Alexkatamar
New Member
Hello! Please help me , I have Chinese inverter with 2 MPPT with allowed current 18A each , my 2s (18 panels) 1p gives Isc 21.58a ,is it critical or controller just won’t take more than allowed ?Thank you for answering !
Current overshoot
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littleharbor2
Solar Addict
Each panel is 21.58 amps? Sounds fishy.
Alexkatamar
New Member
Nope , one panel 10.27a Isc , but I’ll have 2 series fields (each have 9 panels) in 1 parallel
A data sheet of the inverter or model name would allow us to answer your question accurately.
If each mppt says 18amp I would say run 9 panel in series to each mppt input.
littleharbor2
Solar Addict
What Thai said.
Alexkatamar
New Member
Thank you !It would be correct , but one dumb ordered wrong quantity and now I have 25 panels and wanted to connect them all in 2 mppt …I thought maybe I can overload current without serious consequences
littleharbor2
Solar Addict
You can put 100 panels in series and still have the same current. The thing you need to be concerned with is not overshooting the voltage limit for your unit.
You can overcurrent MPPT charge controllers to some extent without any damage. What is the max Voc. of your controller" If 12 of your panels in series come in under the Voc. limit, while considering the coldest temps in your area, you will be fine going with two strings of 12 panels.
You can overcurrent MPPT charge controllers to some extent without any damage. What is the max Voc. of your controller" If 12 of your panels in series come in under the Voc. limit, while considering the coldest temps in your area, you will be fine going with two strings of 12 panels.
Alexkatamar
New Member
Understand it , but I can put in series max 9 panels (48.7v) , my inverter 500v max
littleharbor2
Solar Addict
Is that the Voc. or the Vmp.? How cold does it get in your area?
Alexkatamar
New Member
It’s Voc. The cold in winter mostly warm, but rarely can be max -10 approximately
littleharbor2
Solar Addict
Sounds like it's 9 panels per string, period.
You can put the other 7 panels on a separate charge controller if you really want/need the extra power.
timselectric
If I can do it, you can do it.
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Having more current available than the SCC can use isn't a problem.
Unless you accidentally connect it in reverse polarity (backwards).
Reverse polarity protection has a current limit. And too much will fry it before it can protect itself.
So as long as you don't connect it backwards, you won't have a problem.
Unless you accidentally connect it in reverse polarity (backwards).
Reverse polarity protection has a current limit. And too much will fry it before it can protect itself.
So as long as you don't connect it backwards, you won't have a problem.
littleharbor2
Solar Addict
So, 6s2p per input. That would work, I missed that idea, as long as the minimum voltage is met. (shouldn't be a problem.
Alexkatamar
New Member
Wow! Is it for sure ,was it checked before ? I just don’t want to risk and check it )) And how can I confuse polarity ,because it has different connections ,I don’t know much in it .
You can over current but if your going for 6s2p on two strings with 450w panels your likely to cut off 2kw clipping as @littleharbor2 suggested just buy another SSC to add to the system.
Alexkatamar
New Member
The problem is I have opportunity to set maximum 9-9-7 (3 fields ) on my roof ,cannot make 6x4
Alexkatamar
New Member
Panels 400w 48.7 Voc 10.8 Isc
And inverter 10200w ,500v, has 2mppt controllers input (18a each)
littleharbor2
Solar Addict
If they are all at a similar angle it's just a matter of wiring it up correctly. You may need to make up some extension cables and use some parallel connectors.
Alexkatamar
New Member
2x9 of them has the same direction but different azimuth, and 1x7 field other direction
timselectric
If I can do it, you can do it.
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Yes it is safe.
Current (amperage) is not pushed, it must be drawn.
It's the same as the power outlets in your house. It doesn't matter if you plug in a microwave or phone charger. They will each only draw what they need, no matter how much is available at the outlet.
Alexkatamar
New Member
Thank you very much! And other guys! Appreciate your time ,good luck to all of you!
littleharbor2
Solar Addict
Not optimal, for sure.
Alexkatamar
New Member
Sorry what do you exactly mean ?
timselectric
If I can do it, you can do it.
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When you connect panels in series, they become one large panel.
And should be installed on the same plane. (Direction and angle)
And should be installed on the same plane. (Direction and angle)
Hedges
I See Electromagnetic Fields!
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If you want to do 6s2p but are concerned it could be backwards, therefore excessive Isc could cause damage,
start by connecting just one string of 6s. If it powers up and sees voltage, then shut down, connect second 6s in parallel, parallel back up.
If you orient one 6s South East and the other South West, instead of 2x the current it will only be about 1.5x
Controller says 18A max Isc? Or max operating current? Full spec sheet would help.
If 2x current of panel exceeds max operating current, then using two orientations helps avoid clipping and losing power.
But most of the time sun will be off angle, also panels will be hotter, and current is reduced.
If wires are polarized and correct then it won't get connected backwards. If polarized and incorrect then it will.
Does inverter come with MC4 connectors pre-attached? Most of us have screw terminals so we're the ones to connect them wrong.
Good to check voltage and polarity with a meter before turning on PV disconnect.
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