Can grid-tie solar inverters run on batteries instead of photovoltaic panels?

[akansh]

Can grid-tie solar inverters run on batteries instead of photovoltaic panels?

My question is can I replace the solar panels that are connected to my grid tie (on grid) solar inverters with similar voltage batteries?(Like hooking up batteries to the terminals where solar panels go)

3kw - 260ish volt on DC (VMP) The minimum operating voltage on my inverter is 160v

I charge my batteries using a separate MPPT charge controller and it doesn't have to be
(solar + batteries), it can be (solar or batteries)
Like morning 8-4 solar and evening 4-8 batteries

Is there any way to make this arrangement work? Converting on-grid inverter to battery powered inverter when the sun goes down while making sure no power goes to the grid

"My inverter (similar mine is 3kw) -https://www.upsinverter.com/product/3-6-kw-utl-on-grid-solar-inverter-2/?gad_source=1&gclid=Cj0KCQiAz6q-BhCfARIsAOezPxk2TD-TATgqNts8IZNbKAeI6ndOUcC7ojeKAJExrgs7JV3a6qbhKKIaAuDVEALw_wcB

I have a 3kw on grid system connected to my utility and the inverter has a current limiter functionality to make sure no power goes to the grid, the inverter doesn't provide any more power than 3kw even during surg which the grid takes care of

Reasoning - No net metering option available from my utility and I cant switch as well. I don't wanna spend extra on additional hardware all the hybrid inverters available to me have only 5 years warranty my inverter has 12 + 3 = 15 years and it's cheaper as well (don't know how or why) as mentioned in the above link the inverter already has a power limiter functionality built in (has a split core transformer aka clamp meter to measure the current coming into my house and providing the exact same power or ever so slightly less (upto 3kw) such that none goes to the grid yes it means that it throttle itself down making it not utilise power available to it but since no net metering is there it's wasted any ways.

My Need - I want the inverter to supply upto 3kw to my house when ever needed either from panels or batteries and any load exceeding this can be drawn from the grid (eg. Surge from water pumps)"

 

[12VoltInstalls]

My question is can I replace the solar panels that are connected to my grid tie (on grid) solar inverters with similar voltage batteries?(Like hooking up batteries to the terminals where solar panels go

I ‘think’ I know what you’re trying to do.
I can imagine ways of doing what you describe.

I don’t think what you are doing is a good way of accomplishing anything.

I’d incorporate a critical loads panel and feed it with a 6000W offgrid AIO. You can siphon power with that, OR BETTER: add 10kWh of LiFePo and 8 300W+ panels to it.
~$4500 in materials.

 

[shvm]

My question is can I replace the solar panels that are connected to my grid tie (on grid) solar inverters with similar voltage batteries?(Like hooking up batteries to the terminals where solar panels go)

3kw - 260ish volt on DC (VMP) The minimum operating voltage on my inverter is 160v

I charge my batteries using a separate MPPT charge controller and it doesn't have to be

There is too much going on.
Grid tie inverters are supposed to use grid as their batteries. And they need Grid in order to work.

I don't know how the MPPT will behave when powered by a battery. A part of me says it will work, another says it won't.
It is better to run an isolated experiment with a separate unit.

 

[glandpuck]

You cannot connect batteries to the PV inputs to charge them. You can however, have the battery inputs correctly connected to the inverter, an AC grid or generator connection and NO PV, then just charge your batteries through the build in charger of the inverter using grid or gen set. then if grid or gen set goes down, you run off batteries.

 

[shvm]

You cannot connect batteries to the PV inputs to charge them.

He actually wants to connect batteries to the PV input of a grid-tie inverter to 'discharge' them

 

[glandpuck]

He actually wants to connect batteries to the PV input of a grid-tie inverter to 'discharge' them

Well, if that is the case, then he needs to begin in 6th grade science and work his way up the educational chain and then report back to us on this forum.

 

[kommando]

I do this but only using a Grid tie inverter designed to use batteries as the source, you can connect PV panels but the V range is limited to the battery range.

C

Thread 'Adding a battery to a SUN 1000W GTIL'

Jan 15, 2021

Hello, I am using the common SUN 1000W GTIL with 3 400Wp panels in parallel. The inverter DC input range is 22-60V and the panels peak at 40V.
My intention is to add a battery, but I am unsure whether it is possible using this kind of inverter.

My current scenario is:



My intention is:


Of course I have AC and DC breakers but for the diagram simplicity I left them out.
My question is basically if this proposal is feasible electrically speaking. I know the inverter can work at 2,8V*8 = 22,4V which would be the LiFePo4 battery minimum, but I have doubts regarding...

• corp9592
• Replies: 44
• Forum: Hybrid and Grid-tie Inverters

 

[shvm]

The more I think of it, since, 160V is the minimum voltage input of your inverter,
Managing a 160V HVDC battery and managing/keeping it balanced really is such a royal pain.

I don't see this being viable in the long term competing with the "warranty argument" of considering this in the first place.

 

[OzSolar]

In general terms PV panels have a very limited ability to push amps whereas batteries can deliver nearly unlimited amps. EG: 20 amps vs. well over 1000 amps. Me thinks the power electronics of solar only inverter would likely self destruct if they tried to MPPT a battery.

 

[Hedges]

Connecting batteries to PV inputs of inverter has been done a number of times.

Sunny Boy 2500U was fed from salvaged Prius batteries as a grid-support experiment.

One guy here connected EV battery to PV inputs of hybrid (which thought it was PV direct batteryless configuration). It worked, but little starting surge. I told him to put 4x automotive starting batteries on hybrid battery terminals, and with that it could start and run anything.

With CT to prevent export, this should work. Note that battery terminal will likely go to some voltage relative to ground driven by AC line (non-isolated.)

Issues are cut-off before over-discharging battery, and how you recharge battery properly.

I would like to do similar, either to export to grid during super-peak rates or to support an existing system that has AGM batteries, keeping them at float.

"I charge my batteries using a separate MPPT charge controller"
What charge controller is that?
Does it offer a signal output that could be set to switch based on SoC or voltage? If so you could use that do disable discharge.