AC 200 not charging at full capacity

I have 3, 24v 200 W panels in series for a total of 600 W at 137 V
5.32 A I turn on the unit with full sun showing 137Volts then before
the Watts show on the screen it drops down to 109 volts at around
400 Watts what the hell is going on. Checked voltage at 137 Volts from
panels. The unit is not accepting all the power that is going to it. I hope somebody can help me get this fixed.

Here is “what the hell is going on”. 3-24 volt panels would give 72 volts so there is something magical on your end to get 137 volts. Secondly…the charging rate you need to be interested in is the watts only as that is the rate of charge. You will not get 600 watts out of three 200 watt panels as solar panels do not produce their full rated wattage exept in rare perfect conditions which occur about as often as unicorns appear in my mailbox.

It is perfectly normal for voltage to reduce after charging begins and the system is under load. Any solar panel will output more voltage when not connected to a load than when connected to a load. The charge controller will vary the volts and amperage to maximize the incoming charge. Unless you have actually seen 600 watts of charging on the panel drop to 400 watts on the panel you were not getting 600 watts in the first place. Do you by chance have more than the (3) panels stated above and that is why the voltage you measured was so high? The wattage incoming will constantly vary during the charge cycle due to sun conditions and the MPPT charge controller doing its job. This is entirely normal.

  • Open Circuit Voltage 45.4V each panel x3 =136.2V
  • So the charge controller is reducing the voltage and wattage
  • So if I add 1 more panel will it make a difference or will the charge controller
  • throttle it down?

One more panel would exceed the voltage limit. 400 watts out of 600 watt rated panels are not too bad. If you added another panel, try two sets of two wired in series and the connect the two pairs of panels in parallel. This will keep you under the voltage limit

Ok vmp is 37.6v per panel, if I add a 200W 24V panel then I will have 4 panels all the same.
I can put 2 in series and 2 in parallel and this will work, if so how do I branch connect to the Bluetti?
The total Voltage will = 150.4

No, you need two seperate groups of 2 panels each connected in series. This should give you 75.2 VOC for the connected pair. Now take both of these series connected pairs and connect the two pairs in parallel using two “Y” parallel branch connectors. This should give you a max voltage of 75.2 VMP
and 10.64 amps according to your specs. This would be a theoretical max wattage of 800 watts and on a perfect day with perfect solar panel alignment I would think you should see 650 to 700 watts incoming.

The connection type described above is called series-parallel

Thanks so much for you input. I will order parts and try it out.
And will let you know how it worked out.

No, but if you google series / parallel solar panel connections you will find a variety of info and videos

Hi Scott,
I put the same thread on another forum got different answer, this is what he said.
AC 200 has a max input of 150V which is calculated using Voc not Vmp.
4 panels in series is 184V which is way over your 150V limit.

That may be true, but I never said to put four panels in a series which would indeed exceed the 150V limits.

What I said was to put two sets of two panels each in series and then connect both those sets of series in parallel which would give you approx. 92 volts. You do this by:

Take two panels and connect one of the female connectors to the male connector in the other panel. This leaves you with a pair of panels with an unconnected male and female connector Take these two panel and set them aside.

Now take the remaining two panels and connect them exactly the the two above and set them aside.

This will leave you with two identical pairs of solar panels that are each connected in series but not in any way connected to the other set yet.

Now you need to take these two sets (which act like a single large panel at this point) and connect both sets (of 2 panels each) in parallel with a “Y” branch parallel connector.

You connect them in parallel like this: Take one male connector from each set and connect it into the branch connector that has two female connectors. Now take the female connectors from each set and connect them to the branch connector that has two male ends. That will now leave you with a non connected single male and female connector coming out of the pair of branch connectors. Connect this to your solar charging MC4 cable and you are good to go. If you bought solar panels with crappy little short cables, you may need to make or buy some extensions so that everything will reach but other than that, you should be good to go. The below diagram and attached video explains what to do graphically. It takes longer to describe than to actually connect.

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