More battery banks are ruined over winter than in use. Most of the damage comes from banks left partially discharged for months, or from charging arrangements that are switched off along with everything else.
This is the sequence worth working through before you leave her.
The aim is a bank that stays healthy and a boat that is not quietly drawing itself flat.
A charger left running for months should be one you trust, on the correct profile, in a ventilated space. It is worth checking that the marina supply and the boat's protective devices are sound before depending on it unattended.
Solar can maintain a bank ashore if the panels stay clear, but shading from covers and cradles often means it does not. Where nothing will be maintaining the bank, a fully charged bank isolated from loads is the safer arrangement, with periodic checks.
Before the first outing: check bank voltage against the baseline, test each charge source individually, exercise the bilge pump and its float switch, check for corrosion at terminals after a damp winter, and power up navigation and safety electronics with time to fix anything before you need them.
It depends on whether anything on board must stay live, and whether a maintenance charge is available. Both approaches work; leaving a bank aboard, discharged and unmaintained, does not.
With a modern charger on the correct profile in a ventilated location, this is normal practice. It is worth having the installation checked rather than assumed.
Sometimes, but shading from covers and low winter sun on the South Coast make it unreliable as the only measure.
Yes — a recommissioning check before launch is a common piece of work for us.
We'll check the bank, the charge sources and the safety circuits before you lay up or launch.