How Does 36 cell solar panel Work?

I currently have six 100 watt 12v Renogy Mono panels with the specs below: note 36 cells per panel.

I am looking at buying some 12v Rich Mono panels with the specs below: note 33 cells per panel.

I currently use a pair of Bogart PWM charge controllers.

I want to add more panels and upgrade to a Victron MPPT system and also want the flexibility of connecting the panels in various series-parallel configurations.

The Rich panels are the only panels I can find that match the existing Renogy volts and AH, and my physical size requirements. Moreover, the Rich panels are the only panels I have found that have 12 AWG wires rather than 14 AWG wires. My old Renogy panels have 10 AWG wires.

Question: Will the 33 cell Rich panels pose a problem?

PS: I still do not know if the Rich panels have any diodes. My research is ongoing.

Thank you for any input you can provide!

For MPPT controller, if you are placing panels in series so the Vmp is moderately above battery voltage there is no problem.

Do not use a 32 or 33 cell panel, single or multiple in parallel if you intend to use an MPPT charger on a four-cell stack 12v LFP battery array. You need at least a 36 cell panel for this, or run two or more 32/33 cell panels in series.

There is roughly 0.45v to 0.5v per cell Vmp contribution depending on panel temp. MPPT controller requires some overhead voltage above battery voltage to work properly. Some of the overhead is for the DC to DC converter, some of the overhead is to allow the controller to search for MPPT point. 32 or 33 cell panel is okay for a PWM controller on 12v battery.

Most MPPT controllers will just drop into PWM mode operation if they cannot establish a reliable MPPT point but panel Voc is still above battery voltage.

For MPPT controller, if you are placing panels in series so the Vmp is moderately above battery voltage there is no problem.

Do not use a 32 or 33 cell panel, single or multiple in parallel if you intend to use an MPPT charger on a four-cell stack 12v LFP battery array. You need at least a 36 cell panel for this, or run two or more 32/33 cell panels in series.

There is roughly 0.45v to 0.5v per cell Vmp contribution depending on panel temp. MPPT controller requires some overhead voltage above battery voltage to work properly. Some of the overhead is for the DC to DC converter, some of the overhead is to allow the controller to search for MPPT point. 32 or 33 cell panel is okay for a PWM controller on 12v battery.

Most MPPT controllers will just drop into PWM mode operation if they cannot establish a reliable MPPT point but panel Voc is still above battery voltage.

Normally I would agree with you, but the panel performance values are almost a perfect match.

Normally I would agree with you, but the panel performance values are almost a perfect match.

You are comparing apples and oranges specs. One is for 25 degs C panel, one is for 47 degs C panel.

33 x 0.564v = 18.6v Vmp for a silicon mono cell is not possible unless cells are held to 20 degs C. The Rich spec claims 25 degs which is not realistic with sun panel heating. Maybe in wintertime cold temps. At 47 degs C, which is still relatively low panel temp with sun panel heating it would be 0.516v x 33 = 17.0v Vmp, not the 18.6v listed in their spec.

Renogy lists 18.6v Vmp for 36 cell panel and their spec is for 47 degs C +/-2 degs. That will have about 0.516v Vmp at 47 degs C x 36 cells is 18.576v which matches their spec pretty well.

Monocrystaline cells
OK... sorry, I have not read all of the above because of time restrictions but I do have some comments.

All so called 12V panels that I am familiar with have an open circuit voltage of about 21-22 VDC and Vmp is usually around 18V.

There are good reasons to wire panels in series and that is to minimize the voltage drop in the wires between the panels and the controller. I strongly recommend the OP avoid the pulse width modulation style controllers. MPP controllers are now affordable and allow putting panels in series. The only caution one needs is to understand the so called safe voltages are those below aobut 45V. Think old systems with 48 VDC huge batteries.

I wired my panels (33v) 2 in parallel in series with another 2 in parallel for my boat. Sure, I can get voltages above 70 but I can also get by with almost no voltage drop in the wiring between my total W panels and my Victron controller with two strings of #10 wire. Thanks for all the helpful replies.

I have an existing lead acid battery bank and believe that my Bogart PWM system was the best system for my lead acid batteries. I am now building a 560 Ah Lifepo4 battery bank and will be installing Victron charging and monitoring components.

Given that Rich solar never replied to my inquiry about whether their 33 cell panels have diodes, and given the uncertainty respecting the actual specifications vs. what Rich Solar advertises, I am going to pursue other alternatives.



Thanks again!

Given that Rich solar never replied to my inquiry about whether their 33 cell panels have diodes, and given the uncertainty respecting the actual specifications vs. what Rich Solar advertises, I am going to pursue other alternatives.

I have 4 Rich 100W poly panels that perform very well. I'm not going to pull one off to pop open the diode/junction box but I'd be shocked if they didn't have diodes. They play well with 4 WindyNation monocrystaline 100W panels

Can you explain more what you meant by this? Thank you.

The 'let-go' voltage of DC maxes out a bit over 50V by 'definition.' 40VDC can still kill you but not likely you'll hold on long enough to do that, though it can burn you.
50VDC isn't likely to immediately kill you either but it may and is probable it may immobilize you long enough to inflict severe injury- or kill you. 90VDC can shut vital systems down or un-time your heartbeat and may kill you dead on the spot or wack out your body that you collapse dead later or die that night in your sleep.

Is that true all the time? No. Maybe not even close- but the probabilities are a risk factor too great to ignore or take lightly. I can't remember exactly now (not a joke, it's just long ago) but 24VDC tingled me once. It was more than a tingle really but I suddenly became more respectful of DC is what I remember.

Solar energy's popularity has been growing in the past couple of years. Awareness about its benefit to Mother Earth and one's electricity bill continues to spread. That is why many are starting to install this clean source of energy in their homes and businesses. 

OUSHANG SOLAR are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

If you are thinking of doing the same thing but find it a bit daunting, and you want to know how it works. Don't fret. In this post, we'll discuss how solar panel works, what's the solar panel voltage, how to measure it, and the factors that affect it.

The Solar panel voltage: The Most Visible Component

When you think about solar energy, one of the first things that come into mind is either a single rectangular blue with a grid or rows of this rectangular blue on an open field. It is also called a photovoltaic (PV) panel. The standard solar panel voltage is between 12 volt and 24v solar panel. It is made of solar cells, which both have a negative and positive layer allowing it to create an electric field. 

Once the sunlight hits the panels, an electric current is produced. This current is then moved by voltage then goes through the wires and components of the system like Nature's Home power backup.

The two most common types of panels are monocrystalline and polycrystalline panels. The light blue panels which we're more familiar with are called polycrystalline panels. The black panels are the monocrystalline ones. In essence, the:

• Monocrystalline solar panels are produced from a single silicon crystal, while 
• Polycrystalline solar panels are created out of many silicon crystal fragments that are mixed during the manufacturing stage.

Monocrystalline panels have a higher efficiency but are more expensive because of their complex manufacturing process. And, to reach the same power output as its counterpart, polycrystalline panels needed to be installed more. They are cheaper and less efficient.

You can check out this article What is the Difference Between Polycrystalline and Monocrystalline Solar Panels for more information on the difference between the two kinds of solar panels.

Solar Power Voltage Terms to Familiarize and How it Works

It is important to get the numbers right as you don't want to overload your inverter or underutilize your home power backup. But to help you understand more about pv panel voltage and how it works, here's a list of terms to familiarize:

• AC Volts - refers to the converted voltage from DC Volts to AC Volts.
• Nominal Voltage - is a reference on the voltage class your circuit or system is under such as 300 volts, 120/240 volts, etc. This is different from the operational/operating voltage (i.e. if you have a 240-volt circuit but it is operating at 234 volts).Actual Voltage Measured Under Load - is about the circuit's actual voltage once an appliance has been connected.
  
• Voltage Maximum Power (Vmp) - is measured with a multimeter. It refers to the solar panel's maximum capacity when connected to a load. The actual VMP will differ throughout the day due to shading, temperature and other factors.
• Potential or Open-Circuit Voltage (VOC) - is the circuit's voltage measurement when not connected to a load.

With this knowledge in mind, let's take a look at how it works.  

• A standard solar panel is made up of 36 crystalline cells. And, those cells are quite powerful:
• A cell's voltage under load is at 0.46 volts which is about 3 amperes of generated current;
• Each cell inside that panel can generate 1.38 watts, approximately;
• A single cell has about 0.5 to 0.6 of open-circuit voltage;

In short, a solar panel has:

• Peak Open-Circuit Voltage Output: 18-21 volts, and
• Actual Voltage Measured Under Load: 12-14 Volts.

This is just about enough to power a 12-volt battery.

For more 36 cell solar panelinformation, please contact us. We will provide professional answers.

4 Factors that Affect Solar Panel Voltage

The type of panel used for your solar power system plays an important factor in your output voltage requirements. Other external reasons can cause the panel's voltage output to fluctuate. Some of them are the following:

• Panel Orientation 

To reach the peak performance and maximum of the solar panels and their output voltage, it is a must to ensure that they are tilted towards the sun. While having them lay flat is okay, being in a tilted position meant more sunlight hits their surface at a perpendicular angle. This allows for a more efficient conversion of solar energy to electricity.

• Shading and Location

It is important to make sure that the panels or any of their parts aren't shaded. Having an unobstructed view of the sun meant they can soak in all the energy and be efficient in storing them.

Shaded cells aren't able to generate as much electrical energy as the cells that are fully exposed to sunlight.

That is why it is also good to note if you live in an area that gets to experience more peak sun hours.

For those living in Arizona, a 400-watt panel can produce at least 3 kWh of electricity since it has 7.5 hours of peak sun hours. Meanwhile, if you're living in New Jersey, the same 400-watt panel can only produce 1.6 kWh of electricity because it only has 4 hours of peak sun time.

• Temperature

Like any appliance or gadget, a solar panel's performance is also affected by the temperature. The voltage output decreases as the panel's temperature increases. This is because the electrons within the solar cells move slowly the higher the temperature is. Thus, resulting in a reduced amount of generated electrical energy.

• Panel's Age and Maintenance

Cleaning the panels regularly is necessary to make sure that they receive the right amount of sunlight. Remove any debris and dust that accumulated on top of the panels to avoid a drop in the production of electricity. 

Like any gadget you own, wear and tear also affect the solar panel output voltage a.k.a. the panel's efficiency. 

Typically, solar panels degrade at about 0.5% per year. So, if you have had the panels for 25 years, their efficiency is down to 85%, which is still enough to lower your utility bills. 

To achieve this slow degradation rate, it should be a must to regularly check on the status and quality of each part of the panel and its system. After all, as cliché, as it may seem, prevention is better than cure. Or in this case, way better than wasting your savings.

To put it all together'

One of the first things that come to mind when thinking about solar energy is rows of solar panels on the open field or the roof. After all, they are the most visible component of this renewable energy system. 

Determining the solar panel voltage and how much solar input it needs are required when building the perfect home battery backup for your home or business. But there are factors to consider that may affect the efficiency of the output voltage, such as temperature, location, shading, panel orientation, and age and maintenance.  

Regardless of how tedious the research work can be, the long-term use of solar energy is worth every time and money spent because of its benefits to one's savings and nature.

For more information, please visit custom solar panels.