correct size stuff?

System

I'm really not very familiar with this "stuff" and I need help to make sure I have it right. I want to make sure I have the correct size solar panel (not to big b/c of the cost) and not to small (not enough watts to quickly recharge system correctly). And, I need help to make sure the battery's I'm considering are right size.

I'm setting up a solar water feature at my home with a Rule DC pump. It'll move 1500 GPH. They indicate that it works best with a min of 120 watts power. The box says it draws 4.8 amp @ 12V and 7.0 amp @ 13.6 V. I also got a Sunsaver 10 charge controller.

I understand I do not need to get a panel with 120 watts b/c I'll basically be running it off the battery and the panel recharging the battery.

1. Correct?

I plan on running it 2-4 fours a day if that (more likely not every day-no fish). The battery I was recommended is a Sun Xtender 12 69AH@24 hrs AGM battery. I saw a deal on a UB121100 12V 110AH @20 hrs for less money. I'm new and one is in 24 hrs and the other is 20 hrs.

2. Which one gives the longer run with the pull I'm talking about? Will it really make a difference?

3. What size panel do I need? Should I go for the 120 V panel so if I want I can run the pump right from the panel when the battery is out or will a smaller panel (50-10 watts) work just as good in recharging the battery? Again, I'm not running it all day and night.

Lastly, I'm in Northern Ca.

Sorry for the long post. Hope all the info is in their for help

Windsun

Re: correct size stuff?

If you are running for 2.4 hours, and pulling 7 amps, that comes out to about 17 amp hours.

Assuming 5 hours full sun, you need to put back about 17 AH + around 20% (for losses) in that 5 hours.

17 x 1.2 = ~20 AH.

20 AH/5 hours sun = a 4 amp panel, or about 70 watts.

niel

Re: correct size stuff?

i see windsun mistook that to be 2.4hrs, but that was a range up to 4hrs and that would up the requirements at 4hrs.
28ah x 1.2 ~ 34ah
34ah/5hrs sun = 6.8a pv or close to 120w pv. lowering your time will lower your pv watts needed, but keep in mind you need to aim the pv south at a good angle like your latitude +15 degrees to allow for better winter collection. don't forget that cloudy days will also lessen the amount of power you collect for that day so i'd say stick with a larger pv.
either battery will work for you and if this is your first solar project, it may be better going with the cheaper though larger ah battery to make any mistakes with.

System2

Re: correct size stuff?

niel wrote: »

i see windsun mistook that to be 2.4hrs, but that was a range up to 4hrs and that would up the requirements at 4hrs.
28ah x 1.2 ~ 34ah
34ah/5hrs sun = 6.8a pv or close to 120w pv. lowering your time will lower your pv watts needed, but keep in mind you need to aim the pv south at a good angle like your latitude +15 degrees to allow for better winter collection. don't forget that cloudy days will also lessen the amount of power you collect for that day so i'd say stick with a larger pv.
either battery will work for you and if this is your first solar project, it may be better going with the cheaper though larger ah battery to make any mistakes with.

I forgot to ask but is its better to stay away from used PV panels?

BB.

Re: correct size stuff?

It is not that it is recommended to stay away from used panels...

It is more don't end up paying near full retail for used panels--especially if there is no warranty available (very old, vendor out of business, etc.)...

In the end, it looks like there is not a lot of used panels available out there and they ones that are--aren't cheap.

-Bill

niel

Re: correct size stuff?

if the used pvs work and the price is right for you, i see nothing wrong with that. in fact, pm me on the pvs you are considering and what price is being asked.