McLarry Posted February 15 Share Posted February 15 So I'm stumped... I have an inverter 5.5kva Fivestar and purchased some Canadian solar panels but think my inverter might not be able to take all the panels in a series setup or splitting them into two arrays and connecting those in parallel. Anyone know how to work this out? Chat GPT has me going in circles.. .. My solar inverter solar controller has a capacity of PWN 105 VDC with MPPT 150VDC Maximum PV array power of 3200w Maximum solar charging current is 80A How many solar PV panels can I connect if the specification of each panel is: Normal maximum power(Pmax) of 545w , Optimum operating voltage (Vmp) 41.5V Optimum Operating Current (Imp) 13.14A Open circuit voltage (Voc) of 49.5V and a Short circuit current (Isc) of 13.95A Quote Link to comment Share on other sites More sharing options...
Jacques Ester Posted February 15 Share Posted February 15 Hi McLarry. I would connect 2 panels in series. this gives you an open circuit voltage of 99V. That is enough to start your charging and far enough below your max of 150VDC. 6 panels will work. Connect in the following order. 2 in series en then all 3 strings in parallel. 2S 3P. You will need a combiner box with protection for this. McLarry 1 Quote Link to comment Share on other sites More sharing options...
GreenFields Posted February 15 Share Posted February 15 3 hours ago, McLarry said: My solar inverter solar controller has a capacity of PWN 105 VDC with MPPT 150VDC Maximum PV array power of 3200w Maximum solar charging current is 80A Just a sanity check. Which exact inverter is this? Please give the model code, and confirm the battery Voltage. The solar charge controller is either a PWM-type, or the MPPT-type, not both at the same time. I'm seeing for example a 5.5kVA 24V PWM Fivestar FiveStar 5.5KVA 5KW 24V Pure Sine PWM Hybrid Solar Inverter - Nova Craft (nova-craft.co.za) And a 5.5kVA 48V MPPT Fivestar Five Star 5000W 5.5KVA 48V Hybrid Inverter 80A MPPT | LEROY MERLIN South Africa, The optimum panel configuration could be different between these types of inverters. McLarry 1 Quote Link to comment Share on other sites More sharing options...
Kalahari Meerkat Posted February 15 Share Posted February 15 @McLarry, @GreenFields is right there seem to be many models you would need to give more details on the model and the specifications thereof if it is this one, for instance the 2 panels in series is probably as far as you want to go, but it also is of interest where you are, or at least what kind of minimum temperatures you could be looking at in winter, since the Voc can be more at temperatures that are low. But still, if 150V is the max MPPT input voltage, you probably won't want to go for 3 panels in series, since that is too close for comfort and if you should go to freezing temperatures, I suspect you'd exceed the 150V and unwanted smoke signals may come from your inverter. On the parallel side, if the linked model is correct, not sure whether the 80A refers to the current on the solar end or the output current to the battery, if its for the solar input, then 6 parallel strings should be ok at 83.7 A, but since that is Isc and not Imp, for Imp being 13.14 A with 6 parallel 2 series string you'd be at 78.84 A if my mental 'rithmetic didn't fail me there and this should be within limits... McLarry 1 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted February 15 Share Posted February 15 4 hours ago, Kalahari Meerkat said: @McLarry, @GreenFields is right there seem to be many models you would need to give more details on the model and the specifications thereof if it is this one, for instance the 2 panels in series is probably as far as you want to go, but it also is of interest where you are, or at least what kind of minimum temperatures you could be looking at in winter, since the Voc can be more at temperatures that are low. But still, if 150V is the max MPPT input voltage, you probably won't want to go for 3 panels in series, since that is too close for comfort and if you should go to freezing temperatures, I suspect you'd exceed the 150V and unwanted smoke signals may come from your inverter. On the parallel side, if the linked model is correct, not sure whether the 80A refers to the current on the solar end or the output current to the battery, if its for the solar input, then 6 parallel strings should be ok at 83.7 A, but since that is Isc and not Imp, for Imp being 13.14 A with 6 parallel 2 series string you'd be at 78.84 A if my mental 'rithmetic didn't fail me there and this should be within limits... If 12x545W (2S6P) panels the 3200W PV input is exceeded far too much. Normally the Solar charge input is the battery charge value. McLarry 1 Quote Link to comment Share on other sites More sharing options...
Kalahari Meerkat Posted February 15 Share Posted February 15 1 minute ago, Scorp007 said: If 12x545W (2S6P) panels the 3200W PV input is exceeded far too much. Normally the Solar charge input is the battery charge value. The current is a function of the inverter, it will "let" the current or restrict the current, the scenario I painted/described would allow overpaneling for those cloudy days, but it does mean without implicitly stating the obvious, you calculate out the amount of parallel strings you need to achieve the correct power, unless you want to to provide for those cloudy days,... the important one is the Voltage on the PV input, since the inverter has no control over this, but you can provide more potential current, which won't get used, but would allow on cloudy days, to provide more power than you would get without the overpaneling... Again to clarify, the 2S6P suggestion is just this and would work and would provide more power on cloudy days than otherwise, as for the 7 minutes ago, Scorp007 said: Normally the Solar charge input is the battery charge value. that should then be clarified on the spec sheet since that is a bulldust way of specifying what the solar input would allow current wise to flow... see Deye, SunkenSynk and most others that specify the MPPT limits in terms of Voltage and Current, one could calculate it out, but then the yobos need to specify the efficiency of their MPPT to battery Voltage buck circuit... either way, putting a value for current on the MPPT side that needs some calculations to be done, should then force the product manufacturer to specify how the calculation need to be done to end up with what they should have specified in the first place, I reckon... McLarry 1 Quote Link to comment Share on other sites More sharing options...
McLarry Posted February 15 Author Share Posted February 15 (edited) 8 hours ago, Kalahari Meerkat said: @McLarry, @GreenFields is right there seem to be many models you would need to give more details on the model and the specifications thereof if it is this one, for instance the 2 panels in series is probably as far as you want to go, but it also is of interest where you are, or at least what kind of minimum temperatures you could be looking at in winter, since the Voc can be more at temperatures that are low. But still, if 150V is the max MPPT input voltage, you probably won't want to go for 3 panels in series, since that is too close for comfort and if you should go to freezing temperatures, I suspect you'd exceed the 150V and unwanted smoke signals may come from your inverter. On the parallel side, if the linked model is correct, not sure whether the 80A refers to the current on the solar end or the output current to the battery, if its for the solar input, then 6 parallel strings should be ok at 83.7 A, but since that is Isc and not Imp, for Imp being 13.14 A with 6 parallel 2 series string you'd be at 78.84 A if my mental 'rithmetic didn't fail me there and this should be within limits... @Kalahari Meerkat @GreenFields Thank you both for the feedback. The inverter is PWM so 105V thanks for pointing that out. I had purchased 8 of these panels without knowing the limitations of the inverter Based on the feedback here, what I'm understanding is that I could possibly connect 2 panels in series and have 3 groups of these and then connected the 3 groups in parallel? (So a max total of 6 panels) I'm based on the garden route so no risk of super low temperatures but many cloudy days to come especially in winter. The panels orientation is also not ideally situated towards full North but more North East. If this were the optimal setup would I need a combiner box 3 in 1 out? To make my bad decision wors I presumed I could just connect all 8 panels I purchased in a single string so have bought a 1 in 1 out combiner box Thanks for the advice Edited February 15 by McLarry Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted February 15 Share Posted February 15 4 minutes ago, McLarry said: @Kalahari Meerkat Thank you for the feedback. The inverter is PWM so 105V thanks for pointing that out. I had purchased 8 of these panels without knowing the limitations of the inverter Based on the feedback here, what I'm understanding is that I could possibly connect 2 panels in series and have 3 groups of these and then connected the 3 groups in parallel? (So a max total of 6 panels) I'm based on the garden route so no risk of super low temperatures but many cloudy days to come especially in winter. The panels orientation is also not ideally situated towards full North but more North East. If this were the optimal setup would I need a combiner box 3 in 1 out? To make my bad decision wors I presumed I could just connect all 8 panels I purchased in a single string so have bought a 1 in 1 out combiner box Thanks for the advice Based on the earlier post showing a 3200W PV input 48Vx80A=3840W. 2 panels in series is also getting too close to Voc=105V. Using as single in parallel strings is below 60V and controller will not start. Panels with about a Vmp of 34V are more suited to these PWM controllers. Quote Link to comment Share on other sites More sharing options...
GreenFields Posted February 15 Share Posted February 15 37 minutes ago, McLarry said: @Kalahari Meerkat @GreenFields Thank you both for the feedback. The inverter is PWM so 105V thanks for pointing that out. I had purchased 8 of these panels without knowing the limitations of the inverter Based on the feedback here, what I'm understanding is that I could possibly connect 2 panels in series and have 3 groups of these and then connected the 3 groups in parallel? (So a max total of 6 panels) I'm based on the garden route so no risk of super low temperatures but many cloudy days to come especially in winter. The panels orientation is also not ideally situated towards full North but more North East. If this were the optimal setup would I need a combiner box 3 in 1 out? To make my bad decision wors I presumed I could just connect all 8 panels I purchased in a single string so have bought a 1 in 1 out combiner box Thanks for the advice Eish, not a happy situation, your panels just don't match your inverter well at all. Even if you get super unbelievably lucky and never blow the inverter, your panels will still be losing around 35% efficiency right out the gate. Honestly, I'd try to return the inverter and swap it for one with an MPPT charge controller, preferably a high-voltage input of around 450V so you can put all 6 panels in series. There are a few brands making 5kW inverters of that type in that price range around R10K or a bit less. Otherwise, maybe sell the Fivestar PWM inverter to someone who mainly wants to use it just as a UPS for backup, or has a panel set with lower-Voltage Voc of around 40-45V. Scorp007 1 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted February 15 Share Posted February 15 @Kalahari Meerkat Yes I fully agree on the way Deye/Sunsynk provides the values. If we rewind about 2yrs then they also did not provide this info. It is still common practise for the Voltronic and hundreds of clones to rather provide the battery voltage and battery charging as many replies by me and Coulomb have pointed out in the past. Quote Link to comment Share on other sites More sharing options...
McLarry Posted February 16 Author Share Posted February 16 10 hours ago, GreenFields said: Eish, not a happy situation, your panels just don't match your inverter well at all. Even if you get super unbelievably lucky and never blow the inverter, your panels will still be losing around 35% efficiency right out the gate. Honestly, I'd try to return the inverter and swap it for one with an MPPT charge controller, preferably a high-voltage input of around 450V so you can put all 6 panels in series. There are a few brands making 5kW inverters of that type in that price range around R10K or a bit less. Otherwise, maybe sell the Fivestar PWM inverter to someone who mainly wants to use it just as a UPS for backup, or has a panel set with lower-Voltage Voc of around 40-45V. @GreenFields Thanks again for the advice and agree, a different inverter would be the best solution. From what I can tell something like this would support the 8 panels I have in series -? Link so all in a single string? HY8048 MPPT- 100 -WIFI Specifications: Inverter Mode : Rated Power: 8000VA/6000W DC Input: 48DC,127A AC OUTOUT: 230VAC ,50/60Hz, 23.9A , 1c AC Charger Mode: AC Input: 230AVC, 50/60Hz , 38.5A, 1c DC Output; 54VDC ,30A Max 80A, Default 30A AC Output : 230vac ,50/60hz, 23.9A ,1c Solar Charge Mode: Rated Power: 6000w Mac Charger: 100A Nominal Operating Voltage: 240VDC Max. Solar Voltage :(VOC) : 500VDC MPPT Voltage Range: 120-450VDC Quote Link to comment Share on other sites More sharing options...
Kalahari Meerkat Posted February 16 Share Posted February 16 (edited) 1 hour ago, McLarry said: Link so all in a single string? Yes, 8 X 41.5Vmp = 332V and thus well within the MPPT range of 120-450V.. Again they don't specify the current the MPPT will consume, so it may not run at 13A, one would hope it will, though... Edited February 16 by Kalahari Meerkat fat fingers Quote Link to comment Share on other sites More sharing options...
McLarry Posted February 16 Author Share Posted February 16 6 hours ago, Kalahari Meerkat said: Yes, 8 X 41.5Vmp = 332V and thus well within the MPPT range of 120-450V.. Again they don't specify the current the MPPT will consume, so it may not run at 13A, one would hope it will, though... @Kalahari Meerkat thanks for the confirmation. Could you advise on how the combiner boxes work so if I had a string of 6 panels and another string of 2, split in this way due to roof space issues could I have both strings still connected in series and use a 1 in 1 out combiner box or would I need a 2 in 1 out combiner box? Quote Link to comment Share on other sites More sharing options...
Kalahari Meerkat Posted February 16 Share Posted February 16 Just now, McLarry said: @Kalahari Meerkat thanks for the confirmation. Could you advise on how the combiner boxes work so if I had a string of 6 panels and another string of 2, split in this way due to roof space issues could I have both strings still connected in series and use a 1 in 1 out combiner box or would I need a 2 in 1 out combiner box? This would be one string all 8 panels in series... no combiner needed, just ensure that you run both positive and negative cables together to the 1st panel, where you will connect, let's say the positive to your positive cable, then run the negative close to the positive cable from the panel up to the box on the panel and from the box, with the negative cable from the panel, together to the next panels positive lead and plug the 1st panels negative lead into the 2nd panels positive lead, rinse, repeat until the last panels negative cable plugs into your negative cable... the idea here is to have a transmission line from the inverter side all the way to the panels and not a *large* loop antenna that may cause RFI and get the nearby amateur radio operators come looking for blood Quote Link to comment Share on other sites More sharing options...
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