AC200 Max not taking full available solar

Hello, I have an AC200 Max and have noticed an issue regarding it’s solar input. I have had the unit for about 6 months and use it regularly to power a refrigerator. I have been powering it with five 190 watt panels and it has been doing fine. I recently changed the panel layout to two connected parallel sets of 4 panels connected in series (2p4s). Each string will put out over 600 watts (peak) individually as I have verified and tested this. I have noticed that during the day as the sun gets higher and the solar should be increasing, the 900 watt solar input of the AC200 max stops at about 750 watts. So I’ll turn off one of the two parallel strings and check wattage of that string. Each string is putting out around 500-600 watts, so the combined total for the two strings in parallel should have no problem reaching the 900 watt max solar input, but it does. It seems to be capping out at 750 watts. So I flip the PV disconnect off and on for one of the strings and then the AC200 starts receiving the proper 900 watts into the solar and will keep at the proper amount the rest of the day.

I’ve had this happen the last three days since I’ve installed the second string of panels in parallel. Why would the system be receiving 750 watts (peak hours of the day) and when I flip the PV disconnect off and on it automatically jumps to 920 watts?

Hi @kent

i know this problem from another powerstation of another brand that i own.

It starts with full power and after some time it get stuck at a fixed value. After reconnect the powerstation and the PV its going again the highest possible value.

I never really get why exactly it does work like this. Try multiple different panels, all the same. But this is only one panel.

I had a similar Issue you described with EB240 where Solarcharging stuck on 38W. The problem here was that i use different panels that are wired in series at this time.

Do you using all the same panels in your setup?

Hi Erik,
Yes, all panels are the same. Two strings of four HQST 190 watt panels wired in series

@kent May I know the specification of the solar panel? Did you try to connect the solar panel in series?

The mentioned Panel “HQST 190 Watt” have the following specs:

  • Max Power at STC ( P max ): 190W
  • Open-Circuit Voltage ( Voc ): 24.3V
  • Optimum Operating Voltage ( Vmp ): 20.3V
  • Optimum Operating Current ( Imp ): 9.36A
  • Short-Circuit Current ( Isc ): 10.15A

In his Post he say that he have 4 panels overall. He run 2 pairs of series which are connected parallel together.

Series: 2 x 24,3V + 2 x 24,3V
Parallel: 48,6V + 10,15A + 10,15A

Input: 48,6V 20,30A

Do i get this right @kent @BLUETTI_CARE ?
Yes, the panel specs are correct but the panel arrangement is incorrect
4 panels in series and another set of 4 panels in series, connected together “paralleled”

I’ve do this arrangement before with another Bluetti AC200Max (the first one I owned was destroyed by water) and it always worked fine

If I connect all 8 panels in series it would be over the 145 volt limit

@kent Could you please provide me with the SN and the firmware version of your AC200MAX? I can check if there is firmware suitable for your case.

SN is 2232002619798

DSP 4005.07
ARM 4030.15
BMS 1017.02
HMI 6023.11
BMS1 1014.13
BMS2 1014.13

Ok, you have 8 panels connected in 4S2P combination :tipping_hand_man:, this means that the combination connection results in 2 X the Amps of one panel :tipping_hand_man:; Hence, this exceeds the Max PV input of 15 Amps for the AC200Maxm​:tipping_hand_man:. Therefore, you cannot attatin the max power from the panels :tipping_hand_man::tipping_hand_man:.

The way it works:

The way it works for combinations: xSyP = x panels connected in a series string, then y series strings connected in parallel, … x X y = number of panels ; that gives x times Volts of one panel with y times Amp of one panel to the power station :tipping_hand_man:

@kent Please try to update the DSP version to 4005.08 to test.

Update fixed the problem. System is now taking full available solar charge.


1 Like

Just for your information, if the amount of current (amps) that a solar array can provide is greater than what the system can use it is not a problem. The MPPT controller will regulate the current coming in to system. The primary thing to be concerned about when putting a solar array together is that the Voc is not greater than what the system will allow, as too high a voltage will damage the charging circuits. Having more current available in the solar array is referred to as “over paneling”. The advantage of doing this is that the solar array will provide the maximum solar input the system can take at an earlier time in the day, and during less than ideal weather conditions. This will help generate more power more easily.

I am also having difficulty getting anywhere NEAR the 900 Watts maximum input power from my AC200Max. The current unit is a warrentee replacment for a unit where a number of the power capacitors blew up in a rather dramatic, rapid fire manner.
The old unit would max out at 907 Watts before it blew up.
The current unit’s MPPT controller behaves very inconsistantly, but AT most I have gotten it to around 350 Watts under optimum conditions. Mostly, it is much less, and sometimes the input will be 0. At this moment, it is at 167 Watts… The MPPT controller acts more like a drunken sailor who is about to passing out from heat stoke. The behaviour makes no sense.
I have 1200 Watts of series connected 400W panels which are recently clearned. I am running the tests near high noon in summer at 39 degrees north latitude while nearing summer soltice. The sky is perfectly blue and the altitude is around 6000 feet.
The old unit would be taking in the maximum 900+ Watts under these circumstances.
I am an embedded systems focused electrical engineer with decades of experience. I have spent hours debugging this. I have tested each panel individually, both with the Bluetti and an Ecoflow I have as a backup. I have tried various combinations in series. All panels check out. All connections are solid.
My unit serial number is: 2339002197257. I have updated to the latest available software version just before I wrote this.
Am I missing something?

Just a thought: have you tried setting “dc input source” to “others” instead of “PV” ? normally this disables the mppt. If it works “better”, this will prove that the mppt is failing.

I see what happened. When I tried setting the DC source to “PV,” it evidently did not take. I did not notice this at the time. The previous unit had defaulted to "PV."My suspicion is that if there is already power coming in when the switch is attempted then it will not switch from “Other” to “PV”
Is this a bug or a feature? What is “Other” used for?

In any case, once I was able to successfully switch to “PV” then I started getting 917 Watts in. Yea!

1 Like

happy for you ! :grinning:

Is this a bug or a feature?
This is a feature for me, I cannot change from “PV” to “other” and vice versa if I do not disconnect the solar input.

What is “Other” used for?
“Other” is used, I think, to disconnect the MPPT (which is an awesome mechanism for getting the most power out of your panels). But if you connect for example an AC-DC adapter (or a battery) to the solar input to recharge the AC200max (in addition to the normal DC7909 input for the AC-DC adapter), you must set to “Other” because in this case the MPPT can cause the input power to fluctuate, and on “other” the power remains very stable and takes the maximum power of the adapter (this disables the mppt).

Very helpful, thanks.
So, I could pump 900W in in the “other” setting? What are the required specs to do so?
For example, what kind of (I presume) boost converter would I need to charge off of a heavy duty 12V alternator?

First of all I must tell you that I have never experimented with heavy duty alternators and converters on the solar input of the ac200max, but only AC-DC adapters on this input. What I say probably also applies to alternators and converters, but there may be other constraints that specialists in van and campsite fittings will be able to tell you better than me.

First the specifications of the solar input must be respected. VOC 10V-145VdC, 15A max.
Please note: it is not written, but if the VDC voltage is less than 30v, the intensity will be limited to 8A. If you want to go up to 15A, I advise you to be at least 35V.

And if you want to go up to 900W, as the intensity is limited to 15A you have to go at least up to 60V (if your alternator and boost converter can go up to that point : 60V, 900W) .

This is hugely helpful. I do have a boost converter that maxes at at 60V and 15A. I’ll put that on my experimentation todo list.