question

btank avatar image
btank asked

Does the MPPT have reverse current protection from the battery?

I'm looking at a description of the Cyrix Battery combiner and I would like to confirm if this device can be used for protecting the MPPT from reverse current from the battery.

MPPT data sheet does not explicitly mention reverse current protection from the battery side (but mentioned for the solar side). Does MPPT have its own internal reverse current protection or are diodes necessary to prevent damage from back current?

MPPT ControllersBattery Protectmppt chargingCyrix Battery Combiner
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @BTank

What do you mean by 'reverse current from the battery'?

4 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

btank avatar image btank commented ·

Instead of current flowing from the MPPT to the battery, current flows from the battery to the MPPT which is an abnormal case. Does MPPT have its own protection from this?

0 Likes 0 ·
Matthias Lange - DE avatar image Matthias Lange - DE ♦ btank commented ·

Some MPPTs have a load output so the current have to flow from the battery to the MPPT if there is not enough solar power for the connected loads.

0 Likes 0 ·
anoushmdn avatar image anoushmdn commented ·

Does the current from the battery can flow to the MPPT output and to the PVs at night ?

is there any protection against reverse current flow to the PVs from MPPT ?

0 Likes 0 ·
kevgermany avatar image kevgermany ♦♦ anoushmdn commented ·
Battery voltage will not cause reverse current through the panels.
0 Likes 0 ·
Triton avatar image
Triton answered ·

What if you have a short fault between the pos + and neg - PV generator cables (highly unlikely with Class II cables but I've seen some installers abuse cables badly during install) where the source effectively becomes a shorted "load". Will the MPPT block reverse current flow on both the PV input as well as the Battery Output terminals?

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.