Daisy-chained EcoFlow delta 2 for ev charging

[Alex81]

This threat will make many cringe and I apologize in advance.
A while ago I was able to purchase 3 EcoFlow Delta 2’s (new) for $220 each. For a minute or two Amazon had both a discount and a coupon available, they stacked, EcoFlow actually shipped out the units.

My initial idea was this: daisy chain the EcoFlows, hook them up to solar, slow charge one of my EVs.

I got a hold of some cheap used panels and when I put 3 in parallel I get about 440w out of a set.

2 problems. The delta 2 can’t charge from solar and ac at the same time.
Bigger problem, the EcoFlow needs ground to charge up an EV.

I bought a “floating ground” plug and it works for ev charging. I saw Wills video where a delta pro’s inverter went up in smoke after being connected to the grid because there were now two “grounds” in the system.

Could I safely daisy chain the delta 2’s with the floating ground plug in, as long as they are not attached to the grid?

Given my existing equipment, 3 delta 2’s, 3 sets of 440 in solar panels, how could I get the most ev charging.

 

[BaylentheSky]

That's an interesting thought, would love to know how it turns out for you. By daisy chaining it, do you mean AC Output from 1 unit to AC Input of the other? And I'm assuming the 1st unit would be plugged into solar? Never mind the fact that there will be inefficiency converting AC to DC and back to AC again, it would be interesting if it works. Let's do the math first:
The Delta 2 puts out a maximum of 1800W, but I suspect your EV will not accept more than 1440W when charging at level 1 (120V x 12A). Assuming all 3 of your Delta 2's are full, that's 3 kWH, which means it can supply about 2 hours of EV charging before all running out of juice. In those 2 hours, your solar panels would have generated almost 1 kWh, which means you probably can get an additional half hour of charging out of that whole system. So 2.5 hours is the total charging time you can expect, and about 3 kWH (accounting for all losses) going into your EV.

 

[Alex81]

Yes, ac output of one into the input of the other. I wonder if there would be any pass-through charging. I think my first test will be to have #3 start at 0% and #2 and #1 both at 100%. I’d be curious to know what percentage #2 would end up with after #3 has been fully charged.

 

[Alex81]

Started at 100 - 100 - 4
The middle delta 2 stayed cool for the period that the 1st still had charge left.
Ended up at 0 - 67 - 100
33% loss.
I will try again if I can find something with a steady load of around 1100 watt. Efficiency loss may be rather small after all.

 

[BaylentheSky]

I do know that the Delta 2 inverter is extremely inefficient. I mean most of the portable power stations' are anyway, to fit an inverter into such a small device. By the way, by the time that 67% makes it to the 3rd unit, it's going to be another 18% loss. By the way it's actually 18% loss not 33% because you effectively pushed 2.048 kWh through the system, losing 0.37 kWh would mean it's 0.37 divided by 2.048 = 18%. I think this figure is correct, because I remember seeing a review somewhere on Youtube where they ran a load on the Delta 2 til it's dead and got around 82 or 83% out of it.