Announcement

Collapse
No announcement yet.

Off Grid suggestions needed

Collapse
This topic is closed.
X
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Off Grid suggestions needed

    Hi Everyone,
    brand new here, first posting, I'm looking for some offgrid help,
    so many ppl have so many different ideas and I'm a guy that needs help figuring out who is right,
    I'm tired of the salesmans point of view lol,
    I currently have 4 12v 100ah batteries, 4 250W panels, and one 235W panel,
    what I would like to do is getting a decently priced good controller, and eventually a grid tie all set up for the 24v battery bank

    what do you suggest? mppt or pwm? can I run a grid tie off my batteries and put it on a timer so it runs only during the day?
    thanks in advance
    When Google seems more helpful it's easy to find

  • #2
    You really do not have anything to work with. The 100 watt battery panels are incompatible with the 235 watt grid tied panel, and 12 volt batteries are not something you really want to use. But other than that you have a wonderful plan. Let's lay it out step by step.

    Here is your plan. You are going to generate electricity to store it in batteries, and either sell it to the power company (POCO) or use it yourself. Battery cost alone will cost you roughly 50 to 60-cents per Kwh over the life of the batteries. Then you sell to to the POCO for 13 cents and you loose 37 to 47 cents for every kwh you generate.


    Good luck with your plan.
    MSEE, PE

    Comment


    • #3
      Originally posted by Sunking View Post
      You really do not have anything to work with. The 100 watt battery panels are incompatible with the 235 watt grid tied panel, and 12 volt batteries are not something you really want to use.
      I'm pretty sure you missed something, where did I say I had 100w battery panels?
      and I guess I should have missed mentioned the 12v batteries I have are solar batteries, not just car batteries I mentioned the were 100AH so I kinda thought that was obvious lol, since a good car battery like an optima is only 55AH,
      but thanks for the negative outlook on the whole plan,

      I do recall asking for specific advice and not the salesman approach,

      but thanks for making your post number 13,315. ps it wasn't helpful at all
      When Google seems more helpful it's easy to find

      Comment


      • #4
        Originally posted by lovemshaved View Post
        I currently have 4 12v 100ah batteries, 4 250W panels, and one 235W panel,
        My bad but it does not really change anything much.

        To get the most would require a MPPT controller at a battery voltage of 24 or 48 volts. At 24 volts the minimum battery requirement is 400 AH, and 200 AH at 48 volts which you do not have enough of and using 12 volt batteries at that power level is really a bad practice as you would want 6 volt 200 AH batteries if configuring 48 volts, or 6-volt 400 AH batteries at 24 volts. But it is a moot point to go off grid when you have a grid connection already. All you have done is voluntary given yourself a 400% or more rate increase for those 2 or 3 Kwh per day you could possible generate with what you have that is not compatible with each other.

        Put another way you are spending $1.50 to $2.00 per day to save 30 to 40 cents per day on your electric bill. Once you figure out the economics you will understand.

        EDIT NOTE:

        With what you have, the batteries are the limitation. But here is what can be done. You can use 3 of the 250 watt panels (FWIW 750 watts is a bit much for the batteries and will eat them alive in a year or two) , wire them in series going into a Midnite Solar Kid a 30 amp MPPT controller. Wire the batteries in series to make 48 volts and then feed those into a hybrid Inverter like an Outback GTFX3048LA. Are you having sticker shock yet?
        MSEE, PE

        Comment


        • #5
          Originally posted by lovemshaved View Post
          Hi Everyone,
          brand new here, first posting, I'm looking for some offgrid help,
          so many ppl have so many different ideas and I'm a guy that needs help figuring out who is right,
          I'm tired of the salesmans point of view lol,
          I currently have 4 12v 100ah batteries, 4 250W panels, and one 235W panel,
          what I would like to do is getting a decently priced good controller, and eventually a grid tie all set up for the 24v battery bank

          what do you suggest? mppt or pwm? can I run a grid tie off my batteries and put it on a timer so it runs only during the day?
          thanks in advance
          You have too much panel wattage for a 24volt 200Ah (wired 2 in series x 2 sets in parallel) battery system. Maybe using no more than 3 of those 250watt panels and a 30amp MPPT charge controller will work but batteries wired in parallel will not last long due to unequal charging and discharging.

          Expanding an off grid system to a hybrid grid tie system will cost you a lot of money and might require you to replace some of your equipment based on your POCO requirements for a grid tie system.

          What Sunking is trying to tell you is that a generating power from a solar battery system is 5 to 6 times the cost of buying power straight from the POCO. So to me it would be hard to justify spending money for an off grid system when I have Utility power available.

          Installing a grid tie system with a Net meter contract can pay for itself in 8 to 15 years depending on what your $/kWh charge is and how much you use. An off grid system will never pay for itself and should never be considered a path to save money.

          Comment


          • #6
            Fair enough. I appreciate the info but no one has asked what I've paid for anything. Or if cost is even an issue. Or what I'm trying to power off the grid

            I'm not asking if it's worth it lol I'm asking what I should use to get the job done.

            I have a small little offgrid system already. 280w worth of 12v panels. The same 12v 100ah batteries. And i run. An entire race trailer off it including a 200psi air compressor. Never a shortage of power.

            If just putting these 1.2kw panels on grid is a better option than that's something I'm open to suggestions.
            I'm not worried about saving money. Or spending it.

            Any thoughts?
            When Google seems more helpful it's easy to find

            Comment


            • #7
              Originally posted by lovemshaved View Post
              Fair enough. I appreciate the info but no one has asked what I've paid for anything. Or if cost is even an issue. Or what I'm trying to power off the grid

              I'm not asking if it's worth it lol I'm asking what I should use to get the job done.

              I have a small little offgrid system already. 280w worth of 12v panels. The same 12v 100ah batteries. And i run. An entire rwxe trailer off it including a 200psi air compressor. Never a shortage of power.

              If just putting these 1.2kw panels on grid is a better option than that's something I'm open to suggestions.
              I'm not worried about saving money. Or spending it.

              Any thoughts?
              First contact your POCO and find out what the minimum wattage system they will allow to be grid tied. Then you should be able to determine if you have enough panel wattage and which type of grid tie inverter will work for you.

              Most municipalities allow the homeowner to do about 90% of the install with the last 10% being performed by a licensed electrician so find out what your POCO and local inspectors require including detailed drawings to be submitted to get a permit. Other areas required only Solar Trained Technicians to do all of the install but those are few and far between. Best way is to check with your municipality and make sure you understand what they are asking for.

              If you really want a battery system then look into hybrid systems that can be legally tied to the grid and charge batteries. If money is no object then that is a path you can follow but usually the cost of those systems don't justify the amount of "backup"power they can produce. A good generator is a better investment for emergency power than a battery system.

              Comment


              • #8
                There is no min . where I live. And i have spoke to my hydro company. They told me when I'm ready they will come and change my meter. To one of two choices. A meter that can run backwards and one for net metering that will cost me $1200. There was no mention of anything you spoke of. Solar systems aren't popular here not residential anyways

                does anyone have the answers to what I asked in the first place? i never join forums for this exact reason. No one really ever gives a straight forward answer. It seems like everyone tunes in to see who has more knowledge but acts like it's all classified info.

                Google seems more helpful sometimes this is discouraging
                When Google seems more helpful it's easy to find

                Comment


                • #9
                  Originally posted by lovemshaved View Post
                  does anyone have the answers to what I asked in the first place? i never join forums for this exact reason. No one really ever gives a straight forward answer. It seems like everyone tunes in to see who has more knowledge but acts like it's all classified info.

                  Google seems more helpful sometimes this is discouraging
                  lovewhatshaved? Demanding certain answers usually doesn't work too well - I suppose that is the reason you don't have good luck on the net - attitude.

                  People respond to being asked - not demands.
                  [SIGPIC][/SIGPIC]

                  Comment


                  • #10
                    Attitude? Lol because I want answers to my questions not everything else?
                    If thats attitude. You wouldnt like to see soneone get upset obviously.
                    again thanks for throwing in your 2 cents. Not that it had anything to do with my questions lol
                    what a shock.
                    I'll figure out how to delete myself off here and go back to Google it's way more helpful
                    When Google seems more helpful it's easy to find

                    Comment


                    • #11
                      Originally posted by lovemshaved View Post
                      Attitude? Lol because I want answers to my questions not everything else?
                      If thats attitude. You wouldnt like to see soneone get upset obviously.
                      again thanks for throwing in your 2 cents. Not that it had anything to do with my questions lol
                      what a shock.
                      I'll figure out how to delete myself off here and go back to Google it's way more helpful
                      Please feel free to do so - if you want help just ask.
                      [SIGPIC][/SIGPIC]

                      Comment


                      • #12
                        Sunking already answered your questions. Yes you can put it a timer to turn off you demand so the system won't be used.


                        Originally posted by Sunking View Post
                        My bad but it does not really change anything much.

                        To get the most would require a MPPT controller at a battery voltage of 24 or 48 volts. At 24 volts the minimum battery requirement is 400 AH, and 200 AH at 48 volts which you do not have enough of and using 12 volt batteries at that power level is really a bad practice as you would want 6 volt 200 AH batteries if configuring 48 volts, or 6-volt 400 AH batteries at 24 volts. But it is a moot point to go off grid when you have a grid connection already. All you have done is voluntary given yourself a 400% or more rate increase for those 2 or 3 Kwh per day you could possible generate with what you have that is not compatible with each other.

                        Put another way you are spending $1.50 to $2.00 per day to save 30 to 40 cents per day on your electric bill. Once you figure out the economics you will understand.

                        EDIT NOTE:

                        With what you have, the batteries are the limitation. But here is what can be done. You can use 3 of the 250 watt panels (FWIW 750 watts is a bit much for the batteries and will eat them alive in a year or two) , wire them in series going into a Midnite Solar Kid a 30 amp MPPT controller. Wire the batteries in series to make 48 volts and then feed those into a hybrid Inverter like an Outback GTFX3048LA. Are you having sticker shock yet?

                        Comment


                        • #13
                          Originally posted by lovemshaved View Post
                          Attitude? Lol because I want answers to my questions not everything else?
                          If thats attitude. You wouldnt like to see soneone get upset obviously.
                          again thanks for throwing in your 2 cents. Not that it had anything to do with my questions lol
                          what a shock.
                          I'll figure out how to delete myself off here and go back to Google it's way more helpful
                          I know how you feel, I started a thread on here and had Sunking read me the giant bright yellow label which was featured prominently in the link I posted. I felt like saying "in related news the sky is up". So I know this process can be frustrating. Try to remember that people are trying to be helpful and just have no idea about your particulars/level of knowledge. If there's some background that could help keep them from making bad assumptions then please share.

                          I'm new at this and my off grid system is tiny so take what I'm saying with a grain of salt but I'll endeavor to answer your questions:

                          "what do you suggest?"
                          Grid tie, using your power company as a free battery bank is a brilliant plan. If you're worried about power outages you could go with a hybrid system where you'd just be running off the batteries when the powers off.

                          "mppt or pwm?"

                          Neither but if your determined to be off grid, you have too much solar for your batteries already, so with the components you have pwm might be the better option. (there's no reason to try and milk every watt out of your panels when you're going to have too much)

                          "can I run a grid tie off my batteries and put it on a timer so it runs only during the day?"

                          This question doesn't make sense to me, could you explain what you're trying to accomplish?

                          Comment


                          • #14
                            Originally posted by lovemshaved View Post
                            Attitude? Lol because I want answers to my questions not everything else?
                            If thats attitude. You wouldnt like to see soneone get upset obviously.
                            again thanks for throwing in your 2 cents. Not that it had anything to do with my questions lol
                            what a shock.
                            I'll figure out how to delete myself off here and go back to Google it's way more helpful
                            You already have experience with an off grid system so you should understand the limits and benefits of them including which type of charge controller to get (PWM or MPPT).

                            I have two small off grid systems both with PWM CC. (400watt 12volt 200Ah system and a much smaller 80 watt 12v 65Ah system). Both have a use but they were also very expensive for the watt hours I can get out of them and I should have gone with a MPPT CC for the larger system.

                            PV Charge controller 1.jpg340 watts of pv panles.jpg200ah battery system.jpgSmall Portable PV sys pic3.jpgSmall Portable PV sys.jpg

                            If I want to go bigger I would get a grid tie system (without battery backup). Even if I don't like it I will have to follow the rules and regulations of my POCO and pay for what they require including meters.

                            To me it is not worth the hassle (or potential safety issue) of installing a pv system and connecting it to the grid without the complete approval of my POCO and city inspectors. There are people out there (not asuming you are one) that want to install a grid tie pv system and "bend" or go around the rules to save a few bucks. They are really fooling themselves into thinking what they are doing is ok and safe but they are really getting themselves into a potential legal battle or worse.

                            So if I have not answered your questions fully to your satisfaction it may be because I do not really know your full motivation to what you want to accomplish with a "grid tie battery system".

                            Comment


                            • #15
                              Originally posted by lovemshaved View Post
                              Solar systems aren't popular here not residential anyways

                              does anyone have the answers to what I asked in the first place?
                              Well if they are not popular tells you your electricity is so cheap, there is no reason to use solar. I already answered how you can do this in reply #4. It requires a HYBRID INVERTER and they are real expensive. It is the only way it can be done. Also means rewiring your home if you want to use it in the event of a power outage.

                              Having said all that, sounds like you just want a straight grid tied system. You have 4 250-watt and a single 235 watt panels that can be used. Will require micro-inverters attached to each panel. String Inverters require a minimum 250 volts and your 5 panels in series will not be that high of a voltage, and the 235 watt panel is not compatible with the other 4.

                              That covers all options available to you.
                              MSEE, PE

                              Comment

                              Working...
                              X