48V would be a better choice. It is increasingly popular for off-grid applications because the higher voltage reduces heat and power loss, letting you use thinn

48V would be a better choice. It is increasingly popular for off-grid applications because the higher voltage reduces heat and power loss, letting you use thinner wires, which are both cheaper and easier to install; but 48V is still considered "low voltage" and does not require any special safety precautions.