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.

 

[Squanchy2]

$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.

I looked at amazon. For sure less expensive. The listing i looked at was unclear if the panel had a charge controller. Have you tried the panel behind glass? I was planning to stick the panel to the back hatch glass. Just need to keep the winter snow cleared off.

 

[SparkYellow]

The small black box on the back of the panel controls the charge. If the box has an indicator to display the charging status, then it's smarter than just an electrical connector.

My hatch glass is tinted and the defrosting lines would shade the panel. You can try it though, if it's the optimal position for your parking situation and the wire is long enough. Point to the south so the panel can get the most sun. Windshield is better if un-tinted. The angle of the hatch glass may be a bit steep for the winter sun? The optimal angle is the latitude of your location plus 15 in the winter.

I have two 10w panels as visors at the top of the windshield and they are good for keeping small devices charged. My rechargeable wifi cams come with 5w panels to top them off.

 

[SparkYellow]

To help my weak battery, I set the edge of this 20w panel on top of the infotainment screen for better exposure when I drive. If you will leave the panel on your dash (connected or not) while driving, choose a panel that is entirely black with minimal silver lines (or worse, an orange frame). They reflect onto the windshield.

 

[Squanchy2]

To help my weak battery, I set the edge of this 20w panel on top of the infotainment screen for better exposure when I drive. If you will leave the panel on your dash (connected or not) while driving, choose a panel that is entirely black with minimal silver lines (or worse, an orange frame). They reflect onto the windshield.

Good to know. I was thinking of a dash placement also. The back hatch does have a slight tint on it. Does the panel get hot enough to damage the plastic dashboard?

 

[SparkYellow]

Good to know. I was thinking of a dash placement also. The back hatch does have a slight tint on it. Does the panel get hot enough to damage the plastic dashboard?

Last year I started using a black felt dash mat. It keeps the dashboard from getting as hot in the sun. I also anchor the solar panel to the mat.

With the battery in decent condition, you can just move the panel out of the way when you drive.

 

[N7turbo]

How do you prevent overcharging?

 

[SparkYellow]

The maintainer claims to do that for me. Supposedly all of these "smart" battery maintainers can detect the level and adjust its output. Also, 20w is very low. On my 150-miles trip back yesterday, the panel was sitting on the dash, connected to the battery, and didn't cause any noticeable increase in my obd voltage.

 

[SparkYellow]

Here the connector from the battery (top-left) is connected to my primary maintainer (top-right, plugged into an AC outlet) which is keeping the level at 12.6v. The red/black set is coming from the panel on the dash.

 

[N7turbo]

I can understand adjusting output—but the physical panel can't stop accepting photons and converting them to an electrical charge. It has to be released as heat somewhere.

 

[SparkYellow]

Good question that I don't know the answer to. I thought heat dissipates into the atmosphere? In my application, I only considered how extreme heat would reduce the panel's performance and lifespan. Most portable panels come with USB-A/C ports so it can keep producing after the 12v battery is topped off. Computer/gaming fans can help dissipate the heat.

With small-output flexible panels (35w/40w) on the hood/roof, I use alien tape that is kinda thick to allow some air to go under. (The best tape in the industry is thin like electrical tape for ultimate adhesion.) With the 100w flexible panel on the roof of my stationary van, I use rubber coated magnets with studs, which leaves even more room for air flow. All my rigid panels are mounted on 2 by 4 wood frames and leaned at an angle. They do get hot to the touch under the sun, but not enough to cook eggs or anything.

I noticed recently that my 10A charge controller (kept in the shade on the porch) can get quite hot from working hard. It is now sitting on a dedicated, low-profile fan.

The windshield takes all the heat and can get very hot. I never had a panel get too hot inside the car. For new application though, it is best to monitor.