Yes, to answer your first question. While i was watching the watt meter on the unit the sun cleared the clouds and as soon as the sun hit the panels the meter went from zero (with 64 volts, which failed to trip the overcharge code, hope thats not cutting it too close!) to 40 watts and then on up from there. So it looks like 40 watts may be the minimum the Bluetti EB150 will charge at, or the oanels dont produce any amps until they're in the sun. i Ordered another three panels to run in series/parallel and when they arrive ill let you know how it works out.
Sweet! Thanks for this update.
Going by some Hobotech videos I've watched on YT, there's about a 10% difference between Amps going into the EB150 and Watts displayed as input, due to controller losses. The Bluetti is displaying the actual Watts being delivered to the battery, after controller losses.
So, if you're seeing 40 watts on the display, you've probably got 44.4 Watts coming from your array, at 64 Volts.
Dividing 44.4 Watts by 64 Volts, the EB150 is basically trickle-charging at only 44.4/64 = 1.44 Amps. We can't complain about that, I suppose.
Don't worry about coming too close to the 67V maximum Voc. It's a Pass/Fail thing. Not a problem at 66.9V. And even if you exceed the threshold, there's no harm done other than finding out later that it posted an Error 17 and you haven't been charging when you thought you were.
Just turn off the Bluetti and turn it back on to continue charging.
Thanks for sharing your experience here. You're sort of trailblazing for other EB150 owners. And thanks for ordering another three panels with intent to let us know how that performs! I'm really looking forward to that, even though I've seen a Hobotech video where he demonstrates setting up six panels for the very same reason - charging the Bluetti EB150 on cloudy days.
I have an EB240 that will accept 68V (instead of 67V), but I'm theoretically in a worse situation than you, in that I have three BougeRV
180W panels in series, each of which has a Voc of 23.84V, for a potential total Voc of 3*23.84V=71.52V. That's 3.52V over the EB240's maximum permissible 68V. Oddly, I've never seen an Error 17.
My fear is that sooner or later, it's going to be cold enough outside or the skies clear enough or the panels angled perpendicularly enough for the Voc to exceed 68V. (I didn't know what I was doing when I ordered the panels - and I'm still learning, of course. In hindsight, I should have ordered three 175W panels.) Then again, panels are known to lose a bit of their photovoltaic efficiency in the first few days of use, so maybe that's what saved me.
Another trick that
might work, if getting Error 17's, would be to insert some kind of resistor network to reduce the voltage a tad:
In this article, we will show how you can reduce voltage to any amount by using resistors in a voltage divider circuit.
www.learningaboutelectronics.com
Of course, that resistor network would
always stifle my voltage, reducing the charge rate by a smidge on cloudy days as well as under ideal light. But... with another set of panels in parallel, exceeding the 500W total that the Bluetti can consume (when input amperage exceeds 10A), I could have my cake and eat it too!
I like the idea of springing for another three panels, as you've done, to get that improved performance in less than perfect conditions, Maybe what I should do is buy just one more 185W panel - and run a 2s2p array. Hmmm... That would bring the total Voc down from 71.52V to a no-worries 47.68V, while nevertheless increasing the ideal condition total Watts from 3*185=555W to 4*185=740W. The Bluetti charge controller will only pull 10A of the available 14.8 Amps, under ideal conditions, but that 50% excess amperage for ideal condtions, would be welcome under less than ideal conditions.
In your case, a little arithmetic says that your recent order of an additional three 100W panels to create a 3s2p array will take your array up to a potential 600W or 12A - 20% more than the 10A the controller can use, under ideal conditions. But even a light overcast will have you enjoying double the charge rate you're getting now, under those conditions.
I'm fairly new to this game, but it seems to me that none of these panels actually produce their rated wattage in real-world conditions, so the more the merrier! (But I've read we should never go more than 3 deep, in parallel - as the currents can become too high for the wire guages.)
Do let us know how things go with your system.
Here's hoping you have some cloudy weather soon after you trick out your array.