Battery banks for grid tie feedin

[russ_drinkwater]

I was speaking to an installer who does after installation/retro battery banks to grid tie systems.
The grid tie inverters draw from the battery banks after sundown and feed in when the tarriff payment is at
its peak. Ours is at 44 cents per kw.
Does anyone have any experience with these systems?
Apparently it does not void the original contract.

[russ_drinkwater]

No-one?

[ClassicCrazy]

Seems like you would have to have a very large battery bank. And if you were drawing it down like to 50% or more than that  you would certainly decrease the longevity  of your battery life. So not sure if it would be worth the extra $$ you make selling power back compared to how much batteries cost.

Larry

[russ_drinkwater]

I have the idea they are using tesla powerwalls for the plan.
Seemed like a financial gain for them and not a lot for me.

[bee88man]

Concept is good, substitute the storage to something other than the undurable batteries and you may have a winner...

[CDN-VT]

Water wheel or turbine ..
Solar here  is iffy in the winter on the WET COAST

VT

[ClassicCrazy]

Simple storage - pump the water up on top of a mountain and then use the water and pressure  to run a turbine at night and get the good rate.
Nothing to it eh ?

Larry

[russ_drinkwater]

We have a 30,000 gravity feed water tank to the houses but the flow would be intermittent at best.
The gold standard would be a 5kw wind turbine running to grid feed, but the ones I have seen are
less reliable than solar and have a lower output.
I will bite the bullet and ring him to see the the hard sell costs are for a laugh.

[mike90045]

Seems like you would have to have a very large battery bank. And if you were drawing it down like to 50% or more than that  you would certainly decrease the longevity  of your battery life. So not sure if it would be worth the extra $$ you make selling power back compared to how much batteries cost.

Larry

works good for the folks selling batteries, but your electricity savings will not likely be enough to buy a new bank

[russ_drinkwater]

Yes there is always a gain for the seller.
On the other hand Latronics here in australia make a small hybrid grid tie inverter.
It is 48 volt which is one of the lower end fire up voltage inverters.
It is only 1.1kw, but you can connect a 48 volt battery system into it and
it will charge the batteries and then feed the rest of the solar input into the grid system.
When the solar input drops off below power production levels the inverter will draw from the battery bank and continue
to grid feed. Once the battery voltage drops to 48 volts the inverter will shutdown feed until the morning sun
starts the solar cycle again.
I have bought a few of these for pennies ($200 posted) and they work a treat.
Have not yet tried the battery charge/feed in system yet.