Battery drain

[Squanchy2]

2016 CX5 GT
Having a problem with the battery draining after sitting a week.
It starts, but struggles.
I’m retired, and not driving often.
Parked in an apartment building lot, can’t do a battery tender/maintainer.

The battery is brand new, and rated at 640 cold cranking amps.
Shop checked charging system, starter, and for parasitic draw.
Everything looked fine.
I trust the shop is competent , they do fleet maintenance for a bunch of customers.

I took the car out for 1-1/2 hours of highway driving.
Checked the battery at 12.7 volts.
Let it sit 4 days, voltage dropped to 12.35 volts.
I calculated a draw of around 150-200 milliamperes.
Should be below 50.
Have not added anything to the car, such as a dash cam.
Checked all lights and outlets, nothing has been left on.

Should I take it to the dealer for a second opinion ?

Thanks

 

[HyFlyer]

How about a solar charger that lays on the dash and plugs into cigar lighter outlet or USB port ?

Doesn't seem like it should be struggling with 12.35 volts . How are those cables and connections tight ? Corrosion any?

 

[Squanchy2]

How about a solar charger that lays on the dash and plugs into cigar lighter outlet or USB port ?

Doesn't seem like it should be struggling with 12.35 volts . How are those cables and connections tight ? Corrosion any?

I like the solar charger idea. Found one on the battery tender site.
The outlet at the back hatch stays live with the car off. This could work.

5 Watt Solar 12V Battery Charger with Windshield Mount

Charge and maintain your vehicle's battery with the sun. Once connected, this Battery Tender® Battery Charger will charge and maintain your battery so it's always ready to go when you are. Lightweight, fully-automatic, and easy to use, the Battery Tender® Solar Panels are the only panels...

www.batterytender.com

Connections are good, no corrosion.

The battery goes to around 12 volts after week in the colder weather.
I live near Detroit.

 

[SparkYellow]

$75 is a lot for 5w. I'd go with 20w or 10w. There are many on Amazon for around $30. I wish I could recommend one but my recent purchase hasn't been tested yet.

For my campers parked in the desert sun, the batteries are maintained with 35w panels on the hood (and a separate charge controller under the hood.) They are rarely driven and stay charged except over a period of cloudy/rainy days. Had to jump the battery up to 12v when the sun came back to resume the regular routine.