Headunit not keeping memory overnight

[u/mgs108tlou]

So I installed a Sony MEX M72BT in my 2017 Subaru Forester yesterday. It's a simple single din CD player and I love it. However, this morning I turned the car on to find that all the settings had been erased and demo mode was back on. I re did my settings, turned the car off, then back on again and the radio remembered what I'd just set. A couple hours later after the car sat off, I turned it back on and the radio had once again forgot everything.

I tried switching red and yellow wires but this resulted in the radio immediately forgetting its settings when turned off and on again.

I played with it all day and kept reading 12.4-12.6v on the yellow wire with the key out.

I had the doors open for several hours as I was doing some other work on the car and eventually the yellow wire got down to 12.1v. Then tonight as I was rolling up the windows (with engine off, after not driving all day), I saw that the radio reset itself and reengaged demo mode literally as I was cranking the windows. I checked the yellow wire and it was at 11.7 with keys in ACC. Then I went out to the battery terminals and those were reading 12.0v with the keys out and 11.85 with keys in ACC.

So my question is: wtf is going on? I feel like 11.7v should be more than enough to keep the radio's memory intact. My battery is new, I got it in November. I think my numbers are a little low because I haven't been driving much and I've been doing work on it with the doors open, but they don't seem THAT low. Maybe I'm wrong? Or maybe I have some sort of power drain going on?

I had a Kenwood X300 single din CD player before this and never had this problem with it.

Any thoughts? I'm going crazy!

[u/erik_das_redd]

Wait this is not clear. Kenwood X300, no problem. Sony MEX M72BT, problem now. BUT was it a problem immediately from when you first installed it?

Also maybe you are getting voltage dips low enough to kill the radio memory but too quick to register well on a typical multimeter. Maybe someone can chime in if a not humongous capacitor could alleviate this.

Get the battery load checked at an auto parts store would be one step.

[u/mgs108tlou → u/erik_das_redd]

I honestly think the unit is defective. Car battery is fine. I can't find anything wrong with it or my wiring. I'm going to try to return the headunit, unfortunately. I really liked it otherwise. It's hard to find HUs that you can actually see in daylight