D40 "Load Mode" issue

I received a D40, and I am having trouble with the “Load Mode”. When set into “Load Mode” (all lights lit), the terminals read 13.5V without a load. When I connect it to my fuse panel the Alarm light turns on and the voltage drops off. I’m able to connect the fuse panel via the 12V/10A port (cigarette lighter) without issue, but I need the higher amperage supposedly offered by the D40.

I have had trouble powering certain items and getting the red error light as well but was doing so connecting via a fuse panel. The strange thing on my end is that three of the items that gave the red error code were not switched on but simply plugged in. Polarity of all items was checked with a meter and the same items would function when connected to the cig socket above. Definitely an issue there but unknown what at this point.

You may want to pull all the fuses in the panel, start the D40 and then plug the fuses back in one at a time until the error light comes on to identify which item is the culprit. This is disappointing that the D40 will not power some loads since it was in development for so long.

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@theGrooveTime So you were able to get all the light to flash, and then remain lit (after clicking button again) but when you connected a load to it, it would drop the voltage and throw the error light?

Heres a pic of the "new" v2 D40 unit. that is showing all lights lit up, and in "load mode"...

I ask because, there was a first batch of these D40 units that got sent out, that were the “old” version. Bluetti had sent out emails and tried to stop the deliveries prior to customers receiving them tho, but it sounds like yours might have slipped thru?? I would reach out to @BLUETTI_CARE and they will get you taken care of.

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Thanks for the suggestion, I will try the fuses one by one.

I had a shipment that was on its way and was recalled by Bluetti, this unit is from the second shipment. Is there anything that identifies whether this is a “V2” unit? My manual says V1.0.
When I hold the power button and the battery indicator light is flashing I am able to cycle through until all the battery lights are flashing, then I hold the power button again and the all lights stay lit. Your pic shows the PV/ENGINE light also lit, mine is not. I read the same voltage when tested as you show, but when I connect to the fuse panel it drops off and the red alarm light comes on

Unfortunately @theGrooveTime I dont think there is any identifying marks on the units themselves that differentiate the “v1” vs the “v2”. I too also received the user manual labeled “V1” so that doesn’t necessarily mean you still have the V1 unit.

Also… I will add that I havent actually been able to link up a 12v fuse panel and test it out yet… I just did the test to make sure I had recieved a “V2” unit that would allow me to lock in the mode. And interesting enough… I just noticed that the “V2” user manual actually says that “The PV / ENGINE input is unavailable” under the RV/Load Mode… which raises some more questions to me that I will need to ask @BLUETTI_CARE about… Since the D40 only allows 20amps output when not connected to a PV/Engine… does that mean that the D40, when used to power a 12v fuse box, wont ever allow the whole 30amp output?

But if you’re unable to get the unit to output any power at all while connected in the RV/Load mode, there might be an issue… So if you could man, read over these instructions again to see if you can lock in the correct mode… And then PLEASE come back and update us if you are able to get anything powered up from your fuse panel after using @Scott-Benson thoughts on powering the loads one-by-one.

Maybe @BLUETTI_CARE can be able to tell what model you have based on the SN of the device?

BTW @theGrooveTime here is a link to the updated “V2” D40 User Manual…


From what you describe I think you have version 2 but are experiencing the same thing I am when connected to some loads and then errors out. I have been able to successfully power a 15 amp dv load tester, a rigid tools 12 volt small air compressor and using the output to “car charge” an EB3A. I experienced the symptom you report when plugging in (with the power switches off) a 100 watt xantrex inverter, a 700 watt xantrex inverter, a 300 watt bestek inverter and a larger high volume viair air compressor. All four of these items will run with no load when connected to the AC200L cig socket.

From what I can see, the load output of the optional, upgraded D40 unit is limited to 20 amps while being powered by the AC200L unless connected to solar. This is in contrast to the previous model which output 30 amps of 12 volt power, did not require the expenditure of $200 after a five month wait for the D40 and would actually work with normal 12 volt dc items. The D40 is supposed to be an upgrade but at this point I am having difficulty seeing the value unless all you wanted to do was charge your rv battery.


@theGrooveTime Is it the AC200L, D40 or fuse box alarm that is on? What is the specific phenomenon? Is it always on, flashing or something else?

@m.briney yes, it will not allow 30A output when use to a 12v fuse box.

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After re-reading the manual completely again, my understanding is that the “load” mode is a maximum of 20 amps no matter what since when the load mode is activated, the PV/Engine port is not available. This is very disappointing and not clearly stated to a customer before deciding to purchase.

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I assume that bluetti put protection in the D40, 20 A max, due to inrush current problems, which the AC200L on this 48v port must not be able to manage

In most appliances, capacitors are placed to ensure there are no voltage drops on the supply rails. But when power is initially applied to all the appliances(even “off”) in the same time (with the fuse panel), charging all these capacitors can result in an inrush current which can exceed the nominal load current (and cause a voltage drop, and the activation of protection against short circuits).

[mind game/ mad scientist mode: on] I would be curious to know if in addition to connecting the D40 to the 48V port of the AC200L, a DIY cable connected to the 12V cigarette port of the AC200L (a little more tolerant it seems with the inrush current) to the PV/ENGINE input of the D40… if this both solves the “alarm” problem and allows you to bypass the 20A limitation (provided the AC200L is not overloaded, but there is protection and PV/Engine port not really disabled).

I have a fuse panel with “Reverse polarity protection” fuses, those seem to be the reason the D40 alarm light is turning on. I pulled all the fuses and it was still having the alarm light turn on. I then pulled the “Reverse polarity protection” fuses, and it was able to get my 12v circuits powered up with the D40. The largest loads I have are Fridge, Furnace, water pump, couldn’t test my water heater yet due to not being filled.
Any advice on why the “Reverse polarity protection” fuses are causing the D40 alarm light to turn on would be appreciated

@BLUETTI_CARE I’m referring to the Alarm light on the D40. Before connecting to my fuse panel I have all the Battery Indicator lights illuminated, when I connect to my fuse panel the red alarm light on the D40 illuminates and stays lit

Same thing occurs when I connect some devices but works fine with others. The devices that fail do not even have be switched on when the red alarms light comes on.

Why does the PV/Engine Input need to turn off when in Load Mode? Although the D40 draws enough power from PV/Eng Input to stay on without DC Input connected to AC200L. So not off but restricted? I want to charge my AC200L from the D40, any way to do this? Firmware update?