Grounding

Butch1952Butch1952 Registered Users Posts: 9 ✭✭
Hi Everyone,

I'm new to solar and I'm needing some info, I just have been collecting equipment to install an off-grid system. I've got 2 - 160 watt mono panels, the wire, a inverter and a mppt charge controller. The only thing is that I got everything thats negative ground except for the charge controller and its positive ground is there anyway to use this cc or am I going to have to buy a new negative ground cc. I've asked around and theres nobody around here that has ever deal with anything like this. I did have one guy say that I could just ground the battery and nothing else. That doesn't sound right to me. 

I would sure appreciate any info
Thanks 
Richard

Comments

  • westbranchwestbranch Solar Expert Posts: 5,138 ✭✭✭✭
    what is the make of MPPT CC and  inverter?  what did you pay for them?
     
    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
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    The Charge controller is a Epever Mppt Tracer and the inverter is Reliable inverter both Chinese made (cheap)
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    The cc was $150 dollars and I think the inverter was around the same price.

  • westbranchwestbranch Solar Expert Posts: 5,138 ✭✭✭✭
    so much of what is readily available is Neg ground,....... If me,  I would get another Charge controller to avoid any other Plus vs Neg.ground issues
     
    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
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    Thats what I figured  I should do. Thanks for the info

  • softdownsoftdown Solar Expert Posts: 2,184 ✭✭✭✭
    I would wait a day or two. BB will likely weigh in and tell you the exact possibilities. Grounding may be my weakest subject. Pretty much mastered the rest. :D
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    Thanks softdown if there is a way it would save me a little bit of money.
  • softdownsoftdown Solar Expert Posts: 2,184 ✭✭✭✭
    There are several other quite knowledgeable posters. Its just that I tend to trust someone who isn't selling their service, or way of thinking, a bit more. We have, for example, at least one poster with several decades of experience in selling solar. A large percentage of their ads, I mean comments, could be used in an ad.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    Thanks again softdown I will keep my eyes open for replies.
     By the way can a off grid system be pluged into a transfer box the one I use for my generator?

    Richard
  • softdownsoftdown Solar Expert Posts: 2,184 ✭✭✭✭
    You need to tell us more than "transfer box for my genset."
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    I have a Connecticut Electric Emer Gen Switch  30 amp 125/250 VAC Nema L14-30. Its a 6 position with 2 position barred together for 220. 4 positions 110 15 amp.
    The generator I have is a Generac 5250 surge watts and 4200 rated watts. I was just wondering if a small off grid solar system could be plugged into the transfer switch like I do my generator when I have no power during storms.
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    I emailed epever about my charge controller and ask them this 
    I bought one of your MPPT solar charge controller (Tracer 40 amp) all of my equipment is negative ground and your cc is positive ground I really love your cc. Is there a way to change your controller from positive ground to negative ground? Thanks Richard
         留言时间:2016-11-17
    Mary.Ma
    International Sales Department
    And this is was their reply,
    Hello Sir,
    It can't be change, but if you want negative ground, only one of the three terminal can negative ground, other terminal include positive can't ground.
    Thanks~!
    I'm not really understanding what they are saying.

    Does anybody know what they are actually saying?

    Help please.
    Richard
  • BB.BB. Super Moderators, Administrators Posts: 29,054 admin
    I believe this is the answer (from the manual):

    http://www.epsolarpv.com/en/index.php/Technical/downloadF/id/678
    4) The Tracer-A series is a positive ground controller. Any positive connection of solar, load or battery can be earth grounded as required.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Butch1952Butch1952 Registered Users Posts: 9 ✭✭
    Thanks BB
  • get2anthonyget2anthony Registered Users Posts: 1

    So, I certainly understand the positive grounding on the charge controller side (with the EPEVER A4210). All dc loads, solar panels, battery and charge controller need to be positively grounded. Understood, no problem.

    Even though this is an off grid system, the question remains, how do I ground the 120V AC side (and the inverter) since it is designed (and required by code) to be negatively grounded? This seems incorrect that you could have positive grounds on the DC side and negative grounds on the AC side. But, if not, would you bond those grounds? Again, seems like you would have a ground potential between the two and defeat the purpose.

    Thanks for any input!

    -Anthony

  • EstragonEstragon Registered Users Posts: 3,621 ✭✭✭✭✭

    There is no negative ground on the AC side. If ground bonded, the neutral is held near 0v with respect to ground, while hot(s) vary in voltage + and - for 120v. Neutral grounded, not negative.

    My understanding in an isolated inverter (many/most PSW?), with no direct connection between the AC and DC sides, the AC neutral can be bonded to ground.

    In a non-isolated inverter (many/most MSW and string inverters?), a bond creates a parallel circuit path (short through inverter and dc ground). These seem to "float" either the AC side (unbonded neutral, eg. PSW inverter), or DC side (both + and - are "hot", neither is grounded, eg. string inverter).

    Your inverter is presumably an isolated type, designed to have both AC and DC grounded, so the AC bond isn't the issue.

    The DC side might be though. In positive grounded (negative voltage) DC systems, as is/was common in telco systems, my understanding is negative ground (positive voltage) equipment is powered through isolated DC/DC converters to avoid creating a near-short through a ground connection. I'm not sure if this isolation is needed in this case, and likely depends on specifics of the inverter and related wiring.

    An example of +ive ground issue (specific to OB gear, may or may not apply to yours):


    http://www.outbackpower.com/downloads/documents/appnotes/Positive_Grounding_of_OutBack_Devices_Rev2.pdf

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • TecnodaveTecnodave Registered Users Posts: 390 ✭✭✭✭

    The inverter in question probably is not UL or NRTL listed as it is an inexpensive inverter. Most if not all inexpensive inverters are high frequency inverters and as such inputs are in common with outputs. There is no low frequency transformers. There is no way to ground the either side of the AC output to ground. The positive ground controller is a rarity and should be avoided if possible. Negative ground is the standard. The combination of positive ground and the inverter make this installation not practical. Just my opinion..........d

    2 Classic 150, 2 Kid, 5 arrays 7.5 kw total  2ea.  2S6P Sharp NE-170/NE-165, 1ea. 12P Sanyo HIT 200,  2ea. 4/6P Sanyo HIT 200, MagnaSine MS4024AE, Cotek SK-1500,Exeltech 1100,  2 Banks L-16 battery, Rolls-Surette S-530 and Interstate Traction, Shunts with whizbangJr and Bogart Tri-Metric, iCharger i208B  dc-dc buck/boost converter with BMS for small form lithium 8S 16650 or 10S LiFePO4,
  • TecnodaveTecnodave Registered Users Posts: 390 ✭✭✭✭

    @Estragon,

    The isolated dc-DC converters were used in communications where there was a 48 volt ma bell bank of power to power our 12 volt radio system, can't remember what we used there, been too long @ Motorola & GE

    2 Classic 150, 2 Kid, 5 arrays 7.5 kw total  2ea.  2S6P Sharp NE-170/NE-165, 1ea. 12P Sanyo HIT 200,  2ea. 4/6P Sanyo HIT 200, MagnaSine MS4024AE, Cotek SK-1500,Exeltech 1100,  2 Banks L-16 battery, Rolls-Surette S-530 and Interstate Traction, Shunts with whizbangJr and Bogart Tri-Metric, iCharger i208B  dc-dc buck/boost converter with BMS for small form lithium 8S 16650 or 10S LiFePO4,
  • EstragonEstragon Registered Users Posts: 3,621 ✭✭✭✭✭

    @Tecnodave - I didn't see a specific inverter mentioned by @get2anthony , and the epever didn't appear to be a controller-inverter combo thing.

    Agree that +ive ground is rare (outside of telecom) and best avoided.

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • TecnodaveTecnodave Registered Users Posts: 390 ✭✭✭✭

    @Estragon,

    @get2anthony only mentioned Chinese below $150, that probably is going a high frequency switcher that does not isolates input and output. The EP EVER TRACER is from EPSolar technology ,Shengdeng,China. I had several tracers and disposed of them. they were not accurately calibrate do nd could not top off my batteries , I had to run a generator. I had never heard of them selling a positive ground unit, new home do now I no user settings

    2 Classic 150, 2 Kid, 5 arrays 7.5 kw total  2ea.  2S6P Sharp NE-170/NE-165, 1ea. 12P Sanyo HIT 200,  2ea. 4/6P Sanyo HIT 200, MagnaSine MS4024AE, Cotek SK-1500,Exeltech 1100,  2 Banks L-16 battery, Rolls-Surette S-530 and Interstate Traction, Shunts with whizbangJr and Bogart Tri-Metric, iCharger i208B  dc-dc buck/boost converter with BMS for small form lithium 8S 16650 or 10S LiFePO4,
  • EstragonEstragon Registered Users Posts: 3,621 ✭✭✭✭✭

    I think the $150 inverter was a different poster?

    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • TecnodaveTecnodave Registered Users Posts: 390 ✭✭✭✭

    My bad, reading too many posts

    2 Classic 150, 2 Kid, 5 arrays 7.5 kw total  2ea.  2S6P Sharp NE-170/NE-165, 1ea. 12P Sanyo HIT 200,  2ea. 4/6P Sanyo HIT 200, MagnaSine MS4024AE, Cotek SK-1500,Exeltech 1100,  2 Banks L-16 battery, Rolls-Surette S-530 and Interstate Traction, Shunts with whizbangJr and Bogart Tri-Metric, iCharger i208B  dc-dc buck/boost converter with BMS for small form lithium 8S 16650 or 10S LiFePO4,
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