Solar Panels need an education

[CBari]

I have three bulk fuel tanks at the house all have 12volt pumps on them. They get used 2-3 times a week most weeks and run for 5-7 mins at a time. I currently open the hood and put clips on the battery. This isn't really all that difficult I just thought it might be nice to just flip the switch and start. What I wanted to do was to put a battery by the tanks and wire all the pumps to it. I also wanted to put a solar panel on it to keep charged, but I am unsure if I can put just a panel or if I need to put a charger in between so as to protect the battery from over charging.

Thanks for educating me.

 

[Killgore]

I believe an inexpensive controller from Northern Tool would be desirable.

- Ed

 

[Road Dog]

The voltage from a solar panel panel varies widely with the sun so you need a controller/charger to make it charge the batteries. The next question would be "how big a panel?" How many amps is the pump? A 10A pump for 5 minutes is around 1amp-hr so even a 20W kit might do the trick if you get regular sun.

 

[CBari]

It as been a while since i did physics II so someone will have to have a little help on the sizing. The battery I plan on using is a group 24 gel cell which is an 80Ah battery. The pump pulls 30amps and runs at the most 7 mins maybe twice a day. It would be rare that it would do that two days in a row. Most likely would run maybe 4-5 times a week at the most. I was looking at the battery tender 5watt panel because it has a controller made in it and I have hade good success with their products in the past but not sure if that is enough wattage. It would be located where it would get direct sunlight all day.

 

[The patriot]

You need to watch this:

https://www.youtube.com/watch?v=8SuvAKZt0Vs&index=12&list=PL5ijoMs00Jkd3_WI4-nk-24KzjR1z85gh

It's 1hr+ long, and extremely detailed. Yea, it's ham radio related, but it's relative to your needs. Formulas etc.

 

[jelag]

30 amps X 12 volts is 360 watts.... so a 20 watt kit, running 10 hours a day would produce 200 total watts... not enough if you used the pump daily.. but would keep it charged if you used the pump every other day.. and you had sun most every day... I'd personally look for a controller and panel in the 35 watt range.. maybe Harbor Freight... this should allow you some surplus for those cloud covered days.. I know your 80 amp gel cell is an overkill... but if that's what's available that's great... KEEP IT CLEAN AND DRY

 

[Road Dog]

You need to include time in the equation: 30A x 12V x 7min X 2 = 5,000 watt-minutes or 84 Wh. That's what you need to replace with a solar panel. If your 20W panel (that's peak watts) averages 10W over 10hr then you collect 100Wh. That might be cutting it a little close since nothing is 100% efficient and there will be a big difference between Winter sun and Summer sun.

 

[CBari]

Thanks for the the help guys. I think I will try the twenty as it as been over a week since the last I used the pumps.

 

[Wayne M.]

Far as solar goes, you need to hear from BIGNASTY. He lives off grid.

 

[sag2]

Harbor Freight is not the place for solar. I purchased my 160w portable from these guys. Here is a 40w panel and a controller that should do what you need.

https://www.solarblvd.com/product_info.php?cPath=1_269&products_id=2664

https://www.solarblvd.com/product_info.php?cPath=6_48_275&products_id=2945

 

[The patriot]

Far as solar goes, you need to hear from BIGNASTY. He lives off grid.

Come to think of it, I think he was the one that sent me the link to the vid I posted.

 

[BIGNASTY]

Do yourself a favor and buy a cheap charge controller, its not hard to hook up and it gets expensive if you should overcharge a battery. There are lots of panels on the market I would stay with the big names if you plan on doing this for very long I have BP Solar, Samsung, Koycera, Westinghouse, Mitsubishi, are all good names. Solar panels have come a very long way, it doesn't take much light to charge, naturally a sunny day will charge more but even in overcast my panels charge batteries.

You could do what I do with my radio in the barn. The barn is a time machine for me, the only thing that I have of technology is my radio Sirus a charge controller & battery to power the radio. The charge is done the a Permanent magnet alternator (1970's GM)to charge the battery. The link below is something that will get you pointed in the right direction. What this is a wind generator it really doesn't take much wind at all to turn the fan on the alternator. Im in route to home (my Son said that calving season is in FULL SWING) I will get the info for you if interested.


https://www.youtube.com/watch?v=eCr6O4_-M44

BIG