is it possible that the weather affect the dual battery management of the piranha(dbe 150s) when it is cold and humid it does not kick on or it takes a long time ?
It may be that the main battery is taking a long time to recharge to sufficient voltage (about 13.5 v) for the Piranha to close and connect the aux battery. I hve no idea of the age or condition of your main battery but maybe it's coming to the end of its life, if so this is more likely in cold weather.
