Battery Drain from Short Trips?

What would be considered 'short' in terms of not enough drive time to keep the battery properly charged? I drive 3 miles each way every day, some on weekends, sometimes not. I have a battery that test good with multiple testers and will perform fine for about 6 months then start to lose it's charge very slowly-months-until I charge it overnight with a plug in charger.

 

How old is the battery?

 

I was curious about your question, so I did some Google research and found this website: https://www.tiresplus.com/blog/driv...So7-GNzZhQIio_VVwW4dpRwLY1EO8CS-NBVPhp6Ot-2Mp

This is a blurb from that website.

They Can Reduce the Lifespan of Your Battery
One of the most significant adverse effects of short trips on your car is reduced battery capacity. During short trips, your vehicle’s engine may not run long enough for the alternator to recharge the battery adequately. Over time, this can damage the cells inside the battery to the point that it struggles to hold a charge — a massive bummer if you don’t have a battery warranty.

So, if you’ve been experiencing dim headlights, slow cranking, or frequent dead batteries, short trips could be the culprit.

 

I have a very similar drive pattern. I work from home and only leave the house for jiu jitsu a few days a week which is about 3-4 miles away. Engine barely warms up by the time I get there and consequently I only get about 14.5-15MPG for every tank.

I keep my battery charged with a battery tender like this:

$87 2 Bank Marine Battery Charger 5X2, 10A (5A/Bank) - 12V Waterproof Onboard Battery Charger, Battery Maintainer & Desulfator for SLA/AGM, Lithium (LiFePO4), Calcium & Deep-Cycle Battery- Charged 24/7

https://www.amazon.com/dp/B0D53QM3DZ

You should also consider following the more severe maintenance schedule as well - sensitive topic - so it's up to you but this driving pattern matches the "Extensive idling and/or low speed driving..." profile in the maintenance manual.

 

3 years old. Battery checker-if one can believe it-says State of health is 91%. Old school load tester shows good also. If it's my driving patterns I don't' want to blow $190 on a battery that's not needed.

 

That will do it, its your lack of driving. I drive about 15min to and from work every day and its not enough to keep my extra capacity AGM battery charged for more than a few weeks. You generally need 30min to recharge just the starting of the vehicle and 3 mi each way is not enough.

Get a battery tender and use it to recharge to full capacity every few months. Or take a few hour ride every few weeks.

 

Your driving patterns just about mimic what I do. My work is 3 miles from home, but I only drive my 4R maybe 2-3 times per week, my Tacoma the other days. Weekends can be hit or miss also. I haven't seen any adverse affects to my battery life, so I'm not sure if that's the culprit, in spite of the what was posted by @Borracho Loco or @Ripper238 above.

Edit: I do drive a bit more a couple times a week, when I go to the gym after work during the work week. But that doesn't add a significant amount of miles or time to the days I just commute to work.