Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing CTEK Battery tender

For the short time your Ctek is regulating to 15 volts it shouldn't be necessary to disconnect the battery from the car. It would be a simple precaution to ensure everything is turned off other than say clock and radio memory though. Many car alternators regulate to up to 14.8 volts anyway.

The higher voltage has the beneficial effect of stirring up the electrolyte which may have become stratified due to extended periods on float setting. It can also ward off the ageing process due to sulphation of the plates. More sophisticated chargers drop into this mode automatically every 15 days or so for above reasons.