Connecting 15V DC directly to a charge controller? Is this possible?

[kiwisteve]

I am contemplating a portable power system that would charge a 12V AGM battery from a 40W solar panel via a MPPT charge controller. This will be the default "PV" mode.

When I am in a location that has a mains electricity supply (120-240v AC), I will manually switch the system to the "AC" mode which would physically disconnect the solar panels and instead connect a steady 15V DC supply (from a 120-240v AC transformer) to the charge controller.

My question is: can the 15V DC supply be connected to the charge controller in place of the solar panels? (remembering that it's either the solar panel or the 15V supply, but never at the same time)

Can the 15V DC supply effectively "replace" the solar panels without doing any harm to the charge controller or any other parts of the system?

Thanks for any hints, suggestions or advice.

I'm fairly new to solar, so please forgive me if my understanding is not what it should be.

Regards,

Steve

[Sunking]

No way Jose

[kiwisteve]

that's not much of an answer...

No way Jose

Can you please explain why?

Thanks,
Steve

[Sunking]

Because a MPPT charge controller is NOT a battery charge designed to operate from a CURRENT SOURCE. What you need is something as simple as a diode to drop the voltage to 13.6 volts from a VOLTAGE SOURCE.

[choyak]

Instead of a 15 volt PSU why not use a battery charger (13.8v) and then select between the MPPT output and the charger output to charge the AGM? You would like to have the MPPT disabled (panels out of the light) because it will not have any load.