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Modern solar panel systems come in a wide variety of sizes, from 1 kW systems, 2 kW systems, and the popular 400 watt solar systems.400 watt solar systems  are  powerful enough to provide your home and RV with sufficient electricity, and more affordable.However you still need a battery to store that energy.The question now is how many batteries are needed for this solar system to run efficiently.

How many batteries do i need for a 400 watt solar system?

Two steps will help you size your battery system:

1. Know your energy production capacity
2. Estimating your energy consumption

Energy production capacity

A 400 watt solar panel can produce 1200-2400 watts a day depending on how many peak sun hours are available. You need energy storage for later use.

Solar panel output x sun hours = watts

If your area gets 6 hours of sunlight, a 400 watt solar system may produce up to 2400 watts a day,this number can fluctuate depending on your location and cloud cover.

Check your peak sun hours：Peak Sun Hours Calculator (with Map)

Energy consumption

We cover the three ways to calculate your energy needs.

1. Calculate your daily load manually
2. Look at your electricity bill for average usage
3. Ask a solar installation company to do it for you

Learn more:How to calculate solar system size for your home?

Now that we know the number of average watts you get daily, we can figure out the size of battery needed for your system.

Battery size for  solar panels 400w

400 watt solar panel are generally 12 volts, which means the battery should be 12V too.This will ensure uniformity throughout the circuit.

Watts / battery voltage = battery size

if your system produces 2400 watts a day, divide it by the battery voltage:

2400 / 12 = 200ah

Remember this is for when conditions are perfect with no hindrance in the sunshine. In reality, amp hours are usually between 100 and 150ah.This means that the minimum size battery you would need would be a 150ah battery. This is enough to store the energy produced by your 400-watt system.

With more peak sunlight hours, your panel can produce more than 150Ah, possibly even pushing it up to 200ah. Buying a 200Ah lithium battery is a good choice.A 200ah 12V battery has a capacity of 2400 watts so no energy gets wasted.

How long will it take a 400 watt solar panel to charge my battery?

Generally, it takes 4-6 hours to fully charge a 200Ah battery considering that conditions are perfect, i.e. minimal cloud cover and available hours of sunlight.

Lithium batteries can charge faster than their lead-acid counterparts. Lithium batteries are the best batteries for RV solar systems and off-grid systems.Lithium batteries are more sophisticated and advanced, capable of absorbing more power without incurring damage.

What type of battery should I choose

Lithium batteries are your best choice.

Lithium batteries are more sophisticated and advanced, capable of absorbing more power.lead-acid batteries may require 12 hours (or longer) to reach full charge, whereas lithium batteries can be charged in just a few hours. And Long life, light weight and high power output of lithium batteries.

Of course，if you are on a tight budget, then you could also opt for AGM batteries, which are an excellent alternative to a lithium battery.Their DOD is not as good as lithium but still more efficient than older lead acid batteries. 

Conclusion

400 watt solar panel systems are becoming the go-to for many new solar panel owners.Solar battery storage  are an essential part of the overall solar panel system.

If you  or all your solar panel needs and queries, please contact WinSeven SOLAR