Need experts advice on Solar system to water my fodder

**inetdog** · 03-16-2015, 04:30 PM

Have you tried plugging your numbers into Sunking's off-grid design calculator (in a sticky thread)?

**solar pete** · 03-16-2015, 04:34 PM

Hi tharkuri and welcome to solar panel talk.

Sorry but its not cool to post links when your new. reason being we get inundated with people trying to advertise things for free. Just list your items and if people are interested they can always Google them, thanks for you understanding.

**Sunking** · 03-16-2015, 05:10 PM

You have already screwed up buying a panel. The solar panel is completely useless, and the controller is overkill but will work. You need roughly 80 watt hours per day which means you need:

12 volt battery capacity = 35 AH
Panel Wattage = 40 watts.

**tharkuri** · 03-16-2015, 05:42 PM

Originally posted by Sunking

You have already screwed up buying a panel. The solar panel is completely useless, and the controller is overkill but will work. You need roughly 80 watt hours per day which means you need:

12 volt battery capacity = 35 AH
Panel Wattage = 40 watts.

Ohh noo!!!

How is that possible.. my bad..

I was calculating something like this.. If a solar panel produces 15W / 12 V = 1.25Amps. Thats for aprox 9 hours, which comes around 11.25 amps total during day time. Does my Solar panel already good to produce 135W in this 9hrs?. The pump consumes 1.5amps, which is only 10 mins every 1 hour, 12v*1.5a*4hrs = 72W pump consumes per day... where does this remaining power from Solar goes? I could reduce the pumps running time for 5 mins or so(i have not really tested the pumps performance, based on that i could reduce the fodder size to start with) .

Where does my basic understanding fails??

Regads
Tharkuri

**tharkuri** · 03-16-2015, 05:53 PM

Originally posted by inetdog

Have you tried plugging your numbers into Sunking's off-grid design calculator (in a sticky thread)?

Thanks for that inetdog.. do you mind pointing the link, i could not find that..

**inetdog** · 03-16-2015, 06:09 PM

Originally posted by tharkuri

Thanks for that inetdog.. do you mind pointing the link, i could not find that..

Solar Off-Grid Battery Design - Solar Panels - Solar Panels Forum

http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design

Discuss remote solar applications for homes, cabins, RV and boats. If you have a question on equipment for an off grid system, such as charge controllers or inverters, then post your question in this forum.

To find the rest of the useful stickies for this topic, go to Off Grid Solar and then go to Off Grid Solar Panel Systems.
The sticky threads are in their own section at the top.

**YCsolar** · 03-17-2015, 02:07 AM

Tharkuri, I guess your choice of solar panel, and battery is right, only regulator is overkill, but it doesn't matter.
12V 10AH battery DOD is about 60%, 15W solar panel charge battery need about 1.2 days.

**tharkuri** · 03-17-2015, 02:35 AM

Originally posted by YCsolar

Tharkuri, I guess your choice of solar panel, and battery is right, only regulator is overkill, but it doesn't matter.
12V 10AH battery DOD is about 60%, 15W solar panel charge battery need about 1.2 days.

thanks YCsolar, your sweet words

gives me little hope now.
My original assumption was, even a palm size Solar battery bank can charge up those little USB battery backup.. why can't this 15W 12V panel??

This setup will be deployed in India, so no fear of any long cloudy days.. i can assure that 365 days i will get excellent Sun light.

Even if it misses few schedule during early morning (in case if it runs out of battery juice), it won't kill my fodder.

regards

**YCsolar** · 03-17-2015, 05:07 AM

hope your system can work well, any further question, I am happy to help you. I am working in a solar energy application company, specialize in solar water pump system.

**Wy_White_Wolf** · 03-17-2015, 09:28 AM

Originally posted by tharkuri

Ohh noo!!!

How is that possible.. my bad..

I was calculating something like this.. If a solar panel produces 15W / 12 V = 1.25Amps.

You need to use the actual VMP of the panel instead of nominal voltage. VMP will be in the range of 15.5 to 20V depending on manufacturer. Most likely it is close to 18V. so 15W/18V = .8A.

Thats for aprox 9 hours,

Your confussing daylight hours with insolation hours. No place on earth averages 9 hours insolation. Generally average about 4 hours but with an off-grid system you need to plan for worst case which would be in the 2 to 3 hour range depending on your location.

which comes around 11.25 amps total during day time. Does my Solar panel already good to produce 135W in this 9hrs?. The pump consumes 1.5amps, which is only 10 mins every 1 hour, 12v*1.5a*4hrs = 72W pump consumes per day... where does this remaining power from Solar goes?

System efficiency. Anywhere from 30 to 50% of the produced power is lost

I could reduce the pumps running time for 5 mins or so(i have not really tested the pumps performance, based on that i could reduce the fodder size to start with) .

Where does my basic understanding fails??

Regads
Tharkuri

See red above

Need experts advice on Solar system to water my fodder

Need experts advice on Solar system to water my fodder

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