Greetings all!

'09 MT Sport - Apparently I left one of my map lights on 5 days ago, and only discovered this today. Battery is completely discharged.

I hooked up a charger to it, and immediately the alarm horn started chirping. I tried different combos of pushing buttons on the remote, inserting the key in the ignition, etc., and the alarm kept chirping.

Any advice on how to proceed? As it stands, it looks like I could either leave the charger on - ignoring the alarm and dirty looks of the neighbors, disconnect some wiring, or try push starting my car (and hoping the alarm doesn't go off at that point).

Can't find any info in the owner's manual - just how to reset my radio. Any help would be greatly appreciated.

 

I would try disconnecting the battery's negative terminal and then charging it. After 24 hours it should have enough charge to start the car. Reconnect it (and enter the radio code). The alarm should function normally then.

It's probably a case of enough voltage for some circuits and not others, due to the battery condition, confusing the crap out of the car's control modules.

The battery may be marginal and need replacing. If dead batteries are left in freezing temps they can get damaged (although Texas should get by).

 

I agree... you shouldn't really charge the battery with it connected to the car with both terminals.... spikes can damage the IC chips.

After your radio starts blinking at you, when you reconnect the battery terminals, use the radio numbered buttons to punch in your code for your radio. Your paperwork should indicate what this code number is.

 

One thing you can do is attaching another battery (like to jump start it) and let that sit for awhile (15-30min) to transfer some charge.
See if that also sets off your alarm. Then try starting the car and maybe drive around for awhile.

Once you got that all sorted out sorted, you can attach the charger (hopefully you didn't get the cheapest charger and it is semi-smart).

 

My battery just recently needed a jump because I left the radio on for a while. Though it's starts now, the indicator doesn't have the full blue around the red dot like it should, and I've driven it for a week with no change.

Does this mean I need a new battery? Or can it be "charged"?

 

Keep driving it. The woman left the headlights on, on mine, last winter. I charged it for 12 hours and then started/drove it. The blue ring didn't reappear for a while. I'm not sure when; I was checking it daily and then forgot about it. Weeks later when I thought to check it was back. I don't know what charging logic the Honda uses but it must take a week or more for it to fully charge. Doesn't mean it's bad or excessively low, just not at 100%.

Have it checked (load test at your friendly autozone) just to be on the safe side.

 

the battery and charging system in the car is not smart; neither is the indicator which is just chemistry based (wikipedia on lead acid batteries to learn how it works).

But in general it's just math. The capacity of the smallish battery in the Fit is probably 60-100 amp-hours. If you were near dead, you need all those electrons back. If you were charging with say a 2-amp charger for 12hours that only got you 24amps hours (minus some losses).

When you're charging by driving, maybe you are charging at 10amp minus whatever you needed to start. So that's at least 10hours of driving needed or so.

My point is charging a completely drained battery is in the realm of 100 amp-hours or so, something not fulfilled in just a couple hours. It takes a couple of hours to charge a cellphone, your car battery is much bigger.

If you are determined to get your battery fully charged up if you want the best reliability for your battery, I'd recommend getting a smart trickle charger (such as batteryminder / batterytender) and then plugging it in until it reads full. This may also take a couple days. The batteryminder ones also have a feature that desulfates your batteries (conditions abused batteries for longer life). This should be less than $50 and a good tool to have and may save you next time you run your battery down (won't have to worry about shutting off your car off if you didn't charge battery enough after getting a jump).

But if your car works, and you are driving regularly, I wouldn't worry about it.

 

I frequently hook up a charger to my battery just for the hell of it.. I got the car July 14 2006 and the battery is still going strong.. I'm going to see if I can get by with a much smaller battery or a couple of them using heavier cables when the OEM battery plays out

 

I frequently hook up a charger to my battery just for the hell of it.. I got the car July 14 2006 and the battery is still going strong.. I'm going to see if I can get by with a much smaller battery or a couple of them using heavier cables when the OEM battery plays out... Using 2 or more small batteries will give me the room I need for an oil vapor separator and other Knick Knacks that I need to put under the hood..

 

Smaller than the Fit's OEM battery? What, a 9 volt and 2 AA batteries in series?

 

I had one of those "duh" moments after reading the responses (couldn't find the facepalm icon). Shoulda been obvious that removing the battery from the system (or just the negative cable) would keep the alarm from going off, but apparently it went right by me.

Took the cable off, hooked up the charger and let it run overnight. When I hooked up the negative cable the next morning, my alarm did go off, but mashing the buttons on the remote took care of that. Put in the radio code, set the time, and everything is back to normal.

Thanks for all the help! (Sometimes common sense isn't so common...)

 

They are AGM batteries made by Deka. for power sport use.
http://www.buycheapr.com/us/img/transparent.gif

 

I think it's smarter than you give it credit for. I believe the Fit's battery is around 45AH and the alternator is capable of 100A. Hondas also sense load and drop the field generator in the alternator to avoid parasitic loss when there isn't any load (causing the annoying variation in voltage that dims headlights). If all it had were a dumb voltage regulator, I think it'd cook the battery trying to charge it.

Yeah, the indicator ring is just a specific gravity float.