I’m hoping some one could help me troubleshoot an issue that just came out of nowhere. When I went to bed last night everything was working well with my AC200max, I wake up this morning and the solar charger is no longer working. (The display shows an INPUT VOLTAGE fluctuating from (65 to 85) but there’s 0 power coming in.
I have 2 (545w solar panels with a VOC of 49.90 = total 100 VOC). The panels are mounted to the wall of my house, and the unit is used as a home-office backup unit. So both the panels and AC200max have been in the same spot for over a year. Then it just stopped working.
The confusing part about all of this is, when I unplug and plug back the PV cable after turning off the unit, it automatically turns back on (meaning that the AC200max is aware that a solar is connected but is not charging).
The AC200max was at 65% in the morning (it has 2 additional b230 batteries connected to it) which were all sitting at more-or-less around the same percentage. Both the batteries and AC200max are placed on top of cardboard boxes 14cm high (so they’re not directly sitting on the floor) to avoid quick discharge. But they are next to the window in my home office.
We are currently in winter, Johannesburg (lowest temp last night was around 6° Celsius), by 7am it gradually increases to 7°celcius and by 11am it’s 14°celcius.
It’s been a lot colder before, but it was working fine, till I woke up this morning.
When the true state of charge of the battery is full, it will no longer accept any input from solar. However, the BMS can miscalibrate the SOC on the device, so while it reads 65% on the screen, the battery is actually full. This is why when you unplug and replug the solar it acknowledges it, but no charging occurs. Try unplugging your solar then allow the unit to discharge for a while, then replug back in the solar and see if it charges again. If this happens, you likely have a miscalibrated battery. It’s really 100%
It’s currently evening where I live (6pm) no sun… So I won’t be able to test the solar till morning. I will attempt to drain all 3 batteries overnight to 0% and test the solar charger in the morning. I currently have it unplugged, I will plug it back in 9am in the morning and hope for the best.
You can just drain the head unit as the AC200Max I believe has a built in battery. You want to isolate the two B300s so they don’t attempt to keep “topping off” the head unit (i.e. the AC200M). If you always stay at 100% you will encounter voltage drift from micro miscalculations by the charging logic of the BMS, leading to it displaying at wrong percentage on the display. The same effect can happen if the BMS screws up and thinks the battery is 100% when its not full too! The system won’t allow any input in that case because the BMS believes charging isn’t needed. In this case your display will show 100% but the battery may be at 65%. So you have can a fully charged battery show 65% on the screen, and a 65% battery show 100%! More like PMS not BMS
@sealy1986 Thank you so much for this information I think is makes sense, since the load I put on my AC200M is always around 1000 or so watts, my batteries mostly hover between 85% to 99% for the most part during the day. I can’t remember the last time they drained to zero. So it is possible that with 3 batteries something could be miscalculated. I’m hoping that’s the case, cause I’ve been stressing all day.
Quick Question if I may: If the solar charger was completely shot, would it still display an input voltage or would it be completely shot? I will attach a picture I took this afternoon
A fully charged battery will still show an input voltage, but it won’t draw any significant current (amps), thus why the input power (watts) shows zero. The MPPT controller is also regulating what it will accept as well, but that’s just more so how MUCH it will accept during certain conditions like temperature or the limits of the unit itself. All that voltage reading is essentially telling you is hey there’s a power source connected. If it was zero, then your port is dead or the source is dead. It’s actually a good thing to see that reading. Another reason why you’ll see high voltage but zero watts (no current) is due to high internal resistance. Ohms law dictates that you need a lower resistance for electrons to flow. R= V/I. I=Amps or current. If current can’t flow due to high resistance you get NOTHING. You LOSE. Good day sir! Watts= Volts X Current, but if no current flows, guess what 1000000 million X 0 is still 0.
@sealy1986 - Thanks Eric, Aah, the problems of time zones @niotumi in South Africa, me in Australia, not sure where you are,
However, thanks for jumping in, you pretty well said what I would have, lol.
@Mandp and @sealy1986 Thank You so much for the help… but unfortunately for me, no dice… I woke up this morning to a very gloomy and very cloudy day… super cold with no sun at all, the INPUT Voltage is hovering between (0.0 and 13) unlike yesterday’s (65 to 85).
My only options right now are to order a multimeter online, and new cables to test with, best case scenario its the cables, worst case its the panels or unit… Thank you again, I will keep you UPDATED
We are also in winter here. I have a 6.6kW solar array, rooftop, with a 5kW inverter. Half my panels are east facing, half west, due to the roof orientation. I’ve seen 4.98kW output in summer, but in winter as low as 500W in the middle of the day, in conditions like your photograph. However, there are 2 inputs, 1 from each side at 352VDC and 403VDC. (7 panels one side and 8 on the other).
This is typical house install here and at far higher voltages a mid range power station can accept. So I can not use my grid connected solar to directly charge my power stations.
Once output gets too low, especially in the early morning and late afternoon, the voltage may not be enough to trigger a MPPT controller to start charging. Another point is if your panels are series connected, it only takes one panel or connecting cable or connector to fail and output is zero. Obtaining a multi meter that has the range for your panels and the whole system output is probably the first best step with regard to checking the array.
Hi @niotumi, We’d like to know if any error codes appeared on the AC200MAX or in the app when solar charging failed.
You can also test car charging to determine whether the DC charging module of the AC200MAX is functioning properly.
Additionally, please ensure the DC input source is set to “PV.”
Many thanks to @Mandp and @sealy1986 for their professional input — yes, recalibration can be very helpful.
We look forward to your update.
@Mandp I managed to place an order for a multimeter, new PV cables and MC4 connectors. They should arrive on Monday and I’ll be able to start troubleshooting this issue further.
Thank You for all the info, and suggestions… I still have hope that I might still be able to fix this issue.
@BLUETTI_CARE Thank You for the reply, I haven’t received any error codes on my unit since I purchased it. I’ve had it for about 2 years now, But I only started using solar mid last year. (1st year of purchase my AC200M was only used during blackouts/power cuts and charged via grid). I only started using my unit daily with solar mid last year, and I have made sure to always use it within the correct manual perimeters.
I think that’s why, this issue took me by surprise.
Did you plug the head unit into stable grid power to verify the unit at least accepts a charge? We would then know its isolated to solar-related problem only. With that said, cabling can fail (though uncommon) as well as the junction box inside the solar panel if you have one. Those are the most likely to experience high resistance. This is why I avoid those cheap panels like a plague. You know, the ones with white “goop”. They are junk.
@sealy1986 The wall charger seems to be working fine, I’ll attach an image below… With regards to the panels unfortunately for me, my solar panels are the ones with “white goop” , once the multimeter arrives I’ll then be able to finally figure out what the issue may be. If both the unit and panels are fine, it could possibly be one of the MC4 connectors (that’s the best case scenario). Just incase as well, I also ordered new cables and MC4 connectors incase something went wrong with either cable or connector. By Monday I should be able to continue troubleshooting the issue.
Hi @niotumi, Thank you for the update. It seems the issue is likely related to the solar panel or the PV charging cable. We look forward to your further troubleshooting.
Additionally, you can try charging via car input — if that works properly, it will confirm that the DC charging module of the AC200MAX is functioning correctly.
Many thanks to @sealy1986 for the attention and helpful response.
QUICK UPDATE: Your suspicions may have been right on the money, I’ve been checking my unit every other hour or so, since it stopped charging. Unlike most days with sun out, today however the INPUT Voltage was super low, ranging from (0.0 to 13) with the sun out unlike the usual (65 to 85) . Then all of a sudden late afternoon (3:40pm) I check the unit and see the INPUT Voltage has shot up to mid 90s (I’ve never seen Voltage that high for charging) and then it all of a sudden starts charging “100watts” (current weather: is windy with low sun, late afternoon 4:15pm, 13° Celsius).
It maybe an issue with a cable, connector or panel (possibly some high resistance somewhere in the setup), as you may having been suggesting
The multimeter should help me get to the bottom of this, my order couldn’t come soon enough… (I see light at the end of the tunnel)
Please tell me you did not mount a panel like this on your roof. If so I will need to pray for you lol. If you did, this is the wrong application. That thing would heat warp so badly I am surprised it even lasted as long as it did. The little box at the top is the junction box and if it fails, you will encounter high internal resistance.
R= I/V = 92V/1.03 ≈89.3Ω (since your unit was outputting 95W we know the amps is 1.03)
Assume it should output 10A @ 92V. 92V/10A ≈9.2Ω
So a factor of 10X more resistance.
It is normal for amps to be low, but that would be for normal things like if its shaded, the panel is extremely caked in dirt, or its cloudy outside. Once you know its high internal resistance then its a matter of finding out where. The panel. The junction box. The cabling, etc. A common mistake I see is improperly sized wiring for the appropriate cable run. Be aware though that you cannot test internal resistance from strictly the disconnected panels (open circuit voltage) with your multimeter. It won’t give you internal resistance results. Open-circuit voltage only tells you the maximum voltage potential with no current flow. Resistance requires some current flow, aka a load being applied to the panel. At a bare minimum you can use the multimeter to perform a short circuit current (ISC) test on the panel itself to see if its even capable of supplying current.
@sealy1986 I have 2 (545w Mecer Solar Panels mounted to the boundary wall of my property) with cables running underground in conduit pipes (PV cables 6mm - plus/minus 25metres) leading to my home office. (I opted for wall mounting because it’s easier to clean when it gets dirty or replace if it unfortunately gave out. I chose these panels cause they were very affordable with a 24 month warranty and (since they’re panels meant to be on the roof of a house I would assume they could handle any weather…
