Keep them charged if they are flooded type
If you have a "flooded" deep cycle battery (the most popular type), the batteries will self-discharge slowly (due to internal galvanic currents). Flooded batteries should not be left discharged for extended periods. So if yours are flooded, do NOT let them drain completely. The best way to maintain flooded batteries during winter storage is to take them home, check them periodically, and charge when needed. Keeping them at full charge will maximize the useful capacity and avoid the perils of sulphation.Eric Lorguss/v Explorer 87H285