Depending on quality, AGM might last longer, but personally I don't think I'd waste the money. It may also damage the AGM even sooner if the charging system isn't compatible with AGM. I think the problem with the Leaf and many other modern cars is the hotel loads (quiescent or idle power draw) is high, so if you go for long periods without driving, the lead-acid battery gets deep cycled, and thus has a short life.
Nissan even realized this on the first Leaf and had a small solar panel in the spoiler in back! So yes, a battery tender if you aren't using the car for extended periods would definitely prolong the 12v battery lifespan. Another possibility is just to install a battery disconnect. (Though that means there could be some annoying side effects, such as clocks resetting, etc) A possible solution is a LiFePO4 (LFP) 12v battery, as long as you don't have really cold winters, but I don't like recommending these unless you know for sure your charging system and the BMS of the LFP wont interact in such as way that causes the battery to disconnect when it's fully charged, as this can cause expensive and dangerous problems, as any car's electrical system depends on the 12v battery for stability. See my video here, it's Tesla centric, but will also apply to any other car where a given LFP BMS disconnects when it's fully charged: https://www.youtube.com/watch?v=i27lApNWkyA On Wed, Nov 19, 2025 at 9:40 AM <[email protected]> wrote: > On 2025-11-13 9:50 am, (-Phil-) wrote: > > The Leaf has to be "Ready to drive" (Contactors closed) before it > > will begin supporting the 12v battery. The Leaf also senses the 12v > > battery current on the negative terminal, so do not hook an inverter > > ground directly to the 12v battery, only hook to the nearest chassis > > point. This is needed to keep the 12v charge algorithm working > > correctly. > > so theres like a shunt there, so goto nearest ground point on the > fender? > > i'm using an agm thinikng the deep cycling will better. is there any use > to us a battery tender wiht this battery type? > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20251119/b854131d/attachment.htm> _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
