Published 13 November 2026 · OFM4x4.co.uk

Adding a second panel changes the voltage and current presented to the controller. The connectors may fit even when the electrical design does not.

The quick answer

Calculate the cold open-circuit voltage and current against the exact MPPT limits before choosing series or parallel. Verify each panel's electrical data and the controller manual.


Compare the panel labels

Record open-circuit voltage, short-circuit current and rated power for each panel. Mixing dissimilar panels may waste output. A nominal 12V description is not the voltage the controller sees in all conditions.


Check series limits

Series wiring adds panel voltage. Cold conditions can raise open-circuit voltage, so use the controller's specified method and local minimum design temperature. Exceeding its input limit can damage equipment.


Check parallel limits

Parallel wiring adds current and may need different cable and branch protection. Confirm connector ratings and polarity. Do not assume a portable folding panel's built-in controller should feed another MPPT input.


Commission safely

Follow the controller's order for connecting battery and PV. Confirm battery chemistry settings, expected readings and cable temperature under use. Label any disconnects clearly.


Specification checklist

Before ordering or booking work, have these details ready: Panel electrical labels, controller model, cable lengths, connectors and battery specification.


Frequently asked questions

Can I connect any two panels with matching plugs?

No. Plugs do not establish electrical compatibility or polarity.

For an application check, contact OFM4x4.co.uk with the vehicle and component details above. Confirm the current fitting instructions for the exact product before work starts.

Technical reference: www.victronenergy.com. The relevant product manual takes priority over general guidance.