How many solar panels do I need?

This question is best answered by asking, how much do you use?

By building a load profile that outlines all the power you intend to consume during a day and estimating the duration of each device and its power draw you can build a power profile. A power bill is similar but not to the same level of detail as it only shows a total for the month which you divide by the number of days in that month. That gives you a kWh value. That number is sometimes referred to as the number of units. It's what you are charged for on your power bill. i.e. 500 units for the month at 20 cents per unit (1 kWh) would be $100. 500 units divided by 31 days equals 16.12 units per day. So that's 16kWh, and in New Zealand, the peak sun hours over winter are only 2 hours. So you'd need an 8kW solar array which will produce on a clear day 8kW per hour and with the 2 hours of usable sun energy in a day you'd generate 16kWh of power.

This would generate enough power to offset your consumption, but it's not all at the right time. You use power at night from the grid so you'll be charged for importing power to your house. But during the day while you aren't at home or your power usage is low you'll be exporting to the grid which may result in you receiving a small credit to your account.

You can see how the real way to benefit from solar is to utilise the sun's energy during the day and limit your need for it at night. This is where batteries can help as they store the day's energy for you to use at night.

Huge misunderstanding in the battery industry that the experts all get wrong

Phonetically, the word "Lithium-ion" does sound similar to "iron," but the term "Lithium-ion" refers specifically to the type of battery chemistry where lithium ions move between the anode and cathode during charging and discharging. The "ion" in "Lithium-ion" simply describes the ionic form of lithium involved in the battery's operation, not to be confused with "iron," which is a different element altogether.

To clarify:

  • Lithium-ion (Li-ion) is the general category name for a broad range of rechargeable batteries that use lithium as a primary component. This category includes various specific chemistries like Lithium Cobalt Oxide (LiCoO₂), Lithium Manganese Oxide (LiMn₂O₄), and Lithium Iron Phosphate (LiFePO₄), among others.

  • Lithium Iron Phosphate (LiFePO₄) is one specific chemistry within the Lithium-ion family. Here, "ferrous" (derived from "ferrum," the Latin word for iron) refers to the iron component in the cathode material. This chemistry is known for its stability, long cycle life, and safety, though it has a lower energy density compared to some other Lithium-ion chemistries like Lithium Cobalt Oxide.

So, while "Lithium-ion" batteries encompass a variety of specific chemistries, including Lithium Cobalt Oxide and Lithium Manganese Oxide, "Lithium Iron Phosphate" is a distinct subset of this larger category, with its own unique characteristics. The term "Lithium-ion" is indeed an umbrella term for all these lithium-based chemistries.

Which is better Optima or Odyssey

The choice between Optima and Odyssey batteries depends on your specific needs and preferences, as both brands offer high-quality batteries with their own unique features and advantages.

Optima Batteries:

  • Optima batteries are known for their distinctive spiral-wound design or different coloured tops, Yellow, Red & Blue
  • They are designed to deliver a high burst of energy, making them suitable for starting applications and providing strong cranking power.
  • Optima batteries are also spill-proof and maintenance-free AGM design with pure lead.
  • These batteries are known for their reliability and are often used in performance and enthusiast vehicles and are lighter weight than the same sized Odyssey because of the lower capacity (Ah).

Odyssey Batteries:

  • Odyssey batteries are recognized for their robust deep cycle capabilities because of the increased Ah, making them suitable for applications that require continuous and deep discharging, such as RVs, boats, and solar systems.
  • They too are designed to deliver a high burst of energy, making them suitable for starting applications and providing strong cranking power because they are pure lead AGM.
  • Odyssey batteries are known for their long service life and strong performance in demanding conditions.
  • They are versatile and can be used for both starting and deep cycling applications.

The choice between Optima and Odyssey batteries depends on your specific needs. If you require a battery primarily for starting applications in vehicles and prefer a unique spiral-wound design, Optima batteries might be a good choice. On the other hand, if you need a battery that excels in deep cycling and can handle sustained discharging, Odyssey batteries are a strong option. Consider the requirements of your particular application and select the battery that aligns with those needs. Both brands are known for their quality, so you can't go wrong with either choice.

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