Added more panels but no increased input.

I have 2 ecoflow Delta pros. I have 2 racks of solar panels 4 × 200 W on each rack wired in series, one rack wired into each 1 of the Delta's. Have been using for about a year, works okay, but not enough input to run an AC in summer. Just added another 2 racks, each with 2 x 400 watt panels wired In parallel. Using branch lines i then connected 1 of the new racks into the main feeds of each 1 of the older racks. At first it seemed to be working well, at 08:30, early morning the input was about 3 times what it was previously, but it topped out at 570 watts into each Delta and won't go higher. It should be between 1200 to 1400 watts, given the angles and the total max output of 1600 watts. Can anyone one please figure out what I am doing wrong? The 8 Rich 200 watt solar panels, wired in series are 20.4 v each, the 4 Hyundai 400 watt panels wired parallel are 37 v each.

If you can't read the text in the images you post, we can't either. No idea on the specs of the Hyundai panel. Very blurry.

On the rich solar...

Your deltas can't handle more than 150Voc and 15A PV input. If you put the rich panels in parallel, you will be over 15A, and the system will ignore anything over 15A, so you'll at most get about 75% of the rated output.

Also, if the battery is approaching full charge, charge power will taper to what is needed to maintain the battery at the charge voltage.

Thank you for the reply. Sorry about the blurred photo, took it after installation and the rack placement made it difficult. Attaching a photo of spec sheet I found online, hope it is better, I can't find the amps on it, but I guess I could wire the Hyundai panels in series, total 148 volts to feed one Delta. Any idea regarding the Rich panels for the second Delta, as they also can't be wired in series as 163.2 exceeds the delta's 150 max voltage? Would a mix of parallel and series wired work?

Also, as a side note the first Delta and the 8 Rich panels were sold to me as a bundle. Yet it seems they may be less than compatible with the Delta Pro. My bad for not having a better, or any, technical understanding of the components.

Current at Pmax appears to be 10-11A, so it's the same deal. If you put strings in parallel with 20-22A of input current, the unit will ignore anything over 15A, so you'll be limited to about 75% of the max rated output of the array.

148V may be too much in cold conditions. Power stations tend to be a little more forgiving when you exceed Voc, but I wouldn't count on it.

The power claims and the MPPT limitations of "solar generators" are often misleading and confusing. In order to get 1600W, you need:

1600W / 15A = 107Vmp, not Voc. Voc would run about 133V, which is a potentially a concern with exceeding 150V.

With the above restrictions, you need to carefully select your panels. IMHO, the manufacturer's do this to encourage you to buy their panels that can be selected to get very close to the 1600W output.

4S2P fo the Rich will only get you:

81.6Vmp * 15A = 1224W, BUT it will produce that 1224W for as long as the 1600W array can produce 1224W.

Unfortunately, the higher voltage of the Hyundai means a 2S2P array will only get you:

77.8V * 15A = 1167W

Rich solar: 20.4Vmp, 9.8A Imp
Hyundai: 37.9Vmp, 10.7A Imp

It wasn't entirely clear to me initially how you connected things. Now I think I understand better.

Any strings you put in parallel MUST be as closely matched as possible for Vmp (up to 10% variation). If you have too large a disparity, the higher voltage string could potentially discharge into the lower voltage string, OR the MPPT may figure out it can pull the voltage down even lower and get some power. I'm pretty sure that's what was happening.

38Vmp * 15A = 570W, which was your prior peak.

4S 200W in parallel with 2P 400W is a non-starter.

4S 200W in parallel with 2S 400W meets the 10% variation in Vmp. However, you're trying to move 20A+ when it will only accept 15A, so you get hit with at 25% penalty per array.

You'll get about:

38V * 2 * 15A = 1140W

Thank you very much for the detailed reply it just makes me realize how much I don't know about this stuff.

So if I'm understanding correctly, as regards the Rich panels I can effectively just utilize 6 as opposed to 8, with the 6 panels wired 4 in series and 2 parallel. And the Hyundai panels 2 in series and 2 in parallel.

I understand I won't get anywhere near the output I thought I would but I am happy that the situation is salvageable and not a total loss. Wish I had seen Will Prowse's videos before I purchased the Delta's, but water under the bridge.

I really appreciate you taking the time to figure out a way forward. Thanks again.

CJW said:

Thank you very much for the detailed reply it just makes me realize how much I don't know about this stuff.

So if I'm understanding correctly, as regards the Rich panels I can effectively just utilize 6 as opposed to 8, with the 6 panels wired 4 in series and 2 parallel. And the Hyundai panels 2 in series and 2 in parallel.

I understand I won't get anywhere near the output I thought I would but I am happy that the situation is salvageable and not a total loss. Wish I had seen Will Prowse's videos before I purchased the Delta's, but water under the bridge.

I really appreciate you taking the time to figure out a way forward. Thanks again.

Click to expand...

You could do 4S2P Rich on one and 2S2P Hyundai on the other, OR since it may be easier given the existing connections:

4S Rich (81.6Vmp) in parallel with 2S Hyundai (75.8Vmp) on each Ecoflow.