At Mannerfarm we use four different independent battery systems that we have built ourselves. Read on to learn about all the parts and methods for doing this yourself.

Getting Started

If you have a shack, shed, home office, caravan, house or any other form of building fixed or mobile then adding battery storage is a very good idea. A battery storage solution can provide you many benefits such as:

  1. Full or partial independence from grid connect power.
  2. A means to potentially reduce your energy costs.
  3. Cleaner power supply in both terms of how that energy is produced but also in terms of supply stability to household items.
  4. A great means to really get educated about the cause and effect of power generation and consumption.

The battery system can be designed to be 100% off grid or a hybrid system where the solution can be supplemented with grid power. You may decide to install a small battery system to act as a kind of UPS (uninterruptable power supply) for when grid power fails or a form of hybrid solution. In any case there are a few simple things you need to understand before parting with hard earned money:

  1. Decide what it is you want to use your battery system for.
  2. Work out what it is you want to power from your battery system. This importantly includes roughly how much power each device uses and an estimate as to how long each device consumes power for in a 24 hour period.
  3. Identify maximum loads. That is if all devices your battery supplies energy to what is the potential maximum draw at any point in time.
  4. How long does your battery system need to supply useable power for in the event of little or no charging input.

Once you have some of these key metrics you will be able to formulate an average Watt Hour (WH) or Kilowatt Hour (kWh) draw. This is the start of working out your battery size and from this everything else.

The Sizing

Once you understand roughly what your consumption requirements are for power you can start to  identify the correct amount of battery power you might need. The main factors are

  1. Maximum potential draw at any point in time.
  2. Amount of power that needs to supplied over time (kWh).

These two factors alone will determine how much available energy storage the batteries must be able to supply. All batteries have a capacity rating measure in amp hours (ah). This is the theoretical amount of energy the battery can supply under certain conditions. For more information on battery types go here. Whatever capacity you decide is needed it is always a very good idea to add a healthy margin onto this to compensate for variables such temperature, age of battery (capacity diminishes over cycle life) and transient or parasitic loads.

The battery chemistry type being either Lead Acid or Lithium will greatly affect the sizing of the battery bank. The two differing chemistry types have a very different set of working principles that primarily revolve around "useable capacity". Just because your battery states it is 100ah does not mean that it will be able to deliver that much energy or that you should use all of that available energy. Battery life is determined by many factors but predominantly is measured by Cycle Life Vs State of Charge (SOC). Essentially the deeper you discharge a battery before recharging the less cycle life you get out of it and hence the sooner it will degrade and ultimately fail.

If you are considering Lead Acid batteries then the industry accepted useable capacity is generally 50%. So your 100ah Lead Acid battery will have a useable capacity of 50ah. That is not to say you can take more it just starts to exponentially affect its cycle life. Lithium batteries on the other hand generally have an accepted usable capacity of 80% which is somewhat more than Lead Acid. However each battery chemistry type has its advantages and disadvantages depending on what the required application is.

Ultimately the rest of your system will come together once you have selected the battery type and the overall capacity required. 

The Budget

The biggest cost of any such system is pretty much always going to be the batteries themselves followed by the charging system being solar, wind, hydro or mains. 

In our experience there is only really one component that you should not cheap out on and that is the batteries themselves. Always buy from reputable manufacturers. Our favourite batteries are made by Giant Power (Lead Acid) and Renogy (LIFEPO4). There are a lot of excellent battery manufacturers so stick to the good named brands. As for the rest of the components in our experience they fall into three main categories.

  1. High End Equipment - this includes manufacturers like Midnite Solar and Victron.
  2. Mid-Tier Equipment -  pretty much anything manufactured by Renogy, we really like their products as it balances affordability with good quality and features.
  3. Low End - I hate to say this but a lot of the Chinese manufactured stuff you get from say Ebay isn't real flash but does work and in our experience hasn't started any fires. Just be aware they throw around statements like MPPT when clearly that is a lie.

The Parts

When planning on putting together a battery system with solar and/or wind as your charging the source you need to consider the following components.

  1. Batteries and Battery Connection Wires - if you have multiple batteries then these are the wires to connect your batteries in either series or parallel. 
  2. Busbars - suitably sized positive, negative and earth busbars.
  3. DC Wire - suitably sized DC wire and appropriate connectors. Sizing your wire for the amount of amps it needs to handle and the length of the wire run is critical for safe and efficient operation. Undersizing DC wiring can lead to inefficiencies and in some extreme cases a fire.
  4. Isolation Switches - main battery isolation switch. Your battery bank should always have an isolation switch in the event you need to disconnect the battery bank from its load.
  5. Suitably sized solar
    1. Solar Panels
    2. Solar mounting brackets
    3. Solar wire either 6mm or 4mm twin core (recommend 6mm)
    4. MC4 connectors
    5. Solar charge controller suitable for battery chemistry
    6. Solar panel isolation breaker (generally a 30amp or greater twin pole DC breaker
  6. Suitably sized wind turbine -
    1. Wind Turbine
    2. Mounting system
    3. Suitable DC wiring
    4. Isolation thermal breaker
  7. Battery Monitor - it is very important to get a good quality battery monitor so you can manage your system correctly.

Other components to supply low voltage or 240V might include the following.

  1. Suitably sized pure sine wave inverter to convert DC to 240 mains AC.
  2. Suitably sized DC-DC Converter to supply regulated low voltage output.
  3. Voltage sensing relay to switch loads on or off.

The Assembly

This is the bit you really don't want to get wrong and the only real advice we can provide is that if you aren't sure how something goes to together ask for help or research on YouTube. There are a lot of very good resources available.

The Monitoring and Tweaking

Once your system is installed it is important to monitor battery performance in regards to charging and discharging cycles. This is especially important over the first 12 months of the system to account for all the seasons. As the batteries age it is also important to keep an eye on the voltages and adjust as necessary for any degradation in performance.

The Outcome

A properly sized, managed and cycled battery system can last for a good ten years or more. The important thing is to monitor the system performance regularly and keep up with system maintenance. Tasks such as checking a wiring connections for corrosion, cleaning solar panels and inspecting wind turbine for wear or damage. 

The Mannerfarm Systems

We will go into more detail to provide specific examples of our various battery systems but essentially we have four independent systems being the following.

  • House Hybrid Battery System Lead Acid Gel - this is a mixture of mains and battery electrical circuits providing both 12V and 240V.
  • Shearing Shed Battery System Lead Acid AGM - this is a complete off-grid system providing both 12V and 240V.
  • Cabin Lead Acid AGM - this is a small off-grid system providing both 12V and 240V
  • Lithium Iron Phosphate Test System - an independent LIFEPO4 test system providing 12V supplement into house battery circuits. Read about this one here.

If you are looking at setting up your own battery system but aren't sure what you need why not contact us? We can provide a consultation service to get you on the right track.

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