What Charge controller, No. of batteries, Inverter size to Use with an 800 watt Solar System?

If you are looking for a clean, off-grid power solution as an emergency power backup, boat or camper then the 800 watt solar system may be right for you depending on your appliance power requirements – the power consumption of connected appliances and how long you plan to run them for.

When you select the right size of solar charge controller, batteries, and inverter you can be sure of harvesting as much power as is generated by the solar panels while using the appliances you planned for without the worry of running out of power or your system failing prematurely.

So, read on for guidance on what size of the charge controller to use, how many batteries to connect, and what appliances you can connect to an 800 watt solar system

What Size of Charge Controller for an 800 Watt Solar System?

Depending on the type of connection and whether you plan to scale the solar system beyond 800 watts, you can use a 40A MMPT controller or a 60A Charge controller.

A 60A charge controller can handle about 1,000 watts of solar.

Check the charge controller’s owner manual for the maximum power it can handle.

You can use a higher current rated charge controller but be aware that its entire capacity may not be used unless you plan to grow your solar system.

Portable Solar Panel
Portable Solar Panel

How Many Amps Does an 800 watt Solar System produce?

An 800 watt solar system generates about 40 amps maximum at 24V.

This assumes 4 x200W panels are wired in parallel with each generating about 10 amps at peak.

Connecting them in the 24V minimizes keeps the energy losses at a minimum while using smaller cable gauges.

Related Posts: How many watts of solar can a 40A charge controller handle?

How Many Batteries to Use with an 800 Watt Solar System?

The battery bank capacity at 24V is 200Ah while at 12V, it is 400Ah.

You can use 2 pcs of 200 Ah AGM or GEL batteries in parallel (12V) or 3 pcs of 100 Ah Lithium batteries (12V battery bank).

For a 24V battery system, you can use 4 pcs of 200 Ah AGM or GEL batteries (2 strings of 2 batteries in parallel) or 4 pcs of 100 Ah Lithium batteries (2 strings of 2 batteries in parallel).

This is based on an estimated daily energy production of 2,400wh (4 hours of sunshine) and assumes that your battery bank voltage is 24V.

Calculation

Battery capacity (Ah) = Average daily energy production (Ah) / (battery bank voltage x battery depth of discharge).

For a GEL or AGM, recommended depth of discharge is 50%, therefore battery capacity should be about 200Ah from 2,400 wh /(24V x 50%). Note: This assumes 4 hours of sunshine!

Using smaller battery banks

If you use smaller battery capacities, you will not able to store all of the electrical energy generated by the solar panels.

Using larger battery banks

If you use considerably more batteries (larger battery capacity), there is a good chance that the generated power will not be enough to fully charge the drained batteries which affects their lifespan.

Related posts: How much energy does a 200 watt solar panel produce?

What Size of Inverter to Use with an 800 watt Solar System?

The size of inverter size (watts) you choose depends on the combined capacity (w) of the appliances you plan to connect to it.

In addition to the total power consumption, you need to consider the surge power rating of the appliances you plan to connect to the solar system.

That said, while there is no hard and fast rule, there is a good chance that you will find inverter sizes of capacities ranging from 1,000 – 3000 watts connected.

Smaller inverter sizes may be used but you’ll be limiting the size and number of appliances you can use with the available energy in the batteries.

What Will an 800 Watt Solar System Run?

The list below shows examples of appliances you can connect to an 800 watt solar system.

It is by no means exhaustive and it is quite likely that there are appliances not on the list that can be used on an 800 watts solar system.

350 watt PlayStation or Xbox100 watt SoundsystemSelected pumps
250 watt fridge or freezer300 watt Desktop computerSelected fans
50 watt LED TV300 watt coffee potDVD players
50 watt LaptopLED lightingRecharging phones, tablets

How long the appliances run for depends on the state of charge of the battery and the total power consumption of connected appliances.

If using 2 x 100 Ah AGM or GEL batteries connected in series, the available energy for use is about 1,250 Wh (100Ah x 24V x 50% depth of discharge).

With this 1,250Wh, you can run as an example:

  • Lights: 6pcs each 10w for 6 hours = 300 wh
  • Laptop: 40w laptop for 4 hours =160 wh
  • Fridge: 250W fridge for 3 hours =750 wh

Total 1,210 watt-hours which is 40wh less than the available 1,250wh.

Final Word

An 800 watt solar system typically generates between 3 – 4 kWh of energy daily depending on the amount of sunshine available.

To store the generated energy, you can use 4 pcs of 200 Ah AGM or GEL batteries (2 strings of 2 batteries in parallel) or 4 pcs of 100 Ah Lithium batteries (2 strings of 2 batteries in parallel).

You can use a 40A, 60 A, or higher current rated charge controller with the solar system if you plan to increase the size of the system.

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