# How Many Solar Panels Does It Take to Charge a 200ah Battery?

02/24/2022

You muct want to know more about the 120w solar panels, but after read carefulhy online, sometimes, you even cannot find what you need. So you had better read some post when you are free. Here, in this post, i would like to introduce that how many solar panels does it take to charge a 200ah battery. We need to provide a bit more detail about the battery before answering this question. The capacity is 200Ah, but will the battery be fully discharged?

In fact, you cannot see the phenomen at most times. I can’t remember ever discharging a battery 100%. Some lithium-based batteries can be 100% discharge, but acceptable discharge levels vary depending on battery type and design. The most common high-power battery in use nowadays is the lead-acid type, so I’ll base my answer on this.

As a general rule, a 200Ah lead-acid deep-cycle battery would need a 300 watt solar panel to fully recharge from 50% Depth of Discharge (DOD) assuming 4 peak-sun-hours per day. Charging would be complete in one day with a clear sky.

## How to Estimate Remaining Battery Capacity

You can estimate how much capacity a lead-acid battery has left by measuring the terminal voltage with a multi-meter.

This should be done after several hours of inactivity, when the battery is neither charging or discharging, so that there is almost no chemical changes taking place inside the cells.

## How to Calculate Watt Hours of a Battery – Ah to Wh Conversion

Watt-hours is good for expressing the amount of energy to be replaced, which is convenient as we use the same units to measure solar panel energy generation over time.

Ah is useful when we know how many amps a solar panel can deliver. We can then work out how many hours the battery will take to charge.

However, this depends on constant power output from the panel. If a cloud passes over, then it doesn’t work out so well, as current output of the solar panel falls off.

For the two types of lead-acid battery previously discussed, the probable recharge capacity needed in watt-hours would be:

Auto battery: 40Ah x 12volts = 480 watt-hours Deep-cycle battery: 100Ah x 12 volts = 1200 watts-hours

Now we need to work out how much energy a solar panel can generate in any location.