Ok… I think this is apart of the problem. While I was diagraming the problem I noted that with a non-switched neutral transfer switch there is obviously multiple paths back to “source” (AC300), including your ac charging outlet.
If you’re charging at 15/20amps, then your outlet is only rated for 15/20 amps…
Then on the AC300 output side and depending on your load, you could be pushing up to 25 amps (per leg) from the AC300S…
Put the shared neutral and grid pass-through into the equation and you now have an alternative path all the way back to source through the charging outlet to your ac300…
We know that power will return to it’s source on all paths available to compete the circuit… Which includes the charging outlet.
This means via your neutral you could be pushing up to 25 amps through your 15/20 amp charging outlet… And nothing will stop it because there are no breakers on the neutral…
That is a thought. However my transfer switch was on with no loads connected or turned on. the protran2 can select each circuit to on line, gen or off. All of my circuits were set to line which means going through the panel. So no current ??
I’m using the Bluetti Smart Panel and the AC300 units still turn the AC off after the grid is restored. What are folks talking about “the official Bluetti transfer switch”? Thanks
I’m confident the AC300 is acting like a CFGI breaker and sees too many paths to ground when it switches… the more I read about it, the more I think it’s actually doing the right thing.
Yes it’s a physical issue. Bonded vs unbounded neutrals. I don’t think there is really anything more to figure out. Support told me it won’t be fixable in firmware. (I’m not talking about the Bluetti panel which may have different solution.)
Hello: Reading over all the threads on the AC300 & transfer box problems.
I have (2) AC300’s. I want to do the 240V split phase setup. I will only be charging my AC300’s with solar and NOT from the grid or any kind of power from the electric company.
I am wondering if my transfer box will work with this setup.
My transfer box is a "Connecticut Electric 6-7501 manual 7500 watt, 30 amp transfer switch.
It only has the one neutral line. But after reading about all the problems, it seems they come about having the AC300 plugged into the wall & using grid electricity to also charge the AC300?
If I only have solar panel charging, would I be able to use this transfer switch or most any transfer switch?
Yes - I rewired the neutrals on the switch per the new schematics (which cleared some issues), but the AC300’s still turn the ac off when the power comes back on (zero load or full load).
@recycle - let me provide more context here. When your system is connected to the grid your AC300 will match the grid phases… this means that your Master will match the Leg it’s connected to and the Slave will match the other leg. This takes a moment for the system to do and thus is why when grid power is restored the ac300 will need to do a checksum before allowing grid power.
It makes sense Twister36, but it still happens when I only use one AC300 in single phase on one side of the panel. So it shouldn’t have to recalibrate for the phase.
Coz - This switch is pretty much the same as the Pro/Tran models. It was designed for “emergency” backup power when your grid power is down. It was not designed to run in parallel with your grid power being active.
That one neutral line coming from the transfer switch is probably from your inlet going back to the main panel.
At this time we only know that the use of these non-switched neutral transfer switches causes the AC300 to die with a 008 error message when they are plugged into the grid. However I can’t speak to the other issues it may be causing by mixing two active power sources’ neutral systems together on your other devices in your home.
Hi Amok… actually yes it still has to do it with a single ac300… because of grid pass-through. In order for the system to pass the incoming grid power and merge it with the inverter power it needs to sync the two.
So a transfer switch that switches neutral fixes the issue with AC300s dying but doesn’t solve the issue of the inverter’s AC output being shutoff when grid power is restored even when only one AC300 is in play?
No the neutral switching fixes the AC shutting off when grid power comes back on.
The issue of the AC300 dying (“008 OCP Error”) I’ve actually never experienced – I believe that was a bug introduced somewhat recently that has subsequently been fixed in a firmware update.
