Hi guys I have a 48v battery I want to charge with a 12v panel

Hi guys

I have about 640 watts of solar panel (2x panels 12v)

I need to connect these to a 48v battery I have a victron 150/35 smart controller will this do it if not what controller will I need

The panel voltage in series must be more than 5v above battery voltage to start charging.

Are you saying your panels are 12v 26 amp panels?
Highly unusual.
I would imagine it’s more like 26 volt 12a panels.

Can you post a picture of the panel information

The modules are labelled 12V because they work well with a PWM controller in a 12V system. In reality, they have a voltage of around 18V at maximum power (Umpp). The Victron MPPT 150/35 cannot increase the voltage. It can only reduce it, while increasing the current. For this to work with a 48V battery, at least four of these modules must be connected in series. In that configuration, the output drops to almost zero even with a very small amount of shade. A maximum of five modules may be connected. That would be better. The 150/35 would then be a perfect fit, and the system would be less sensitive if a small shadow occurred.

typically, the Voc of the low voltage panels is 20V, so 3 in series should work…

Best to get 2 normal (Voc 35 - 40v) panels and use in series.