Proper car care during this quarantine period for both traditional and hybrid electric vehicles is well-documented given that they’ve been around for quite some time. But what about battery electric vehicles? The imposed quarantine measures seen around the world due to COVID-19 will be the first test of how battery-powered vehicles will cope with long periods of non-use.

Ford’s “battery expert,” Bob Taenaka, senior technical leader, Battery and Cell System Development weighs in on how the battery reacts if EVs aren’t used or charged regularly.

Taenaka says, the most important thing is to make sure that the 12-volt battery (yes, EVs still have the traditional lead-acid battery) stays charged, and that the high-voltage battery has adequate charge—10 percent or more—to prevent it from potentially draining to zero percent.

If an EV has been plugged in or driven for at least 8 hours in a month, the 12-volt battery should be adequately charged.

For the larger traction battery, Taenaka recommends keeping it at a state of charge between 10 percent and 80 percent.

A high-voltage battery above 10 percent state of charge can go for more than six months without charging, but the 12-volt battery will drain much faster, especially when connected to the vehicle.

If there are no plans to drive the EV for longer than 30 days, it’s best to disconnect the negative terminal of the 12-volt battery. If the EV or plug-in hybrid can be plugged in, keeping it charged will also charge the 12-volt battery. If no charger is available, a 12-volt battery charger like those from CTEK can be used to keep it topped up.