#solarpower #solarpanels #solarbattery

A 300 watt solar panel can charge a 12 volt battery in 4 hours in favorable weather conditions. A smaller solar panel can be used with a 12 volt battery, but it is going to require more sun hours to complete the charge.

So What Solar Panel Size is Best for Charging 12 volt Battery?

There are many factors to consider when buying a solar panel, But for battery charging purposes it will depend on the battery size and how quickly you want it charged. it also depends on how many sunlight hours are available.

Suppose there are 6 hours of sunlight per day in your area. You have a 100 amp hour 12 volt battery, which is equal to 1200 watts.

A 100 watt solar panel needs two days to charge a 12 volt 100 amp hour battery. This is based on the assumption the panel produces 600 watts a day.

A 300 watt solar panel will charge the same 100 amp hour battery in a single day. If the panel generates 250 watts an hour, it only needs 5 hours to recharge the battery. And if the module reaches peak output of 300 watts, the battery will be ready in four hours.

If you are looking for a 300 watt solar panel, we recommend the Rich Solar 200 watt Solar Panel Pack. it works great for various outdoor settings including RVs.

There are two kinds of solar panels, monocrystalline and polycrystalline. Monocrystalline solar panels are more energy efficient because they are made from a single source of silicon. Polycrystalline combine several silicon sources, which is inferior to silicon.

How big is the difference? It depends on the quality of the solar panel design and manufacturing process. In some cases monocrystalline panels are up to 15% more efficient, but in other cases it is negligible. It comes down to the manufacturing procedure.

How Long Does it Take to Charge a 12 volt Battery?

If you have a 12 volt 100 amp hour battery and a 300 watt solar panel, the charge time from 0% to 100% should be 5-6 hours, assuming there is 5-6 hours of available sunlight. it also helps if you have a fast charging battery like a 12 volt 100 AGM battery so the process doesn't take forever.

The calculation earlier gives you a charge time of 5 hours, but it could reach 6 depending on the sun. The charge time will also depend on the following factors:

Solar panel watts

Battery capacity

How much the battery is drained

Charge controller

Available hours of sunlight

We assume the panel generates 300 watts an hour. This is possible but if there are clouds or dirt on the solar panel, output will be lower. In some cases the solar panel will not reach 300 watts an hour, probably 250 watts or so.

If the output is les than 300 watts, battery charge time will take longer. By how much depends on when the skies clear up. keep in mind too that the sun's position in the sky changes. As the afternoon draws to a close, the sun goes down the horizon and the solar panel receives less light. This is going to reduce power output and batteries will take longer to charge.

How Much Solar Power Do I Really Need to Charge Batteries?

The rule of thumb among solar power users is to add 10% to 20% more power than what your estimated needs are. First we will explain how to calculate solar power watts for 12 volt batteries.

Multiply the battery capacity (ah) x voltage.

The result is the watts. Divide the watts by the number of sunlight hours available.

With a 12 volt 100 amp hour battery, we get the following: 100 amp hour / 12 volt=1200 watts. 1200 watts / 6 hours of sunlight = 200 watts.

So now you have 200 watts. That should be enough to charge the battery, right? While 200 watts can work, you have to bet on ideal weather. Second, you'll be pushing the solar panel to the limit. Not only the panel, but other components like the charge controller and battery. It is better to have a reserve or buffer present.

That's why most solar power users add another 20% to the calculation. So if the calculation gives you 200 watts, add 20% (200 + 20%) to get 240 or better yet 300 watts. This will be more than enough to charge the battery even if the weather is less than ideal. if you have a 0 watt0 watt solar panel the charging will be longer.

Battery Capacity Explained

Solar battery capacity is measured in amp hours (ah). The battery stores the power generated by the solar panel and this current is converted by an inverter into usable AC electrical power for TVs, refrigerators, fans and other appliances.

1 amp hour is equal to 1000 (milliamp hour). Power bank capacity for smartphones, mobile devices and portable solar generators are measured in mili amp hour.

A lead acid battery at 0% takes 5 to 6 hours to charge based on the formula given above. If you recharge the battery at 50%, the charge time drops to 2.5 hours, assuming the weather is the same. If you do not let the battery level drop below 50%, you can charge it with a 200 watt solar panel.