Expectations Exceeded - thanks to this forum

Coach Dad
Coach Dad Solar Expert Posts: 154 ✭✭
in Off Grid Solar & Battery Systems #1
My off grid solar electric system has been running for about a month now and I'm very impressed. The system has exceeded my expectations.

I owe a lot of the success of this installation to the people on this forum. I've been reading this forum and planning things for almost 2 years before taking the plung. While I didn't post too much, the few questions I had were answered and corrective measures were taken.
My thanks to: Cariboocoot, BB, neil, solarevolution...
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Expectations Exceeded - thanks to this forum

    Coach,

    Please feel free to document your system as it stands now and what you are running/how much power you are using per day, etc...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Coach Dad
    Coach Dad Solar Expert Posts: 154 ✭✭
    #3
    Re: Expectations Exceeded - thanks to this forum

    My System
    6- 235w Trina panels (TSM-235PA05) wired in 2 series strings of 3.
    2- Pole mounts (mounted on 2 homemade pole mounts (Lots of welding.) Plan is to change the angle 4 times per year
    1- TriStar MPPT60 charge controller with TS-RM-2 meter and using custom settings via MS-view software.
    1- Magnum MS4024PAE inverter with ME-BMK battery monitor kit and ME-ARC remote control
    4- PVX3050T 6 volt 305AH AGM Sun-Xtender batteries wired in series for 24 volts @ 305ah.
    1- MidNite solar MNDC250 panel with 250 amp breaker, 30 amp breaker for the TriStar input, 80 amp breaker (GFP) for Tristar output
    1- DC (Delta LA-602) lightning arrestor at the DC panel
    1- AC (Delta LA-302R) lightning arrestor at the AC panel

    Here is my block diagram
    Attachment not found.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Expectations Exceeded - thanks to this forum

    Thank you very much Coach Dad for documenting your system. I am sure it will be helpful to others.

    A couple quick questions/suggestions...

    First, did you earth ground your battery bank negative bus to the ground rod?

    Second, on the + battery voltage sense lead back to the MorningStar TS solar charge controller--It may be overkill, but you may want to think about placing a small fuse near the battery bank (1 amp or smaller, in industry, we would use a flame proof resistor. Typically the current is very low for sense voltage and a resistor would protect against excess current). If the battery voltage sense wire is ever shorted, it could overheat the sense wire. If the sense wires are well protected mechanically, a fuse may be overkill (but, with safety, overkill is not a bad thing).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Coach Dad
    Coach Dad Solar Expert Posts: 154 ✭✭
    #5
    Re: Expectations Exceeded - thanks to this forum

    Hi Bill,
    -No I didn't ground my battery negative.. The instructions specifically stated that.. I shouldn't do so if I'm using a GFP.. This is what the instructions say...
    Attachment not found.
    But I did use the DC panel as my ground tie point. Is this OK????

    - Adding a fuse to the TriStar sense wire is a good idea. I will do it the next time I'm at the cabin. I'm surprised that TriStar doesn't suggest that in their instructions.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #6
    Re: Expectations Exceeded - thanks to this forum

    Are you using a DC GFP breaker setup--I did not see one in your drawing? (I do not believe that the DC GFP is a good ideal. I think it is unsafe).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Coach Dad
    Coach Dad Solar Expert Posts: 154 ✭✭
    #7
    Re: Expectations Exceeded - thanks to this forum

    Hi Bill
    I didn't draw the GFP into the drawing because I didn't know how to draw it until AFTER I installed it and I didn't go back and update the drawing,,,, but I listed it on my list.

    the bigger question is,,, WHY do you think it is unsafe?
    the second question is,,, isn't it required by NEC?
    Please let me know... because safety is important to me.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #8
    Re: Expectations Exceeded - thanks to this forum

    Here is a long thread, plus a white paper I wrote on the issue:


    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Coach Dad
    Coach Dad Solar Expert Posts: 154 ✭✭
    #9
    Re: Expectations Exceeded - thanks to this forum

    Bill, thanks for the link regarding the GFP....
    There is a ton of good information in it. You should turn that into a sticky in the advanced solar electric forum…

    Did you ever get a reply from NEC?

    The final consensus on the forum is that the GFP should not be used.

    Just to be clear,,, If I remove the GFP, I should ground the “Battery side of the SHUNT” to my ground bus, NOT the “Load side of the SHUNT”… Correct?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #10
    Re: Expectations Exceeded - thanks to this forum

    Thank you for the kind words Coach.

    No, I never did get an "official" reply after I wrote the paper... One person on the forum did ask and it came back that I was using non-US standards in my discussion, so what I wrote did not apply (not correct--I was arguing physics and engineering principles and consequences of of the US requirements).

    In regards to shunts... In general, the shunt is on the Negative side of the battery bank (assuming negative/Earth/Safety grounding of the battery bank). This is done (at least from my guess) to keep all of the shunt connections near ground (if a meter sense lead or exposed shunt is shorted/touched, there is no hazardous current flow because the shunt is essentially at ground).

    So, when connecting the shunt, you connect one end of the shunt the battery negative terminal (or common negative connection of the battery bank). And the other end of the shunt is connected to safety ground. The grounded end of the shunt is now the "battery bus negative/return common).

    This allows the shunt to measure (or "see") all current flow though the battery bank. If you were to connect any return leads to the other side of the shunt (battery to shunt connection), then those loads (or charging sources) would bypass the shunt and will be "missed" by the battery monitoring system.

    Note, if you do not DC earth bond the system, every thing above still applies (connect the loads/charging sources on the "not battery" side of the shunt so that all current through the battery bank is "seen" by the shunt).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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