How to change system voltage (12V to 48V) on SmartSolar MPPT 150/35 (autodetect)

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lukasnovak asked Aug 5, '22

How to change system voltage (12V to 48V) on SmartSolar MPPT 150/35 (autodetect)

I'm running SmartSolar MPPT 150/35 on 12V battery. All works fine.
I'm going to change the battery to 48V, but user manual is written that autodection of voltage is only for the first time.

The battery voltage is automatically detected at the very first power-up of the solar charger and the battery voltage is set accordingly. Further automatic detection is disabled.

Options:
1) Can I set voltage to 48V in app while it is connected to 12V battery?

or

2) Can I set voltage to 48V in app while after it is connected to 48V battery?

or

3) Is there a simple way to reset MPPT to factory to perform autodetect again?

Presume that PV input is disconnected in all cases.

Thank you

MPPT Controllers battery system voltage

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Answer 1 · 2022-08-05T10:11:56Z

jacobjned answered · Aug 05, 2022 at 10:11 AM

As you have rightly mentioned, safe practise to have PV disconnected. If given a choice, I would say connect it to the 12V Battery and then change/programme it to 48V. After this, then you can connect it to your 48V Battery bank.

Also just to confirm, your PV voltage should 6V higher than the Battery Bank voltage for the MPPT to "wake up and start charging".
Example, if you had some '12V' PV panels, all in parallel, with a Vmp of 18V, and you change your MPPT to 48V, it will not wake up the MPPT upon reconnecting the PV panels. You will need to change the arrangement, and say put some in series and parallel arrangement.

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lukasnovak commented · Aug 05, 2022 at 01:12 PM

Option 1) is also my preferable choice.

It is a little bit weird to have MPPT on 12V and configured for 48V.

My presumption is that MPPT can work on battery voltage 0-60V and system voltage is only definition for PV input to know what kind of battery is charging.

I have 3x 370Wp panels in series, Voc=41.75V, total voltage 125,25V. Changing system voltage from 12V to 48V doesn't affect MPPT charger in my connection.

In paralell connection is your note correct - 41,75V < 48V+6V so this doesn't work.

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