Need Advice- Upgrading my off-grid solar system in Ohio

HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
Hello,

I have a small solar system I made about 6 years ago for my off-grid cabin I built in Southern Ohio.

(1) 80W 12v PV Panel that charges my 300AH battery bank consisting of (4) 12v 75AH deep cycle wet cell Transcontinental brand batteries wired in parallel.
A cheap Sunforce 30A charge controller and a Cobra 1500 W Inverter

I connect the inverter to an AC wired breaker box that has 5 AC circuits running throughout the cabin
I also have a few DC circuits in the cabin that I wired to a DC fuse panel that connects directly to the battery bank.

I have a gas generator that I use as a back up power source to run power tools etc while working on the cabin or to charge the battery bank in the winter if needed

I am in the process of upgrading my system and thought I would come here for some advice.

The cabin is used on the weekends year round for the most part. I primarily only run lights, radio, 12v water pump for the shower and occasionally a small tv and dvd player.

I would say I have had pretty good luck with the system as it is currently, but would like something a little more reliable.

I have little issues with keeping the batteries charged during the spring and summer months, but tend to run into some trouble during the winters in Ohio..which leaves me with 4 or so months where snow can gather on the panel during the week while I'm not there, a lack of sun, freezing temps making my batteries cold, etc.. :grr

My first four batteries lasted me for two years before I had to replace them seeming how they would not keep a charge anymore.

My current set which is exactly the same brand type etc..are now starting to fail me after only a year and cant seem to keep them charged.

I have been doing a lot of research on charge controllers PWM v MMPT, true deep cycle batteries, and battery system monitors and want to do some upgrades.

I just purchased the Morning Star Sunsaver SS-MPPT 15 A Charge controller and the RTS remote temp sensor.

I am also going to purchase the Trimetric 2025-A or -Rv to monitor the batteries.

I am planning on purchasing Crown 6v 225 AH deep cycle (flooded) golf cart type batteries but want to make sure I get the right amount AH that my system can support so to say.

I was going to buy 4 of these 6 volt batteries and wire them in series and then parallel to end up with 12V and 450AH

Then I got to worrying that perhaps my panel was not enough to keep a bank this size charged so.... thought I may just buy 2 instead and have a12v 225AH battery bank.

Though it would be 75AH less than my current bank, the batteries are "true" deep cycle and are better quality than what I have. However, I would really like to have the 450AH battery bank ;)

Any advice or suggestions on battery bank size vs. solar panel output would be great, thoughts on my recent purchase of charge controller and battery monitoring, and or any advice at all!

Thanks 8)
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Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Welcome to the forum.

    Your major problem is insufficient panel for the batteries you have, much less for any increased capacity. Right now you have 300 Amp hours @ 12 Volts and only one 80 Watt panel? You must rely on that generator a lot as the one panel probably puts out less than 5 Amps, which is nothing to that much battery. This is the "a small panel will recharge the batteries eventually" theory, and they forget to tell you about how much it shortens battery life.

    If you go with four 225 Amp hour 6 Volt deep cycle batteries you should have an array around 700 Watts and an MPPT type controller capable of at least 45 Amps.

    Now, do you actually need that much battery capacity? That's about 2.5 kW hours stored energy, or as much as I run my cabin on including full-size refrigerator.

    I suggest you start by reading through the deep cycle battery FAQ's and see what you're up against for battery charging/maintenance: http://www.solar-electric.com/decybafaq1.html
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    welcome to the forum,
    you should've had longer lifespans with those batteries and the reasons why you didn't get long lifespans is because you are draining the batteries too far (beyond 50%) and you don't have sufficient pvs to charge the batteries with. a good goal is 10% of the battery bank ah total. also now when you see a pv with, for example your pv, 80w, know that this is under stc conditions and you are unlikely to see these conditions normally. a rough estimate might be 77% of the stc rating is what you may see. in the case of your 80w pv you are usually seeing 61.6w and at 12v this amounts to about 5.1a at the most. this is a 1.7% charge rate and is good enough to float charge the batteries after they are full, but are unlikely to give much of a charge to them. that was a deficit charge and allowed sulfation to set in thus destroying your batteries quickly. i can't say for sure how much battery capacity you actually do need as you need to asses the draws and the times for them or, as you made a point of saying you want to get, use the battery monitor and see what you are drawing.

    being you are shy on pv power you jumped the gun buying a controller that limits you to 15a.
  • westbranchwestbranch Solar Expert Posts: 5,180 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Nice detailed description, there is one thing missing and that is the amount of power you draw from that system. If you can list the consumption in watts and the amount of time each item is used the picture will be complete. Then the work can begin, all good systems are based on the loads needing supply (power)
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • icarusicarus Solar Expert Posts: 5,400 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    See my signature,

    We consume ~800 WH/day, and the system is nearly perfectly balanced.

    All design considertations begin with the loading. A well balanced system should have battery life of better than 5 years if you are reasonably careful.

    Tony
  • unicorniounicornio Solar Expert Posts: 217 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    Heisenberg wrote: »
    Hello,

    I have a small solar system I made about 6 years ago for my off-grid cabin I built in Southern Ohio.

    (1) 80W 12v PV Panel that charges my 300AH battery bank consisting of (4) 12v 75AH deep cycle wet cell Transcontinental brand batteries wired in parallel.
    A cheap Sunforce 30A charge controller and a Cobra 1500 W Inverter

    as someone have rightly said, with this pv and this charge controller that you have, you can only get energy enough to compensate for self-discharge of the battery ... also can be a problem at that facility have batteries in parallel, almost be better that you used only one of them ... maybe that's the reason you last only two years ...

    if you need to put the four batteries, for example, if you charge it with the genset, make sure the wiring and connections to battery have you made so that losses are compensated... in this forum you can find the wiring techniques you need to use to connect some batteries in parallel, that it's much more complicated than it seems ...;-)

    welcome to forum!...:-)
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Thank you everyone for the great advice. It is obvious that I am going about this in the wrong way and I am glad I came here first. My initial thoughts were to make up for the lack of performance in my system by increasing my AH with more and better batteries without realizing that it was the lack of proper charge all along (to say the least). I now see that my sets of batteries have suffered much abuse as would any future batteries I may have ended up purchasing.

    The amish community in my part of Ohio utilize solar systems quite a bit, and most of my system was built on the advice given by Amish that I meet in my line of work. I am not sure why they had suggested that I would only need 1 80W panel, but the damage has been done so it doesn't really matter now.

    Upon listening to your advice, I have given some thought to a new approach and want to see what you guys think. I have not determined the exact amount of power that I draw from the system as of yet, but as a general idea, I am converting most of my power from DC to AC with a 1500 watt inverter and primarily run 5 circuits throughout the cabin, which is mostly used for lighting, charging cell phones and listening to a radio. Aside from that, I may on occasion watch a movie with a small tv and dvd player, but that is rare. In the winter I may kick on a blower fan that is hooked to my woodburner just to speed up the heating process, but again, that is rare as well. During the summer months I have a small 12v water pump that is used for brief moments to pump water to an on demand propane water heater during showers. I use all CF light bulbs and typically buy the lower watt bulbs assuming they draw less? In total, if every single light in the cabin was turned on, including lamps and fixtures, there would be 15 CF bulbs. However, I never have them all on at once.

    Additionally, at present time I am only at my cabin on the weekends, which would mean that if running lights I would be using the system on friday and saturday nights, for variable amounts of hours.
    However, if I were able to spend some more $ and upgrade to the big leagues of solar it may help convince my wife of turning the weekends to full time ;)

    So anyway, my new idea is to stick with the 15A charge controller I purchased and do the following:

    1. Purchase an additional 80W (or bigger) panel. Giving me (in a perfect world) a potential of 10a charge and still be under the 15A rating of the controller
    I also am assuming I will get a more efficient charge with a MPPT charge controller vs. the current sunforce one I am using now.

    2. Since I originally intended to purchase 4- 225 AH batteries, and now realize I may not necessarily need that much AH, I want to consider spending the money on one 12v deep cycle AGM sealed type with maybe 100AH? That way it would be much less AH to maintain, still be within my usage limits and not have multiple batteries wired together. I will also note that I am thinking the sealed type battery would be more ideal for my situation as I would not be as limited to the location of the battery bank with ventilation, etc.. and have the bank in a more desirable location

    So in summary I am seeking advice on my "new idea" and am curious of your thoughts. Would like to know any battery suggestions for a 12v sealed agm type and the amount of AH needed based on my general description of power usage.

    thanks :cool:
  • westbranchwestbranch Solar Expert Posts: 5,180 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Batteries, AGM are good but expensive and sadly you are still in the early learning stages of battery use and abuse. I would go for a set of golf cart batteries s and a good 3 stage charger to use with your generator. this will keep them healthy, then (or now) determine the amount of PV you need and what type of charge controller you want/need and then proceed.
    YMMV

    add: GC batts are ~ 225 Ah rated for this application and you will need from 12 to 25 Amps from your PV... means new panels and CC
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Well let's see:
    80 Watts plus 80 Watts is 160 Watts. About 4.5 Amps each I think, or 9 Amps maximum if using a PWM type controller. An MPPT controller would not add much to this (maybe 1 Amp) and it is doubtful it would be worth the extra money: 20 Amp Sunsaver $78 http://www.solar-electric.com/ss-20l.html, 15 Amp MPPT $223 http://www.solar-electric.com/mosumpsochco.html That's a lot of money for one more Amp of peak current.

    What will 9 Amps do for a 100 Amp hour battery? About 9% peak charge rate, which is fine. What can you expect from 100 Amp hours @ 12 Volts? As much as 600 Watt hours.

    Problem is, you don't know how much power you need so you're still guessing with a high probability of guessing wrong. I just tested one of those stove blower fans: on high it was over 50 Watts. Run that for a night and the power is all gone.

    AGM batteries are fine, except for costing more per Watt hour than their FLA equivalent. They are also less forgiving of mistakes.

    Just my thoughts. Others will have their own input no doubt.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    seeing that your loads are primarily ac you should get a killawatt meter.
    http://www.solar-electric.com/kiacpomome.html
    with this meter over a 24hr period you can see the kwh you require over a day. once you see this add another 20-25% for inverter efficiencies to give a good idea of the dc draws in kwh. for watt hours (wh), just multiply it by 1000.

    also, you can't judge your usage by that of others, let alone the amish who may be very sparingly using the power they have.

    btw, if you leave the inverter on even though there's no ac loads on it it will continue to draw operational dc power.

    the subject matter of solar can be quite encompassing and we rarely say this, but i would suggest you start reading the forum to better educate yourself. granted you can't read it all, but for somebody to get their education from a group of people who have just started to scratch the surface on electricity due to their beliefs shows you may be about as educated on it as they are.

    i should mention that i intend no offense to you or the amish as i commend you and any in the amish for going this way.

    we will still be here to help so you may continue to make your inquiries here and try to keep it in this thread that you started.
  • BB.BB. Super Moderators, Administrators Posts: 29,976 admin
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Guessing your inverter is probably an MSW (modified square wave) type inverter... Do you have any problems running your CFLs (buzzing, hard starting, short life?). Do your 120 VAC power adapters run Hot or have any failed? If not--then the inverter is probably fine for your needs.

    There is a small 300 watts TSW inverter @ 12 volts from MorningStar with some low power modes (remote on/off, low power search mode) which can be handy (puts inverter in standby and uses less power) when you have no AC loads. Also, for some electronics (and wall worts, some laptop computer power supplies, and such) TSW inverters are "easier" on the electronics.

    Also, there are Battery Monitors which can help you better manage your battery bank and log your power usage/loads/charging. AGMs are very nice batteries, but have no way for you to measure state of charge with a hydrometer--A battery monitor is very helpful.

    If you continue to enlarge your battery/PV system--A DC Current clamp meter can be very handy too for diagnosing problems and monitoring current flow (this one is not too expensive and also has all the standard DMM functions).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Yes my inverter is an MSW type. It's the Cobra CPI 1575 1500 Watt inverter

    I have noticed a small bit of buzzing in the CFL's but have not noticed shortened life as I have not replaced any since using the system for several years now.

    My 120 VAC power adapters don't seem to be running hot and have not had any failures yet. I do notice a small amount of buzzing that comes from the AC breaker panel while the inverter as well.
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Anyone have thoughts on or experience with these batteries?

    http://store03.prostores.com/servlet/vmax/the-42/vmax-tanks-solar-wind/Detail

    Amazon.com has this 100AH for $250 and free shipping
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    i'm not familiar with them, but if you try them then do let us know how you like them. it may take many years to really know how well they did. price seems alright.
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Power (W) 80 Watts
    Open Circuit Voltage (V) 22.2 Voc
    Short Circuit Current (A) 4.87 Isc
    Maximum Power Voltage (V) 17.6 Vmp
    Maximum Power Current (A) 4.55 Imp

    If I had 3 of the above panels wired together in parallel, assuming perfect conditions and all relative losses aside, I would have 13.65 peak amps of charge?

    As one of you had said, a general rule is to have 10% of your battery AH as the amount of charge to receive from from the array to keep the batteries charged.

    So 136 AH would be the maximum battery bank this panel set up would charge effectively at their peak charge?

    What if I had a 225 AH 12v battery bank, that in reality was never exposed to enough power usage to really drain them all that much?

    When you say that 10% of the total battery AH should = the amps of charge from the panel, I'm assuming that this is necessary to have enough charge to return the batteries to fully charged.

    Therefore, say if I drained the batteries in one weekend from 225 Ah to 125 Ah. Assume I used 100 Ah that weekend, and upon evaluating my usage, I found that was the average and never more of a drain on the weekends, the panels would need to have enough amps to charge 100Ah throughout the following week while not in use and not the entire 225?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Yes, on a 12 Volt system three of those panels in parallel through a PWM controller would give you 3 * 4.55 Amps = 13.65 Amps max.

    On 225 Amp hours of battery the peak charge rate would be: 13.65 * 100 / 225 = 6%. Still acceptable, but any loads experienced during that time could severely deplete that rate making charge times longer. Possibly too long to complete in even a good day.

    The "it will recharge while I'm away" method (low panel to Amp hour ratio) can work, providing there's the 5% minimum charge rate and no loads drawn while charging. It becomes a problem if the DOD goes too high while you're using the panels (greater than 50%) or if the weather turns bad and the batteries haven't been fully recharged; the longer they spend partially charged, the faster the sulphation and shorter the battery life.

    It's not like they'll just drop dead in one cycle, but it will shave years off whatever potential (undetermined) life they had.
  • westbranchwestbranch Solar Expert Posts: 5,180 ✭✭✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    the draw you describe is the time to drag out that generator and do a bulk charge, time dependent on the charger, and let the PVs finish off the absorb and more specifically, and importantly, the float portion of the charge.

    you are getting the ideas down right so far, now the tricks of the trade come into play to keep your battery investment healthy...

    keep asking the questions.:cool:
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    westbranch wrote: »
    the draw you describe is the time to drag out that generator and do a bulk charge, time dependent on the charger, and let the PVs finish off the absorb and more specifically, and importantly, the float portion of the charge.

    you are getting the ideas down right so far, now the tricks of the trade come into play to keep your battery investment healthy...

    keep asking the questions.:cool:

    Thanks again for all the good advice guys

    I have been using this charger for my current system to charge the batteries with the generator

    Is this appropriate for the type of charging I need or do you suggest a different type of charger

    http://www.tractorsupply.com/schumacher-speedcharge-100-30-12-2a-4046951
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    From what I can tell despite its claims for "deep cycle" it is basically an automotive charger. As such it will not run through the Absorb stage. Fine for carrying on the "Bulk" stage if panels need help, but won't really do the full regime.

    Chargers that will are few, I'm afraid.
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Attachment not found.

    Please advise with any suggestions to this layout I have made

    Thanks
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Whoops.

    First, you don't get 12 Volts out of two 6 Volt batteries wired in parallel; they need to be in series.

    Your panel fusing is wrong for that configuration in that each panel needs a fuse before it connects with any other panels. It would go: panel --> fuse --> combiner (point where all panels come together). However if you're going to use the MS MPPT 15 you might as well put the panels in series: it will take up to 72 Volts input. This will simplify panel wiring and improve efficiency between the panels and controller (higher Voltage = lower V-drop for same size wire).

    Okay?
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Whoops I did know that about the batteries to be wired in series and not parallel. Not sure what happened there:confused: Got a little too excited

    If I wire in series I am unsure about the proper fuse placement.

    Does this look correct? Attachment not found.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Wire the panels in series and you don't need a fuse at all. The 15 Amp breaker will serve as a disconnect. Since the panels can't produce more than 5 Amps total there is little worry about over-current.
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    Wire the panels in series and you don't need a fuse at all. The 15 Amp breaker will serve as a disconnect. Since the panels can't produce more than 5 Amps total there is little worry about over-current.

    Okay. Really appreciate all the good info. So with This will simplify panel wiring and improve efficiency between the panels and controller (higher Voltage = lower V-drop for same size wire).

    Should I not be as concerned about increasing the amps from the panels to get the most charge for my batteries?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    Heisenberg wrote: »
    Okay. Really appreciate all the good info. So with This will simplify panel wiring and improve efficiency between the panels and controller (higher Voltage = lower V-drop for same size wire).

    Should I not be as concerned about increasing the amps from the panels to get the most charge for my batteries?

    The MPPT charge controller will do that for you; basically find the best Voltage * current to produce the maximum charging possible.
    With a PWM controller and the panels all in parallel the charge current is limited to panel current * the number of panels. About 13.6 in this case.
    With an MPPT controller it's more like panel Watts * efficiency derating / battery Voltage. About 15 (which is the controller's limit) in this case.

    This is really maxing out a 15 Amp controller, btw.
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    The MPPT charge controller will do that for you; basically find the best Voltage * current to produce the maximum charging possible.
    With a PWM controller and the panels all in parallel the charge current is limited to panel current * the number of panels. About 13.6 in this case.
    With an MPPT controller it's more like panel Watts * efficiency derating / battery Voltage. About 15 (which is the controller's limit) in this case.

    This is really maxing out a 15 Amp controller, btw.

    I appreciate you sharing all this knowledge. Would you mind suggesting a safe and cost effective solar panel combiner box. I was reading through some old threads regarding that topic. I am thinking of staying away from the AC QO combiner boxes as originally planned. With my array in series I would only need one spot in the box with a high enough rated breaker for the amps and voltage of all three panels correct?. What do you think of this one below or do you have any suggestions for one that would better suit my small set up?

    http://www.solar-electric.com/mnpv3.html
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    Heisenberg wrote: »
    I appreciate you sharing all this knowledge. Would you mind suggesting a safe and cost effective solar panel combiner box. I was reading through some old threads regarding that topic. I am thinking of staying away from the AC QO combiner boxes as originally planned. With my array in series I would only need one spot in the box with a high enough rated breaker for the amps and voltage of all three panels correct?. What do you think of this one below or do you have any suggestions for one that would better suit my small set up?

    http://www.solar-electric.com/mnpv3.html

    Or what about this combo

    http://www.solar-electric.com/baby-box.html

    http://www.solar-electric.com/mnepv.html (one of these)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    I would go with the latter, as all you really need is a disconnect. And it does allow for future expansion to some degree. Probably more than you will use. :D
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    I've been reading through threads on the subject of grounding and I am now more confused than I was before I began reading.

    I want to make sure I earth ground my panels and equipment properly and I realize this is a very detailed subject. I currently have no grounding on my system at all.

    I want to ground my solar panels frames to earth ground with my fear of lightning strikes
    My new true sine inverter has earth ground terminals on the dc side and indicates earth ground connected to the neutral output on the AC side
    My charge controller has a earth ground terminal as well

    Now, my current AC breaker panel was wired for my previous msw inverter to have no neutral/ground bond and is not earth grounded and would be considered a sub panel if I am correct?
    The input to my AC breaker panel has a plug wired to the end that I have been plugging and unplugging from the built in outlet on my msw inverter

    I was considering the following:

    Installing a ground rod or two into the earth and running the proper wire to a ground bus bar inside my cabin allowing multiple ground connections
    I would then connect the following to the bus bar that is connected to the ground rods:

    Solar panel frames
    Inverter DC input and AC output where indicated
    Charger controller where indicated

    Additionally, I was going to wire the inverter to it's own outlet to which I would plug and unplug my current breaker panel plug to and from, rather than wire it directly to the breaker panel.

    Any thoughts?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio

    Yes: grounding is confusing. :D
    Even those who know about this stuff can disagree, and then the Powers That Be throw some new regulations at you and it all changes again.

    What I would do (and others may disagree) is run 6 AWG from the panel frames/mounts directly down the side of the building to an Earth ground. That should reduce the problem of lightning-energized panel frames as much as can be done.

    The electrical safety ground is another matter, as there is both the AC and DC side to consider.

    Everything that has a grounding lug should be grounded to one point only (single point grounding). Ideally each with a separate wire leading to that point but that's not strictly necessary nor always practical.

    For true sine inverters it is okay to have the one, and only one, neutral-ground bond on the AC. With a modified square wave inverter it is best to avoid this N-G bond as most of them can't take it.

    The DC side gets tricky because the NEC now mandates DC GFCI. There have been several discussion about this on the forum, the conclusion to which seems to be that the way it is done isn't great and maybe it's best to not have it at all instead. In the "old days" we just tied negative to ground and that was it.

    The thing about grounding is that it does nothing until something goes wrong. Then if it isn't right, you find out about it in a potentially very bad way.

    As long as your inverter is small enough you can connect it to distribution with a standard plug (as in doesn't exceed 15 Amps output).

    Caveat: I'm about going nuts trying to keep up with code, so the contents of this post may not be right anymore.
  • HeisenbergHeisenberg Registered Users Posts: 21 ✭✭
    Re: Need Advice- Upgrading my off-grid solar system in Ohio
    Yes: grounding is confusing. :D
    Even those who know about this stuff can disagree, and then the Powers That Be throw some new regulations at you and it all changes again.

    What I would do (and others may disagree) is run 6 AWG from the panel frames/mounts directly down the side of the building to an Earth ground. That should reduce the problem of lightning-energized panel frames as much as can be done.

    The electrical safety ground is another matter, as there is both the AC and DC side to consider.

    Everything that has a grounding lug should be grounded to one point only (single point grounding). Ideally each with a separate wire leading to that point but that's not strictly necessary nor always practical.

    For true sine inverters it is okay to have the one, and only one, neutral-ground bond on the AC. With a modified square wave inverter it is best to avoid this N-G bond as most of them can't take it.

    The DC side gets tricky because the NEC now mandates DC GFCI. There have been several discussion about this on the forum, the conclusion to which seems to be that the way it is done isn't great and maybe it's best to not have it at all instead. In the "old days" we just tied negative to ground and that was it.

    The thing about grounding is that it does nothing until something goes wrong. Then if it isn't right, you find out about it in a potentially very bad way.

    As long as your inverter is small enough you can connect it to distribution with a standard plug (as in doesn't exceed 15 Amps output).

    Caveat: I'm about going nuts trying to keep up with code, so the contents of this post may not be right anymore.

    Okay, So for now I will run the 6awg from panel frames/mounts to earth ground

    The new inverter will be the Morningstar 300 true sine. It indicates a 3a inline fuse on the Black Ac output line, so I shouldn't have an issue wiring it to a standard plug then I assume.

    Does the neutral ground/bond already exist within this (morningstar 300) inverter itself, or does that occur if and when I would connect earth ground to the neutral ac output on the inverter as the diagram indicates?

    What if I just earth ground the panels (frame) and do not ground any equipment? Is this what they call a "floating system"?

    My solar "utility room" is approx 30ft from the ground in the cabin loft. It would get pretty expensive to "single point ground" each unit that has a grounding lug.
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