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here's a chart for pump motors, yours may be like these.   There are also PF losses.   The big problem is the starting surge needed by a motor, 12V systems often have trouble as batteries age, and are unable to surge to start the motor
My 6kw inverter logs my half HP water pump at 1,000 w consumed.

Welcome to the forum JC.

You are starting out correctly... Looking at your loads first. You might be on the low side of the estimates for Watts--Motors can be 80% efficient pretty easily (1/.80 eff = 1.25x more current)... If you can measure your current draw with a shunt or DC Current Clamp meter, it will help.

The Math:

• 745 Watts * 1/2 HP * 10 minutes * 1/60 minutes per hour = 62 Watt*Hours
• 62 Watt*Hours / 10.5 volts (worst case) = 5.9 Amp*Hours

So, your 7.33 AH is a bit more worst case and good to use.

If you assume 7.33 AH over 10 minutes, the average draw from the motor:

• 7.33 AH * 60 minutes per hour * 1/10 minute run time = 44 Amps average draw (worst case)

For a flooded cell lead acid battery, draw of C/8 maximum is good:

• 44 amps * 8 hour discharge rate = 352 AH @ 12 volt battery bank minimum based on size of load

And I would recommend for system that runs daily, that you have 2 days of storage and 50% maximum discharge, or a minimum of 4x your daily load:

• 7.33 Amps * 2 days storage * 1/0.50 max discharge (for longer battery life) = 29.33 AH based on daily usage

A 1,200 WH @ 12 volt battery would be a 100 AH battery. For a flooded cell battery, that is pretty high current draw...

Now, you have choices... Flooded Cell lead acid batteries are about the cheapest per Amp*Hour... 2x 6 volt @ 200 AH batteries in series times 2x parallel strings gives you 4 "golf cart" batteries at 400 AH or ~$400. 2x golf cart batteries (12 volts @ 200 AH) may be on the small side (C/5 discharge rate is pretty high).

Another option is AGM batteries. They are lead acid batteries, sealed (no electrolyte to check), and you can use a 100 AH @ 12 volt AGM battery pretty nicely in this location. For example:

https://www.solar-electric.com/fullriver-dc105-12-agm-sealed-battery-12v-105ah.html

Is ~$307. 

AGM batteries are sensitive to over charging. AGM and FLA batteries do not like to be taken "dead". And should be stored at >~75% state of charge. FLA batteries are good because you can measure specific gravity and state of charge. AGM batteries are sealed, but not as easy to determine state of charge (battery voltages for lead acid batteries and state of charge are rough estimates and pretty variable).

And there are Lithium Ion batteries... LiFePO4 prismatic cells are very nice... Support very high current draw, and high charging current. But you have to study up on them. They are still leading edge technology and you probably would need a BMS (battery management system) to protect the cells from over/under charging or over discharging. And they are not cheap.

Regarding your solar array... Two sets of calculation. One based on size of battery bank. For Lead Acid batteries, 5% to 13%+ rate of charge recommended (10%+ for full time off grid/heavier usage).

Based on energy usage and hours of sun (assuming system runs in winter too):
http://www.solarelectricityhandbook.com/solar-irradiance.html

Stockton California
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 37° angle from vertical:
(Optimal winter settings)

Jan	Feb	Mar	Apr	May	Jun
3.67	4.41	5.56	5.78	5.74	5.80
Jul	Aug	Sep	Oct	Nov	Dec
5.91	6.20	6.33	5.91	4.40	3.59

If you assume running every day in winter for 10 minutes:

• 7.33 AH * 12 volts = 88 WH per day
• 88 WH per day * 1/0.61 DC System eff * 1/3.59 hours of sun per day = 40 Watt panel minimum (December "break even" day)

And then there is based on the rate of charge... 5% rate of charge minimum (assuming system runs every other day or a couple times a week). 10% recommended for flooded cell lead acid deep cycle storage batteries and if system runs every day. But, we have a wide range of battery bank types and sizes. Worst case 400 AH @ 12 volt ("big" battery bank made from golf cart FLA batteries):

• 400 AH * 14.5 volts charging * 1/0.77 panel+controller deratings * 0.10 rate of charge = 753 Watt array (10% rate of charge for 400 AH battery bank).

Supplying relatively high levels of current for once a day for a couple times a week (irrigation gate valve?) with solar has lots of tradeoffs.

You, kind of, have to over design to make a reliable electrical system. But because of the little AH per day need, typical FLA batteries may not be an "optimum fit".

Golf cart batteries are (relatively) cheap. And would probably last 3-5 years, if water level and state of charge is monitored (typically once per month). Others like Li Ion would be a good fit, but are not cheap themselves, and if something goes wrong (batteries killed due to poor sun, water damage, theft, etc.)--FLA are nice because they are cheap.

You might try 2x 6 volts @ 200 AH battery string first (2x golf cart batteries) and see how it works for you... If the voltage sag is too great, you can add a second parallel string (mixing "old" and "new" batteries--that are years apart in age--Can be an issue later).

Your thoughts/questions?

-Bill

I am interested in running a 1/2 hp hydraulic power unit (12 V DC) once per day for about 10 minutes. It will need to run during the day some days, and at night some days. Some days it will not run at all (it will not run for more days than it will run) 
I believe that my power requirements would be 62 Wh and 7.33 Ah. 
Are my numbers correct?

What type of system would I need, can I get away with a single 12 V battery (~1200 Wh) and a 60 watt panel?

I am a novice with solar energy, any input or advice would be greatly appreciated!

Thanks

Just to be sure... are there any negative wires other than the shunt to battery wire on the battery side of the shunt (eg. DC loads, meters, other inverters)?

How/where is the system grounded?

faccnator said:

McGivor, that was at dusk. This is now at night. With the swapped shunt leads. This is even more wrong.

That would make sense being evening didn't notice the time on the screen shot first time, but those are indeed some strange numbers on the graphics, appears the shunt is either not calibrated correctly or faulty. 

Why is the DC input to the MPPT so low 53.3V, this should be somewhere closer to 100V,  battery 51.2V float? float should be ~54V,.assuming 48V nominallead acid.
How are panels configured and what are the specs?
What are the settings for th MPPT? 
What battery type is in use?

I’ve looked at the shunt 100 times and I swear I have it wired the correct direction but I’m going to swap the leads for good measure. I’ll report back

faccnator said:

Also the MPPT is in float and the battery monitor is showing 82% charge. What am I doing wrong?

Listen to Dave. His time in solar harkens back to B.C.