Battery Requirements for a 2,000-watt Solar Energy System: What You Need to Know

A 2,000-watt solar system might be just what you need to supply power to your shed or cabin. Unfortunately, not all kits ship with batteries in which case you’ll need to purchase batteries on your own.

So what size (Ah) of batteries should you use and how many do you need to run the appliances in your shed or cabin with 1,000 watts of solar panels available?

Read on to find out how many batteries and what size you can use.

Note: The information provided here is only a guide. The fact is this is just one of the possible battery sizes and numbers you can consider with a 2,000-watt solar system.

Always contact the kit supplier for guidance or a qualified solar professional.

The Right Battery Size for a 2,000-watt Solar

There’s no one battery size that is prescribed for a 2000-watt solar system. The optimal size of battery you should use depends on:

  • the combined power consumption of the connected appliances. The higher the power consumption, the larger the battery bank will need to be
  • whether you plan to store some or all of the generated solar energy. Should you choose to store a fraction of the energy from the solar panels (a waste!) then you can use a smaller battery bank
  • the usable capacity of the battery type you end up with. You should only use 50% of the more affordable but heavier AGM battery compared to the recommended 80% of the more expensive but longer-lasting and lighter LiFePO4 batteries

When you use LiFePO4 batteries

Should you plan to store all of the generated 8000-watt hours of generated energy to store all this energy using LiFeP04 batteries, you can use battery banks with the following capacities:

• 333 Ah at 24V
• 166 Ah at 48V

How Many Batteries to Use?

You can, for instance, use 4 x 100Ah 25.6V LiFEPO4 as 4 parallel 25.6V LiFeP04 batteries, OR 2 x 100Ah 48V LiFEPO4 as 2 25.6V, 100 Ah LiFeP04 batteries connected in parallel.

When you use AGM batteries

To store 100% of this energy, you’ll need at least double the capacity of the LiFeP04 batteries because AGM batteries should only be discharged to 50% of their capacity for them to last.

Therefore consider the following AGM battery bank capacities to store as much of the available energy:
• 333 Ah at 48V
• 166 Ah at 24V

How Many AGM Batteries to Use?

You can, for instance, use 4 x 200Ah 12V LiFEPO4 as 2 parallel strings of 2 x 200Ah 12V AGM batteries connected in series.

*Note. This is just one of the several battery combinations you can use.

Can you add more batteries later?

This is not recommended. Make sure you decide on a battery bank size and the number of batteries to use from the get-go. Install them at one. Adding more batteries later affects the batteries’ ability to charge uniformly which affects their lifespan. All batteries should be of the same age!

You may also be interested in this post. The Battery requirements of a 1,000-watt solar system

How Long to Charge the Battery Bank?

The batteries will charge in about 6-8 hours if discharged to the recommended depth of discharge – 50% for AGM and 80% for LiFePO4. The charging time will be shorter if they’re partially discharged.

What Voltage to Use for the Battery Bank?

I’d recommend you use at least a 24V or 48V battery bank preferably.

This way the solar panel charge current is lower (than when you use 12V) and you can use thinner and more flexible cables which are easier to work with and keep the power losses in the connecting cables lower.

Related Topics

1. Tips to Maintain the Battery Bank for Best Performance

  • Confirm that the battery type selected on the charge controller matches that of your battery bank for your battery bank to last
  • Make sure you install a suitably sized fuse on the positive battery cable connection to the inverter to protect the wiring against shorts
  • Keep the battery posts clean and free from corrosion to avoid loss of power during charging and discharging of the batteries
  • Make sure the battery bank is installed in a properly ventilated space to avoid overheating and damage to the batteries

2. Inverter Size to Use

There’s no one inverter size as it depends on several variables. For a 2,000-watt solar system, you may want to consider a 3,000-watt 24V inverter or larger (assuming the battery bank voltage is 24V).

Inverter Capacity (Watts) to use

Your choice of size of the inverter to use depends on the combined power consumption of the connected appliances and their surge power rating.

Add up the power consumption (watts) of the appliances you plan to run off your solar system and select an inverter size that can power them with at least 20% of inverter capacity left to spare.

For example, if the combined appliance consumption is 800 watts, go for at least a 1,000-watt inverter or larger.

Inverter Voltage

The inverter’s voltage should match the battery bank voltage to prevent damage to the inverter. For a 24V battery bank, make sure to connect a 24V-rated inverter.

Closing Thoughts

With a 2,000-watt solar system, as a starting point, you can use 2pcs of 100 Ah 48V LiFePO4 batteries connected in parallel (200Ah, 48V battery bank) or 2 parallel strings of 2 x 200Ah connected in series (24V, 400Ah AGM battery bank).

Note. This is only a guide. There are other battery combinations you can use.

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