LED lighting, and a small refrig for equine meds (beer is an equine med. Go with it). The roof is sloped 15 degrees from horizontal. The ridgeline runs north/south. PV panels (300w Renesolar surplus) will be evenly divided between the east/west facing sides. I have a bunch of these panels and ample roof space.

My question is two-fold:

1). Is there a problem with oversizing the input PV wattage for a Classic 150 provided the output current is limited?  I would be using the current limit feature of the Classic to cap the max output to the batteries (4 x GC2's, 24v) at about 30 amps, and even half of that could get me by, but I do need to assure I can actually get a full charge even on hot, cloudy summer days, or cold low-angle cloudy days in winter. Taking this question to the absurd for illustrative purposes only, if I applied a *megawatt* of PV panels at 100 volts to a Classic 150, set the 150's output current limit to 30 amps, would the Classic complain or just give me 30 amps/24volts of output whenever the sun (or moon? Lol) was shining?

2). Assuming the answer to #1 is "yep. You can do that", when the available PV power exceeds the charging needs of the battery bank, does the Classic exit MPPT mode? Can I configure it to tell me when this occurs so I can run some non-critical loads (ie fly-zapper, ventilation, sprinklers, pond aeration).

Thank you for any help advice or comments you can spare!

Grey

[CDN-VT]

Old school engineer here. First time caller, long time listener.

I'm about to take my horse barn off the grid as a "dry run" prior to tackling a much larger PV system for my home (rural, south Texas, Houston-ish). I'm 100% DIY and want to learn small before making more spectacular mistakes. 

Background: The barn system will be supporting a shallow well, some basic LED lighting, and a small refrig for equine meds (beer is an equine med. Go with it). The roof is sloped 15 degrees from horizontal. The ridgeline runs north/south. PV panels (300w Renesolar surplus) will be evenly divided between the east/west facing sides. I have a bunch of these panels and ample roof space.

My question is two-fold:

1). Is there a problem with oversizing the input PV wattage for a Classic 150 provided the output current is limited?  I would be using the current limit feature of the Classic to cap the max output to the batteries (4 x GC2's, 24v) at about 30 amps, and even half of that could get me by, but I do need to assure I can actually get a full charge even on hot, cloudy summer days, or cold low-angle cloudy days in winter. Taking this question to the absurd for illustrative purposes only, if I applied a *megawatt* of PV panels at 100 volts to a Classic 150, set the 150's output current limit to 30 amps, would the Classic complain or just give me 30 amps/24volts of output whenever the sun (or moon? Lol) was shining?

2). Assuming the answer to #1 is "yep. You can do that", when the available PV power exceeds the charging needs of the battery bank, does the Classic exit MPPT mode? Can I configure it to tell me when this occurs so I can run some non-critical loads (ie fly-zapper, ventilation, sprinklers, pond aeration).

Thank you for any help advice or comments you can spare!

Grey

Yes to Both , Im way over panelled for my bank (summer) winter Im hoping in right there.

use waste not of any method the the classic aux  you fancy to trip a extra load on .

What is the shallow wells depth & what pumping system are you thinking ? Mine is 15' and Im using a rule bilge pump to a cistern and then to a sure flo pump for pressure water  Tap & sink , the bilge pump fill the water trough for the critters .
Mine is also 24Vdc Bank for that one with a PYLE  , 12 Vdc is a norm for the smaller DC stuff.

VT

[GreyCoyote]

Thank you, CDN-VT! Much appreciated to know I'm not milking without a bucket in my senior years! Lol.

On the subject of the well, it is 320 feet deep, but the static water level is the same as yours: ~15 feet in the end of the summer, a bit less in spring. I'm using a really cheapo Harbor Freight shallow well pump on 120 VAC with a big pressure tank. The horses use maybe 60 gals a day on the very hottest of days, which translates to 6-7 minutes of runtime at ~600 watts. I could improve on this, but its really just peanuts as far as watt-hours are concerned. We use so little water there that I tend to leave the autofill valve on the trough cracked or run a sprinkler every few days just to keep the pump happy and the water fresh.  But I may take a page out of your book and also stick a Rule high flow-low lift pump in there to keep the pond up. Might even put it on its own panel on a constant run-with-the-sun arranngement.

Thanks again for your thoughts!

[CDN-VT]

In the garden shed / barn i use a iota 12Vdc battery maintainer set to 14,2 Vdc , this is on a harbour freight timer  https://www.harborfreight.com/digital-timer-95205.html . That way when the classic is charging the bank , I can use power , the inverter wakes up & supplys power to the HF timer thats has turned on the Iota 12Vdc charger & then all the tractors & snow blowers & Quads ,bikes  etc get a charge to keep up all the batterys . I use drop light reels that I have each one fused & a diode so no back feeding  and alligator clips to hook up quick .In the winter most is drained , serviced & in storage with these charging wires on till spring , the snowblowers are 110Vdc start and the larger one uses a 12vdc battery , they are moved forward & @ the ready (If I left them at the back I would need them ), so the fuel is left out till they are needed but in the front now.

I 'm Hoping WestBranch gets all the white stuff , around here it makes the place stop.

VT

[GreyCoyote]

CDN-VT;

Lol! Thats genius! Its "Rube Goldberg" as all bejeepers, but it is also a very slick, maintainable hack with simple parts and easy troubleshooting. Really cool.

Segue: I was at CostCo today and almost wandered home with 4 ea GC2 batteries. (Un?)Fortunately saner heads prevailed, but as soon as my inverter comes in, I'm sneaking over there again. 88 bucks.

[CDN-VT]

Weigh them wet & then trip over to an interstate supplier / truck
Weigh theirs . It's not the acid , plastic  is missing  , its light of LEAD .

Im sure in the wintertime , horses don't drink as much as in summer , same as the beer fridge ,beer is pulled out faster & the door should be revolving on some. So the loads are lighter in the winter here , come spring later the bird houses are in full swing with the incubators running, Thats when my loads are the greatest .
Im using a 24Vdc system (Inverter set that ) because my Man lift is 24Vdc , the other parallel battery system   is a converted NMHI cells from (Toyotas car s) second gen batterys that I reconfigured a bunch to make my packs ,for this area.
I run 5 solar systems , all different . Hydro is due online next year I hope.

VT