EliteSolar
New Member
- Joined
- Sep 22, 2020
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I don't know, but I have an assumption about this that it definitely won't back feed and here it goes:
Let's assume the AC IN has just two ways to go into the system: Through the bypass relay and through the battery charger (which is actually just an AC/DC converter to a DC rail plus the battery charger which feeds from this rail).
Now there are three cases for running without a battery:
This would have the AIO do the following:
- load is below what PV can provide
- load is above that but below AIO power rating and
- load is above AIO inverter power rating (in your case the 3.6kW).
Now for the question how to test this:
- If load is below what PV can provide, the inverter runs on PV only - that's the easy part.
- If load is above PV but below AIO inverter power rating, the AC IN provides the power difference needed via the AC/DC converter in addition to the PV power - not the most efficient way, but it would work.
- If load is above the AIO inverter power rating (or PV is off), the system switches to Bypass mode.
IMHO the only way to test my hypothesis is to run your system with a load above PV power but within AIO inverter power rating (case 2). Using a power meter in front of the AIO should give you a slightly higher power draw as if you'd connect the load directly to grid AC (as the AC/DC converter loss will be missing).
I guess, a hair dryer running as load on a partly cloudy day will do ...
Now this is a wild speculation, but could answer your question. If there is no difference in power draw, the AC IN would directly feed the AC OUT instead of running AC->DC->AC. And then there might be a chance, the system potentially could back feed ...
That's correct.
I mean that's how I understand the system to work.
When it mixes/blends ( power below the 3.6KW ), the AC IN feeds on the AC->DC-AC ( because in this mode, without battery, it shows it NOT to be in bypass mode in the manual ). (With battery it shows in bypass mode, someone explain this has to do with the ac charger. Even more confusing. )
( so running PV with batteries it would be in AC bypass mode to mix/blend power , running without batteries wouldn't ) ?
So in my setup , without batteries , up to 3.6kw , when blending power, my inverter theoritically doesn't go into bypass mode. Only when it exceeds that it will completely switch to BYPASS mode.
When in bypass mode, AC IN directly goes to the AC OUT, according to a guy that opened and examined an MPP Solar unit similar to mine, like this :
" when the AC bypass mode is enabled, the AC input and AC outputs lines are bridged together via relay switches, the inverter feeds the energy created from the solar panels on to the bridged AC input/output lines by raising the AC voltage via internal semiconductor power switches (IGBTs), in the same way that a normal grid-tied feed-in tariff inverter does. The only difference is that this inverter can never feed energy back into the grid. This must be limited in the software, even though in hardware it is possible to do. "
This is so confusing
Sure there are. But I was thinking more about instantaneous power flow or very small amounts of energy. Very small amount of net kW-Hours more like kW-seconds.
Do some meters use their data over power line or wireless signaling to inform the utility of some certain level of sell-back ?
boB
My meter is a new smart digital meter and according to a post by "robby" in the forum , it could "let the power company know that something is going on and they will send someone to investigate. If your not legally grid tied they may cut your power on the spot until you get the Inspection work done."
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