Very low charge from two sp 350 panels into be AC200 Max

Just received the AC200 Max with two sp 350 folding solar panels this weekend. First time charging with panels connected in series I am only getting 150 watts average with a clear sky (not a single cloud) no shading at all. Under these conditions I would expect maybe around 600 watts. Tried each panel individually but both gave the same output at around 60 to 80 watts. The highest watts I seen very briefly was just over 200 watts. Turning the DC power out on with no load improves the charge by 10 watts. The AC charger was giving 490 watts so that looked normal. Am I missing something or did I get a defective product?

Regards Rick

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Might be close to fully charged. That’s what mine does when it gets close. I am interested in those panels. I have 180 BougeRV 5 of them to charge mine.

Right out of the box the AC200 Max was at 63% charge. It did get to 88% with 4 hours of solar panels in unobstructed sunlight late morning to mid afternoon with the performance describe above. I think that would be less than expected.

63% to 88% = 25% of the unit’s capacity = 0.25 * 2,000Wh = 500Wh. Spread over 4 hours, that’s an average of 125W, which agrees reasonably well with the 150W reported.

That performance really does seem very low for one 350W panel, much less two. (For comparison, I can get 150+ watts from a single SP200 panel, so something definitely seems wrong.)

On a related note, I’ve been a bit concerned about the Amazon reviews for the SP350: The SP120 and SP200 both have very good reviews, averaging around 4.6 stars. However, if you filter reviews to just the new SP350, there are only two reviews: Both give just one star, and both complain about very low output. As such, I do wonder if there is something wrong with the SP350?

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Something doesn’t seem right. I would expect you to get around 250-275w per PV350 on a clear cool day. Was the AC200max set to PV input mode? Can you measure the voltage of the PV350 panel when it is not connected to see what you get?

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When I first checked the settings the DC input was set to other. Tried a couple times to change to pv but it would not change. Then this morning I tried again before hooking up the panels and I was able to switch to pv on the input. But I have a high thin cloud layer so performance can’t be compared to cloudless conditions. I will update when that happens.

Update: So clouds cleared out and performance improved. Saw a peak on watts going in at 493. But performance varied with large swings 350 to 490. Any small change in angle at the sun or a wisp of cloud cover degrades performance. Even when sunlight and panel position is stable there were swings in performance +/- 20-30 watts. Is that normal? Is 70% of rated out put normal?

Thanks Rick

I have some inconsistent results on the actual recharge from PV.
Four 245W panels in series, a voltage of about 120V, charging varies enormously from 180W to 500W and even 600W, without a reasonable explanation. Always having the same sunny condition !!!
Some tests:

  1. Supplied PV and AC power supply sometimes interrupts PV charging
  2. PV and AC power supply supplied sometimes very powerful PV charging
  3. I disconnect the AC power supply, the recharge from the PV decreases significantly
  4. AC power supply connected and solar panels connected AC always at maximum absorption 460W

70% of rated output is pretty normal. The rated output assumes tropical sun with sub artic temp. Not really going to happen. Typically good day and angled nicely you will see about 75% of rated. 70% isn’t unreasonable.

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What kind of panels are those 245w ones? What is their voltage and current specs?

I apologize for my english (google)
I wrote wrong, they are number 3 Schuco MPE 245 P5 08 panels
245 W
Voc 37.7 V
Isc 8.74 A

I tried everything
I have checked with my digital meter the volts and amps on several different panels
They all show high watt readings but when plugged into the Bluetti max I get half the wattage
To get 900 watts input I would have to buy 1600 watts of panels
I think the problem is the MPPT controller
How can I test that?

What panels are you using?
You can expect 75% of panel’s rated output on a good day.
How are you connecting the panels? How many are you using?

The issue is not what panels I’m using.
The issue is the measurement I’m getting with my multimeter and how it compares with what the MPPT controller is allowing
It’s way off!!!
If a 150 watt panel only gets 60 watts in direct sunlight, that’s way less than 75%
How do I inspect the MPPT controller?..… it’s obviously not working correctly

How are you connecting it/them to the AC200? What are the specs?

I think the Chinese tricked me into a ch

I think the Chinese tricked me into a cheaper PWM controller instead of the better MPPT controller!!
What I measure with my multimeter should match what the controller is reading…. Not 50% less!!!

Hi, if you are trying to show you are measuring Watts with the meter in your pictures, that is not correct. For Watt measurements you need to monitor both voltage and current. Looks like your meter is only measuring voltage based on the pictures. It would certainly explain the discrepancy.

If by “chinese” you are referring to Bluetti, then no, you have an MPPT controller in there. By the way, Bluetti is an American based company, but like everything else, their equipment is manufactured in China.

Now, looking at the pictures you have, it seems that you’re measuring at a connector, but I don’t recognize that connector for the AC200MAX. It looks more like the one I have for the AC300?

It is actually the connector for the AC200Max, I have the same.

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