Announcement

Collapse
No announcement yet.

Problems with my rv solar system

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Problems with my rv solar system

    Hello,
    I'm extremely new to the solar panel world and I am having some issues with the system I recently installed on 5th wheel rv.
    So to start my system consists of
    3-120watt solar panels wired in parallel
    Morningstar ts-60 controller
    4- 12v agm batteries wired in parallel
    Xantrex 3000 watt power inverter
    So my problem is my batteries will not stay charged if I have my refrigerator running. It seems like my system cannot keep up with it. I have shut the refrigerator off and left it for a day or two and the batteries get fully charged. If I turn it back on, within a day the low voltage alarm goes off and shuts it down. I have load tested the batteries and they all pass. I'm not sure if I have something set wrong on my controller or if I have installed something wrong. If anyone out there has any ideas of what I could troubleshoot that would be greatly appreciated.

  • #2
    Originally posted by Dean View Post
    Hello,
    I'm extremely new to the solar panel world and I am having some issues with the system I recently installed on 5th wheel rv.
    So to start my system consists of
    3-120watt solar panels wired in parallel
    Morningstar ts-60 controller
    4- 12v agm batteries wired in parallel
    Xantrex 3000 watt power inverter
    So my problem is my batteries will not stay charged if I have my refrigerator running. It seems like my system cannot keep up with it. I have shut the refrigerator off and left it for a day or two and the batteries get fully charged. If I turn it back on, within a day the low voltage alarm goes off and shuts it down. I have load tested the batteries and they all pass. I'm not sure if I have something set wrong on my controller or if I have installed something wrong. If anyone out there has any ideas of what I could troubleshoot that would be greatly appreciated.
    A/C refrigerators are very difficult loads, your symptoms are classic for not enough solar, too much inverter and not enough battery capacity for the given load(s). Most 120w panels have a maximum current of about 7 amps (only for short time midday) x 3 = 21amps, if your batteries are larger than 50ah each that is a serious mismatch with the panels and that must be corrected immediately or you batteries will be destroyed.

    Comment


    • #3
      Originally posted by LETitROLL View Post
      A/C refrigerators are very difficult loads, your symptoms are classic for not enough solar, too much inverter and not enough battery capacity for the given load(s). Most 120w panels have a maximum current of about 7 amps (only for short time midday) x 3 = 21amps, if your batteries are larger than 50ah each that is a serious mismatch with the panels and that must be corrected immediately or you batteries will be destroyed.
      Thank you for your response. Ya I guess I'm pretty new at this. What do you think I should do to resolve this problem?

      Comment


      • #4
        12 volts is too low voltage of a battery bank to be running a 3000 watt inverter much less refrigeration. your solar array is half what you need, maybe 1/3. Your inverter is likely junk, If you want refrigeration, you should run 24 volts and get a 24 volt refrigerator.
        4X Suniva 250 watt, 8X t-105, OB Fx80, dc4812vrf

        Comment


        • #5
          or you could run a propane refrigerator.
          4X Suniva 250 watt, 8X t-105, OB Fx80, dc4812vrf

          Comment


          • #6
            Originally posted by Dean View Post

            Thank you for your response. Ya I guess I'm pretty new at this. What do you think I should do to resolve this problem?
            First to try and salvage something out of what you already have we need to know what kind, and how many amp hours each battery is? are you running anything other than the refrige? You do have a good controller but being PWM style it will give you a maximum of about 250W from your 360w worth of panels and you will only get that at high noon on full sun days.

            Comment


            • #7
              If your drawing is accurate you have the worst scenario in battery wiring possible. You should at least connect your charging and load to diagonal, opposite corners of your battery bank. This will cause the charge and load to travel through the entire bank. The way this is drawn your charge is entering one end of your bank and is encountering progressively higher resistance as it try's to reach the far end of the bank. Also your load is being drawn from the weak end of the bank. I'm no expert here but IMHO I would go with 4, 6 volt GC2 (golf cart) batteries in series parallel configuration with positive and negative buss bars and equal length, appropriate size cables from the buss bar to the batteries.
              2.2kw Suntech mono, Classic 200, NEW Trace SW4024

              Comment


              • #8
                Originally posted by LETitROLL View Post
                First to try and salvage something out of what you already have we need to know what kind, and how many amp hours each battery is? are you running anything other than the refrige? You do have a good controller but being PWM style it will give you a maximum of about 250W from your 360w worth of panels and you will only get that at high noon on full sun days.
                So the batteries are AGM sealed basic 12v deep cycle batteries. They are rated at 106ah @100hrs.
                Am I running anything other than the refrigerator? Not a lot. Phone chargers, maybe a small lcd tv at night for an hour or two, maybe a little stereo for an hour, a few lights at night

                Comment


                • #9
                  Originally posted by Dean View Post

                  So the batteries are AGM sealed basic 12v deep cycle batteries. They are rated at 106ah @100hrs.
                  Am I running anything other than the refrigerator? Not a lot. Phone chargers, maybe a small lcd tv at night for an hour or two, maybe a little stereo for an hour, a few lights at night
                  So you do have a investment worth saving in the batteries, to protect them try and make sure they get recharged near full every other day or so, and try to not let them fall below 50% S.O.C. The inverter is way oversized for this level of system, but actually the rest of the system is not that terribly far out of balance, it should work well for all your other load(s) mentioned, it is just not near enough solar input to keep up with most any regular refrigerator (small or large). The multiple issues to be aware of when using an oversized inverter is (1) it is wasting a little more of your limited watts then necessary vs a smaller more efficient one, and (2) because of its high output capability if something goes wrong on the load side it will attempt to pull a very large amount of amps from your batteries, so it is critical from a safety standpoint (fire), to have properly sized fuse and wiring between the batteries and inverter. Lastly as for refrigeration, a system this size if you have very sunny long days will run the average refrigerator for a few hours per day depending on the sun hours and refrige draw, but you would have to turn off the fridge and "coast" the rest of the time for the batteries to have any chance of staying fully charged. Adding more solar, and/or getting a much more efficient fridge are the only real options to solve that issue.

                  Comment


                  • #10
                    Originally posted by Dean View Post
                    Hello,
                    I'm extremely new to the solar panel world and I am having some issues with the system I recently installed on 5th wheel rv.
                    So to start my system consists of
                    3-120watt solar panels wired in parallel
                    Morningstar ts-60 controller
                    4- 12v agm batteries wired in parallel (They are rated at 106ah @100hrs.)
                    Xantrex 3000 watt power inverter
                    So my problem is my batteries will not stay charged if I have my refrigerator running.
                    Not sure what your problem is at all. That is what you planned for it to do. Working perfectly for a undersized inadequate system.

                    6 obvious mistakes are:

                    1. You wired your panels in parallel with a MPPT controller. You threw away the main purpose of using a MPPT controller. A MPPT controller allows you to use much less expensive GT panels wired in s series. You can fix that, but you are still left without out enough panel wattage because you failed to calculated how many watt hours per day you needed.

                    2. You do not have enough panel wattage to support your batteries and load.

                    3. You may think you have 106 AH batteries, but far from it. Sure they say 106 AH at C/100. You fell for a numbers game manufactures sometimes use. Especially manufactures who make poor quality batteries. Good Consumer batteries are rated at 20 Hours, Industrial batteries are rated at 8 Hours. So you are probable asking what is the difference? Well Peukert Law is the difference. Example a Rolls 24HT80 is a battery similar to yours as it is rated at 100 AH at a 100 hour rate. However at the 20 hour rate is 80 AH. I suspect your fridge draws even more than the 20 hour rate when used from an inverter more like on the order of 10 to 12 rate. Well at that rate you are down to 70 AH per battery. Take a look and see the Rolls version can be as small as 29 AH at the 1 hour rate or as much as 100 AH at the 100 hour rate. A pair of Trojan L16RE-B have more capacity than yours have. You do not want to wire batteries in parallel.

                    4. A 3000 watt Inverter is way too large for any 12 volt system, and grossly undersized with only 300 AH of batteries. Your poor little batteries can only supply up to 75 to 100 amps at best. A 3000 watt Inverter at 12 volts requires just over 300 amps. Not only does it not work very good, but an extreme fire danger.

                    5. This is not certain because you did not mention it. But I bet you did not install an Electronic Battery Isolator to allow your RV alternator to charge the batteries when the engine is running. Your vehicle alternator can generate more energy in an hour, than your panels can generate in a week.

                    6. Again not certain this is the case, but you do not mention a generator and a battery charger. Any Off-Grid Battery System requires a generator with a charger capable of C/8.

                    So as you can see, you got exactly what you planned for. If you had implemented 5 and 6 would have covered up problems 1,2, 3, and 4. The largest mistake you made is you did not do any research, and plan your system out. The first step is determine how many watt hours you need in a day. Once you know that, then you can build a system to meet the demand. If you failed to plan, you planned to fail, and that is what you did.
                    Last edited by Sunking; 05-01-2016, 12:46 PM.
                    MSEE, PE

                    Comment


                    • #11
                      Originally posted by Dean View Post

                      So the batteries are AGM sealed basic 12v deep cycle batteries. They are rated at 106ah @100hrs.
                      Am I running anything other than the refrigerator? Not a lot. Phone chargers, maybe a small lcd tv at night for an hour or two, maybe a little stereo for an hour, a few lights at night
                      Have you used a watt meter to check the TV's power usage? I had a small 15" TV that draws 2.1 amps @ 12 volts and I also have a 40" TV that draws 1.8 amps @ 19 volts, I recently purchased a 13.3 inch that only draws 0.6 amps @ 12 volts. different TV's use more or less power, when I purchased my 13.3" I took the 12 watt meter with me to the store, I plugged the device into all the different makes of 12 volt powered TV's and selected the one that used the least watts for screen size. You have more problems with sizing though. if you are trying to power an AC refrigerator with a 12 volt inverter, it will fail, even if you upgrade your array to match your demands. Your best bet, if you really want this to work, is to double your array size and switch to 24 volts, get a 24 volt refrigerator and a step down converter for your 12 volt TV and lights. Notice no inverter.
                      4X Suniva 250 watt, 8X t-105, OB Fx80, dc4812vrf

                      Comment


                      • #12
                        OP,
                        You should have plenty of battery and solar for your described setup and usage and it seems balanced to me. Although I agree about the inverter being way oversized. You have more solar and battery capacity than us and we can run without concern for battery power. I have not seen you mention on this thread if you're running a residential compressor fridge or an absorption fridge. Everyone has assumed residential fridge, but I'm going to assume absorption since you said you're in a 5th wheel. Is it a 2 way (120V AC or propane) or 3 way (120V AC, propane, or 12V DC)? If 3 way, don't run it on 12V because even with solar working as hard as it can you'll come out behind. Don't run it off your inverter either because it is probably a 300 watt or more draw, before taking into account inverter efficiency. Are you leaving it on "auto" and therefore it switches over to 120V AC from your inverter and therefore you batteries? You should be running it on propane when off of shore power. You normally have to put the power option switch on to "gas", not "auto". Does it have a door defrost heater or some feature like that? They are known to be big 12V power hogs that kill batteries if you're not plugged into shore power. An absorption fridge should only have about a 1 A DC draw when on propane.

                        Edit: another thought. Are you sure that your converter has been disabled when you are off grid? Otherwise your inverter will supply power to it and it will suck your batteries down.
                        Last edited by ewarnerusa; 05-12-2016, 09:44 AM. Reason: Converter thought
                        I'm an RV camper with 470 watts of solar

                        Comment


                        • #13
                          Originally posted by ewarnerusa View Post
                          OP,
                          You should have plenty of battery and solar for your described setup and usage and it seems balanced to me. Although I agree about the inverter being way oversized. You have more solar and battery capacity than us and we can run without concern for battery power. I have not seen you mention on this thread if you're running a residential compressor fridge or an absorption fridge. Everyone has assumed residential fridge, but I'm going to assume absorption since you said you're in a 5th wheel. Is it a 2 way (120V AC or propane) or 3 way (120V AC, propane, or 12V DC)? If 3 way, don't run it on 12V because even with solar working as hard as it can you'll come out behind. Don't run it off your inverter either because it is probably a 300 watt or more draw, before taking into account inverter efficiency. Are you leaving it on "auto" and therefore it switches over to 120V AC from your inverter and therefore you batteries? You should be running it on propane when off of shore power. You normally have to put the power option switch on to "gas", not "auto". Does it have a door defrost heater or some feature like that? They are known to be big 12V power hogs that kill batteries if you're not plugged into shore power. An absorption fridge should only have about a 1 A DC draw when on propane.

                          Edit: another thought. Are you sure that your converter has been disabled when you are off grid? Otherwise your inverter will supply power to it and it will suck your batteries down.
                          I appreciate that you tried to help him, and did not berate him for being a beginner and an "enthusiast." Thank you. I often read the posts of n00bs here (Yes, I'm a n00b) and just cringe for them.

                          Comment


                          • ewarnerusa
                            ewarnerusa commented
                            Editing a comment
                            Thanks. I'm a newbie to this forum as well, but I do have experience RVing and I researched and installed my own solar charging system in our camper based on what I learned online. I'd do it differently if I was building it from scratch today with what I've learned since then, but I think that's how gaining experience works. I feel like I know enough to speak intelligently about solar in an RV environment, but make no claim to being an expert! I have also cringed at some of the responses to posts that I've read, including responses to my own posts, but as a newbie here myself I am trying to keep my head low and offer what I think is good relevant advice.
                        Working...
                        X