Solar panels: 60 cell panels, 24V battery, and DSSR20

23 Jun.,2025

 

Solar panels: 60 cell panels, 24V battery, and DSSR20

I've been trawling the posts regarding solar panels used in conjunction with SBMS0 and DSSR20. In many posts there is usually a mention of "matching the panels to the battery" and one such example is the advice to use solar panels with "60 cells" with a 24V battery.Can someone explain what the "match the panels to the battery" comment actually means in terms I could apply to any panel/battery setup?I'm in the midst of planning our 24V system and the solar panels I had previously selected had 60 cells... However, on going to purchase them the site has updated their listing with some new(er) solar panels, the spec sheet indicates these solar panels have 120 (6x20) cells.Does this mean I'm out of luck here and these new(er) solar panels won't work with my 24V system?There is no magic :)About 80% of the world production of PV panels is made out of 60 cell PV panels (that may have changed a bit in recent years where some of that may have been taken by 72 cell PV panels ) and then a much smaller fraction is made of smaller 36 cell PV panels and even smaller fraction some strange non standard number of cells in series.Each PV cell is like a diode but is an open diode very flat and large surface and so works as a generator in presence of light.Since each cell is a diode the max voltage across will be just around 0.7V that is when the diode (PV cell) will short all the energy produced by light so all energy is lost in the diode (PV cell).To be able to use the energy you will want to connect a load that reduces that voltage so the current instead of being sorted by the diode (PV cell) flows through your load.And in our case the load is actually a battery and that is perfect as battery is basically at constant voltage.If you look in the spec of your PV panel the 335W model you have 41.32V open circuit voltage so if you divide that by the 60 cells in series you get 0.688V almost that 0.7V rounded number that I mentioned before.Now if you look at the last graph you see a current vs voltage based on panel temperature and in a sunny summer day panels will be at 60 to 70C so looking at that purple +70C curve you see you get max current only if voltage is somewhere around 27 to 28V  and LiFePO4 will be around 26.5 to 27V for most of the time thus you will be at or expremly close to max power point can get to 99 even 100% efficiency in some particular scenario (100% efficiency will ignore the voltage drop on wire) but anyway closer to max power point than an MPPT can get but that is for a particular panel temperature.If you get an average over a year depending on climate that average will be likely similar or better than what an MPPT can do without the cost and complexity of an MPPT.Dmitry, All PV panels are split in groups of 20 to 24 cells in series each group has a bypass diode.So  a typical 60 cell panel will be split in 3 equal parts of 20 cells and each of this groups will have one bypass diode so that if small part (even a single cell) of that one third of the panel is shaded the other two unaffected parts can still produce max current but this only works with larger series string panels and MPPT like you normally find in residential grid connected solar arrays.Since that is made of two smaller 60 cell panels it will have a total of 6 diodes that is what they try to explain by 20x5PV panels are constant current sources so when connected to a battery they will have the exact battery voltage no matter how many cells in series they have or what the ambient temperature is and the current will not be higher than short circuit current that is just slightly higher than max power point current. So no battery voltage will not be affected by the PV panel as PV panels are constant current sources.Barry,Yes in real life it will be less than 28.4V for an 8s LiFePO4 battery. Battery voltage will drop quite a bit as soon as the charging current is stopped to probably around 27V or less depending on Load. Thanks for the information, Dacian,Again, sorry for dummy question. I have carefully inspected SBMS0 manual and tried to search in this group... but still I don't understand how SBMS disconnects the battery. Please point me to the appropriate resource where it is explained if you have one in mind. I thought that the magic is happening in DSSR20, but I am not sure, because if it happens in DSSR20 then it affects the current through the load / inverter.
Second if you say that charging stops if one of the cells reaches 3.55V, then there is a chance that another cell is undercharged so the pack is left unbalanced. Is that possible? If yes, does it make sense to use passive balancers that will dissolve current on the batteries which are already charged?

Thanks!
The SBMS0 will not disconnect the battery but it will need to be able to disconnect all loads and all chargers.The DSSR20 is just a PV charger that can be turned ON or OFF by the SBMS0.  The SBMS0 needs to be able to control also the inverter and if you have DC loads it needs to be able to turn those OFF also with something like a Victron Battery Protect that has remote ON/OFF and so it can be controlled by the SBMS0The cell balancing is done during charging and so it can be done for many hours each day if necessary and even if battery is unbalanced at initial connection it will become balanced withing a few days or weeks depending on how imbalanced it is and from there the battery will be kept in balance.The so called passive balancers are completely useless and no it makes no sense to use those. Hi Dacian,I am new to solar and trying to understand this myself as I build out a solar setup for my motorhome.  If what you said above about panels being constant current and therefore the voltage will match the battery, then why the need to match 60 cell panels to 24v battery?  Does that mean that I could use a 72/144 cell panel with my 24v battery?  If so, is there a disadvantage or advantage to doing that?  I have been debating between lower voltage and wattage 60 cell panels, or higher voltage and wattage 72 cell panels.  I have limited space on my small motorhome, so I was thinking the higher wattage 72 cell panels would allow me to get more charge from less panels.  Would I still be able to use DSSR20s with this setup, or do I need to go with an MPPT in this case?I am also thinking about adding panels on top of a trailer that I often pull behind the motorhome.  This would allow me to have greatly expanded abilities as it is a 20ft trailer, but I don't always take it with me so I would need to be able to connect and disconnect it without difficulty or interfering with the system.  It seems like with the distance from where the batteries are compared to the trailer that I might be better going in series connection to get higher voltage to use smaller wire for this case?  Is that true, or would I still be better off using DSSR20s for this?

How to Choose the Best Solar Panels in

A lot hinges on the type of solar panels you choose to install. High-quality panels from a reputable manufacturer can last decades and save you a great deal on electricity costs over the years. On the other hand, panels from manufacturers who prioritize initial cost over long-term performance can leave you with an underperforming system that won’t stand up to the test of time. Learning how to choose the best solar panels is an important step in creating a long-lasting, money-saving solar system. First, you’ll need to narrow down your aesthetic, budgetary, and energy production goals. Then, you can filter through all the options and end up with the perfect solar panels.

OUSHANG SOLAR supply professional and honest service.

We want to help you make the choice that’s right for you and your goals. That’s why we’ve assembled a list of six things you should consider when selecting your solar panels.

How to Choose the Best Solar Panels - Top 6 Considerations

1. Comparing Solar Panel Types - Monocrystalline vs Polycrystalline

There are two main types of solar panels: monocrystalline and polycrystalline. Which one you choose will impact the overall look of your system, its cost, how much electricity it will produce, and how much space your system will cover.

Monocrystalline panels have an overall darker tint to the cells and are typically the more efficient option. Panels with a higher efficiency mean you can produce more electricity with fewer panels, so your overall system takes up less space. However, for all their advantages, monocrystalline panels are often the more expensive option.

Polycrystalline panels have a bluer tint and are typically less efficient than monocrystalline, meaning you’d need a few more panels to generate the same amount of electricity. However, they do often come at a lower price, and despite the additional panels you’ll need, will likely be the cheaper option. For a more in depth breakdown of cost, check out our complete guide about how much solar panels cost. 

2. Panel Color: The Back Sheet and Frame

Another way you can control the look and price of your solar system is through the selection of backsheet and frame color.

Each panel is composed of several silicon cells that are placed on a back sheet. This back sheet shows through the gaps between the cells and creates a grid-type design. Some manufacturers offer solar panels with black back sheets instead of the typical white.

Black back sheets create a more uniform-looking panel that blends into darker roofs. However, black holds heat, so black back sheets may get hotter than traditional panels, which could slightly reduce the panels’ efficiency.

There are also two options when it comes to the color of the metal frame around the borders of the panels: black and silver. Black frame panels can be more aesthetically appealing but will cost more. Aside from that, both black- and silver-frame panels should perform identically.

3. Determining the Right Solar Panel Size for Your Home or Business

Solar panels come in two different sizes: 60-cell and 72-cell. The size refers to the number of cells (the small, crystalline silicon wafer) on the solar panel. On average, 72-cell panels are about a foot longer than 60-cell panels.

Their larger size makes 72-cell panels better suited for large, wide-open spaces like commercial roofs and ground-mount systems. 60-cell panels are typically better suited to fit in tighter spaces, like on the dormer of a home’s roof. However, this isn’t a hard and fast rule and will vary from location to location.

Overall, 72-cell panels tend to be more economical, as they generate more electricity per panel than an otherwise identical 60-cell panel.

4. Panel Production: Output Rating and Efficiency

Both the panel’s output rating and efficiency will impact how much power it can produce.

The output rating is the three-digit number in the solar panel’s name. It represents how many watts of electricity the panel will generate under ideal conditions.

Most panels have a wattage between 250 watts to 400 watts, with a few panels exceeding the 400-watt mark. A higher wattage means more electricity generated per panel, but it will likely mean a higher price tag. Though you’ll need fewer panels to reach your generation goals, it likely won’t offset the price increase.

However, wattage isn’t the only thing to look for. You should also consider the panel’s efficiency, which is the percentage of electricity it produces from the energy it receives from the sun.

The more efficient a solar panel is, the more kilowatt-hours of electricity it will produce per watt of power capacity. This is especially important if you’re concerned about the amount of space your solar system takes up.

For example, let’s compare two 300-watt solar panels: one that’s 21% efficient and another that’s 17% efficient. Both will produce 300 watts of power under ideal conditions. However, the one that has a higher efficiency will be physically smaller and take up less space than the one that is less efficient. So if you have high electric bills and a small amount of space to install your solar system, you’ll want to look for efficient panels.

The company is the world’s best 60 Cell Solar Panel supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

5. What Kind of Solar Panel Warranty Will You Be Getting?

An important indication of overall panel quality is a robust warranty from the manufacturer. Many high-quality solar panels are guaranteed for 25 to 30 years and can continue working even after their warranty expires.

Purchasing solar panels that will last is essential to the long-term success of your system. The longer your solar panels generate electricity, the more money you save. Purchasing panels backed by a comprehensive warranty will help guarantee their success.

Most manufacturers offer two kinds of warranties: performance and product warranties. The performance warranty assures that the panel will be capable of producing a specified percentage of power during the warranty period despite degradation. The production warranty protects your panels from material or workmanship issues.

6. Overall Quality and Brand Considerations - What Makes a Good Solar Panel?

You want the highest quality solar panels at the best price. However, there are a few important factors to consider when evaluating the quality of a specific solar panel.

To get a true measure of a solar panel’s quality, you’ll want to look at its guarantee, the manufacturer's reputation, customer reviews, and the panel’s technical specifications for efficiency, temperature coefficient, and power tolerance. 

Another way to measure a solar panel brand, though imperfect, is by looking at what “tier” the solar panel manufacturer falls under. When researching different brands, you’ll likely come across lists that separate manufacturers into tier one, and even tier two and three, though there is no formal definition for tiers two and three.

Most assume tier-one solar panel manufacturers tend to be the stronger brands. However, this isn’t necessarily the case. According to Bloomberg New Energy Finance Corporation (BNEF), the tier system for solar panel manufacturers refers to how bankable a solar company is. While it’s fair to reason that a bankable company must have quality products, there are plenty of companies out there that do not meet the tier-one specifications but offer great, high-quality panels. 

Overall Quality

Quality is a comprehensive measure that encompasses several aspects of a solar panel, including:

  • Efficiency: Higher efficiency panels convert more sunlight into electricity, which is especially important in limited space scenarios.
  • Durability: Look for panels that can withstand environmental conditions like high winds, snow loads, and temperature fluctuations. Standards such as IEC can be indicators of durability.
  • Performance in Different Climates: This section addresses how the performance of solar panels can vary in warm climates and the importance of temperature coefficients.

Brand Reputation

The manufacturer's reputation can be a strong indicator of panel quality. Consider the following:

  • History and Experience: Brands with a long history in the industry and a track record of innovation and reliability are often preferable.
  • Financial Stability: A financially stable company is more likely to honor warranties and be around to service any future claims.
  • Customer Reviews and Industry Ratings: Feedback from real users and ratings from industry organizations can provide insight into the brand's reputation and customer satisfaction.

Another way to measure a solar panel brand, though imperfect, is by looking at what “tier” the solar panel manufacturer falls under. When researching different brands, you’ll likely come across lists that separate manufacturers into tier one, and even tier two and three, though there is no formal definition for tiers two and three.

Most assume tier-one solar panel manufacturers tend to be the stronger brands. However, this isn’t necessarily the case. According to Bloomberg New Energy Finance Corporation (BNEF), the tier system for solar panel manufacturers refers to how bankable a solar company is. While it’s fair to reason that a bankable company must have quality products, there are plenty of companies out there that do not meet the tier-one specifications but offer great, high-quality panels.

Choosing the Best Solar Panel for Your Home or Business

While some manufacturers on our list are objectively the “best” in terms of efficiency, warranty, or price, the panels that are right for you will depend on your specific situation.

You should go with the panel that offers the best value, balancing price with performance and quality. It’s about getting a system you’re happy with that’s cost-effective and has the best ROI. 

Here are a few factors to consider:

  • Assessing Electricity Use: Guide readers on how to assess overall electricity use
  • Assessing Roof Characteristics: Roof characteristics are used to choose the optimal solar panel setup.
  • Cost vs. Efficiency: Discuss how to balance the cost of solar panels with their efficiency to get the best value for your investment.

What are the Best Solar Panels on the Market in ?

There are many solar panel brands, but only a handful have risen to the top for our team at Paradise Energy. 

With 16 years of experience installing solar for thousands of customers, we've gained valuable insight and experience with many panel manufacturers. We use that insight to select the brands that we can confidentially offer our customers. Our top three brands are:

  • Axitec
  • QCells
  • SEG Solar

Each of these brands was carefully chosen based on specific performance metrics such as customer service, company standing, and product specifications, including performance, aesthetics, warranties, and pricing.


Wrapping Up: Choosing the Best Solar Panels in

There’s no one-size-fits-all answer to which solar panels are the best. That answer changes based on a variety of factors, like your budget, how much electricity you’d like to generate, the space you have to install the system, and what aesthetic concerns you have.

With the sheer amount of options available, this process can be overwhelming. Trying to determine the best combination of panel size, output rating, and efficiency is the most economical for your space, all while ensuring the panels are high quality and backed by extensive warranties takes experience. At Paradise Energy, we’ll maximize your budget and space with panels that suit your specific goals, whether that is budgetary, energy-related, aesthetically driven, or a combination of them all.

For more information, please visit custom solar panels.