Preventing battery rundown in car unused for 3 months

[Mike Hughes]

My 2017 Nx300h will be parked unused for 3 months over the winter. In the past the Battery has gone flat over much shorter periods. How do I avoid this - is it as simple as just detaching the live terminal, or will this cause problems with the on-board computer, settings etc? mike 

[scudney]

Get yourself a trickle or solar charger that plugs into the obd port 

[NemesisUK]

Is the car garaged? Do you have safe access to mains electricity?

If yes something like a CTEK maintenance charger would be perfect, it's what they are designed to do, keep the 12v Battery topped up over long periods of inactivity.

The attached doc describes how Toyota/Lexus  maintain the batteries both 12v and traction during storage

 

Maintenance of hybrid battery.pdf

[Mobeam]

2 hours ago, scudney said:

Get yourself a trickle or solar charger that plugs into the obd port 

Should it happen i.e flat Battery etc.....Is it Ok to trickle charge/ or use a normal plug in Battery charger,  without disconnecting either of the cables from this Battery, assuming that the power switch is turned off?

[LenT]

4 hours ago, Mobeam said:

Should it happen i.e flat battery etc.....Is it Ok to trickle charge/ or use a normal plug in battery charger,  without disconnecting either of the cables from this battery, assuming that the power switch is turned off?

A CTEC trickle charger comes with leads that are permanently connected to the Battery posts, specifically so that they can be plugged in to the charger without having to remove the Battery cables.

The CTEK has safety systems that ensure the Battery cannot be overcharged.  You don’t have to disconnect either of the Battery cables.

[Brian R]

Just to add my two pennies worth and from experience with numerous batteries courtesy of electric fencing. If a Battery is deeply discharged, you might find some smart chargers are unable to kick-start the charging process. Fortunately, there are some that have a greater output and should be capable of initiating a charge process. One such is this one: CTEK 10 amps charger/maintainer

Personally I use an ancient i.e. 45 plus years old conventional charger and usually for only 10 minutes or so before connecting up whichever smart charger comes to hand.

BTW, my car is permanently connected to a smart charger which I simply plug into the mains and then let it do its bit. I'd also add a 10 amp charger is going to charge at twice the rate say a 5 amp would, and on occasions this may be helpful.