Poway Off Grid Solar Panel Upgrade

bwoltz
bwoltz Registered Users Posts: 23 ✭
in Off Grid Solar & Battery Systems #1
Current System

Trace 4024 Inverter
Trace C40 PWM Charge Controller tied to 12 95 watt photowatt panels on a pole.. (use to have tracking but tracking system damaged by high winds)
Outback MX60 MPPT connected to 12 90 watt BPs on a tracker..
The Trace interconnect box and mouning panel with transfer switch.
12 Trojan L16P-2V
Onan NHD 6500 converted to propane. (about 6600 hours on it)


Here are pictures of the system

Attachment not found.

HU2.jpg

I plan on using 10 SW230 panels and a Midnite 150 MPPT charge controller.. Here is the calcs from Midnite

MidnightC150data.png

I also plan to add a battery monitor, and will also add a network hub with wifi to network to the house but here is the BOM of Wind and Sun stuff. Will use 4 gauge for most of the heavy wiring.. Panel breakers to input breaker wires will be 4 gauge wire about 40 feet long.. If you look at the picture of the system there will be 2 5 panel racks ground mounted to the left of the left tracker. The below list does not include PVC conduit or some misc stuff like terninal lugs that I plan to get locally..

UpgradeBOM.jpg

The system currently will power the house and keep the batteries charged if we conserve during the summer.. Winter is another story... Doubling the solar power should reduce the 300 hours that the genset runs to about 50.. Which should save me about $1000 in propane each year..

Thanks for any comments.

Bruce
HU1.jpg 47.2K
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Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Poway Off Grid Solar Panel Upgrade

    it may pay for you to up the wire thickness as a 40ft run of wire at 80a and at about 59v vmp shows a v drop % of about 3.4% and that is only that section of wire. v drop percents elsewhere will add to this v drop percent making things worse. #2 would show about 2.16% which is closer to, but not under the 2% many here would recommend. ftr #0 would show about 1.36%.

    you could get fancy to save a few $ and put #0 on the - and #2 on the + to give you 1.76% for the v drop total on that section.
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #3
    Re: Poway Off Grid Solar Panel Upgrade

    Neal,

    First off, thanks for taking a look at this proposed build.. It's always good to have another set of eyes..

    I suspect that you might have read the wrong numbers off the Midnite solar sheet.. Unless I'm missing something wouldn't the MPPT current be about 38.6 amps? Short circuit a little more..

    One thing is the sizing of the breakers.. I'm thinking the ones at the solar array only need to be about 12 amp breakers and input to the MPPT about 60.. This is sized 150% to the source but in reality all you are protecting is the wire with the breakers and providing a disconnect.

    I know I'm being lazy with the wire size choice.. #4 is the largest size that the terminals on the midnight solar can accommodate.. I hate adding a connection to reduce a wire from #2 to #4..

    Thanks again.

    Bruce
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #4
    Re: Poway Off Grid Solar Panel Upgrade
    bwoltz wrote: »
    Unless I'm missing something wouldn't the MPPT current be about 38.6 amps? Short circuit a little more..

    You're not missing something.

    Its funny how location affects the way people see things... the first thing I noticed on your current array was that your panels were mounted in portrait orientation. Around here (snow country) we would find a way to mount them in landscape orientation.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
    Re: Poway Off Grid Solar Panel Upgrade

    bwoltz,
    you are correct that i looked at the wrong set of numbers. they say your eyes are the first to go.:confused: i got 1.65% putting in the correct number.

    btw, if a larger run wire would've been needed, the #4 minimum isn't really a big problem as all one needs is a small bus connection to go from the larger run wire down to the #4 which would now be a smaller jumper wire. it could also be a nut and bolt arrangement with a few washers if the wires end in lug connections.
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #6
    Re: Poway Off Grid Solar Panel Upgrade

    I suppose that I could use these..

    http://www.solar-electric.com/16220-2.html

    Still I'll probably go with the 4 since it's easier for these old hands to work..

    Thanks,

    Bruce
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #7
    Re: Poway Off Grid Solar Panel Upgrade

    FWIW,

    I ordered the above stuff along with the panels..

    I changed the order slightly. I decreased the combiner breakers to 12 amp, Midnite input breaker to 60 amps and chose the combiner has an external disconnect lever. I'm not sure the disconnect is needed as the panels don't feed into the house but into the shed.. The 2008 NEC seems a little vague here.. 15 years ago when this system was originally built, I suspect that the NEC had very little to say about off grid PV systems.. I would have preferred the system to be 48 volts at that time but the contractor was concerned about the ground fault requirements at the time and I was doing all I could to get the shed done plus handle the genset.. plus working long hours at my regular job..

    Bruce
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #8
    Re: Poway Off Grid Solar Panel Upgrade

    Sort update.

    1. The Outback battery monitor requires a newer version MX60 to Get it's power than what I have.. I think it's now called the MEX60.. Also needed which I missed was the display and hub.. I was able to return the Outback Battery monitor and purchased the Pentametric Display and system monitor. (Thanks NAWS!)

    2. Presented plans to Poway and they were approved.

    3. Bored the holes on the ground it and S150 bobcat and 12 inch auger.. The footing plans called for 40 inch deep 12 inch holes.. 6 for each set of panels. Probably way over kill for a system that will weight less then 350lbs each.. (2 sets) I suspect that this was due to me picking the wrong soil type (too soft).. Even if I only had to cut 24 inch deep holes the the bobcat rental would have been the same.. So I'm paying for a little more concrete.. The ground is hard DG and doing it by hand or with a handheld power auger would have been murder. As it is the outside teeth on the auger were worn to nothing after 12 holes..

    Bruce
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #9
    Re: Poway Off Grid Solar Panel Upgrade

    sounds like you're well on your way with it. let us know how it works out for you as we like success stories too and not just problems people present to us.

    the auger was rented too? worn auger = you bought it or did they cut you a break on it?
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #10
    Re: Poway Off Grid Solar Panel Upgrade

    The auger was part of the rental along with the motor that drives the auger.. Motor runs off the Bobcats hydraulic system.. I suspect that that they'll just reweld the teeth and use it again..

    Passed the footing and underground electrical inspection with the city yesterday.. Pumped cement today..
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  • rplarry
    rplarry Solar Expert Posts: 203 ✭✭
    #11
    Re: Poway Off Grid Solar Panel Upgrade

    Bruce
    Just curious what made you decide to go off grid in Poway? I have a house in University city not far from you and as far as I know grid power is available there. I admire your decision, but most people balk at the expense of a solar system.
    Larry
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #12
    Re: Poway Off Grid Solar Panel Upgrade

    There is power all around me.. Just none eased to my property.. Kind of a long story but as the house was being built, property owners on one side wouldn't let me drag a line along and existing road easement even tho the road was the only thing on the land. On the other side, the owner wanted money way above the cost of the system..

    Bruce
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #13
    Re: Poway Off Grid Solar Panel Upgrade

    Here are some pictures of the construction including the worn out auger..

    Buddy working hard.

    Boreholes.jpg

    Auger

    Wornauger.jpg

    Foundation done..

    foundationdone.jpg

    Start of wiring for the Classic.

    Classic.jpg
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #14
    Re: Poway Off Grid Solar Panel Upgrade

    you aren't kidding worn out. i bet those final holes took quite some time with it like that.
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  • bwoltz
    bwoltz Registered Users Posts: 23 ✭
    #15
    Re: Poway Off Grid Solar Panel Upgrade

    Well the system is pretty much done.. I got my money's worth on the bobcat..

    You can see that I'm running 3 different charge controllers. A C40, MX60 and classic 150.. I adjust the MX60 and Classic to different absorb and float voltages so they don't get confused while trying to do the MPPT thing.. The C40 is pretty dumb so it don't have a problem.. The batteries are pretty much charged by 11am right now..

    Added a Pentametric battery monitor and it seems to be doing pretty well.. Take a little getting used to on the programming but isn't that bad.. Batteries only drop about to 80-85% over night when sing the TV, computer lights and fans..

    PowerPanel_zps2bb3f1fe.jpg

    PowerPanel1_zps1ea8bb23.jpg

    Therack.jpg
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  • LOTW
    LOTW Solar Expert Posts: 25 ✭
    #16
    Re: Poway Off Grid Solar Panel Upgrade

    Hey there, just wondering what kit you used to convert the generator? I just bought the same machine, (gas), and want to convert it to propane, after I get the ignition problem fixed. Originally thought I would buy the onan oem propane carb, but seems to be discontinued or something. Did you use an aftermarket kit? Did you remove the entire auto choke situation?
    bwoltz wrote: »
    Current System

    Trace 4024 Inverter
    Trace C40 PWM Charge Controller tied to 12 95 watt photowatt panels on a pole.. (use to have tracking but tracking system damaged by high winds)
    Outback MX60 MPPT connected to 12 90 watt BPs on a tracker..
    The Trace interconnect box and mouning panel with transfer switch.
    12 Trojan L16P-2V
    Onan NHD 6500 converted to propane. (about 6600 hours on it)


    Here are pictures of the system

    Attachment not found.

    HU2.jpg

    I plan on using 10 SW230 panels and a Midnite 150 MPPT charge controller.. Here is the calcs from Midnite

    MidnightC150data.png

    I also plan to add a battery monitor, and will also add a network hub with wifi to network to the house but here is the BOM of Wind and Sun stuff. Will use 4 gauge for most of the heavy wiring.. Panel breakers to input breaker wires will be 4 gauge wire about 40 feet long.. If you look at the picture of the system there will be 2 5 panel racks ground mounted to the left of the left tracker. The below list does not include PVC conduit or some misc stuff like terninal lugs that I plan to get locally..

    UpgradeBOM.jpg

    The system currently will power the house and keep the batteries charged if we conserve during the summer.. Winter is another story... Doubling the solar power should reduce the 300 hours that the genset runs to about 50.. Which should save me about $1000 in propane each year..

    Thanks for any comments.

    Bruce
    · Share on Twitter

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