Low solar panel output?

Product Discussion Solar Panel
29

Flagstaff, Arizona - I will clean them and see what happens.

Meanwhile, I asked two AI engines, at midday in June in Flagstaff, Arizona, how much energy two 200-watt portable solar panels should produce.

AI Perplexity - On a clear June midday in Flagstaff, expect your two 200-watt portable solar panels to produce about 315 watts combined—possibly a bit more under ideal conditions, or a bit less if factors like heat or panel angle are suboptimal

Chat GPT - At midday on a clear June day in Flagstaff, Arizona, solar conditions are excellent due to the high elevation (~7,000 ft) and low humidity, which reduces atmospheric attenuation of sunlight.

Estimate of Solar Power Output

Two 200-watt portable solar panels (total: 400W rated power) can be expected to perform near their rated capacity under ideal conditions. Here’s how to estimate real-world output:

Condition Expected Output
Optimal (cool, clean, angled) 360 W
Realistic Midday Average 320–340 W
Suboptimal (hot, flat, dusty) 280–300 W

I’m getting less than half of what they consider to be “suboptimal” results.

I will clean them and see what happens.

30

I’d read somewhere that dirt didn’t really affect solar panels so I never cleaned them.

When I cleaned them - the power jumped up from 55 watts to about 115 watts and then up to 165 watts at 4 pm in a somewhat cloudy afternoon (!!!) - but then it went back down to 55 (maybe because it was cloudier). The light is too variable right now, but there’s clearly hope.

I will check back when I have clearer skies

Thanks for the idea. :)

31

Absolutely dirt can kill the panel’s performance. I glazed over your video and didn’t pay close attention, but now rewatching it again your panel was CAKED! The panel doesn’t even have to be entirely caked, just caked in the wrong spots where the bypass diodes would kick in. I’ve read as much as 25%. So 2 panels would be 50% loss in power which is at max 200 watts. You said the highest you got was around 180’ish if I remember. Makes perfect sense.

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32

Things were looking good, but no dice. Cleaned panels are putting out 125 watts again in full sun at midday. Very confusing!

33

And when you separate them what is the volts + amps of each “clean” panel. Also what is the latitude of your current location?

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34

48 and 56; latitude - 35.198284

35

Yeah that is clearly not right. I have the original PV200 plugged into my Bluetti power station that only outputs 8A max and its still getting over 100 watts right now where I’m at with some cloud cover AND I’m 10 degrees higher in latitude than you are. There have been several complaints about the newer series panels not performing to expectations. Myself included. I have the newer PV350 and its performance is not up to par. Had it replaced. Same exact performance. @BLUETTI_CARE Please forward our concern to your internal quality control team to look at the performance of your new folding solar panels. They do not appear to be up to par with previous generations.

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VIDEO OF MY PV200

36

Thanks - this is getting more and more interesting.

I have 4 solar panels on the top of the van dating back from 2016 and (for the first time) I used the volt meter to assess their power output (volts x amps = watts) from 3-4 pm and compared them to Bluetti portables.

Solar panels on the van - not tilted towards the sun

  • 2016 - Grape 160 W - 83.4 W
  • 2019 Newpowa 175 - 153 W
  • 2019 Newpowa 175 - 58 W (ouch!)
  • 2025 Renoga 170 - 131 W

The Bluetti 200W portables tilted toward the sun.

I was unable to access the leads as they are covered up, and sticking the Klein meter prongs into the connectors didn’t work. The Bluetti app told me, though…

  • Bluetti 200 W portable -(12/30/2023) - 84 W
  • Bluetti 200 W portable (11/24) - 40 W (!)

The almost 10-year-old Grape 160 - lying flat on the van - is doing as well as the 12/2023 200-watt Bluetti - tilted toward the sun, and the newer 200-watt Bluetti is doing the worst of all. (If one was going to do worse I’m happy it was that one as I never liked it - it’s stiff and awkward and hard to prop up properly)

I am just learning this stuff, but unless I have something wrong, my Bluetti 200-watt portables are really underperforming…

That’s really surprising to me as Bluetti has an excellent reputation but I did go through 2 AC 180s after the charging outlet failed on them 3 x’s (once after Bluetti repaired one of them). (Bluetti was good enough to refund all the AC180s, and I now have the AC200, which so far has been superb.)

My next step is probably to get a portable 200W panel from a different manufacturer and test it.

In the meantime I will assess them tomorrow. Those two panels should not have dropped that much - they should last 20 years).

(I will also probably replace at least one of the solar panels on the van).

37

I recently acquired a newer Bluetti power station that has “PV Pro” setting available in advanced setting. I noticed that if you set the DC input source set to “Other” it capped the power station around 50W using my PV200 (Gen 1). If I switched the DC input source back to “PV” I got around 135 watts with PV Pro enabled. Likely not your problem just sharing for others. The 50W limitation can be user induced though as I’ve demonstrated. Hopefully Bluetti reviews our concerns and addresses the concern. As one of your panels is still under warranty, you have a valid case for a replacement. I completely agree with the design flaw of the new panels. They are WAY too awkward to prop up. I feel like it is going to collapse on itself and the panel will get damaged easily.

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38

Thanks.

I just retested everything - sun straight overhead and the app said the newer panel was producing about 40 watts. (The older one - 80 watts).

I still don’t know if the Bluetti is tamping down the power from the panels - I will need to buy a non-Bluetti panel to test that - but at least the newer panel is doing extremely poorly.

Interestingly, the power from the Bluetti portables was the same with the sun straight overhead and at 4pm yesterday, with them tilted. The solar panels on the van, on the other hand, produced more energy with the sun straight overhead.

With the results similar to yesterday’s tests I feel confident about the results. I don’t know that I could be doing wrong.

39

You have multiple data points to demonstrate that the performance is not the direct result of the environmental conditions itself as the nearly 10 year old flat mounted panels at 25W less watts produce more output in the exact same conditions.

BTW the power station you are performing these tests on is a “Elite 200” and not an AC200 correct? AC200 has a minimum PV input voltage of 35V and I read that at the very low end of the spectrum it can output very low amps, which would explain the poor performance, but in your video you had an Elite 200 which operates 12-60V @ 20A max. You do have an ELITE 200 V2 not a AC200, correct?

On the other side of the coin I did see in past threads where MPPT controller was unstable for some on their Elite 200 V2. It would pull higher voltage initially when they connected their panel in series, and then a few seconds later capped to 16V. At that voltage your output would be low. This still doesn’t explain why the one panel is 80 and the other is 40 though, which is why I vote for “something wrong with panel”.

40

Hi @Cort, Thank you for providing the detailed information.
We have consulted the R&D department and confirmed that the open-circuit voltages of PV200S and PV200D are different, so they cannot be used in series or parallel. Please select panels of the same specification and connect them in series to charge the AC200. This might also be the reason for the low charging power.

Thanks to @sealy1986 for the explanation. Indeed, when the surface of the solar panel is dirty, the light transmittance decreases, and sunlight cannot directly shine on the battery cells. The degree of attenuation is proportional to the level of dirt.

41

Hi @sealy1986, We have forwarded your feedback to the Quality Department. During our internal testing of the solar panels, no issues were found, but we will still attempt to replicate the problem you encountered.

Yes, the PV-pro mode of Elite 200 V2 allows the power station to obtain more PV input power when connected to low-voltage solar panels. Regarding the current limitation issue with your other power station, please provide the specific SN code and firmware version so that we can check if there is a firmware update to lift the restriction.

As for the stand design of the solar panels you mentioned, we are indeed considering upgrading to other appearance types of solar panels.

42

Thanks for checking but my gosh your 200 series cannot be used together! This is good to know (How would anyone know?) It just gets weirder and weirder, though.

The panels say they are 200D and 200S but both the panels were supposed to be 200Ws

The Oct 30, 2024 order detail that Amazon provides:

BLUETTI Solar Panel, 200 Watt for Portable Power Station EB3A EB55 EB70S AC2A AC70 AC180 AC200L AC200MAX AC300, Foldable Solar Charger with Adjustable Kickstands for RV, Camping, Blackout - leads to this link on Amazon

https://www.amazon.com/dp/B09B9RJLM7?ref_=ppx_hzod_title_dt_b_fed_asin_title_0_0&th=1

and it matches the description in the order detail

BLUETTI 200W Solar Panel for Solar Generator EB3A AC2A AC50B AC70 AC180 AC200L Elite 200 V2 AC300 AC500 B300K,

The December 30, 2023 order details which Amazon provides after the fact, does not, however, match the link I used to get the product. The order detail says I got a 200S:

BLUETTI Solar Generator AC180 with PV200S Solar Panel Included, 1152Wh Portable Power Station w/ 4 1800W (2700W Surge) AC Outlets, LiFePO4 Emergency Power for Camping, Off-grid, Power Outage

The Amazon link that I used to buy the product, says I bought a 200W:

BLUETTI Solar Generator AC180 with 200W Solar Panel (Ships Separately), 1152Wh Portable Power Station w/ 4 1800W (2700W Surge) AC Outlets, LFP Power for Camping, Off-grid

So I ordered a 200W and got a 200S.

Still Low Charging

Thank you for recognizing that the charging power is low :) But I have tried both panels by themselves, and I am still getting at most around 80 watts for the older 200-Watt panel and substantially less for the other, and the fact that they don’t play well together can’t account for that.

The reason I got the second 200W panel was that the first one was taking so long to charge the powerbank.

In the meantime, so far as I can tell Bluetti shipped me the wrong panel twice. Ordinarily I wouldn’t care but apparently it does matter…

Bluetti-newer-panel

Bluetti_older_panel

43

The solar industry (not just Bluetti) all partially stretch the truth in terms of what solar panels are capable of producing realistically. The standard test conditions are inaccurate and don’t reflect real world performance. Their advertised rating is all in a perfect world scenario and mostly a fantasy. A more realistic approach is 70% of its total capacity (under no clouds and perfect alignment). There is ZERO reason why you should not be able to achieve that. That’s 140 watts. My PV200 panel can produce around that mark consistently, so luckily for me my PV200 is meeting expectations. What’s not normal is 40 and 80W.

44

Regarding differences in open circuit voltage here’s what I learned:

For parallel connections, use panels with the same or very similar open circuit voltages (within about 0.5–1V of each other) to minimize losses and avoid potential issues…They are within 1 volt of each other (25.6/24.6)

45

The reason why you want the voltage close when running in parallel is if one of the panel has “significantly lower voltage” than the others, the higher-voltage panel can/will back feed into it, producing waste heat, energy, but more drastically failure. Bypass diodes should step in, but it can only handle so much. This is why Bluetti always says put matching panels in parallel (i.e. PV200 with PV200) NOT PV350 with PV200

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46

This has turned into another learning experience. I had never heard of OCV before and I didn’t know that the panels should be roughly equal in power. I’ve been running different kinds of solar panels on the van for years (lol). They are roughly equal in power but have had greater differences in OCV and functioned OK - although two are in bad shape…

I asked AI Perplexity - which seems to be doing pretty good thus far - about this…It said

Pairing two 175W solar panels (Voc 21.8V), a 160W panel (Voc 22.2V), and another 175W panel (Voc 24.48V) with an MPPT controller will not damage the panels or the controller, as long as the combined array voltage and current remain within the MPPT controller’s rated specifications . However, you will experience some efficiency loss,

The difference between 21.8V, 22.2V, and 24.48V is within about 10–12%. This is generally considered acceptable for parallel wiring, though the closer the voltages, the better the efficiency

Minor efficiency loss (typically <10%) is expected due to the voltage mismatch, with the highest voltage panel operating below its maximum potential

The MMPT controller - a Tristar 60 AMP MPPT - is apparently able to handle that as its doing fine- and yes, thank you - it’s an Elite 200 V2.

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47

That’s what I thought! Thanks for the numbers :)

48

The key word in OCV is “open circuit”. It’s what the panel produces by itself while under no load. It’s an “open circuit”. Example my PV350 is 46.5V OCV. When you plug in the solar panel, open up the app and quickly look at the voltage. It’ll be near the OCV. Then once the unit clicks over, it will go down to around the “VMP” (voltage at max power) numbers. In the case of the PV350 a solar noon Sun will net you around 37.5V. When planning your solar configuration you have to factor in the OCV of the panels and not the power they produce while actually being used.

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