mrsteve avatar image
mrsteve asked

SMART SOLAR MPPT RS, PV voltage spike higher than 450V..

Hi all, question: How do i reduce the max PV voltage?

I have a ESS system running with a Multiplus 48/5000 and 48/100AH Lifepo4 battery,

the battery will upgraded to 280AH in the near future.

Parallel to the system i have an 3000W AC inverter (about 3600Wp on roof).

I would like to swap out the AC inverter for the MPPT RS 450/100.

Problem is, a couple times a year the voltage peak from the PV is about 465/470V!

I know this because i had an Chinees offgrid inverter for a year and got a couple alarms above the 450V mark. Like i said, only a couple of time but i know the 450V is a hard limit for the MPPT RS.

Besides disconnecting 1 PV panel (all in serries) to get the voltage down,

is there another way to control this peak voltage or "transform" it down somehow?

A device i do not know of?

I rather not dissconnect 1 PV panel as i live in a rental house,

altought i doubt new people will notice that in the future hahaha..

If the MPPT RS is not an option i might opt for a FRONIUS PRIMO on the AC 1 out of the Multi,

that way the high voltage would not be a problem.

Thanks for your advise on this!


MPPT SmartSolarFroniusmppt rs
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1 Answer
cocodanila avatar image
cocodanila answered ·

It might work for a while but then in a cold morning it will shut down the array at 454V!! Or in a very bright day as well...

MPPT RS is a brilliant machine (shutdown during night time, very efficient in shadows if you are like me next to the streets cables or overlapping panels during winter), and converting all in DC coupling, due to direct loading of the batteries you might find out that the system efficiency will actually increase even if you loose one panel. But going into DC, you need to invest in expensive cables, so good luck in your searches!! Coco

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Alexandra avatar image Alexandra ♦ commented ·

Confused here.

You can swap an AC PV inverter for a DC mppt, which requires quite a modification to the system wiring and switchgear, but not disconnect a solar panel? Which is an easily reversible change.

You can use some DC SPDs for voltage clamping. But definitely not something I would say is a good solution as you are now consuming another item and potentially leaving the system unprotected when no one notices it is no longer working.

Also the max voltage of the PV array is 8 times the float of the battery, which is not always 450v so best to check on that as well.

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mrsteve avatar image mrsteve Alexandra ♦ commented ·
Yes, i can swap out AC / DC inverters and i install ESS sytems as well, thats not the problem.

The question was if there was another way besides disconnecting 1 panel to keep the voltage down.. maybe a device i do not know of that shaves of a certain amount of peak voltage? Thanks for your reply.

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mrsteve avatar image mrsteve commented ·
Hi, yes i was thinking the same, the higher effecienty would make up for losing 1 panel maybe.

Expensive cables are no problem, the ESS system is costly as well.

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