Hi. I have a small problem with my car's battery not keeping its charge because I am not driving the car as much, plus, since my place of employment is closer to my house I only drive 1 mile each way. So, I am guessing that the car is not on long enough to keep the battery charged for long. I used to drive 22 minutes to work, now I drive about 5 minutes or less.
To help me keep track of my battery voltage, I use a cigar plugin battery monitor that keeps me constantly informed of the car's battery status, which is currently showing around 12.03 volts. But it fluctuates depending on how long I drive the car. If I drive 20 minutes or more, when I shut off the car, it will show around 12.4 volts.
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https://www.amazon.com/INNOVA-3721-Battery-Charging-Monitor/dp/B000EVWDU0
I am looking for ways to maintain the battery in my car, but because I live in an apt complex, I can't run an electric cord from my window to my car.. plus, it is not allowed.
So, I did some searching on the web and came across this battery maintainer:
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https://www.walmart.com/ip/Battery-Tender-JR-High-Efficiency-800mA-Battery-Charger/782270305
I was thinking of using my
Bluetti EB3A (300w) or my
Pecron E600 LFP (600w) power station with this device and keeping the unit in my car during the day (I work the night shift), while it charges and/or maintains or gives me the extra boost in the battery. I don't need any jump-starts. I just need to have the battery fully charged. Maybe every day or every other day or so.
If solar is suggested, I did try one of the small panel solar maintainers for car batteries, but they did not charge the battery at all, even though the voltage coming from the solar panel says 18 volts or higher on my external all-purpose digital meter that I use to officially test more accurately the voltage source. Note: this solar panel is from 12 years ago. So maybe it is no longer working properly. I don't know. I did hook it up to my Bluetti EB3A but it did not charge it all all. Instead, the charging "Input" indicator would just flash or blink constantly on it.
I would like to know what do you guys think about that item(s) above? ..or do you have other/better suggestions?
Or, I am open to trying other ideas, TIA.
OP. Short distance driving is a real issue.
Here are comments from my experiences.
1. A fully charged, healthy automotive battery will read 12.85 to 13+ volts after you turn the car off. Once it starts reading 12.5 ish after a full charge, it’s time to replace. Also very cold temps cause voltage to go down…talking below freezing.
2. The alternator alternates voltage. The more electrical demand the higher the voltage. Think mid 14’s for high demand to mid 13’s for low demand. If your alternator won’t put out 14+ have it checked.
3. High demand can be from needing to charge a partially or fully depleted battery, cranking the audio up to 11, having the aircon on high, using the headlights, etc. Think mid 14’s voltage output
4. Low demand would be battery fully charged, no audio, no ac, headlights off. Think mid 13’s voltage output.
From my experience, it takes a good 45 minutes of driving on a regular basis to keep the battery fully charged. My batteries will read more than 13 v right after turning the motor off. This is a surface charge and will decrease to the actual charge voltage as the battery sits. Batteries will read very high 12’s (like 12.8+) after sitting overnight. This is before turning the car on.
The best solution would be to fully charge your battery with a high quality unit that will do a “reconditioning” charge. This can take more than 24 hours. I use Victron chargers. They cost money.
After reconditioning use the charger at least once a week on its normal charge mode for your battery type.
If you are cash challenged, go for a long drive once a week. On your drives to work keep the radio and the ac off. Headlights too if possible.
Solar panels put out somewhat constant voltage. The amps vary depending on how much sun they are getting. Full sun will produce rated voltage and amps. Full sun is when the sun is high in the sky and when panels are pointed directly at the sun.
Solar maintainers add a pwm charge controller. They will put amps into your battery. Amps will vary, voltage will be somewhat constant.
Solar maintainers. Check amps out when connected to your depleted battery. Check all connections. You should see amperage output when in full sun and connected to the battery.
Maintainers will output full rated Amps when pointed straight into the sun. They’ll lose 5-10% when behind glass. As the temp rises inside the car you lose even more. At 150 F you’ll lose 25%. That’s 0.35% for each degree above 77F.
Behind the windshield, in full sun, on a hot day you can expect to lose 1/3 of rated output.
Mounting the solar maintainer outside of the vehicle will work best. With high mid-day sun, mounting on the roof will work. With lower sun (winter months), mounting to the outside of the windshield will work. Point windshield to noon day sun.
If your battery discharged from a full charge overnight, suspect the alternator. A failed diode will cause battery current to travel through the alternator to ground, draining the battery.
Another simple thing. Clean and tighten all battery connections. Take cable ends off battery. Clean the battery posts and inside of battery clamps with a brass brush. Remove any corrosion. Reinstall to proper torque…meaning tight without stripping any threads.
Repeat this process with the positive wire to the alternator and the starter. Find the ground strap. Remove one end, clean and freshen up the connecting surfaces. Do this on both ends. Reinstall.
If you found any wires or connectors that are worn or frayed, replace them.
You can do the above yourself if you are handy. The money saved will likely allow you to buy a quality charger like a Victron, and maybe a torque wrench?
Best of luck. Report back to let us know if you found a workable solution, or if you have issues and seek advice.
