Solar Panel To Battery Help

[PureHarvest]

I will probably do another battery/pump combo, and will get a DC pump to avoid needing the inverter. But then trying to hook it all to a plug-in timer becomes more difficult.

[zeuspaul]

Back of the napkin I would figure 100 watts for an hour per day or 100 watt hours per day.

An 85 amp-hr (standard automotive size) battery holds 85 x 12 or 1000 watt-hrs. Use the 50% discharge rule of thumb for lead acid deep cycle batteries so an 85 amp-hr battery has 500 useable watt-hrs.

Design for three days without sun. 300 watt-hrs might be a good number.

An 80 watt panel will provide 80x5 or 400 watt-hrs per day in five hours of sun. There are inefficiencies so 300 watt-hrs from the 80 watt panel might be a good guess.

You will need a charge controller so you don't overcharge the battery.

For a first look I would use an 85 amp-hr battery with an 80 watt panel and a controller.

[Worth1]

Originally Posted by PureHarvest

I will probably do another battery/pump combo, and will get a DC pump to avoid needing the inverter. But then trying to hook it all to a plug-in timer becomes more difficult.

You just need a 12 volt powered volt timer relay to turn your new 12 volt DC pump on and off.
https://www.google.com/url?sa=t&rct=...jH0Ci8hXfPaYvQ

Here is the goof ball move I have seen people do with these things.
It is a time dry contact relay that runs a set of dry contacts.
Dry contacts are just a switch like your light switches in you house.
Wet contacts are just that they supply electricity.

You have to run one conductor through the switch first and then to the pump.
The other conductor goes straight to the pump.
This way when the relay closes it turns on the pump.
The power consumption of these timers is almost nothing.

People are hooking both pump wires to the timer expecting it to work.

Now to your inverter you should dump.
400 watts is the maximum amount of power it can consume.
I like to convert watts to amps because it makes things easy.

The maximum amount of power/currant your inverter can handle is 3.478 amps.

I am going to post this and be back.

Worth

[Worth1]

Okay I looked in the PDF manual for you inverter and it draws .5 amps at no load.
This means it is running all of the time as I knew it did but needed to know what the no load consumption was.

[PureHarvest]

Thanks worth.
Ima dump the inverter and get a DC pump and timer.

[Worth1]

So your inverter is drawing 12 amps a day even if it isn't being used.
Get rid of the inverter get the timer that runs off 12 volt DC and get a pump that draws the same amount of currant your ac pump is drawing.
This is about 1/10 horsepower.

If you get the solar fence charger that puts out 1.1 amp per hour under optimum solar conditions you will have more than enough to run your system.
This was calculated at a 1.5 amp currant draw that your system would take running for 30 minuets every day.
The solar charger would charge it back up in a little over an hour I kid you not.
I also did the battery calculations for this and the battery requirement is only a 4 amp hour gel cell battery.
If you were to jump up to a 12 amp hour gel cell battery you would would be doing great.

http://www.solardealz.com/20-Watt-So.../zs-20g-6a.htm

[zeuspaul]

Do you already own the pump and inverter? Is it hooked up and working now? How do you charge the battery? How often do you have to charge?

It may not be the optimum design but why not keep the existing components and just add the solar panel and controller and maybe a timer before the inverter. Then replace the AC pump and inverter when they fail?

Use the money you save towards a bigger solar panel so you don't have to worry about wasting a little electricity.

[Worth1]

Like this.

Solar panle.jpg

[PureHarvest]

The current AC pump I have was given to me free. The inverter I already owned from years ago.
Did buy the battery last year. It was around $75.

I need to add a second pump this year to feed a portion of my bags differently.
So I will have 2 tanks that hold 250 gallons and 2 pumps.

I'm thinking I'd rather buy two DC pumps to match rather than buy another AC and have to buy a big panel.

I don't mind running the battery down to the house once a week for an over night charge.
It would be easier to have 2 of the same pumps, and it doesn't sound like 2 AC pumps and an inverter are the best use of that battery without also getting a big panel.

To sum up, my options would be;

A: Buy another AC pump. Now I have two pumps to run off of one battery and inverter. Buy Panel big enough to keep that battery charged.

B: Buy two DC pumps. Run them off battery with DC timer. Charge battery manually (maybe once a week?)

[PureHarvest]

The AC pump I have now does:

Power Source: AC
Voltage: 115 volts
Wattage: 104 watts
Amperage Capacity 0.9 A

New DC pump like the AC I have now is about $100

[PureHarvest]

So my battery fully charged has 100 Amps?
And running a DC pump for a 1/2 hour per day uses 1.5 amps?
So two pumps would draw 3 amps a day?
I could go two weeks before using near half the battery, and then do a recharge at home on a regular battery charger.
I could do that no problem. No panel needed.
Now if I hit a homerun with sales, maybe I will buy a panel and enjoy the convenience of never moving the battery.

[Worth1]

Originally Posted by PureHarvest

So my battery fully charged has 100 Amps?
And running a DC pump for a 1/2 hour per day uses 1.5 amps?
So two pumps would draw 3 amps a day?
I could go two weeks before using near half the battery, and then do a recharge at home on a regular battery charger.
I could do that no problem. No panel needed.
Now if I hit a homerun with sales, maybe I will buy a panel and enjoy the convenience of never moving the battery.

It has 100 amp hours not amps it can out out a tremendous amount of amps in a split second.
I rounded up for leeway to 1.5 for start up of the motor.
So lets say everything draws 3 amps a day at the very most you will then be using 21 amp hours in one week from a 100 amp hour battery.
No problem at all you could even go for 2 weeks before charging and only use 42 amp hours.

This is what I would do and skip the solar panel.
Even then If I wanted to charge the battery off grid I would go with wind power.

[PureHarvest]

Sweet. I'm rolling with two DC pumps and DC timers.
Charge the battery every other week. I can handle that no problem.

Now about that wind power...I'm all ears.

Thanks for running numbers and spending time with this!

Many headaches prevented and $$$ saved.

[Worth1]

I just looked at a 200 watt wind generator they put out 16 amps at 12 volts DC in about a 20 mile an hour wind.
This is a no brainer for people that are allowed to have one.
They can produce electricity rain or shine day or night.
A heck of a lot more bang for the buck and the reason Texas is the largest wind power producing state in the US.

Worth

[PureHarvest]

What's it cost?
What do you do when the wind stops?