The Delta Pro doesn't require the XT60i cable, but it does if you want to get full solar. The regular XT60 cable will limit your input.
That said, you continue to say that your Bluetti getting more solar input proves the Ecoflow "is the problem", when that simply is not true. Again - it could be true - but it does not guarantee that it's true.
The problem could lie in your cable(s). It could lie in some setting you have that you don't realize you have turn on. It could lie in something as simple as different sun conditions, locations of the panels/time of the day/sky conditions when you tested the units.
I'll state it again - the odds that you have acquired two "broken" Ecoflow Delta Pro's with an obscure weird limiting of the solar input in the same way are flat out astronomical. It's possible, but we're talking the odds of you winning a 7-figure lottery kind of luck here. If this were a known issue, the odds would make more sense and be lower. But this isn't some known issue or this thread probably wouldn't exist as you'd have searched google for "why is my DP not charging at full capacity" and found the solution/answer in about 15 seconds.
The reason they may have told you the low charging rate was normal could be as simple as they understand that where you are located, how many panels you have, how far your cable run is, the conditions of the sky, the tilt of your panels, the temperature outside - all of that matters to have much power your panels will produce. As an example - for about 2 hours a day my panels peak around 94% of their rated output on a perfectly sunny day. I don't have them dialed in for the current angle of the sun - just pretty close. Starting around 10am I'm only getting about 60% of the rated input for those panels. It increases from there until about 1pm when I peak, and it stays at the peak for about 2 hours, then until about 5:30pm it slowly drops back down to that 60% range. After that it drops off big due to trees and shadows.
All of my stuff is working fine. But if I do a "test" on two different systems and run one at 2pm and one at 10am, I'm going to get very, very different results. It doesn't mean one is not working right. And if I went to customer service and said "I'm only getting this amount of solar" they would be correct in telling me that's normal even if I didn't detail to them my entire set up, how my panels were angled to the sun, my location, the sky outlook, etc.
I don't think you are offending any "ecoflow fans". We're just trying to help you figure out what's going on and or explain what *could* be causing the issues you are coming across.
