schematic

So lets say i have a
100W panel and
6 12V 75amp-hr batteries and
a charge controller and
a 2000W generator and
a 600W inverter and
a 16amp AC charger to plug into the generator and
a bunch of heavy gauge wire and
a trailer that needs AC.

I can figure out how large the wire needs to be at any given spot, and i will oversize it anyway. i know that in order to get 12V out of my 6 12V batteries, i need to hook them up in parallel.

i think that i want to hook my charge controller to the positive at one end of my battery string and the negative at the other end so that i go across the whole bank.

at the each end of my string of batteries there are two terminals, one positive and one negative. lets call them p1 and n1 (at one end of the battery bank), p2 and n2 (at the other end).

lets say that i am going to hook my charge controller to p1 and n2.

question one: should i hook my generator to p1/n2 or to p2/n1?

question two: can i run the generator with the solar charge controller hooked up and charging?

question three: should the inverter be hooked to the same terminals as either the charge contrller or the generator or neither or both?

question four: can i skip the AC charger from the generator and just run the generator output to my solar charge controller (assuming that the CC has enough capacity for the generator and the panels at the same time)? is there an argument against doing that?

question five: i will ground my solar panel frame using the provided terminal, but do i need to provide any other ground protection on the DC side?

question six: is there any problem with just slamming a big copper rod in the ground and hooking my bare-wire ground from the trailer on it to protect the AC side of things?

thanks!

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,433 admin
    Re: schematic

    I will take a shot at a few of your questions:
    kingfisher wrote: »
    So lets say i have a
    100W panel and
    6 12V 75amp-hr batteries and
    a charge controller and
    a 2000W generator and
    a 600W inverter and
    a 16amp AC charger to plug into the generator and
    a bunch of heavy gauge wire and
    a trailer that needs AC.

    I can figure out how large the wire needs to be at any given spot, and i will oversize it anyway. i know that in order to get 12V out of my 6 12V batteries, i need to hook them up in parallel.
    Wire gauge needs to be able to handle the current, but you will need to fuse/circuit breaker the wire(s) before they get routed outside of the battery box (anywhere the wires and chafe, cut, short).
    i think that i want to hook my charge controller to the positive at one end of my battery string and the negative at the other end so that i go across the whole bank.

    at the each end of my string of batteries there are two terminals, one positive and one negative. lets call them p1 and n1 (at one end of the battery bank), p2 and n2 (at the other end).

    lets say that i am going to hook my charge controller to p1 and n2.

    question one: should i hook my generator to p1/n2 or to p2/n1?
    My suggestion would be to connect all positive loads to the same point.

    For the ground, you will probably want to connect from n2 to load shunt to ground/ground bus... Having all current go through one point allows you to monitor current into and out of the battery bank. Ideally, then connect with a battery monitor so that you can know the state of charge of your battery all the time. Kind of like your fuel gauge in your gas tank.
    question two: can i run the generator with the solar charge controller hooked up and charging?
    Assuming all of the wires are correct and the battery chargers are correctly adjusted for battery type, temperature compensated, etc.--no problem. You will probably want your generator to charge up to 90-95% state of charge and let the solar panels charge the last bit.
    question three: should the inverter be hooked to the same terminals as either the charge controller or the generator or neither or both?
    See above--all connections to connect back to one point/bus bar (appropriately sized and fused). If there is a choice, the chargers should have the "best connection" point to the battery (if not using sense leads--most accurate battery voltage).
    question four: can i skip the AC charger from the generator and just run the generator output to my solar charge controller (assuming that the CC has enough capacity for the generator and the panels at the same time)? is there an argument against doing that?
    Not sure what you are asking--You have a 2kW AC generator--you need something to create ~17vdc... Your generator may have a 12v @ 10amp output (like a Honda eu2000i)--generally those outputs will not work correctly when connected through a charge controller (IIRC there is a warning in my eu2000i instructions that say direct connect to battery... Although, I am sure it is not a multi-stage battery charger--so it is not really useful except in an emergency).

    If you want to connect a car type Alternator through your charge controller--that will not work either... Car alternators have their own charge controller and won't pass current through the charge controller--plus if regulator is bypassed, the alternator "disconnected" voltage can easily reach over 100 volts and cause other damage.
    question five: i will ground my solar panel frame using the provided terminal, but do i need to provide any other ground protection on the DC side?
    The solar panel frame ground is for lightening protection--you can attach the frame ground to your trailer ground. Probably a good idea--but if your panels get hit by lightening, you will still be in a world of hurt.
    question six: is there any problem with just slamming a big copper rod in the ground and hooking my bare-wire ground from the trailer on it to protect the AC side of things?
    We have had lots of discussions about lightening grounds... My 2 cents. Don't worry about it unless you are planning on being on site for months at a time. Even then, this will only really help if you have, for example, extension cords to items outside of the trailer (water pump, tv, radio, lights, etc.)... And even then, if there is lightening in the forecast--you should disconnect the external cords anyway as anything can get a strike (not just your trailer). Also, unless this is your permanent site (i.e., vacation property), it can be pretty difficult to get a useful ground (rocks, dry ground, etc.) without multiple rods/and or 8' rods.

    Your DC battery side will be grounded to the trailer chassis. Your inverter will have a DC safety ground. The AC neutral is grounded in home wiring and can be done with a true sine wave inverter, but cannot be done with a MOD square wave inverter--just leave the AC side alone. Not worth the worry or protection. AC grounded neutral on your trailer will probably not protect against lightening.

    By the way, the 100 watts of solar panels with all of those batteries will not handle much day to day load and will be more like an oversized trickle charger. Your generator/charger will provide almost 100% of your daily loads.

    Do you have an idea of what your daily loads will be? It is possible that 6 x 12volt batteries are really overkill for your application unless you are going to draw lots of power and use your generator a lot to provide power (and then, it may make more sense to just fire up the generator for your loads--except small lighting and radio type loads at night).

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