What Size of Battery and Charge Controller for a 200-watt Solar Panel?

if you’ve got a 200-watt, 12V solar panel already for use with setting up an off-grid solar system and need guidance on what size of the battery, and charge controller to use that is optimized to work with the 200-watt solar panel then read on.

In this post, you’ll find what size of battery (Ah) and charge controller to use with the solar panel on hand

Note: The information provided is a guide. Always contact a qualified solar professional for help in sizing and installing a reliable and safe solar system if you don’t have the skills.

What Size of Battery (Ah)?

You can use a 100 Ah AGM, GEL, or Flooded Lead Acid (FLA) battery or a 50Ah Lithium Battery with a 200-watt solar panel.

This will ensure that it is fully recharged each day keeping in mind the assumptions below.

  1. the batteries are discharged to 50% of their capacity in case of AGM, GEL, or Flooded Lead Acid (FLA) batteries and 80% for LiFeP04 Battery
  2. the solar panels receive a minimum of 4 hours of direct sunshine each day.

With a smaller battery capacity than that indicated above, you’ll not harvest all the energy generated from the solar panels.

On the other hand, if you connect a larger battery capacity bank, it may charge fully with appliances that draw more than the recommended depth of discharge of the batteries. This can shorten the battery lifespan.

How Many Batteries?

Note: The battery combinations below are only a guide. It is possible for your off-grid solar setup to work with other battery combinations other than those listed below.

You can combine several batteries to achieve the indicated battery capacity of the recommended battery bank.

AGM: You can use 1 x 100Ah, or 2 x 50Ah (connected in parallel) AGM, GEL, or Flooded Lead Acid (FLA) batteries.

Lithium: You can use 1 x 50Ah or 2 x 25Ah LiFEPO4 batteries connected in parallel.

Estimated Charging time

The estimated charging time is about 6+ hours. Actual charging time depends mainly on how deeply discharged the batteries are and whether it is a bright day or overcast.

Related Questions

What Size of Charge Controller?

You can use a 20 A PWM charge controller or larger (if you plan to grow the size of the solar system). The rated current output of a 200-watt solar panel at 12V is about 11A (20A is usually the next available standard charge controller size).

Closing Thoughts

You can use a 200-watt, 12V solar panel to charge a 100 Ah AGM, GEL, or Flooded Lead Acid (FLA) battery or a 50Ah Lithium Battery with a 20 A charge controller or larger.

This assumes 4 hours of sunshine on average. Note, This is one of the several battery and charge controller combinations you can use.

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