What voltage do the panels operate?

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Thomas_Darby
Thomas_Darby Member Posts: 39 ✭✭

I know the panels collect different amounts of energy (Watts), but what voltage levels do they operate?

I know Watts = Volts x Amps, so this will help me understand the different electrical variables involved.

Why would the solar panels operate at different voltages?

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  • jg164
    jg164 Administrator, Moderator Posts: 291 admin
    edited October 2022 Answer ✓
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    @Thomas_Darby,

    Thanks for the added clarification!

    Its not ideal to use different types of panels in the same parallel solar circuit because differences in voltages will result in some losses because they can pull each other up or down in voltage and may produce heat as they combine just like connecting imbalanced batteries but they will never fully balance.

    The Voltage specs of the B100BC and N50 are very close and should not cause much of that effect. As a rule I would not combine panels in parallel that are off by more than 2V in OCV or Vmpp and if you have a DMM I would recommend verifying at least OCV before combining to see what you are actually getting.

    N50 SOLAR

    • Rated Power: 50W
    • Open Circuit Voltage (Voc): 21.5V
    • Maximum Power Point Voltage (Vmpp): 18.0V
    • Cell Type: Monocrystalline

    B100BC SOLAR

    • Rated Power: 100 Watts
    • Open Circuit Voltage (Voc): 21.5V
    • Maximum Power Point Voltage (Vmpp): 17.2V
    • Cell Type: Monocrystalline

    Using a 4:1 8mm to HPP combiner will allow you to use 2x N50s and the B100BC all in parallel and the current limit of the HPP connectors is 45A.

    Whether we are talking about combining panels using a chaining port or using a combiner 4:1 adapter, either configuration places all panels in parallel to the device to be charged ( Yeti, Sherpa etc ) and each panel adds current to the power equation not voltage.

    One thing to note about Chaining ports is all panels that are chained use the last Nomad's output 8mm cable to carry all the power. That 8mm connector can handle up to 10A max and will get hot or melt if too much current is run through it. I would not run more than 100W of actual power chained. You should be fine with 2x N50s chained but you should get better output using the 4:1 8mm to HPP combiner.

    One more thing to note. I see a common issue with people using an HPP or 8mm extension between a combiner and a Yeti. If you must extend the circuit, extend between each panel that needs more reach and the combiner to maximize power transfer and avoid voltage drops and confusion as to why the output is lower that way.

Answers

  • jg164
    jg164 Administrator, Moderator Posts: 291 admin
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    @Thomas_Darby,

    Each Solar panel product we make is made of different kinds of solar cells. Each cell has its own voltage and current it contributes to the panel. To build a panel with output power and voltage within a range, cells are arranged in series and parallel circuits where series add volts and parallel ones add current. Some cells may be different kinds that have different electrical characteristics. Once they are in a panel and in the sun but not connected to a Yeti, Sherpa or what have you, this is the OCV(Open Circuit Voltage) and is typically a few volts higher than what you get when the panel is connected and powering something.

    Does that answer your question?

  • Thomas_Darby
    Thomas_Darby Member Posts: 39 ✭✭
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    As an engineer (but not an electrical engineer), I already understood the nature of cells being connected in parallel and in series, and understood that their state of excitement in the sun caused different levels of power to be generated at different times of the day.

    The aim of my question is to understand which panels may be chained together to charge different products. I was advised that because the panels operated at different voltages, some do not work with other products. So I am interested in knowing what voltage the panels generate. But as you say, that depends.

    So let me narrow it down. I have a Yeti 1500X and a Yeti 200X and some phone charging packs from other companies. I have a Boulder 100 Briefcase and two Nomad 20 solar panels. I know I can chain the Nomad 20s to charge the Yeti 200X faster than with a single panel. I believe I could chain up to four of them, and I believe the reason I wouldn't want to chain more is because line losses start to become substantial after that. But, two Nomad 20s seem to do very well for the Yeti 200X.

    However, if I want to use all of my panels to charge my Yeti 1500X, I was cautioned that the panels operate at different voltages. May I use the 4x combiner cable to connect the Boulder 100 Briefcase panel and a pair of Nomad 20s to the Yeti 1500X? Or do they operate at different levels and would not work together?

    While your answer didn't answer my question, it is helpful to return to the fundamental concepts of the problem once in a while. This may help me sort something else out later. Thanks.😉

  • yosemite
    yosemite Member Posts: 20 ✭✭
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    I got the yeti 1500x and use 2xboulder 200's and added two renogy 100w panels. From what I have read the panels will default to the lowest voc, vmp panel. Wish I would have known this before I bought the renogy panels.

    But now I am using the renogy to charge a tank and the gz panels to charge the yeti.

    To anyone buying panels you can get 5x100 watt panels for the price of 1 Boulder 200! And the renogy seem to have a better output

  • Thomas_Darby
    Thomas_Darby Member Posts: 39 ✭✭
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    Thanks again. This is helpful to me because it increases my understanding of the variables involved. In my circuits class, I never had to solve a circuit that had parallel batteries; they would have probably been represented as one "equivalent" battery. Likewise, I never had to solve a circuit where a battery was being charged, so some of the intricacies of voltage balance were never taught to me.

    So the panels are a "voltage source" and not a "current source"? This doesn't help me solve the (my) problem, but might help me sort out other questions later.

    I recall a battery was represented as a closed circuit element with a small resistance. The current source was represented as an open circuit element. So two batteries (voltage sources) in parallel would have effects from the other battery across their current path.

    How do you represent the other battery, the Li Ion battery, in a circuit diagram? Is this also a battery with the "charge" reversed and a small resistor? If that were the case, then a higher voltage on the solar panel side could "force" current back into the Li Ion battery.

    However, in my circumstance, I am using Nomad 20s, not Nomad 50s. Is the voltage difference (VOC) different enough on them from the Boulder 100 Briefcase to indicate that would be a losing approach? I think that's what you're going to tell me. And if so, I'm glad I heard it from you before I connected the parts and gave it a try.

    While there are not many folks like myself cobbling together a system in an attempt to use everything to achieve a goal, it may be wise for GZ to put together an advisory on matching panels for charging Yetis. It sounds like using the 4x combiner could get you into a fix if you don't know anything about how this stuff works. Indeed, in my case, it sounds like I "knew enough to be dangerous."

  • Sidney
    Sidney Member Posts: 4 ✭✭
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    You need to stay within your Yeti's input voltage.

    VOC in the early morning could rise and exceed what the Yeti can safely handle. I would use a charge controller to limit voltage spikes with dissimilar panels to protect the Yeti.

    Vimp should be more stabile not as big a concern.

  • Thomas_Darby
    Thomas_Darby Member Posts: 39 ✭✭
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    I have decided to get the 4x 8mm connector so I may add solar panels to my setup.

    The original setup had a Yeti 1500X with a single Boulder 100 Briefcase.

    With the 4x 8mm connector, I will try charging with the Boulder 100 Briefcase along with my two Nomad 20s.

    I also ordered more Boulder 100 Briefcase panels, so I will try it out that way also. By combining these panels I want to see what the system can do. If I lose power in the winter for a few days, I want to know what my best options are. And in the summer, when I go camping, I will enjoy having the handy power for whatever purpose.

  • JWAndersen
    JWAndersen Member Posts: 1 ✭✭
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    My two Boulder 100 briefcase panels work on a voltage of Maximum 17.2 volts. What kind of connectors do I need to connect these two briefcase panels together? They will be connected to a Yeti 1500x

  • Thomas_Darby
    Thomas_Darby Member Posts: 39 ✭✭
    edited December 2022
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    Based on what I'm learning, JWAnderson, you will need the 4x Combiner (Product SKU: 98060) to connect multiple Boulder 100 Briefcases together. The 4x Combiner plugs into a high powered port on the Yeti 1500X. Sounds like we will have similar setups. I ordered two more Boulder 100 Briefcase solar cells and the 4x Combiner so I will be plugging 3-Boulder 100 BC units into my Yeti 1500X when it gets sunny again. In this configuration, it could theoretically charge the Yeti 1500X from 0-100% in five hours, but due to the Stadium Effect I expect it would be longer. However, unless I forget to check on it, I don't plan to run the Yeti 1500X down below 15%. There are other "contributing factors" that could cause the charge time to go longer.

    I don't know if it helps, but I have decided to cycle my Yetis (I have a 1500X and a 200X) once a month just to go through the motions. I am keeping records of how long it takes to charge the Yetis and what loads I am using and stuff. I want to be sure that when the time comes I know what to expect from the units.

    I wish you the best of luck and a Happy Holidays.

  • Dede
    Dede Member Posts: 1 ✭✭
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    I have a question, I have a different brand solar panel as well 3 of 400 watts. Would like to check if this will be compatible with the 6000 type. As long it’s not over I believed it still work, please advise… thanks


  • jg164
    jg164 Administrator, Moderator Posts: 291 admin
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    @Dede,

    The Open Circuit Voltage(VOC) and the Working Voltage(VMP) are both well over the input limit of 50V for the Yeti 6000X. They will not work connected to the HPP or 8mm ports and might cause permanent damage to the 6000X.

    Please see my post in the link below for more info and an alternate way to connect them to the 6000X

    https://community.goalzero.com/discussion/comment/1142#Comment_1142