I have a 2008 Fit with 133,000 KM (70,000'ish miles). Had the battery replaced just under two years ago. Since this past summer if I have for what ever reason, turned the car off and sat in it while listening to the radio the battery dies. For instance I arrived to pick a friend up for work and sat outside with the radio on for no more than 5 minutes. By the time she got to my car the battery was dead. I took it to the dealership that installed the battery and they ran $200 worth of diagnostics and couldn't find anything wrong with it, except the said the post-factory car alarm hadn't been wired in right (it seemed strange that this would be the issue since I hadn't had the problem before, but the alarm came with the car when purchased in 2010). They unplugged the car alarm but this didn't fix the issue. I took it to my usual (non-dealership) mechanic for a second opinion and he couldn't find anything wrong with it except a loose battery cable. Today it was -30 something. I was to much of a wimp to stand out and pump my own gas so I took it into a full service gas station and got 20$ worth of gas. While it was being pumped I left the radio and heat on. It takes like about 10 seconds to mupm $20 worth of gas. But in that time the battery died. After jump starting it the radio/clock appears to be toast - the display reads "enter code". I am assuming that the $200 worth of diagnostics that Honda ran plus the testing my mechanic did would have included evaluation of the alternator. What else could be causing the battery to die (after cold starting in -40 degree weather). Could a faulty radio drain the battery?

 

dont use your accessories while the engine is not running, especially not your a/c or heater. you are weakening your battery each time you do this for a prolonged time.


dont run your engine while pumping gas.


check youtube on how to check for parasitic drain.


GL

 

Easiest explanation is the two year old battery is bad. It should have had the reserve capacity to run the accessories while you pumped gas. That it didn't points to a bad battery. And yeah, turn off the car completely next time you pump gas. When you feel the urge to listen to the radio without running it, make sure the ignition switch is in the accessory position and not the "run" position; this uses excessive power to run things line the fuel pump, engine controls etc.

When you say $200 worth of diagnostics, did you actually pay $200? I'd find a different place to get service.

 

Thanks Steve. I only went to the dealership because I was told I had to if the battery was under warranty. Am going to take it to my regular mechanic and ask if we can hook it up to a new/different battery and then turn the engine off and leave the radio on and see what happens. Do you think if I do this and I am able to start it, I can go back to the Honda dealership and say, yo dudes the battery is bad and you owe me a new one or do I save myself the aggravation and just suck up the cost?

 

Battery warranties are typically pro-rated after a comparatively short time. Your dealer won't give you a new battery after two years, but you may be eligible for some percentage off/refunded if the battery is faulty. (And I agree with Steve that this seems likely.)

How much driving are you doing between these difficulties? Possibly the battery just isn't getting adequately recharged if the trips are short. With a fully-charged battery, you should be able to even leave the headlights on for a few minutes while you pump gas and still restart the car afterwards—not that I recommend doing this, of course, but it's well within the capabilities of a properly functioning battery. The headlights use far more power than the stock radio.

 

Drew said it best.

If you had it diagnosed by Honda in the past 60 days they should check it again for free. If it's been more than 90 then probably not. $200 is a lot to spend and not find the problem.

 

First of all $200 is out of sight to diagnose a charging system problem. Find another mechanic.

Automotive battery charging basics.

1. A fully charged battery will read 12.6 or 12.7 volts after sitting for at least one hour.

2. A battery that reads 12.0 volts is almost dead and will not start your car.

3. An alternator charging your battery will read 13.8 to 14.2 volts. Most are temperature compensated these days and will read on the high end when cold.

4. A cold battery will not take a charge, so for the first 15 minutes or so even though the alternator is placing 14.2 volts across the battery the current the battery is taking is being converted to heat internally in the battery and warming up the battery.

5. Every time a lead acid battery is near completely discharged and recharged again the battery looses some of it's storage capacity.

So what you need is a digital volt meter across the battery to see what is going on. Without one you are just guessing.

Honda has something call VLD variable load detector. The VLD is used by the body to tell the Body computer to tell what current draw the accessories in the vehicle are taking. I then can compute when the battery is near fully charged. When it thinks the battery is near fully charged the computer reduces the alternator voltage to same some energy which translates to more miles per gallon. Yes, I know you use liters but for this discussion that is unimportant. I have never seen this VLD in any vehicle application other than Honda. If you have added aftermarket accessories incorrectly the VLD will not detect them and those accessories will slowly discharge your battery.

If you want to diagnose this problem I suggest that you get a Volt meter or VOM some kind and learn how to read it.

Walmart (US) has a cheap one that plugs onto the Cigarette lighter/ accessory socket and you can watch it as you drive. You can find it near the batteries in the automotive department for around $14.00 (it is probably slightly higher north of the US Canada border). You are probably use to that but it is not worth the gasoline to drive to Niagara Falls, NY to save a few bucks.

Equus Innova 3721 Battery Charging System Monitor - Walmart.com

Here is the same one on Amazon.com


OR here if you want one one with a cord so you can place in a location for easier reading.

001046632 - Walmart.com

001050253 - Walmart.com

 

If the battery and charging system checks out OK, I'd be looking at the aftermarket alarm to see if it's still drawing current despite whatever the mechanic did to "unplug" it. I've heard of many aftermarket sound systems and alarms that were installed in pretty messed up ways.