Battery dead after winter storage
 

Stored my Z for December-March. This is the midwest, so it can very cold in the winter, though this year it was milder. I had it connected to a battery tender trickle charger, as recommended. I was storing the car at a relative's house and he told me the trickle charger was pretty much always in the red state, which means it's charging and hasn't reached close to fully charged. I didn't think much of it, because in late November the battery was fine at my pre-storage oil change.

On the other hand, my Z is an 09 and I haven't replaced the battery as long as I've owned it (< 2 years). Assuming it has the original battery, that's going on 4.5 years or so battery life from the factory. Only 18K miles though.

So anyway, I went this weekend to pick up the Z and it was totally dead. The starter could only get a few clicks in before it just quit. On each click I saw the LCD briefly flash on/off so clearly the battery was dead and it wasn't the steering lock. I tried jumping it with my jump pack and that was taking too long, so I switched to cables. I had to rev the other engine for a good 20+ minutes continuously before the Z would finally start.

After driving it for a couple hours, the battery seems recharged again and the car starts up fine. The voltage on the triple meter looks good while the alternator is charging - a solid 14.5V or so. I'll check the battery voltage with my multimeter later, but I've also got an oil change this week so I'll have them run the test anyway.

My first question is, why did the battery tender seemingly not do anything while the car was in storage? Is there a point in the battery's life where it is discharging faster than the battery tender can charge? Thus the battery tender was always struggling to keep up? Or is it possible the battery tender wasn't properly connected? The only thing I wonder about is whether or not you're supposed to connect the negative clamp to the '-' battery terminal, or to the engine block. I used engine block.

Is the battery getting close to needing a replacement? I tried searching the forum and it seems like there isn't really a consensus that I could find as to when the battery goes. 4 years seems like pushing it but I'm not sure.

Thanks.

Mine did the same thing this year after getting it out. It took a charge, but I will be replacing it soon.

I been storing my Z the past 3 winters and is only this one that the battery went dead. Now I don't put anything on it just leave it there but still I know what u guys mean. I mean I got 15k on my 2010 is time for a change. After I jump it with a jumper box it was fine didn't have to do it again. Now where in the Midwest do you stay??? I'm in Chicago

probably not hooked up right or your battery was low with water, your tender is defective, or your car has major drain.

my battery is 4yrs old no issue starting. hell, my G's 9yrs old and still on original battery. no issue. all i did was checked water level at age 4 and 8, and used battery tender when parked for more than a few days.

will be checking my Z's battery water level this summer. :)

I'm leaving town for 6 weeks, flying back to NYC.

What should I do about my Z? Should I disconnect the battery?

My first guess is that the tender was not connected properly - not making a good connection. Edit: or polarity reversed.

Second guess is that the battery was not fully charged when put up for storage. Most tenders are not really intended to charge a battery.

Third guess is that you have something drawing more power than the tender can keep up with. Have you made any mods that might be drawing power when the car is shut down?

Fourth guess is a bad battery tender.

Last guess is the battery is bad. Although it's not unheard of for a battery go go bad so soon, it's not all that common, either. Since it seems to be taking and holding a charge, the battery is probably OK.
Check the electrolyte level in the battery and add distilled water (not filtered water, not deionized water, but distilled water) if needed. You can remove the frame around the battery cover if you need more room - see one of the pull-the-SLU-fuse DIYs for details on removing it.

Invest in a battery tender. Disconnecting the battery is not a good option on modern, computer-controlled vehicles. You will lose tuning data, radio presets disappear, and the windows will forget how to roll up.

I went 7 years on my 350z with the same original battery that came with the car when I lived up north storing it for 5 months during each winter
I had a religeous schedule for prepping for storage. It worked for me
1. Change oil
2. Fill tire pressure to 38 psi in all
3. Put in gas stabilizer (amsoil) with a full tank of gas
4. Wash car/wheels and dry to ensure no bugs or dirt is left on the car
5. Start the car once a week and let it run for 15 min each time
6. Roll car forward or backwards a couple inches each week to prevent flat spots in tires

For 7 seasons I didn't have one problem with battery, performance loss or any other significant issues that you can run into while storing.

Now that I'm down south I only put my car up for the 1 cold month we have and still run an amsoil gas stabilizer and start up once a week while rolling the car either forward or backwards to prevent flat spots in the tires.

I hope this helps gentlemen.

-Chad

when you store a car for the winter you should take the battery out and bring it in out of the cold.

yah, pre-2000 that may have been true.

My car was always stored in a heated garage... ;)

Your relative disconnect the battery tender for a long time maybe.....