Battery issues after 6 months

I'm having battery problems after 6 months and have to use a trickle charger every few days (and a few features still don't work). Dealer did a full charge last week and it's already declining. I'm also getting terrible gas mileage compared to first 4 months and not nearly the electric miles I should. We are wondering if both 12v AND hybrid battery are going bad? I'm tracking everything now, as we have strong lemon laws in my state.

Did the dealer perform a full diagnostic on both batteries and the charging system? If not, this would be the next step you should take.

They did that first. Then I got a call saying they found a concerning code about the amplifier from a few months ago. They replaced the battery first (per the service manager) then an diagnostics again the next day. Then I got the call about the amplifier needing to be replaced. Fingers crossed i get my car back today and all charging issues have been resolved!

Keep a detailed log of every time you have to charge, any warning lights, the mileage you're getting, and any communication with the dealership. Since you've already had the dealer look at it, and the problem is persisting, it might be worth contacting a lemon law attorney in your state. They can advise you on the best course of action and what your rights are. Hopefully, you can get this resolved quickly and get a car that actually works as it should!

That’s worrying, a hybrid battery shouldn’t degrade this quickly. Are you seeing any warning messages or just reduced EV miles and poor gas mileage? Also, does the 12V battery drain faster when parked for a few days? If so, something might be staying active and pulling power when it shouldn’t. Either way, if the dealer isn’t giving you solid answers, I’d start pushing for a deeper diagnostic check. Could be a software bug, a failing battery cell, or something parasitic draining power.

Update - They replaced our 12v battery AND found that the amplifier was faulty and causing unnecessary drain on the battery 24/7. Amp was replaced. These 2 changes fixed all the features that were constantly going into deep sleep and the lag time for the computer to start up, but it did NOT fully fix our MPG issues. I'm averaging only 22ish MPG vs the 30-34 we had for the first few months after purchase and what is advertised. I've been tracking our MPG and electric miles used since then - my phone is FULL of pictures of the trip tracker, LOL. I have a call out to the sales manager again letting them know that we are still not happy about this and we need to investigate further or we will be pursuing the lemon law in our state (which is fairly strong and in our favor). My spouse has postulated that the lithium battery may have been damaged during the months of 12v battery issues related to the amp. This is just a guess...and of course, the dealership wasn't willing to replace it when they replaced the 12v, I'm sure because of the cost. Regardless, they have 1 more day to respond to our messages or we will take our issue to the manager, or possibly the dealership owner, with whom my spouse is professionally acquainted through a local business owner association.

**Also, all the software has been updated.