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First outing on new solar setup.

ChrisKChrisK Member Posts: 273
edited July 2018 in Battery/Electrical & Solar
We camped at Woods Canyon Lake east of Payson, AZ this weekend. It is a no services campground. This was the first outing with our new solar setup. Overall, it worked very well. 

Here's what we have:
Optima Blue Top AGM battery. Just one for now. I think it is rated at 50ah

Victron 75/15 MPPT solar controller.

2x ALLPowers 100w 18v flexible solar panels:
https://www.amazon.com/gp/product/B07195WHHX/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

As a reference point, we ran the fridge on propane but the Alde was off the whole weekend since we didn't need any heat.

This setup had no trouble keeping our battery charged. We had varied conditions from bright sun to thunderstorm downpours. 
This campground has a lot of trees. In the mornings, the panels were mostly in shade yet the system still managed to get the battery back up to 13v by 9am. I was usually showing about 25-35a being used in the shade. As soon as the panels were in direct sun at about 10:30am, the watts jumped up to as high as 120 and the battery topped off pretty quickly. The rest of the day was just a maintenance charge. We had no problem running any electrical item in the camper including charging our phones and a 12v fan I 3D printed. We could run the vent fan with no problems but the fan I printed was more efficient. What I found amazing (yes, I'm a solar newbie) was that we were still generating power with 100% cloud cover. We were showing 13a being used to charge.

We did run the generator briefly the first full day since we had 3 straight hours of rain and clouds after that and I was afraid our battery hadn't charged enough. Thinking back, we probably didn't really need to. 

The strange thing I found was looking back through the history recorded on the Victron app, it showed peak power provided to the controller by the panels was 250w. Is that normal? Will panels, at times, generate more than their rated watts?

I'm curious to see how running the Alde will affect the results. I'm already planning more battery capacity. I'm also planning on adding an inverter to the system. I'd like to be able to charge my computer and bike battery. 
2014 T@b S Max AKA T@dpole
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,506
    Amps = watts / volts.   So, 13.8 = 250/18 so yes, the 250 watts was appropriate to your two 18 volt panels.  With your 200 watts of PV panels and charge controller you are off to a good start!
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    RatkityRatkity Member Posts: 3,770
    50 amp-hr battery is really low. When plugged into shore power, the voltage monitor should read 13.7 or 13.8 amps (like @Sharon_is_SAM said via her math). The other times, you are using the little amperage that your particular battery supplies. Even my last group 24 was 85 amp-hr. 

    I do think your 2x 100W panels are an excellent start! When you can, ditch that icky battery!!! :)

    2017 820R Retro Toy Hauler from 2015 Tabitha T@B from 2009 Reverse LG Teardrop (but a T@Bluver at heart)
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,506
    edited July 2018
    @ChrisK, we use a Renogy charge controller with dummy lights and a Victron BMV 700 battery monitor that allows us to observe charging in real time due to the shunt.  We never use watts as a part of our solar/battery monitoring.  We watch the current (amps) change from negative (outflow) to positive (inflow) and voltage production in addition to the battery State of Charge which is multifactorial and calculated.  Here is a demo screenshot of the Victron MPPT and the BMV taken from our Bluetooth dongle that allows us to monitor our battery from our phones.

    How do you know you have filled your battery?  A certain battery-based voltage combined with no further current?  




    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    ColoradoJonColoradoJon Member Posts: 415
    edited July 2018
    Don't be fooled by the voltage reading at the battery.  Under charge the voltage will show greater than 13v - it doesn't mean that your batteries are charged.  It just means that your batteries are *charging*.  The voltage reading at the battery will fluctuate depending on how much sun the panels are receiving and the current state of charge.  Your comment of 13v by 9:00am just means your batteries are receiving a charge, not that they are fully charged!  If you want to use your battery voltage to determine state of charge you will have to disconnect your solar charger, turn off all power consumption, wait a half hour, and then check the voltage.  Even then the reading is only approximate.  Use a battery monitor lie @Sharon_is_SAM if you want a more accurate representation of SOC.

    Your panels can provide 5.56 amps per panel (100w / 18v) per hour in optimal conditions which is an average rating.  You may get more or less.  I'm not sure what you mean by 120 amps?  Maybe the controller was showing wattage?
    Jon & Angela | Florissant Colorado | 2017 Outback S
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    ChrisKChrisK Member Posts: 273
    edited July 2018
    Yup, I meant watts. I'll correct that. (Done)
    Note above, I said it was up to 13 volts but I did not say it was fully charged. Later I said the panels topped off the battery. This was evident by the fact that very little current was being used to charge them and they were just in maintenance (Float) charging mode. 
    2014 T@b S Max AKA T@dpole
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    ColoradoJonColoradoJon Member Posts: 415
    Ah, gotcha.  I was a little confused by your wording, no fault of yours :)

    13v - 13.6v in full sun would certainly indicate a maintenance charge.  I leave my Zamp controller set to show amperage in, and when it drops below 2 amps in full sun I know that my batteries are close to full charge.  I don't have a battery monitor, but I do have the dual 6v golf cart battery set up.  Boost your battery capacity and you can camp off grid for a long time!
    Jon & Angela | Florissant Colorado | 2017 Outback S
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    ChrisKChrisK Member Posts: 273
    edited July 2018
    One more thing. I think the system can be more efficient. I had left it set to factory default setup. After I got home, I realized there is also a setup built in to the system optimized for spiral wound AGM, which is what I have. 

    About the battery. Yes, I know 50ah is not much. For now, it is all I have. I'm doing this in steps. For now, I could afford the system itself. As we probably won't be true boondockers (no longer than 3 or 4 nights) it is probably overkill but I wanted a system that can recover a battery setup more efficiently. I'm still researching what I want for my final battery setup. I might just add another AGM battery to double my capacity and be done with it. Time will tell. So will our bank account.  =)

    Sharon_is_SAM - I realized that these systems charge in very similar ways as my RC car chargers. They charge a lot at first for speed of charge and as they get closer to being charged, the amps or watts or whatever you watch drops off. Keeps the system from overcharging the battery. As the solar (not battery - that changes with load) numbers get closer to zero, you are closer to being full. As long as you realize that, either monitor works. Its all about watching the trends. It was interesting to turn things on and watch how it affected those numbers.

    One additional point. When towing, the system can help the tow vehicle keep the T@b battery charged when running the fridge on 12v.
    2014 T@b S Max AKA T@dpole
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,506
    @ChrisK, thanks for that explanation.  Makes sense.  As the battery fills, the panel current drops as it meets more resistance to charge.  The same effect occurs on our BMV, the current entering the battery drops.
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,506

    @ChrisK, do you have a picture of your 3 D printed fan?
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    jkjennjkjenn Member Posts: 6,391
    I have something going on with my solar set up and I am not sure what it is. I am barely able to get a 1 amp draw and I know that is not right. I thought it was the controller but that was not it. I am wondering if there is a short in the panel and of course my multimeter is no where to be found...

    I did notice that one panel has developed a bubble, which could be it. 

    2021 T@b 320 Boondock "Mattie Ross" | 2021 T@b Nights: 239 | Total nights in a T@b 455 | 2022 Jeep Grand Cherokee L Overland | T@b owner since 2014

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    ChrisKChrisK Member Posts: 273
    Sharon_is_SAM said:

    @ChrisK, do you have a picture of your 3 D printed fan?
    I'll post it when I get home.
    2014 T@b S Max AKA T@dpole
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    ChrisKChrisK Member Posts: 273
    jkjenn said:
    I have something going on with my solar set up and I am not sure what it is. I am barely able to get a 1 amp draw and I know that is not right. I thought it was the controller but that was not it. I am wondering if there is a short in the panel and of course my multimeter is no where to be found...

    I did notice that one panel has developed a bubble, which could be it. 
    Best way to check if a panel is bad is to isolate it. It you are running parallel connectors, remove them and connect each panel individually to test it.
    2014 T@b S Max AKA T@dpole
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    jkjennjkjenn Member Posts: 6,391
    ChrisK said:
    jkjenn said:
    I have something going on with my solar set up and I am not sure what it is. I am barely able to get a 1 amp draw and I know that is not right. I thought it was the controller but that was not it. I am wondering if there is a short in the panel and of course my multimeter is no where to be found...

    I did notice that one panel has developed a bubble, which could be it. 
    Best way to check if a panel is bad is to isolate it. It you are running parallel connectors, remove them and connect each panel individually to test it.
    Thanks..I had started doing that and the sun went under a cloud...the woes of living in Western PA! Second to Seattle in cloudy days.

    2021 T@b 320 Boondock "Mattie Ross" | 2021 T@b Nights: 239 | Total nights in a T@b 455 | 2022 Jeep Grand Cherokee L Overland | T@b owner since 2014

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    ChrisKChrisK Member Posts: 273
    Sharon_is_SAM said:

    @ChrisK, do you have a picture of your 3 D printed fan?
    Here it is. I downloaded the design from one of the 3D printing file sites. The base is my design as the one that it was supposed to use was not very printable. It uses as simple 80mm computer fan yet blows pretty well. I can power it from 12v or 110v. I just swap a cord. I did this one in orange because I had some extra and I wanted to test the concept before using the blue to match the camper.


    2014 T@b S Max AKA T@dpole
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,506
    You made your own fan...how cool is that!
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    ScottGScottG Administrator Posts: 5,435
    edited July 2018
    Definitely cool--but I don't quite get it...

    Does the round part turn or otherwise help distribute the air from the computer fan?
    2015 T@B S

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    ChrisKChrisK Member Posts: 273
    ScottG said:
    Definitely cool--but I don't quite get it...

    Does the round part turn or otherwise help distribute the air from the computer fan?
    Yes. It This is how those $$$$$ Dyson fans work. I believe the shape of the circular body helps accelerate the air to give it more flow and distribute it over a larger area.
    2014 T@b S Max AKA T@dpole
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    RatkityRatkity Member Posts: 3,770
    Sharon_is_SAM said:
    You made your own fan...how cool is that!
    pun intended? :lol:
    2017 820R Retro Toy Hauler from 2015 Tabitha T@B from 2009 Reverse LG Teardrop (but a T@Bluver at heart)
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,506
    No pun intended.  That job goes to someone more clever @Ratkity👈
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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