Ever since we had our second child we haven't been able to take our '98 convertible out as often as we'd like. I'd gone through a couple of batteries already, simply the fact that (sadly) we'd go weeks without really driving the car.

I finally bought a new battery and a battery tender. Still weren't able to drive it that often, but I'd go out every couple of weeks and make sure to start her up. No issues. Car has been on the tender for about 18 months now.

Then, a few days ago, with the battery still on the tender, I tried to start her up and found the battery completely dead. I was able to jump it using my Subaru and get the engine running. Let it run for a good thirty minutes, until the voltage was back up to 12-13V per the dashboard readout. Put the tender back on the battery and thought all was well.

Three days later, I tried to start her again and found the battery completely dead again. This time when starting I heard that weird buzzing noise coming from the fuse box. Understand that's the relays freaking out due to low voltage. Didn't have a chance to jump her this time.

So now the car is sitting completely dead. Figure I'll have to buy a new battery, but wanted to ask if keeping it on a tender for a long time would shorten the life of a typical battery. Is there something else I should be doing to keep the battery going, besides just driving the car more often?

Thought the tender would help out, and it did for 18 months. Don't want to just keep buying batteries though if there's potentially a larger issues here.

Any thoughts? Recommendations? As always, thanks in advance for any help. This forum is awesome!

 

I would hope the problem is not with the battery tender. Did it ever show the battery as being fully charged? If not, that would alert you to there being an issue with the battery itself. Good luck with finding the cause.

 

I had an issue with the power seat breakers on my '02 so I replaced them and now I see about a .18 mA draw.

I keep a tender (Deltran Battery Tender Junior) hooked up during the winter and sometimes I won't use the car or even start it for 3-4 months. After finding the draw, I have never had a problem. And use a good tender like the Deltran or a CTEK unit.

You will have to find the parasitic draw before simply replacing the battery. IF the draw is substantial, all that will happen is the new battery will become discharged.

It could be that your battery may still be able to be recharged. Remove it and take it to a reputable auto repair shop (not one of the chain auto parts stores!) and have them put it on a charger and then have them do a load test on the battery. A fully discharged battery will take some time to reach a full charge especially if the charger doesn't have a decent charging rate. That can beat buying a new battery.

 

Could be as simple as dirty terminals. They corrode even just sitting

 

Wait...18 months on the tender?

If I know mines going to be sitting for more than a week or two, the battery gets disconnected and comes out.

Then every once in a while I'll put the tender on and bring it up to solid green light and disconnect tender.

 

I know. I try to get out and start the car every few days...Regardless of what I find out though, I'm going to start doing what you suggest; just disconnecting the battery if it's going to sit for more then a couple of days. Figure it's better to reset the clock and such then it is to keep killing batteries.

 

Thanks everyone for the suggestions. Looks like as soon as the snow goes away I get to try to track down the electrical gremlins in the car. Electronics are my biggest weakness when it comes to working on cars, but there's not better way to learn then to just jump in and try it right?

I'll let you know what I find out. If there are any other suggestions please let me know. Thanks again for all the help!

 

I had an issue similar and had to take my 2017 Z51 convertible to dealership.

I had disconnected the battery for a period of couple weeks. I was putting sound proofing and the Soler TB and TC. When I reconnected the top would not go down and the trunk would not open. I took it to the dealership and it had to be "taught" its position.

So basically I had the same issue.

Ken

 

What kind of tender do you have? a tender should be able to compensate for an amp and a half drain. A good tender should be able to stay on a battery since its diagnostics will shut it down. If the tender does not have a Desulfation cycle, crystals will form in the down time and kill the battery. a Cheap tender runs the risk of a bad regulator since cheap tenders use the absolute cheapest parts and with zero quality control.
Bill aka ET

 

It is possible that your car has a battery drain. There is a lot on this in Tech, search "battery drain".

Check the following, especially the video on how to test for battery drain in post # 15:

https://www.corvetteforum.com/forums...t-charger.html

My car had similar symptoms several years ago, it turned out to be the driver seat switch. I initially stopped the drain by pulling both seat breakers then diagnosed to confirm.

My car has been on a battery tender 24/7 except when at the track or cruising for ten years. The battery tender is under the hood along side the fuse center in front of the battery with a chord to the fender well with a plug. I hook it up every time I park in the garage. I don't have to open the hood to do so.

I have not noticed any deterioration in expected battery life as a result of the above practice. I use an Optima Red Top but may go to a Yellow Top next because I have two other vehicles with Yellow Tops that are 9 and 10 years old respectively and still going. No leakage from an absorbed mat battery.

 

I'm wondering the same thing. A Deltran Battery Tender should easily keep a battery charged. I use the full size ones on my cars and a junior on my lawn tractor. I also have a CTEK, a Schumacher (that's 18 years old), and an Optima . I have too many cars.
I'm also a big fan of Optima Yellow Tops as they can take discharging and recharging better than a conventional battery.

 

This post is 6 yrs old guys. Since I have come back to C5 forum section I see a lot of really old post that I am others still reply to. I have tried to look at date before commenting. Would like to see these really old post go away, good or bad idea. B well to all