How to Size Your Solar Battery System for 24/7 Day and Night Energy

How to Size Your Solar Battery System for 24/7 Day and Night Energy

October 14th, 2020 in Tips
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Last modified on October 20th, 2020 at 11:43 pm

If you’re looking to install a solar with battery backup system in Florida, sizing it correctly is essential to meet your performance expectations. If you underestimate the needed kWh to power your loads through the night and you could wake up sweating in the dark – you’d rather have more battery capacity than not enough. Another key parameter to calculate is the AC output (or Amps) needed when your solar system functions in “Standalone Mode”, all batteries have different outputs with/without the grid. Proper sizing is step one of our solar consultation, next is a quality design using reputable equipment, and finally the best way to purchase.

The question many new solar owners ask, “What size solar battery system do I need?”. Here’s the answer:

What Size Solar Battery Do I Need?

The best way to get all your questions answered is to schedule a consultation, during the consultation we will evaluate your usage and match a custom solar battery solution to your home.

Taking into consideration weather conditions, temperature and peak power demand are 3 important factors we account for in our custom solar battery hybrid systems. You need enough runtime in your battery bank to power your loads through low light conditions/at night and also proper AC Output to the loads. Undersizing your AC Output may cause your battery inverter to cycle on overload and/or trigger an overcurrent issue resulting in loss of power with possible damage to your equipment. A lot of “out of the box batteries” have output limitations that fail to meet the demand required when the battery cycles. Our consultation evaluates your needs sizing your solar and battery bank to provide the proper runtime matched to amps to power your loads when you need them the most.

Step One: Size the Solar

The solar array needs to be large enough to offset your utility usage and charge the battery bank, upsizing the solar a little is recommended for optimal performance in low light conditions. We always say “you’d rather have more than not enough”.

Check Your Energy Bill

If your home is grid-tied, finding your daily kWh usage is pretty simple and can be done using a power bill and our sizing tool. Sizing your solar array by kWh is much more accurate than going off the dollar amount of the monthly bill.

Use Our Solar System Sizing Tool

Our Solar System Sizing Tool
Off Grid Solar

Off-grid location? Our engineers can design a solar micro grid when utility power is too expensive or non existent, there are many variables to consider when looking at these types of systems and may be costs involved to accurately size and quote. We have extensive experience working on the outlying islands surrounding Florida with dozens of our solar offgrid designs providing power to homes in some of the most beautiful remote locations around. When you need reliable solar power make sure you’re dealing with an experienced contractor with a NABCEP certification and Solar license.

Step Two: Calculate the Battery Capacity You Need

Sizing the needed kWh in your battery bank is easy with our Battery Sizing Tool!
Battery Sizing Tool
There are 3 main parameters you’ll want to carefully compare when you’re shopping solar with battery backup;

  • kWh = Runtime or energy stored in the battery.
  • AC Output = Amps or peak power needed to start and run loads.
  • D.O.D. = Depth Of Discharge which is the usable energy in the battery bank
BATTERY BANKS AC Output
(Peak & Continuous)
D.O.D.
(Depth Of Discharge)
16 kWh 66 A @240V (10 Sec) | 33A @ 240V 100%
22 kWh 66 A @240V (10 Sec) | 33A @ 240V 100%
32 kWh 132 A @240V (10 Sec) | 66A @ 240V 100%
48 kWh 156 A @240V (60 Sec) | 84.99A @ 240V 100%

How Many Kwh Do I Need in My Battery Bank?

More than less! The kWh in a battery bank are used at night or in lowlight conditions when the solar production may not be enough to power the loads. An easy way to calculate this if you have a utility company is take your peak kWh usage and calculate 66%.

AC Output?

This parameter is often overlooked by off the shelf solutions and is just as important as the kWh in your bank. The peak power is the battery inverters ability to start and run your loads. Since all batteries are DC voltage (24-400V) we need to invert to usable AC voltage (120V-240V) to be compatible with the US grid and/or power loads. Our consultation is the best way to be sure your AC Output on your solar with battery backup is sized properly.

D.O.D. (Depth of Discharge)?

The depth of discharge indicates at what level the battery can discharge before recharging. With today’s lithium battery chemistry this range is usually between 80-100%. Some of the biggest names in batteries are on the lower end of this number while our custom battery banks have 100% D.O.D giving you more usable energy when you need it.

Safety Buffer (Days of Autonomy)

We always suggest making a safety buffer. By adding some reserve storage space, you’ll gain access to energy during cloudy days, the night, power outages, storms and other situations where your panels are struggling to generate enough energy.

You wouldn’t drive your car for hours with the gas light on, so why is your home any different?

Decide how many days of autonomy you want your solar system to be able to provide. Between one and two is usually wise. Don’t sell yourself short!

Can I Add a Battery to My Existing Solar System in Florida?

Yes! We can design an AC Coupled battery bank to retrofit your existing grid tied solar with battery backup. Our grid tied battery backup will cycle when the grid fails keeping your loads on through unexpected power interruptions. Here at Florida Power Services “The Solar Power Company” we make adding solar batteries to existing solar panels easy using no money out of pocket loans with rates between .99% – 2.99%.

  • No more paranoia about running out of electricity!
  • Full power, day and night!
  • Protection for storms, cloudy days and grid blackouts.
  • Low monthly payments!

How Long Will Solar With Batteries Last?

Solar battery technology has come a long way from Lead Acid batteries with short 3-4 year life expectancy and low depth of discharge (around 50%) to powerful Lithium Ion batteries with life expectancies of 20+ years and 100% depth of discharge. Lithium Ion batteries are extremely durable and require no maintenance giving them some of the longest lifespans of the batteries commercially available today.

Can Solar Battery Back-Ups Save Money?

Solar battery banks vs generators do save money in Florida! After factoring in the cost of fuel, maintenance, and life expectancy of a generator the solar with battery backup lasts twice as long with virtually no maintenance or costs after installed. You’ll also be significantly boosting your property value, not to mention solar with battery backup makes your home more attractive to prospective buyers should you decide to sell in the future.

2020 Is the Time to Act to Save Money!

As 2020 heads towards its conclusion, there is still time to save thousands of dollars. But act fast! After this year, you’ll no longer be able to get the massive 26% reductions through Federal Tax Credits.

For example, if your solar power installation in Florida costs $38,000, you can receive Solar Tax Credits of $9,880 in 2020. Don’t miss out on this great opportunity, we have limited installation availability due to demand. Contact us now for a solar consultation and beat the deadline.

Solar Batteries in Florida

Contact Florida Power Services “The Solar Power Company” today to get started on your solar battery installation, or to receive expert advice on battery sizing and solar financing. We’ve helped homeowners and businesses throughout Florida transform their properties into one built for the future; now it’s your turn.

Get a Custom Quote

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