question

JORGE GONZALEZ avatar image

Can or I cant to connect two MPPT in parallel mode in the PV Side?

We need to conect two Smart MPPT 150/100 in parallel mode, both sides (PV and Battery)

There is not information about it, please coud You help me.

In advance, thanks so much


Jorge G

smart solar set-up help
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4 Answers
JORGE GONZALEZ avatar image

Really I understood your answer, but in this moment i have not option to get a larger controller.

Please your advice, It could be destructive? or will just work just one of them?

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I don't think it is destructive but you will get much less power.

JORGE GONZALEZ avatar image JORGE GONZALEZ Matthias Lange - Service Team Döbeln DE ·

Thanks so much for your reply,

Really in this moment I cant split the PV array, but soon I will doit. Just I need to connect it in a parallel mode for few weeks.

@JORGE GONZALEZ

Just to be sure: how are the panels wired now? what voltage / current do you have now and what will you have after splitting?


JORGE GONZALEZ avatar image JORGE GONZALEZ Daniël Boekel (Victron Energy Staff) ♦♦ ·

Hello, thanks for Your support:

now we have:

36 solar panel, 9 array of 4 panel in serie.

the solar panel VOC is 37,2V x 4= 148,8V

We have each panel in 250W .. 36*250W= 9000W

permanent load current=25Amp

So we need to recharge our 1000AH with a DOD of 50% with more less 150 amp.

We need for a few time tohave both controllers in parallel mode (PV Side), please could You give me your Tips or advices???

at the end, I uderstood that in the victron controller, if the current is less than 2 amp, it will limit the current avoiding to overchage the battery...but this is not the case. (because our currente is higher than 20 amp)

please, Also could you share with me how work this limitation that avoid to overcharge the battery???

Thanks so much

Jorge G

After split the PV array we will have two arrays one with 5 rows and another with 4 rows

Yes the same advice as every time you ask:


Use one controller until you split the strings.


I don't understand what you mean by:

'at the end, I uderstood that in the victron controller, if the current is less than 2 amp, it will limit the current avoiding to overchage the battery...but this is not the case. (because our currente is higher than 20 amp) '

JORGE GONZALEZ avatar image JORGE GONZALEZ Daniël Boekel (Victron Energy Staff) ♦♦ ·

About to use just one controller, even one of them became burned we need to wait for next visit, i have not option.

About Battery overcharge protection, Im sorry, perhaps my question was not enough clear. i will try to explain again:

some time ago talking with a Victron distibutor about the diversion dump load resistor, they told me that in your units it is not necessary because each controller avoid overcharge the battery, when the current is less than 2 amp. but this explanation or operation description is missing in your technical documentation. Please could You give me the oficial victron point of view about the diversion resistor.????

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"the solar panel VOC is 37,2V x 4= 148,8V "

This calculation looks wrong.

Please review your panel specs and temp calculations.

hello, sorry why is wrong?.. just I need to confirm that the input voltage dosent be more than 150Volts. (Also we use NOCT with 34V, but I prefer to use STC, because i need to protect my controller

1586187732672.png (15.4 KiB)
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Justin Cook - Bay Marine Supply USA avatar image

@JORGE GONZALEZ, it is not possible to connect two separate MPPT controllers to the same PV array. You can size up to a larger controller as appropriate to your array size, or you can split your array into a manageable size for the two 150/100s that you reference to handle, but these are the only two options.

It is also not possible to configure an MPPT controller to be a PWM controller; these are two vastly different types of SCC that behave in entirely different ways.

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JORGE GONZALEZ avatar image

Please could You explain me why it could be a problem?, is it destructive? If the problem is MPP, because each controller will try to get their best performance. even that it would work, perhaps the controller doesnt share the load but.. must work.

Why do you (think you) "need" to do that?, because we have a big PV array and i have not option to split it in two arrays.

Could Ypu tell me if we can configure the controllers to work like PWM and not in MPPT mode?

The load current is around 1000W in 48 Volts, so we need to recharge with at less 120Amp.

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Matthias Lange - Service Team Döbeln DE avatar image

On the battery side it is no problem but on the PV side.
Both charge controllers try to find the MPP and this ist not working.

Why do you (think you) "need" to do that?

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