Wiring our system (new to solar)

imapimap Registered Users Posts: 9
Good Morning

I have been pouring over this forum since I first found it and am now more confused than before.:blush:

Can you please provide some help for a poor confused new person who thought they had some understanding but have learned that they had none!

Some starting details:

We don't yet have our panels but are planning on 4-230w sharp panels
24v system
8 t-105 batteries in series to create 24v
TR1524-120-60 Off Grid Inverter/Charger - 1500 Watts - 24 Volts - 120V/60 Hz - 35 Amp Charger
MorningStar TriStar TS-45 Solar Panel Charge Controller

We are in a very small cabin with very little to run. We have LED lights, one laptop, an RV refrigerator, two cell phones, and a grundfos well pump.

All of our wire runs will be very short (5 feet max) in house (between inverter, batteries, house service panel). The outside run will be about 80 feet from the panels into the house. We currently have no power at all. So completely starting from scratch. We anticipate getting our solar panels next week, but would like to wire the batteries and inverter and run the generator to power the batteries until we get our panels. If I am understanding this inverter, when we run the generator whatever power we don't use, the excess will be sent to the batteries.

We have the generator hookups to the house. Can we run them to a 30 amp breaker box inside and then run them to the inverter from there? The electrician at the "box" store told us to run the two line wires into the panel and then just use a single pole breaker out of that and run the hot, neutral, and ground to the inverter. Should this work okay? I don't have a lot of confidence with them as we have had issues with getting correct information from them before. ;) We want to be safe, but we also don't have the resources to buy all the "pre-made" boxes, bells and whistles, from the solar manufacturers. So, we could really use some information on how to set up the wiring coming in from the generator -- to the inverter -- to the service panel. I think we understand the setup from the panels to the charge controller to the batteries, to inverter (with 2 disconnects).

Neither my husband or I are electricians, but we have learned a lot from this project. :D

This is a great forum with loads of information. Thank you for taking the time to help those of us that are a bit... "challenged".

Have a blessed day!

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar)

    Welcome to the confusion.
    Er, forum.

    Okay first little problem I see:
    8 t-105 batteries in series to create 24v

    Eight of these 6 Volt batteries in series would be 48 Volts, not 24.
    What you mean is four in series to create a 24 Volt string, then two of these strings in parallel.

    Second: got the manual for the inverter? You can't beat that for correct information on how to hook it up.
    In general, your "box store guy" is right. IF your generator puts out 120 VAC you need only connect it to the inverter's AC IN with an appropriate fuse or breaker (again; check the manual) keeping the AC Hot, Neutral, and Ground wires oriented properly.

    Now those batteries will be 450 Amp hours @ 24 Volts. The array will be 920 Watts, from which you might expect maybe 30 Amps peak current on a good day. That may be just a tad light for that battery bank (about 6% maximum charge rate) so you may find yourself relying on the generator if you discharge the batteries much.
    We have LED lights, one laptop, an RV refrigerator, two cell phones, and a grundfos well pump.

    It's a good idea to get a more accurate set of numbers for power usage. Especially that pump; Grundfos makes a lot of different pumps, and some of them would murder that power set-up you have.

    How are we doing so far? :D
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar)

    Thank you for such a speedy, helpful reply!
    Eight of these 6 Volt batteries in series would be 48 Volts, not 24.
    What you mean is four in series to create a 24 Volt string, then two of these strings in parallel.

    Yes, I should have said that it would be 2 strings of 4 for 24v.
    Second: got the manual for the inverter? You can't beat that for correct information on how to hook it up.
    In general, your "box store guy" is right. IF your generator puts out 120 VAC you need only connect it to the inverter's AC IN with an appropriate fuse or breaker (again; check the manual) keeping the AC Hot, Neutral, and Ground wires oriented properly.

    The thing I am stuck on is the generator to inverter hookup. Our generator is 120/240v. We used a 4 prong generator plug in to the house. It goes into the small panel box with the two hot lines going in to the line in feeds and a single pole breaker coming out of the 30amp breaker to the inverter. The panel box has one bar in it that he told me to hook the neutral and ground to. That seems not right to me, but is it okay?
    Now those batteries will be 450 Amp hours @ 24 Volts. The array will be 920 Watts, from which you might expect maybe 30 Amps peak current on a good day. That may be just a tad light for that battery bank (about 6% maximum charge rate) so you may find yourself relying on the generator if you discharge the batteries much.

    So, if I am reading this correctly, we need to about double the number of panels we were planning on buying?
    It's a good idea to get a more accurate set of numbers for power usage. Especially that pump; Grundfos makes a lot of different pumps, and some of them would murder that power set-up you have.

    The pump we purchased is the grundfos 10 sq05-160 1x200-240v 5.2 amp. Hmm... do we need two inverters to power this thing?
    How are we doing so far?

    I think I was better before.:confused:
  • bill von novakbill von novak Solar Expert Posts: 850 ✭✭✭✭
    Re: Wiring our system (new to solar)
    imap wrote: »
    The thing I am stuck on is the generator to inverter hookup. Our generator is 120/240v. We used a 4 prong generator plug in to the house. It goes into the small panel box with the two hot lines going in to the line in feeds and a single pole breaker coming out of the 30amp breaker to the inverter. The panel box has one bar in it that he told me to hook the neutral and ground to. That seems not right to me, but is it okay?

    It is likely that the second phase is simply not connected to the inverter. You cannot feed a 120V inverter with 240 volts, so one of the hot phases is generally left disconnected. To use both, you either need two inverters (if they allow 120/240V operation) or a transformer.
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar)
    It is likely that the second phase is simply not connected to the inverter. You cannot feed a 120V inverter with 240 volts, so one of the hot phases is generally left disconnected. To use both, you either need two inverters (if they allow 120/240V operation) or a transformer.

    Thanks Bill. I was thinking that this was not correct. We will disconnect one of the hots. Now, educate me please. What is a transformer and how does it work?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar)
    imap wrote: »
    The thing I am stuck on is the generator to inverter hookup. Our generator is 120/240v. We used a 4 prong generator plug in to the house. It goes into the small panel box with the two hot lines going in to the line in feeds and a single pole breaker coming out of the 30amp breaker to the inverter. The panel box has one bar in it that he told me to hook the neutral and ground to. That seems not right to me, but is it okay?

    Possibly not. What you have coming from the generator is 240 VAC "split phase": two "hot" lines, one "neutral" which is "half-way between" the two hot lines, and one ground. In normal household wiring there would be one connection for each of the two hot lines: L1 and L2. Across these you get 240 VAC. Then there would be a separate bus bar for the neutral to connect to. Any 120 VAC loads would connect between this neutral bar (white wire in standard cable) and a breaker fed from either the L1 or the L2 (black wire in standard cable). The ground wire (bare in the cable) connects to another bus bar for the ground from the generator.

    This is where it gets tricky. With utility power the neutral and ground bus bars are tied together only at this one point (the service panel). The generator has a "floating" neutral (check the generator manual to be sure this is so); not tied to ground. But when used in this configuration it would be joined just like the utility feed. This ground bus bar is also connected to an Earth grounding rod usually via bare 6 AWG stranded wire. The rod will be at least 8' long. Sometimes multiple rods are used. If this Earth ground is not present do not tie the neutral and ground wires together. Very important!

    But wait, it gets worse. The correct wiring now depends on the inverter and how its output is used. The TR1524 is a MSW (Modified Square Wave) type inverter. It is unlikely that it will accept a neutral-ground bond anywhere in the system. It will probably go up in smoke if one is present. Check the manual carefully! if it does not say anything about it, do not connect the neutral to ground anywhere. Really; the inverter could be destroyed the moment you turn it on. Floating neutral (no bond to ground) is perfectly safe. Thus you do need two isolated bus bars in your breaker box in order for this to work.

    Don't be upset if you find this confusing; proper grounding of systems is one of the trickiest bits of electrical wiring, especially when inverters and generators are involved. Even experts will disagree on how this should be done. The simplest solution is to buy a true sine wave inverter that can have the neutral-ground bond, but even then you have to be careful that there is only one such connection.
    So, if I am reading this correctly, we need to about double the number of panels we were planning on buying?

    About 1400 Watts would be desirable for that battery bank. With the 230 Watt panels six would be good. This will probably "max out" the TriStar 45 MPPT. Any chance you could get the 60 Amp version? Or an Outback or MidNite controller (which are somewhat better)?
    The pump we purchased is the grundfos 10 sq05-160 1x200-240v 5.2 amp. Hmm... do we need two inverters to power this thing?

    That is a very good choice in a pump. It is 115 Volt and has a "soft start" which will not nail the poor inverter with a sudden high load when it comes on. It should be fine, even though I normally recommend a pure sine inverter for any type of AC motor; this one is least likely to suffer ill effects from MSW.
    I think I was better before.:confused:

    Well it's confusing stuff. Complex. Gives me a headache. :D
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar)
    imap wrote: »
    Thanks Bill. I was thinking that this was not correct. We will disconnect one of the hots. Now, educate me please. What is a transformer and how does it work?

    You don't really want to know, okay? :p

    Oh; you do? Sure?

    A transformer is two sets of wire winding around a core used to increase, decrease, or isolate AC power. In this application it would step down the 240 VAC to 120 VAC and approximately double the current capacity as a result.

    Sorry you asked?
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar)
    You don't really want to know, okay? :p

    Oh; you do? Sure?

    A transformer is two sets of wire winding around a core used to increase, decrease, or isolate AC power. In this application it would step down the 240 VAC to 120 VAC and approximately double the current capacity as a result.

    Sorry you asked?

    Stop! It hurts my head. It sounds like something to look in to. But not right now.
  • bill von novakbill von novak Solar Expert Posts: 850 ✭✭✭✭
    Re: Wiring our system (new to solar)
    imap wrote: »
    What is a transformer and how does it work?

    Simple explanation - it turns 120 volts into 240 volts and vice versa.
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar)
    But wait, it gets worse. The correct wiring now depends on the inverter and how its output is used. The TR1524 is a MSW (Modified Square Wave) type inverter. It is unlikely that it will accept a neutral-ground bond anywhere in the system. It will probably go up in smoke if one is present. Check the manual carefully! if it does not say anything about it, do not connect the neutral to ground anywhere. Really; the inverter could be destroyed the moment you turn it on. Floating neutral (no bond to ground) is perfectly safe. Thus you do need two isolated bus bars in your breaker box in order for this to work.

    Ok, we have the system ground, but will add another bus bar for the neutral and ground to be separate.
    About 1400 Watts would be desirable for that battery bank. With the 230 Watt panels six would be good. This will probably "max out" the TriStar 45 MPPT. Any chance you could get the 60 Amp version? Or an Outback or MidNite controller (which are somewhat better)?

    I think we can increase the panels by two and can send back the controller to upgrade that.

    I'm glad we are good on the pump.

    Now, with what we have at the moment; the inverter, batteries and generator, is there a way to make this work for us now until we get the charge controller changed and solar panels here? I haven't looked into anything else but running it with the solar panels.

    My husband would be so happy with that. And of course, then we are all happy.:-)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar)
    imap wrote: »
    Now, with what we have at the moment; the inverter, batteries and generator, is there a way to make this work for us now until we get the charge controller changed and solar panels here? I haven't looked into anything else but running it with the solar panels.

    Yes; use one "leg" of the generator to run the charger built in to the inverter. (BTW this is one of the few MSW inverters that is "stackable": if you buy a second one you can have 240 VAC in and out of them.)
    My husband would be so happy with that. And of course, then we are all happy.:-)

    Happy husband, happy .... er, that doesn't seem to work. :confused:
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Wiring our system (new to solar)

    I don't see that you have mentioned your generator model or brand. Some 240 volt generators only allow half their output on one of the 120 volt legs. If yours is like that and you need full power at 120 volts, you can use a transformer to step down the full 240 volt output to 120 volts.
    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Wiring our system (new to solar)

    One more thing... don't commission your system until you get your panels. A generator-battery-inverter system is NOT eligible for Federal tax credits. If you hook up the same system with panels & controller, all of it (except generator) is eligible for the tax credits.
    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • raydiasraydias Solar Expert Posts: 68 ✭✭✭✭
    Re: Wiring our system (new to solar)

    Just a novice question, wouldn't a DC pump be more efficient in this design compared to using the inverter setup?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar)
    raydias wrote: »
    Just a novice question, wouldn't a DC pump be more efficient in this design compared to using the inverter setup?

    Not necessarily.
    If it were simply a matter of AC vs. DC with everything else the same DC would win. But there can be issues with the installation such as wiring distance from source to pump which makes the higher Voltage AC desirable. Likewise, an array driven Grundfos would be excellent - unless you can not put the array where the pump has to be or you can't afford the investment in a separate pump array.

    I use an ordinary off-the-shelf 120 VAC water pump. I can control it's time of use, the inverter/batteries/array is large enough to accommodate it, and if the pump fails it takes me 3 hours to drive to town and back with a new one.

    We don't know the details of the OP's layout and well so it's hard to say if there's a "more optimum" choice.
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar)
    vtmaps wrote: »
    One more thing... don't commission your system until you get your panels. A generator-battery-inverter system is NOT eligible for Federal tax credits. If you hook up the same system with panels & controller, all of it (except generator) is eligible for the tax credits.
    --vtMaps

    Thank you for this information. We need all the credits we can get!!;)
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar)
    raydias wrote: »
    Just a novice question, wouldn't a DC pump be more efficient in this design compared to using the inverter setup?

    Hi Ray

    Initially, we were not going solar. My husband and I had differing visions on this, and of course he prevails. So, we are wired for AC.

    Unfortunately (or not), we have been waiting for a long time for the easement of the other land owner that the power company lines need to cross. As we were going to do a backup solar setup, my husband decided we could do this now so that we would have something going. I am hopeful that he will be so happy with it that we won't have to have the power company come in.

    Our well is about 160 ft from the house, and the panels will be about another 80 ft beyond the house in the opposite direction. So, we are just staying with the AC as it works well with what we already have set up.

    Have a great day!
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar) adding batteries

    Hello All

    Well, with all of your assistance, we have our generator wired in the the panels and have electricity in that way.

    We are now working on setting up the batteries. It is hard to pull it all together as there is so much information out there, it can be confusing. This is what I think we need to do:

    4 awg to batteries from the charge controller with a fuse close to the batteries

    From batteries to inverter 4/0 gauge wire with 100 amp fuse at batteries.

    Is this correct for the wire sizes?

    Still trying to understand the requirements for grounding the batteries and the msw inverter. Off to do some more reading before we discuss that.

    Thank you in advance for all your help. Y'all are great!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar) adding batteries
    imap wrote: »
    4 awg to batteries from the charge controller with a fuse close to the batteries

    Likely 6 AWG is the largest wire that will fit the controller's terminals. This is capable of carrying up to about 60 Amps so it should work fine providing the distance to the batteries is not too great (over 10 feet for example). Fuse at battery for line to controller is good. Make sure its current capacity is not higher than the wire can handle.
    From batteries to inverter 4/0 gauge wire with 100 amp fuse at batteries.

    Overkill! 4/0 wire can handle 300 Amps. Your inverter will draw less than 100 (1500 Watts / 24 Volts = 62.5 Amps). 2 AWG will actually handle this providing the distances aren't long (best to keep them under 5 feet). You may want to "size up" to 0 AWG, but 4/0 is an unnecessary extra expense.
    Still trying to understand the requirements for grounding the batteries and the msw inverter. Off to do some more reading before we discuss that.

    Biggest thing to avoid with grounding an MSW type inverter: neutral-ground bond on the AC output.
  • imapimap Registered Users Posts: 9
    Re: Wiring our system (new to solar) adding batteries

    Thank you Cariboocoot for another exceptionally fast response!

    It is most appreciated as we have limited online time and this is very helpful! Also glad we asked these questions before buying any of the wire.
    Overkill! 4/0 wire can handle 300 Amps. Your inverter will draw less than 100 (1500 Watts / 24 Volts = 62.5 Amps). 2 AWG will actually handle this providing the distances aren't long (best to keep them under 5 feet). You may want to "size up" to 0 AWG, but 4/0 is an unnecessary extra expense.

    So, is the 100 amp fuse okay with this or should we use a small amp fuse? The distance that we are going is less than 5 feet.

    So for the ground from the inverter, can we just run the neutral to the neutral bar in the AC service panel and the ground to the ground bar in the AC panel. We have two ground rods running from the panel out of the cabin. Or do we have to do something else?

    You have no idea how much we appreciate the help from all the folks here. You are saving many people many big headaches.:D
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Wiring our system (new to solar) adding batteries
    imap wrote: »
    So, is the 100 amp fuse okay with this or should we use a small amp fuse? The distance that we are going is less than 5 feet.

    100 Amps should be just right. Always check the inverter's manual, however; can't beat the manufacturer's recommendations (usually).
    So for the ground from the inverter, can we just run the neutral to the neutral bar in the AC service panel and the ground to the ground bar in the AC panel. We have two ground rods running from the panel out of the cabin. Or do we have to do something else?

    Yes. Just be sure there is no connection between the ground and neutral. Only the ground bus bar is connected to the grounding rod(s).

    Some may recommend grounding the battery (-), but that's another "check the manual" because some MSW inverters don't work with that either.
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