Hi all - I’m looking to buy my first ever EV soon (probably a Model Y, Polestar 2, or BMW i4) and have quick question. I’m often gone from home for a few weeks (sometimes months) at a time, and I currently keep a trickle charger on my 12V battery the whole time (it’s a “smart” CTEK charger that doesn’t overcharge the battery). That charger recently broke after many years of use, so I’m wondering whether there’s any need to replace it.

I know the answer may differ across EV models, but in general: if I leave the car in a garage for a few weeks it’s plugged into the main EV charger whole time, is there any need for a trickle charger?

Any quick thoughts would be greatly appreciated.

  • Kiwi_eng@alien.topBEnglish
    1·
    10 months ago

    You should not need to worry about this. But, note that some EVs are less happy when doors are left ajar for longer than it takes to get in or out of the car. The best thing to do for EVs with conventional 12V batteries (not 2021+ Teslas) is to add a BM2 battery monitor (voltage logger) so you can check the behaviour and not do stuff that aggravates it.

  • WeldAE@alien.topBEnglish
    1·
    10 months ago

    probably a Model Y, Polestar 2, or BMW i4

    The Model Y has a Lithium 12V battery that is pretty integrated into the car and doesn’t need replacing. The car deals with it so you don’t have to do anything special. I would 100% plug any EV in that you are leaving that long and set the charge level to 50% or something like that.

  • SpriteZeroY2k@alien.topBEnglish
    1·
    10 months ago

    I had a CTEK MXS 5.0 and a Noco Genius 10. The CTEK got too warm when charging 12v batteries so i eventualy took it back. IMO it’s always good to have one of these handy just in case. 12v lead acid batteries don’t like to be discharged for long (even a few days) before damage occurs.

  • ScuffedBalata@alien.topBEnglish
    1·
    10 months ago

    I know the Tesla and probably the Polestar will maintain the 12v automatically. Leave the car plugged in anyway.

    Some of the legacy carmakers like Nissan and Chevy (on the bolt, etc) don’t have this and you might want to trickle the 12v. THey only charge the 12v when the key is turned to ACC, which is pretty lame.

    I don’t know about the i4.

  • SatanLifeProTips@alien.topBEnglish
    1·
    10 months ago

    Watch the shitty cable connector on those otherwise good CTEK chargers. You can cut them out and replace them with the ‘2 pin version of the trailer connector’. Make sure the hot pin is the female.

  • dcamrehsifgnik@alien.topBEnglish
    1·
    10 months ago

    Certain models (e.g. the ID.4 let you switch on an option that maintains the 12v from the main battery. You might even be abke to keep the car plugged in and start and stop charging sessions with your app. But at 80% charge, without any connections from the app, I’m sure the ID.4 can supply the main battery for months.