I thought I knew what I was doing but the information my research has uncovered is so varied and overwhelming on the subject that my head is about to explode. I am by no means a math whiz nor a solar system designer however, I have repaired existing systems before. My current conundrum is to simply select batteries for a new solar system. I made myself appear somewhat like an expert to some friends living on a Bahamian island and now have come up short. The specs on batteries on websites range from watt-hours, amp-hours, kw-hours, etc.. leaving me lost. Perhaps someone can shed some light on the subject for me.

Some of my math was correct when comparing it to the plethora of solar calculators on the web.

Here is the challenge.

Looking to operate 8 CFL for up to 12 hours a day (during the nighttime only - year round) with a new 45 watt array.

The wattage of the lamps is unknown so for calculation purposes I am using 23 watts (100w incan. equiv.) per lamp as the assumed load = 120v @ 184w / 1.5a - rounding up to 2 amps (24 amp-hours?)

Assuming a 20 percent loss after the "break in" period of the panels per the manufacturer specs

and per online calculators only 5.5 hours of average solar recharge time per day

using a 300 watt inverter.....

Not wanting to discharge the batteries less than 50 percent....

(They only have access to deep cycle marine batteries.)

How many 12 volt batteries will it take to achieve this goal?

What should I be looking for?

Most of the specs on the marine batteries are rated in CCA which has confused me even more.

I also thought I could find a 12 volt timer or photo cell to cycle off the inverter during the day to save juice.

Thank you for looking at my problem and I would be most grateful for any response that may help me.

Some of my math was correct when comparing it to the plethora of solar calculators on the web.

Here is the challenge.

Looking to operate 8 CFL for up to 12 hours a day (during the nighttime only - year round) with a new 45 watt array.

The wattage of the lamps is unknown so for calculation purposes I am using 23 watts (100w incan. equiv.) per lamp as the assumed load = 120v @ 184w / 1.5a - rounding up to 2 amps (24 amp-hours?)

Assuming a 20 percent loss after the "break in" period of the panels per the manufacturer specs

and per online calculators only 5.5 hours of average solar recharge time per day

using a 300 watt inverter.....

Not wanting to discharge the batteries less than 50 percent....

(They only have access to deep cycle marine batteries.)

How many 12 volt batteries will it take to achieve this goal?

What should I be looking for?

Most of the specs on the marine batteries are rated in CCA which has confused me even more.

I also thought I could find a 12 volt timer or photo cell to cycle off the inverter during the day to save juice.

Thank you for looking at my problem and I would be most grateful for any response that may help me.

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