How should I install flexible solar panels and route the wiring on a Hallberg-Rassy 29?
I want to fit flexible solar panels to my Hallberg-Rassy 29 to keep the domestic batteries charged when cruising. Where should I mount them, and how should I bring the wires below deck and connect them?
Answer
On an HR29, start with two independently supported flexible panels of roughly 80 to 100W each, placed where boom shadow is lightest without obstructing sailing or access. Run each panel's cable through a properly sealed deck gland to an MPPT controller close to the domestic batteries; two small controllers are useful when the panels receive different amounts of shade.
Check space and shade
Make cardboard templates to the actual panel dimensions, including junction boxes and cable exits. Check them with the sprayhood raised and folded, the companionway open and the boom swung across. A position that looks clear at the berth may be shaded or obstructed under sail.
On an HR29, investigate these locations in order:
- Sprayhood top: useful if fitted, but it needs suitable support and clearance from the boom, mainsheet and folding frame.
- Coachroof: practical where the panels clear handrails, hatches, running rigging and your normal footing.
- Removable cockpit installation: useful at anchor, provided the panels can be securely stowed before sailing.
Sprayhoods, deck fittings and battery arrangements vary with year and previous alterations, so there is no universal HR29 drilling position or cable route. Avoid permanent adhesive on teak: removing it can damage the timber, while trapped moisture makes inspection difficult.
A 160 to 200W installation is a sensible starting point for battery maintenance and modest cruising loads. Its ability to support a fridge depends on measured daily consumption, season and shade. Panel wattage alone cannot tell you that.
Support panels for easy removal
Flexible panels tolerate a specified curve. They should not flap, crease or repeatedly bend across individual cells. Follow the panel manufacturer's minimum bend radius and mounting instructions.
For a sprayhood installation, have a sailmaker fit reinforced attachment points and use a smooth backing arrangement approved by the panel supplier. Eyelets attached to loose canvas alone often leave the panel flexing between supports. Check that the hood frame can carry the added weight and wind load.
On a coachroof, use the manufacturer's approved bonding or removable mounting system. Some panels require direct bonding; others benefit from a supported backing with ventilation beneath. An arbitrary pattern of adhesive blobs can leave cells unsupported and collect water.
Choose a position where you can avoid stepping on the panel, even if it is advertised as walkable. Keep junction boxes clear of feet and leave enough cable slack to remove the panel without pulling its connections.
Route cables through a deck gland
Plan the complete route before drilling. From a sprayhood, secure the leads along the frame with UV-resistant clips, leaving a service loop at each folding point. From a coachroof panel, follow a protected edge rather than crossing a walking surface.