Would it be possible to connect two or more Elite 200 (or 30 or 100) serially through the DC IN/OUT?
The idea is just connect DC/PV Input port of one unit (let’s call it “first unit”) with DC Output port (or even a USB-C 100W port) with the of the other (the “second unit”).
I can see three scenarios, based on the “first unit”'s load:
a) when it is less than or equal to roughly 100 W
Theoretically the “second unit” would drain its load first, then the “first unit”, extending considerably the time the power is provided to the load.
b) When it is higher than 100 W but less than 200 W
I believe that it wold be a limit situation, where the “second unit” would be almost completely depleted before the “first unit” runs out of charge.
b) When it is higher than 200 W
It would be possible to the “first unit” run out of power even before the “second unit” does and it would limit the full use of the charge of both units.
I was worried that this scenario would cause risks to the “second unit” USB-C port, but I read at the manual that the max current using the DC input port would be 8.1A (x 12V ~= < 100W), not exceeding the maximum load at the USB-C port of the “second unit”. So, no worries here.
I believe that it would also be possible connect the units using the AC output of the “second unit” to the “first unit”'s AC input. However, this connection would consume energy converting DC to AC on the “second unit” and using DC would save some extra Watts.
Can 2 power stations be connected, one to charge the other via AC? - Yes
Can 2 power stations be connected, one to charge the other via DC? - Yes
Can 2 power stations be connected, to increase output power, either AC or DC? - No
Do Bluetti recommend this be done? - No
However, I do this in a grid out with 2 x AC180s and have noted this in other posts. AC180-1 powers my wall outlets and its input is then connected to AC180-2s outlet, in a quasi UPS mode, in pass through power. Is it the most efficient use of power? - No, but it’s all I have. When AC180-2 is near depleted, I can plug in another power station to carry on supply, whilst AC180-2 is recharged via solar, Charger 1 or fuel generator. The benefit of AC charging is; If my load is less than the charge rate, which it often is, AC180-2 will deplete before AC180-1’s SOC begins to drop. That will not be the case with DC. I have a 3rd AC180, 2 x AC70s, Elite 100 v2 and an AC200P, for added battery capacity or singular use.
Doing a similar setup via DC - AC180-1 will only provide output at 12VDC and 100W max. AC180-2’s cig socket outlet to the DC input of AC180-1 to charge it, will only give you approx 85W charge as the input current will be 8A max at 12V. If you are using USB-A or C outputs at the same time, then the charging rate will be lower than the load. This logic applies to any power station with only a 12VDC - 10A cig socket output. The 30V - 10A output of larger power stations are a different scenario.
One more point - Low wattage DC loads can often be less efficient than moderate AC loads, due to efficiency losses.
Consider this - The Elite 100v2 has a battery bank at 52VDC. It converts this to AC with a PSW inverter to 240VAC (AU & EU) or 120VAC (US). On the DC side it also has to convert 52VDC to 12V, 5V & 5-20V to the DC outlets via a step down transformer. Conversion occurs regardless of output type, lol.
