I have an unusual maintenance question – or perhaps it is becoming more common. I have a 2011 Camry Hybrid, but I live downtown and do not use it often. It is now a little more than one year old and I have only 3,000 kilometres on it. Moreover, my wife and I go away for three months every winter and leave the car in our underground heated garage. I will detach the small battery's terminals before I leave. Obviously, the suggested maintenance schedule does not make much sense for me. Do you have any suggestions with respect to maintenance? – Michael
The consensus is that leaving a hybrid with nickel-metal-hydride batteries such as yours stored for three months should be okay, but four-five months might be pressing it a bit.
With the car shut off, there is no parasitic drain on the main battery so it will retain a charge for a long time. The same is not true for the service battery, the 12-volt unit common to most automobiles. Instead of unplugging it, I would suggest you invest $50 at the local car parts or Canadian Tire store in a battery minder, also called "smart charger," "intelligent charger", etc.
I have used one called Battery Tender for several years. Unlike the older generation of "trickle" chargers that apply a constant current and ultimately damage a battery or lower its full state of charge, these new units provide a charge until the battery is at a "full" state and then shut off the current. They contain electronics that monitor the battery and, when there is a slight drop in voltage, they apply a small charge, but only long enough to top it off, maintaining a high level of charge.
There is no such system available to the consumer market for the main battery pack in hybrids. These high-voltage units are extremely powerful/dangerous and should never be tampered with by anyone other than a technician trained in their use. Were a main battery pack to be fully discharged, it would require a trip to the dealer and a special recharging station.
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