I understand why grid tied inverters shut off when grid is down - are there any simple solutions that detect this and switch to alternative reference eg ups and dump excess info batteries? Google brings up 29 year old stuff, or all in one inverters that do this. I’m after a simple add on….
Any effective cheap approaches for enabling battery grid tied system to work in outage?
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sunshine_eggo
Happy Breffast!
Nope. AC coupling with a suitable off-grid inverter is the only option.
GT inverters do not regulate themselves. They expect an infinite "battery" to charge - the grid. They output maximum available power from the PV array at all times. So the device providing the grid must be able to handle the entire GT output. They must be capable of frequency shifting to force the GT array to disconnect when the battery is full.
If you have 10kW of GT power, you need a 10kW off grid inverter capable of AC Coupling/frequency shifting + batteries to provide a grid for the GT inverter.
sunshine_eggo
Happy Breffast!
AC Coupling
AC Coupled Solar Power System - use your existing system to feed power into a battery based inverter/charger to charge the battery bank.
www.altestore.com
sunshine_eggo
Happy Breffast!
What you describe is no different than isolating from the grid and running with a generator. You're just using battery as fuel with inverter/batteries. This is possible even without grid-tie solar. You gave the impression that you wanted use of PV array based on "dump excess into a battery."
If you are still proposing using your PV array, please refer to:
Whatever forms the grid for the GT inverter must 1) be able to handle its full unregulated output and divert it between batteries/loads as needed and 2) make the inverter supplied grid "dirty" to the point that the GT array disconnects and stops sending power once batteries are full.
timselectric
If I can do it, you can do it.
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"Any effective cheap approaches for enabling battery grid tied system to work in outage?"
If you have a "battery grid tied system" (a hybrid AIO) . It should already work in an outage.
If not, then you need a hybrid AIO.
If you have a "battery grid tied system" (a hybrid AIO) . It should already work in an outage.
If not, then you need a hybrid AIO.
wattmatters
Solar Wizard
A GT inverter requires a grid of sufficient capacity to operate. Either the utility supplies the grid, or you do.
Any item operating in parallel with the grid must meet all grid connection standards.
There are plenty of effective ways of doing this, however none are cheap, while "simple" is subjective.
pollenface
Solar Addict
Suicide lead with main switch turned off at the meter box
Bossrox
Solar tinkerer
I'm not grid tied but it would seem to me just a transfer switch that disconnects the grid & switches your system directly to your house load would be the answer but good 200 amp transfer switches aren't cheap.
can you explain this in words a newbie will understand?!
by this I think you mean that if running from battery/solar when grid down, there needs to be a way to make the 'grid' send suitable signals so that the inverter shuts down pv input if there's not enough load.
I get that. I'd be happy if I could just simply switch to
battery -> inverter -> load and use battery until they ran out or the grid came back on - is there a simple way to do that? isolate solar array. and isolate inverter from grid? what else would I need for that to then work?
sunshine_eggo
Happy Breffast!
Yes. As I mentioned above, that's no different than a regular generator setup except the battery is the gas. Research how to wire for generator input. I could simply be as easy as a transfer switch that selects between mains or an alternate input.
For uninterrupted partial backup, you could split off critical circuits from your main panel to a separate panel and have those always powered by the inverter/batteries with grid always feeding the inverter. The inverter/batteries would act as a UPS and switchover to backup power when the grid goes down.
wattmatters
Solar Wizard
Best not. It's called suicide cord for a reason.
But here's a random video talking about it:
timselectric
If I can do it, you can do it.
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That's never a good idea.
pollenface
Solar Addict
An extension lead with a male plug at each end. One end goes into the inverter, the other into a power outlet in your house, but the main switch MUST be off at the meterbox. I would even lock the meterbox so no one can accidentally turn it back on.
pollenface
Solar Addict
I agree.
timselectric
If I can do it, you can do it.
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It's dangerous, and should never be considered.
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