What are the Best Batteries for an Off-Grid Power System?

What are the Best Batteries for an Off-Grid Power System?

Best Batteries for Off-Grid Power System

Solar power and other renewable energy sources allow people to go off-grid with their power generation. Being off-grid is liberating in a lot of ways.

It means that you aren’t dependant on a third party and that after the initial investment in your power generation you can keep your property running from your own power.

There are some downsides, however. When you are connected to the grid, you can send surplus power there, and during periods where you are not generating enough power on your own, you can call upon the grid for the rest of your supply.

That is not an option when you are off-grid, so you need to use batteries to store surplus power for use later.

Choosing Batteries for Your Off-Grid System

When you are selecting batteries for an off-grid system, you should take into account a number of specifications, including:

  • How much power the battery can store in kilowatt-hours
  • How long the battery will last
  • The Depth of Discharge of the battery (how much it can be discharged before it will have its useful life shortened)
  • Whether the battery is stackable
  • The power the battery can deliver, in kilowatts
  • The charging/round-trip efficiency

The number of kilowatt-hours a battery is rated for will give you an idea of how much use you will get out of the battery, while the rating in kilowatts will indicate what the battery can power.

You can add up the number of watts of all the appliances you want to run, and work out whether the battery can power them.

Note that starting appliances up can sometimes require a little more draw than running them, so the ‘starting power’ of a battery is sometimes listed separately.

The Depth of Discharge of the battery is the amount of charge that it needs to retain in order to continue to function normally.

If you discharge a battery beyond its DoD, then it will no longer perform at optimum capacity.

For example, if the DoD is 85%, you should always recharge a battery before it is depleted to 15% or lower capacity.

The round-trip efficiency of a battery is how much energy can be used from a battery as a percentage of the energy that it takes to charge it.

So, if it takes 10kWh to charge a battery and you get 9kWh out of it, then you have a round tip rating of 90%.

Solar batteries can be made from several technologies, including:

  • Lead-acid
  • Lithium-ion
  • Saltwater

Lead-acid is the oldest technology and is good for people who want low cost, high volume storage.

Lead-acid batteries have a comparatively short lifespan and low DoD but they are inexpensive and this factor makes them popular with homeowners.

Lithium-Ion is the ‘standard’ battery these days. Lithium-ion batteries are lighter and smaller and tend to last longer, but they cost more to make.

Then there are saltwater batteries which are fairly cutting edge.

They are still untested and relatively unproven but they are something that appeals to homeowners that are looking to go as environmentally friendly as possible.

Saltwater technology is still fairly expensive and it is hard to find manufacturers that make those batteries for home use.

Maintenance-Free Batteries

Many lead-acid batteries are made to be ‘maintenance-free’, with gel or absorbed glass mat.

The idea here is that the batteries will hold their charge longer and have a greater Depth of Discharge than standard batteries.

This means that you don’t have to worry about topping off the batteries with de-ionized water, so they can be useful for homeowners who don’t want to have too many extra solar-power related chores to do.

At Choose Solar, we provide purpose-built mounting equipment for the solar power industry as well as high-quality solar batteries and inverters and are your number one choice.

We have been supplying and installing farm solar power battery systems across Australia for the past 20 years.

For all your solar installation and solar power needs, please call us today on 03 9761 5371 or send us a message through our contact page.