I am trying to configure my solar to charge my AC180. I have 2 250 W panels. rated at 30.3 v and 8.37 amps In parallel they work fine but I get 16.74 am and the 30.3 v. The AC180 is only taking about 8 of the 16.74 amps so in a parallel configuration I am only getting about 210 Watts. From the specs, If I put them in series, I just go over the 60 v limit. ie 60.6 v with 8.37 amps. After all I have read here about not exceeding the 60 v maximum I am hesitant to switch to series. Is there any other way to lower the voltage coming out. I will have a long wire run 50 feet to the AC180 would that drop be significant enough to be safe. Or would covering some of the panel so it doesn’t get so much light or some other physical thing I could do, lower my voltage to within limits. I am in Arizona and they get a lot of light.
partially covering panel will usually drop the amps more than volts. Get a multimeter and experiment with voltage drop with your 50ft extension
Hi @vicki81
You could use a voltage Step Down Module or also known as buck converter. This will take a higher voltage and output a less high voltage with more amps
greetings
Erik
I will take the following MPTT charger (take exactly the references that I give you below, not the other models from Victron, there are many)
Victron Energy SmartSolar 100/20 https://www.amazon.com/Victron-SmartSolar-MPPT-Controller-Bluetooth/dp/B075NPQHQK
explanation : SMartSolar =with Bluetooth
100/20 → you can ajust the tension, above 30V to avoid the 8 amp limitation and under 60V not to burn the mppt of your AC180.
Don’t reverse plus and minus! when you connect to the DC input of your AC180! (check with a multimeter before connecting: voltage and polarity)
PS 1 Bluetooth will allow you to configure with your smartphone… there are a lot of parameters, it may seem complicated… but there is a fairly detailed manual. After that you will become a very enlightened amateur! You will also have lots of interesting statistics on the power delivered by your panels.
PS 2 Some will say that it may be a problem to put a Victron mppt on the AC180 mppt… my experience with an AC200max is that it works well! you will tell me “why did I need a Victron mppt when there is the AC200max mppt which supports up to 145 V?” quite simply because the MPPT of my AC200 max cannot find the Maximum Power point of my configuration of solar panels in parallel, while the Victron succeeds.
Vicki has said she can’t use more amps. She would need a buck converter to take it down from 60v to just under 60v to get the results she’s after … I haven’t seen any buck converters in that range
If she connect all the panels in series, there is enough room for a bit of a current increase. One Panel seems to have about 4 amps.
No, Erik, the AC180 is limited to how many amps it can draw
Correct.
500W Max, VOC 12-60VDC/ 10A is mentioned in the official documents. The 10A cant be used all the time, 8A is more a reliable value. Here two panels have in parallel 30.3V and 8.37A. This means in series we have 60.6V and about 4A. The converter can be set to take 60V 4A and output 50V 4.8A to have the same result. This is still within the 8A range.
Nope, putting the panels in series does not half the amps, they remain at 8a
Erik, you need to read Vicki’s post again. She has 500w of panels, not 250w
Yeah, it’s a bit of a pain shopping for solar panels that will make the most of your system.
As for the panel ratings, is that 30.3 Voc and 8.37 Isc? If it’s not Voc then definitely DON’T wire them in series as you’ll likely get the “Over voltage” alarm.
I guess it would be tempting to see if you can add a bit of shade, say with Duct Tape. I know on one of my 550W bifacial panels it doesn’t take much to lose 100 watts from a small bit of shade, but I never measured the voltage.
If you only need to lower the voltage by 0.6 to 1.2 volts, consider adding 1 or 2 diodes in series with your panel cable. For convenience, you can purchase diodes that are designed for solar panels and connect directly to the solar panel cable.
Assuming these diodes are silicone diodes, each diode in series should drop the voltage by 0.6 to 1.0 volts, depending upon the current being drawn. HOWEVER, what I’m not quite sure of is the whether the diodes will protect sufficiently in an OPEN CIRCUIT VOLTAGE situation.
In other words, when the Bluetti AC180 is fully charged, does the solar panel input circuit of the AC180 change to an OPEN CIRCUIT condition?
Any other opinions on all the above are welcome.
This is probably an issue that Bluetti tech support should answer.
–pete–
Hello
I think there is a risk with this method (blocking diode/shottky diode): this occurs when the diode fails. In 2 cases this goes well: the diode is “cut” (open circuit), the diode lets current flow in the opposite direction (conduct electric current in reverse bias).
But there is a case where this can go bad : the diode fails and is in short circuit : there is no longer any voltage at its terminals (or very low voltage) so it can no longer reduce the voltage of the panels ! in this case, danger !
Snips, I understand your points and it’s wise to consider the risks when parts could fail over time. So I’d recommend using 2 diodes in series because risk is very small that both diodes will fail simultaneously. Also choosing a diode rated for 2 to 3 times the AMPS (20amps diode) normally required will help to avoid any failures.
In this particular case, the over-voltage condition is less than 1 volt, so it’s important to know from Bluetti if 61 volts on the input of the AC180 will merely produce an error code, but not actually damage the device over a short period of time less than 12 hours.
It’s also important to know whether the diodes are shottky or silicone because silicone provides a much higher voltage drop than shottky. Unfortunately, the specs on Amazon do not specify the type, so more detail needs to be determined by the manufacturer or seller of the diodes.
“quite simply because the MPPT of my AC200 max cannot find the Maximum Power point of my configuration of solar panels in parallel, while the Victron succeeds.”
When I switched from Series to Parallel on the AC200MAX I also noticed the poor tracking performance and asked Bluetti about it in the below thread. After updating the firmware to DSP4005.08 performance was much better. I wonder if you still need the Victron.
AC200MAX and B300 Expansion Battery misreporting charge level - Product Discussion / BLUETTI AC Series - BLUETTI Community (bluettipower.com)
Hello Pete2004,
With what has been said, the people concerned will be able to make an informed decision!
Thanks!
Thank you for this information. My 2 AC200max have the DSP4005.08 firmware, when I have a free weekend… and some sunshine (!) I will retest with my 12 flexible 100W DOKIO DFSP100 panels. PS I also advise against taking these panels for compatibility problems when they are mounted in parallel with the Bluetti and because they have some “hotspots”.
Thank you so much for the response to this question. I have solved the problem but not the way I though I would. I have upgraded to the Bluetti 200L, which handles a series configuration much better. As a result of the upgraded ability to handle more volts and amps I have added 2 more panels and have the whole thing working in series. These are used panels and they are not exactly aliened with the sun because of where I have to place them but I am getting 800 watts out of my 1000W array during peak hours here in Arizona and I am a happy camper. This whole discussion has been very helpful. I still have the 180 and am now running a refrigerator with it. I am hauling in the sun with the 200L and distributing to the 180 and 4 100 amp hour batteries. Thanks again for the help. I will be back later as I try to figure out how to use that energy in the batteries in the most efficient way for me. I am not trying to run a whole house. Just 1 refrigerator and 1 freeze.