AC300 to Transfer Switch

Hey guys, @t4602yf @recycle @mjb8706

When you guys killed your systems… did you kill both or just a single unit? I got some more information today from Bluetti Support and I’m interested to see what you say…

just one unit for me

As I previously posted, neither of my original ac300s were blown out. The ac output/inverter shuts down after restore of power from simulation of grid power outage. Then bluetti requested me to send back one for analysis, then the new one they sent me blew out on 008 OCP when I retested power restore after simulated grid power outage.,I have a suspicion that bluetti might have had a bad batch of ac300s with neutral wiring issues. Now they said they implemented hardware and firmware to guard against this issue.

Just one for me. I have only a single-phase (one Ac300) setup.

@twister36 can I ask you what those devices that send an email when power goes out are? I want to buy one. I’ve got my router/modem on a separate UPS like you so that would be a great way to alert me. Thanks.

Sure, they are MySpool.

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Hey guys, @t4602yf @recycle @mjb8706

Sorry another question, as I’m still working to diagram the root cause/issue with the non-switching neutral transfer switches. Were you charging your AC300 with a 30amp outlet or the 15 amp outlet?

I do not have 30a set up at home. Only on my propane generator. So charging from 15a grid circuit.

each of my ac300s are on separately phased 20 amp outlets. (well…both were before the code 8 occurred at my first unit). each unit is set to draw only 15amps. My plan was to set that draw down to 7amps max.

I’m charging at 15 amps too (the outlet is actually 20 amp dedicated to just the Bluetti).

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 ??

Technically it could still be used as a path for other circuits to return power… I’d have to diagram that to see if it’s possible

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

a diagram of this would be helpful. and this would not apply if the neural was switched back to the transfer switch like the generac 9855, correct?

Mine trips with no load as well.

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.

This article, I think this explains it.

I read somewhere along the line they had some kind of update for their panel to rewire the neutrals… have you asked support about it?

Your issue will be resolved once the new firmware is released.

That’s not possible… It’s a physical issue.

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.)

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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?