Somfy 12 V DC Battery Y Harness Somfy 12 V DC Reloadable battery harness. This Y splitter allows the connection of 2 battery tubes / battery wands (# 901420, sold separately - This reloadable battery tube uses eight long-lasting, readily available lithium AA batteries (not included) to power your Somfy shades and blinds.) Simple plug and play, no tools required. 25 CM long. This is Somfy's latest version of the Y harness. It connects a little differently than previous versions, but is still very simple to use. Instructions: 1. Plug 2 battery tubes into the Y cable. On one end, this Y harness has two male connections, which will plug directly into your battery tubes . 2. Plug the Y cable into your 10" extension cable. The other end is a female connection which will plug into your 10" extender cable that came with your battery tubes. 3. Plug your extender cable directly into your motor.