How Many Amps Does A 50 Watt Solar Panel Produce?

How Many Amps Does A 50 Watt Solar Panel Produce? -Featured Image

How many amps does a 50 watt solar panel produce? This type of solar panel is on the smaller side of the spectrum. But it does have it’s uses because it is lightweight and compact. For use as a portable this means it can be easily carried and moved around.

When it comes to installing 50 watt panels to a smaller vehicle it has its charging uses. They can be fixed to vehicles such as RV’s, campers,Vans, trailers or boats. Their amperage, wattage and voltage are small so they are ideal to keep batteries topped off.

Using them along with a solar charge controller to trickle charge batteries can be very effective. They come in 3 varieties: portable folding, rigid and flexible.

You are thinking that you might want to use the 50 watt as a backup or for use with a solar power station. But you want to know how fast and by how much it will charge a battery. And that comes down to the number of amps it will produce

How Many Amps Does A 50 Watt Solar Panel Produce?

“A 50 Watt solar panel can produce 2.69A depending on the solar panel’s maximum power voltage (VMP). I arrived at that 2.69A figure by dividing 50 watts by the panel’s VMP 18.6V. I found the VMP in the manufacturer’s specifications. In this case I used the Renogy 50 watt 12V monocrystalline solar panels specs”.

The calculation I used to find the amps is a standard calculation. This means that you can use it to find any solar panels amperage. But if you can’t be bothered with the math. You can always look up the panels specs because the amp output is usually expressed as;

The Optimum Operating Current (IMP)

Different Manufacturers 50 Watt Solar Panels Produce Different Amps 
This is a video from Into The Ordinary https://www.youtube.com/channel/UCyD3sEJLC52UzR1wjtclsPw explaining What is an amp? – Electricity Explained – (2}

The calculation I used implies that different 50 watt solar panels will produce different amperages. You would be right in thinking that. So for arguments sake let’s look at a few different manufacturers of 50 watt solar panels.

50 Watt Solar Panel 50 Watt Solar Panels VMP 50 Watt Solar Panels IMP
Renogy E-Flex Portable18V2.77A
ACOPOWER 12V Monocrystalline19.8V2.53A
Solartech 12V Polycrystalline 17.5V2.86A
Solarland 12V Polycrystalline18.64V2.68A
GrapeSolar Monocrystalline Flexible17.6V2.84A

As you can see there isn’t a definitive answer to how many amps a solar panel produces. But what I will say is that at full power (full unrestricted sunlight). Depending on the 50 watt panels VMP you can expect between 2.5A and 2.9A.

For further reading you can follow this link;

Related >>>>>>>>>> How many amps does a 100w solar panel produce? 

What is The Relationship Between Amps A 50 Watt Solar Panel Produces and Volts?

You may have noticed from the table above that there is something funny going on between the volts and amps. Looking at the table more closely you will have noticed that the higher the voltage  the lower the amps. And the lower the voltage the higher the amps. 

How Many Amps Does A 50 Watt Solar Panel Produce? - Volt and Amp Meters

Simply put if you want higher amps you should look for a lower VMP rated solar panel. But remember this can have a detrimental effect when it comes to charging in low light conditions. 

This is because a battery needs around 13V to 15V from the panel to be able to charge. The voltage a solar panel produces is regulated by the amount and intensity of the available sunlight. This means in low light conditions for example in the morning or late evenings, 

If the volts drop below 13V the battery will not charge at all. And remember if there are no volts there will be no amps. This is something to consider if you believe the number of amps the panels produce is more important.

What is The Relationship Between The Amps Volts and Watts A 50 Watt Solar Panel Produces?

Something else to think about is the relationship between 50 watt solar panels amps, volts and watts. The equation to find a solar panel’s wattage is to multiply the amps produced by the volts. Again for the volts you would use the VMP. 

Let’s reproduce the table outlined earlier but this time relate it to watts as well. Using the multiplication of amps (IMP) and volts (VMP) to calculate the watts. They all should be 50 watts shouldn’t they?.

50 Watt Solar Panel 50 Watt Solar Panels VMP 50 Watt Solar Panels IMP Solar Panel Watts
Renogy E-Flex Portable18V2.77A49.86 Watts
ACOPOWER 12V Monocrystalline19.8V2.53A50.09 Watts
Solartech 12V Polycrystalline 17.5V2.86A50.05 Watts
Solarland 12V Polycrystalline18.64V2.68A50.06 Watts
GrapeSolar Monocrystalline Flexible17.6V2.84A49.98 Watts

As you can see they are not exactly 50 watts and a couple are slightly under but the differences are negligible. The panels that are slightly under are probably due to the recurring numbers in the calculation.

So next time you buy a solar panel and you think it isn’t performing to the manufacturers specs. You can do these calculations yourself and take them to task.

Having said that the specs they put out are results produced from ideal conditions. They usually call them Standard Test Conditions (STC)

Homer Energy Say;

PV manufacturers rate the power output of their PV modules at standard test conditions (STC), which are a radiation of 1 kW/m2, a cell temperature of 25°C, and no wind. Standard test conditions do not reflect typical operating conditions because full-sun cell temperatures tend to be much higher than 25°C (Source; homerenergy.com)

How Many Amps Does A 50 Watt Solar Panel Produce? - Clouds

Another way manufactures show solar panel test results is using Nominal Cell Operating Temperature (NOCT)

SolarDesignGuide say:

The Nominal Operating Cell Temperature (NOCT) (sometimes referred to as Normal operating cell temperature) is defined as the temperature reached by a solar panel under a set of conditions that are more in line with real world conditions than STC: (Source; solardesighguide.com)

The NOCT test uses an ambient air temperature of 20° rather than the actual cell 25° temperature used in STC.

So if you are looking for a 50 watt solar panel. Look out for those panels that have their performance tested under NOCT conditions. But in the end it doesn’t really matter because these tests are not done in real world conditions. Neither test takes haze, cloud, rain, snow, the seasons and time of day into consideration.

For further reading about solar panel performance under cloudy conditions follow this link;

Related >>>>>>>>>> What is the output of a 100 watt solar panel on a cloudy day? 

What Batteries Can A 50 Watt Solar Panel Charge?

A 50 watt solar panel is capable of charging any battery type;

  • All Sealed Lead Acid – AGM, Flooded and Gel
  • All Lithium
  • Calcium
Varta Lead Acid Battery

It boils down to if the solar charge controller can charge the battery type you have. 

How to Calculate The Amp Hours A 50 Watt Solar Panel Will Produce To Charge A Battery

Lots of people are under the impression that the solar panel wattage is related to the battery amp hours (AH). What do I mean by that? Well a 50 watt panel charges a 50Ah battery, a 100w panel a 100Ah battery and a 200w a 200Ah battery.

This is 100% not the case so let’s take a look at what a 50 watt solar panel will charge. We know because of our earlier calculations in the post. That the panel will produce between 2.5 and 2.9A. But we will use the IMP of the Renogy E-Flex Portable Solar panel which is 2.77A.

Renogy EFlex 50 Watt Portable Solar Panel
Renogy EFlex 50 Watt Portable Solar Panel

Remember 2.77A can only be produced under ideal conditions. That is full sunlight, with no wind and a solar cell temperature of 25°

Where Do Sun Hours Fit Into The Calculation?

To start we need to understand that it comes down to sun hours so we will assume 6hrs of full sunlight. That is 11am to 4pm. Yes I know that is only 5 but there is sunlight before and after those hours. We are taking those into consideration because they do exist. And I think 1 extra hour is a reasonable approximation.

So if we multiply 2.77 by sun time 6hrs that equals 16.62.  This is the number of amp hours the 50 watt panel will produce. You can immediately see that 16.62Ah would only keep a 30Ah or less lead acid battery fully charged. This is because of the 50% capacity lead acid battery discharge rule.

Sunset and Sunrise

If you don’t know what that rule is, it means you can’t discharge a lead acid battery below 50%. Using the 30Ah battery that means it can’t be discharged below 15Ah without damaging it.

But because a LiFePO4 battery can be discharged to 10% capacity the battery would have to be 15Ah or less. 

So keeping a battery over 100Ah fully charged with even a 25% discharge would be difficult with a 50w panel. But it could be used to keep larger batteries topped off. It would be ok for regular use with a 50Ah battery modestly discharged to 75% of its capacity.

If you would like to know more about Lithium batteries you can follow this link;

Related >>>>>>>>>> What size solar panel and controller is needed for lithium ion batteries?

My Closing Thoughts

The amps a 50 watt solar panel produces varies between manufacturers and models. Higher voltage equals lower amps and in low light conditions it is better to have a higher voltage panel. 

Also the wattages between different 50 watt panels can vary. But it’s only a tiny amount so there is nothing to worry about. When it comes to actually charging batteries. A 50 watt panel is suitable to keep a 50Ah battery charged if modestly used. And a 30Ah or less battery fully used.

Batteries over 50Ah can be used with a 50w panel but realistically just to keep them topped off. 

If you would like to take a look at some 50 watt solar panel specifications and information you can by following this link;

I hope you enjoyed this post and have found it helpful. If you have any questions about 50 watt solar panel amp production. Or want to leave your own personal review, please feel free to leave a comment below.

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4 Comments on “How Many Amps Does A 50 Watt Solar Panel Produce?”

  1. Oh now I get a better understanding of how many AMPS a 50 watt solar can produce current.

    solar energy is one filed that is rapidly growing due to it’s productivity, safety and the ability to conserve nature. That is why it is more valuable to pay attention to it. 

    i will finish by saying it was nice reading this blog thanks allot.

    1. Hi Limo

      Thanks I am pleased you found the post informative. Yes 50 watt panels produce low amps compared to the larger solar panels. But they do have their uses and are capable of keeping smaller batteries charged. 

      They can’t really re-charge larger batteries but they can keep batteries up to 200Ah topped off.

      Regards

      Steve

  2. I didn’t know these smaller solar panels exist. I need to tell my parents about them. I think the panels would work well with their RV and I love that they can charge all battery types. I appreciate that you did all the calculations for readers, as it can be quite confusing to some of us that aren’t as familiar with solar panels and how much energy they can produce. 

    1. Hi Alicia

      Solar panels work great with an RV I am pleased that you understood the calculations. They are not that complicated mainly simple multiplication and division. I try to present them as simply as possible.

      The calculation I have presented in the post can be used to find any size solar panels amp production.

      Regards

      Steve

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