CanisLupus
Posts: 106
Joined: Thu Sep 15, 2016 10:48 pm

12V Battery maintainer circuit

Sun Aug 02, 2020 9:24 am

I think it would be possible to have a 12V Battery maintainer programmed to turn on for a short period (1/2 hour ?) whenever the vehicle is turned off . The DC-DC converter would need to be on during this .

alohart
Posts: 2071
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: 12V Battery maintainer circuit

Sun Aug 02, 2020 10:55 am

The high-voltage system remains on for at least 30 minutes after a door, the frunk, or the hatch is unlocked or opened. The high-voltage system also remains on for a while after an i3 is shut off (not sure how long). If the 12 V battery's voltage is below a certain limit, the DC-DC converter will turn on to charge the 12 V battery during these periods. So the 12 V battery can be charged after an i3 is shut off without the need for an additional maintainer circuit.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

CanisLupus
Posts: 106
Joined: Thu Sep 15, 2016 10:48 pm

Re: 12V Battery maintainer circuit

Mon Aug 03, 2020 7:44 am

What I'm thinking of is a maintenance cycle . Low current battery maintainers or tenders have a mode that helps in the longevity of the battery . Desulfation is one word that I've seen , I'm not sure that it is applicable to our 12V battery though . But improving the battery's longevity would mean a lower frequency of replacements . A conflict of interest .

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