DC Charging AC300+B300x4

Have the AC300+B300x4 connected into a transfer switch (Reliance Pro/Tran2) and cannot charge via 110AC grid due to the neutral bonding issues. Emergency backup for me, works well, just want to leave it connected so pursuing dc charge options.

I bought a simple AC-12V DC power converter, plugged in the cigarette plug to DC1 on the aviation plug and batteries just never charge. They always stay in Standby. Ac300 sees ~12.5v and gets ~98-100 watts.

Is there a min voltage/wattage needed for the car plug to be recognized /charge it?

Yes, DC1 is set to Other and Yes Solar panels work fine. I have the T500 on DC1 charging it now at ~500 watts but perplexed I can’t charge via Car cigarette plug.

Any thoughts? Thx!

Hi @anthonyris
did you try to charge your powerstation via the Car cigarette plug? So use it as a input?

This Port is not meant to be a charging port, its only for output on your powerstation. The cigarette plug should be in your car and the other end where the Solar is normally connected.

If your connection is right, you also cant charge the powerstation to the end because most of the 12V car outlets arent strong enough. So what is you SoC when trying?


@anthonyris Have you consulted an electrician for the wiring? I will send you the wiring diagram for connecting AC300+ switching power supply to the grid, so you can check it.

If there is charging power, it means it is charging. With 100W of power distributed to four battery packs, the current flowing into each pack is small.
Only when the current is above 1A will it show that it is charging. You can try connecting only one battery pack to verify.

Thx, wiring is correct, in use for some time now.

The AC300 simply doesn’t charge on low watts via the DC1 input. It shows it is charging when above 200w or so, or if I have multiple inputs (solar + car charger).

In a previous post, @BLUETTI mentioned that the AC300 will show “Standby” at low watts “but it’s charging”. Not my experience, Sat at ~40% SOC overnight.

Confused Erik. Are you asking if it was connected properly?

Here’s how it was connected: 12v cigarette plug to AC300 via CP2’s DC1 input, set to Other.

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For me it just sounds like that your using the cigarette Plug on you AC300 as input

Appreciate it may seem that way to you, but no, I am not. I am feeding the CP2 input on the side aviation port. Pretty standard. Included a graphic that should help you understand. See Method 5.

That DC input can take 2 inputs, DC1 and DC2. It’s in the diagram in the manual.
Regardless: @BLUETTI : what is the minimum voltage to activate the DC1 MPPT controller and what are the minimum watts?

The minimum voltage to activate the DC1 MPPT controller is 12v.
Do you mean that the power drops from 100% to 40%? Please check if the BMS version is the latest version.
If not, upgrade the BMS version and do a charge/discharge cycle.

Thx for the reply. I said above “it sat at 40% SOC” just to underscore that it wasn’t charging at 12v, showing ~98w input.
BMS are all updated, 1 b300 is diff version due to being newer.
With t500 or over 200+ watts, it shows “Charging”. There’s another thread with same issue in the forums from last year.

Question is: How can we get the AC300 to accept charge at 12v w/low watts (like a car charger normally outputs)?

It will not display when the current is very small. When only one B300 is connected, it will show that it is charging. However, if four are connected, the power needs to be higher in order to display that it is charging.

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Thx for the clarity.