Question on a "different" setup

[Ntrain2k]

I'm planning on my future setup and am looking at a slightly different way of doing things.

I'm wanting to use a charge controller that will divert to a grid tied inverter when the batteries are charged, but monitor and switch back to the batteries.

Another possibility is one that will divert to a second bank rather then a grid tied invertor.

Is there an "affordable" unit that will do this, or is there a circuit that can be built to handle it prior to going to a standard charge controller?

TIA for thoughts and replies.

[kurt]

you can buy grid tie inverters that hook directly to your battery bank and go into sell mode when the batteries are full and stops selling at a voltage point you set you could set it up sorta like a diversion controller except it sells back to the grid instead of dumping to a dump load resistor of some kind.  you would then just hook your solar directly to the battery bank and have a separate diversion controller and dump load in case the grid goes down.  

i think you are over thinking the plumbing trying to do it the way you are thinking.

[Ntrain2k]

I'm not wanting the batteries used for the grid in any way at all. They are for a separate system.

[ghurd]

They became a single system with "a charge controller that will divert to a grid tied inverter when the batteries are charged".

G-

[Ntrain2k]

"Another possibility is one that will divert to a second bank rather then a grid tied invertor."

I want none of the stored power going to the grid.Only any possible excess not needed for charging.

Better way to put it?

[TomW]

2K;

Maybe you should back up a few furlongs and explain what the motivation is and why you want to go this route?

Just a thought since you seem to have a strange set of "needs". I always find it easier to offer advice based on what is needed rather than the preconceived notion of what they "want" of the person seeking advice. if that makes sense?

Tom

[ghurd]

We understood what you want.

What you are asking for is not different at all.  It is a standard system.

The stored power is not going to the grid.  Only the "extra power" goes to the grid.

Otherwise the inverter would run the batteries flat, which a decent GT inverter will NOT do, because that is not what anybody wants to do.

Two general choices.

First is a battery charging RE system that sends the extra power to the grid.

Second, pretty much sends all the power to the grid, only keeping enough to keep the batteries full.

Either way, the RE keeps the battery full, and anything beyond that, the excess, goes into the grid.  The steps may be in a little different order, but the end result is about the same (full batteries with the excess going to the grid).

You seem dead set against #2, but I figure it is probably more efficient for anything large enough to bother with grid tie.

That type of inverter tends to have a higher voltage input, so less conversion and line losses.

I have a feeling by "affordable", you mean those non-UL listed things, and you read they took the 24V bank flat.  That is because the dudes selling those things seem to have no idea how they were intended to actually work in a real system.

Unless there is a real good reason to have 2 battery banks (like one bank is a 19.2V nicd or something), then it is more efficient to combine both banks into a single bank.

If there is a good reason to have 2 battery banks, the second bank still needs it's own dump load controller.

[Ntrain2k]

So a standard charge controller will do both 3 stage charging, as well as diversion?

My intention is to replace as much as possible in the household with DC and inverter power. I don't have the budget to completely replace grid power, but it's another step in the right direction.

So far I have the lights, tv and computer taken care of. I have a DC fridge, just not hooked up yet.

I just want to make sure my battery bank is the priority, then any extra I'd like to feed back to the grid, UL if I can find a unit that will work in this configuration. I'm not worried about getting a check from the power company, but if I have a little excess that can offset what I do use, I'd like to get it if possible.

Thanks

[ghurd]

"So a standard charge controller will do both 3 stage charging, as well as diversion?"

How should we know which one you picked, it's intended parameters, or how you will decide to configure it?

My wife wants a new car.  She likes the blue one, with a hint of turquoise, and it can look a bit pearl under HID lighting.  It has aluminum mag wheels and cup holders.  It is cool.

How many gallons of gas will it use if she only drives it to work?

How much will the insurance company charge me for full coverage, with a $250 deductible?

Would the blue one be better than the green one I like?

That is pretty much what you are asking.

"UL if I can find a unit that will work in this configuration".

Look harder.  

They are common, except on ebay.  Any reputable dealer/manufacturer will have info.

Connect the DC fridge.

The good ones are impressive.

[Ntrain2k]

""So a standard charge controller will do both 3 stage charging, as well as diversion?"

How should we know which one you picked, it's intended parameters, or how you will decide to configure it?"

I have not picked one, I asked in my original post if one exists that will do what I am looking for.

Do you have a suggestion(s)?

Thank you.