The last time I got my battery replaced I think was 2008, I cannot remember(and the date was not marked on it in the little bubbles). I do mostly short trips, under 20 mins and some long ones about 40 mins to an hour.

I noticed the voltage drops across the battery terminals to about 11.7 or so when I turn the ignition just before starting, and across the terminals it seemed to drop to 9v on starting(when it started ok, problem seems to be base on how long I have let it sit). Though today after leaving it just before ignition, it barely started the stopped, then I started it again, it struggled, seemed weak.

When the engine is running, the voltage is about 14.2v.

Fluid levels in battery seemed ok as far as I could see. Maybe I should just change it anyway considering its age, but really do not want to fix something that is not broken.

The battery looks fine, nothing obviously wrong with it, maybe a little bit of white near one of the sides of the vent, but nothing really noticeable.

 

if you want to rule out a parasitic draw, take off the negative terminal clamp. put one end of your DVOM on the clamp, and one on battery negative. drop should be less than .5, anything more you have a parasitic draw

if you dont have a parasitic draw the battery is probably on its way out, 5 years is about the average life for one and 14.2 running means your alternator is fine

if you have no parasitic draw, just take it to Autozone or wherever to get the battery tested

 

That voltage drop is normal with the key in the "on" position prior to starting. You've got multiple systems running at that time, fuel pump priming, ect. Now if your resting voltage (no key in ignition) is 11.7 that's another story, still not the end of the world though, you could still crank her over.

 

Battery is supposed to have 750 CA, the guy measured it at 447 or something like that. So a teeny bit low, but not much.

 

447 out of 750 isnt enough to cause slow cranking. might still be the battery, but if the problem persists i would get your starter tested, could be the hold-in section of the solenoid on its way out. hard to say

 

Well, I did notice that after popping open the battery cap to check it, and sealing it back again, it now is a little more difficult to start, no idea. It would not do that after it got over that, as if it lost a little bit of its strength, and it was 446 after driving it for a while. The charger indicated it was already charged. Though I found the one hose that goes from the heater valve to the vacuum line was popped off, may need to zip tie it. Whole engine is overdue for a hose replacement as many are old and dried up, probably a few leaks.

 

Checking your altenator should be done with the engine running then turning on load after load.....with headlights, fan motor, foglights, applying brake lights, Hazard lights and observing output voltage somewhere around 12.5v.....If your output voltage drops below 12.0 V with all the systems (loads) on your altenator can't keep up and needs to be replaced! I would also test the battery amperes....

 

Funny thing is I worked on a 96 Maxima today that wouldn't start (turn over) cause someone apparently installed the battery in reverse polarity...and blew the main fusible link!

 

i did that once on a crappy old Mazda MPV too, got the polarity reversed and a huge spark. only blew the main fuse and not the ECU thankfully

alternator i just check with the vehicle idling no loads, usually thats good enough. anything below high 13V low 14V its not charging enough

 

This means your alternator and charging system is fine.

Connect a voltmeter to the battery terminals, then turn on all the accessories - headlights, blower motor, RR defrost, wipers - everything. Pull the fuel pump fuse and have someone crank the engine while you watch the voltmeter.

Anything less than 10V when cranking, you have high internal resistance in the battery and should be replaced.

If the battery tests OK but you still crank slow, connect one leg of the voltmeter to the positive terminal and the other leg to where the starter cable bolts onto the starter. Crank engine and watch voltmeter - if it reads more than half a volt or so replace the starter cable.

Otherwise, replace the starter itself.

Oh and forget about autozone - if brains were black powder those monkeys couldn't blow their noses.