AC300 Split-Phase setup questions

I really appreciate all of your feedback regarding this setup.


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I know we’re chatting on the other forum related to transfer switches… but what other questions do you have that we can help you with?

I would like to know about charging my AC300’s in Split-Phase from the grid. I ordered Bluetti’s cable made for this, but I am hearing that charging from the grid is potentially damaging to the AC300s. Therefore I was advised to use the T500 instead. Can the T500 be used with batteries while they are connected to their respective AC300’s in Split-phase setup?

Charging from the grid depends on a couple of factors. Please remind me what transfer switch you are using.

If you have switched neutral transfer switch then you’ll be find charging from the grid. If you have a non-switched transfer switch then you have a change to complete the circuit back through your charging outlet (multi-paths to complete circuits).

I’m glad that you got the official split phase charging cable. This will ensure you have proper split phases coming from your grid, which is required. For more information on split phase please see: Bluetti AC300 - Video #2.0 - Checking your 120v or 240v Outlet for Split Phase Power - YouTube

I would also make sure that you add a surge protector on your charging cable to protect yourself from voltage spikes and lightning, etc.

Lastly, there are some limitation with grid charging at the moment. Support is working on a fix for this.

For my setup, I choose to use x4 T500’s to charge my system on a schedule controlled by smart outlets. I will continue this setup until the limitations with grid charging are resolved.

Hi @Tjcampbell06 , Based on your question, I am sending you the diagram of AC300 split-phase mode, hope it can help.

1)In split phase system, you may charge it via PV with the same method you charge one of them, id est charge through DC Input port on AC300. You may also dual charge it via PV
and the BLUETTI 30A-AC-charging-cable simultaneously. (AC input only through the BLUETTI 30A-AC-charging-cable but not the original AC charging cable)
2)Before you begin installing your Reliance Controls transfer switch system, you need to create a plan for the appliances you choose to run during a power outage. In setting up a transfer
switch to get the most power from your two power stations in split phase power system, it is desirable to “balance the load” between the two phases of your transfer switch. Devices which will
consume the most of the two power stations’ wattage should be divided between the two.

Dear Bluetti: I did this exact setup just as you described. The only exception to what you’ve provided is that my manual transfer switch is a Generac 8654 HomeLink Manual Transfer Switch that was installed for me to use my Gas Generator to power my emergency circuits in my home. This panel was installed by a licensed electrician and works perfectly with my Gas Generator connected to it. So when I purchased my two AC300s, my for B300s, and the AC Fusion box with communications cable, I connected everything, configured both of the AC300s as depicted in the diagram you provided. When the AC Fusion box LED lights were illuminated, I connected the AC Fusion box to my Generac Homelink manual transfer switch using the 200-240V outlet on the AC Fusion box to my inlet port on my manual transfer switch. Immediately several circuit breakers on my manual transfer switch tripped and along with a GCCI breaker and ARC Fault breakers as explained by electrician that would trip given the floating neutral from the Bluetti AC300. What is a mystery is why my two Air Conditioning blower units got fried when this happened (we’ve been with A/C since last Sunday in very hot Texas). My electrician indicated to me the breakers in my manual transfer switch that went to my furnace blowers were not ARC Fault breakers (and thus didn’t trip), but should not have blown out the transform in one Air Conditioning blower and the blower motor in the other Air Conditioning unit. According to my electrician the furnace breakers doesn’t care about the floating neutral and is very surprised at the damage to my Air Conditioning units. I am inquiring because I purchased this whole setup to run power to my emergency circuits (of which the furnace blowers are two of them) and I don’t want to spend all this money repairing my Air Conditioning system just to potentially have this happen all over again when I connect the Bluetti AC 300’s in split-phase.

FYI…after air conditioning units were not working I turned off the breaker to the furnace units before I tried connecting the Bluetti AC300s in split-phase after I purchased the bonding plug to see if that would stop the ARC fault and GFCI breakers from popping and it worked - none popped.

I do want to make sure that the Bluetti AC300s in split-phase will not damage my furnace again when running power to the Generac HomeLink Manual Transfer switch - can you tell me how to take measurement or check settings to make sure my furnace units powered through the manual transfer switch won’t get damaged again?

According to my electrician, this should not have happened. My question to you is - why would it have happened?

I look forward to your response.

Thanks for the reply. Yes, my Generac HomeLink 8654 Manual Transfer switch has a switched neutral transfer according to my electrican.

I hope to get my official split phase charging cable from Bluetti in the next few days, but am I reading everyone right that even using this cable to charge my split-phase setup is risking given power surges from the grid? Is this why you use 4x T500s to charge your split-phase system instead of the official split phase charging cable?

Can you charge with your 4xT500s while your AC300’s are in split-phase setup?

You mention surge protection for the charging cable - do you mean an inline surge protection? Do you use this? I was thinking about adding in an EMP Shield system Whole Home Generator EMP Shielding & Lightning Protection (SP-120-240-G) - EMP Shield for my home panel and solar generator setup - do you think this would be sufficient?

I also have a Generac Homelink, but mine is just a 50amp. Since you have a transfer switch that switches the neutral you are not at risk to kill your AC300 by charging it via the grid. It’s those who have older AC300 and have a transfer switch that does not switch the neutral who are at risk of killing their systems.

Yes I can charge my system using the T500’s while in split-phase… the AC300 head-unit has no idea that the T500’s are directly connected to the B300 batteries. I’m using the T500 instead of the direct split-phase ac charging cable, which I do have, because currently with DSP firmware 4031.11 and below there is a known bug with handling surge loads when connect for grid charging through the AC300’s. I will send you a private message with my unlisted YouTube video that documents the issue and what I sent to Bluetti support. They are currently working on a new firmware to resolve this issue.

So no matter if you use the Split-Phase Charging cable or you end up using the T500’s to charge your system you want to ensure that the incoming power to your AC300 from the grid is filtered/protected by a surge protector. This way if your home experiences a surge or your grid get’s hit by lightning your AC300 and it’s components will be protected. I ended up getting a 50amp surge protector for my system.

I too have the EMP Shield surge protector in my main panel and will be installing another in my transfer switch. Yes the EMP Shield would help protect your home’s grid power from voltage spikes coming down your electrical wiring, but I would always say go spend the extra money to get another surge protector for the AC300 anyhow and protect your expensive investment.

Here are two unlisted Youtube videos that I made showing voltage reading from AC Fusion Panel in Split-Phase setup with and without use of the Neutral Bonding Plug. First video is without bonding plug and second is with bonding plug. I would like to know if using bonding plug is going to help avoid the power surge that I experienced last week when I used my split-phase system to power my Generac Homelink Manual Transfer switch that power my emergency circuits of my house to include both of my furnace blower units that both got fried when I powered my manual transfer switch with my AC300’s in split-phase without use of the bonding plug. Your feedback is critical since I’m vary wary of connecting to my panel again after spending $2k repairs my furnace blower transformers and motor.

Hi @Tjcampbell06 , It could be that you connected the wrong cable and caused the device to burn out. I’m sending you the wiring diagram now. Could you please re-check it again?

There are a few other issues that I need to reconfirm with you.

  1. When did your AC blower burn out?
  2. Have you purchased our AC charging cable? As shown in the picture below. So that the equipment can be effectively grounded.

Glad you caught yourself on the second video that the L shaped prong is the ground. :slight_smile:

However both readings in both videos are correct. The first measurement is expected when you have a floating neutral since there is no bonding between ground and neutral.

I too am using the neutral bonding plug, as it’s required to have a bonded neutral generator when connecting to your home via a transfer switch.

I believe you’ve seen my video on this subject, but I would suggest that you test your GFCI/AFCI breakers/outlets that may be running from the AC300’s and verify they work. This will ensure your devices that protect you from faults are working properly.

No, I didn’t connect the wrong cable from my AC Fusion box to my input port to the Generac HomeLink 8654 Manual Transfer Switch. I used a NEMA L14-30R to L14-30P cable to make the connection, which is exactly what I use with my Gas Generator and that has always worked perfectly with all emergency circuits in the manual transfer switch including my furnace blowers. Maybe I need to make another Youtube video and just show you exactly what I did and send it.

Did you watch the other Youtube videos that I sent to you showing voltage measurements from the 200-240V receptacle on the AC fusion box with and without use of the bonding plug? If so, are these reading what you would expect? This answer is important since it will dictate whether or not I want to connect this again once my A/C unit gets repaired on Monday.

Honestly this whole process has been very complicated, expensive, and frustrating. I really am so ready to just send all my AC300’s & B300’s back for a refund at this point if I don’t get some timely and transparent feedback from Bluetti Support about my issue since the whole reason to purchase over $10K worth of equipment is to power my home in case grid power goes down and that is done through a manual transfer switch since you home fusion panel is unavailable to purchase.

I have read all your booklets, materials, blogs, and community posts and I’m still struggling with this equipment. YES, I have purchase the AC charging cable, but it has yet to arrive at my house. So are you saying that without this charging cable - my AC300’s in split-phase can damage equipment on my circuits?

In speaking with my electrician who installed the manual transfer switch, he indicated that my furnace blowers would not care if my power source was a bonded neutral or floating neutral. So should I not connect my AC300’s in split-phase to my manual transfer switch until I get the AC charging cable and have it connected to my units and to grid power?

Thanks for the feedback. Yes, I have checked the ARC Fault and GFCI breakers - they all work and did trip when I was connected without using the bonding plug. The damage that was done to my furnace is still baffling despite the fact that those circuits are not on ARC fault or GFCI breakers in my manual transfer switch according to my electrician who installed the manual transfer switch. According to him my furnace circuit would not care of the power source is from a floating neutral or a bonded neutral. I had two other non-GFCI or ARC fault breakers in the manual transfer switch and they didn’t get damaged when I connected without the bonding plug, so now I am very wary about connecting my system back to the manual transfer switch even with a bonding plug given the nearly $2k damage to my furnace blowers that happened the first time.

Did you furnace circuit blow as soon as your connected your AC300? or did it blow when the unit turned on?

Also is your furnace hardwired or is it connected via a plug? If it’s connected via a plug, I would unplug it and test that outlet.

The furnace blowers were already running when I connected my AC300’s in split-phase. They are connected to 20 Amp breakers in my manual transfer switch that were non-GFCI or ARC Fault and thus they didn’t trip. I heard the GFCI and ARC Fault breakers trip, then my A/C units started surging faster and slower (they were already running at the time) and my manual transfer switch started buzzing until I turned off the AC Out function on the Bluetti Master.

My furnace blowers are hard wired to the 20 Amp CB’s that are in my manual transfer switch.

I spoke with my electrician about this and he suggested that once the main A/C unit gets repaired (tomorrow - thank goodness, it has been a very hot house for the last week here in Texas), that I should turn off the furnace breakers, then disconnect the wires going to both my furnace blowers, then turn on breakers and measure voltage coming out of the wires with my multi-meter and verify proper voltage before connecting the AC300’s back to the panel.

Now keep in mind that when the furnace blowers were knocked out, I decided to try the connection again, but this time with the bonding plug in the master AC300. I turned off the furnace breaker and reset the remaining breakers, then reconnected the AC300 again - this time everything worked and no GFCI or ARC fault breakers tripped at all. My measurements of the voltage from the AC fusion 200-240V outlet with the bonding plug showed good voltage - so I would believe that once my A/C get repaired and I can confirm the voltage at the connection to the furnace blowers that I will be ok going forward. That is plan anyway.

Just got my 30A-AC Charging cable, but don’t have an outlet to plug it into yet. So any reason that I cannot plug it into my 30 Amp L14-30 output port on my Gas Generator and use it as a charging source?

Excellent video and very informative since it nearly matches my system perfectly. My manual transfer switch is a switch neutral. I think I’ll be buying another bonding plug for my slave AC300 before I connect my split-phase up to my manual transfer switch again. You’ve by far been the most helpful person in this community and I really appreciate your feedback.

You mentioned hooking up a ground rod to your AC300 setup - how exactly will you accomplish this? Did you have a grounding rod for your gas generator too (I think you mentioned you had one - is that correct?).

In my setup, my grounding system from my main panel, which has a grounding rod, is connected to my transfer switch. It’s the only thing shared amongst the two panels. Therefore I should have connectivity to that grounding rod from the transfer switch… but I still need to do a test to verify this.