su8pack1

I put the Battery Tender Jr on 6 days ago after the car sitting for about 3 weeks. Sometimes it takes 3 to 4 days to get it back to 100%. Today the Tender is flashing red meaning a problem. I put another Battery Tender on to check and the same thing. I have 8 tenders with 15 batteries to maintain. Then I put the big battery charger on and was able to get the door open but nothing else and the window won't index back up. The big charger won't charge it either. A short I guess. Have to get a new one tomorrow. I replaced the original battery after 4 years with this one, identical replacement now 2 years old. The funny thing is that old battery now 6 years old comes up to full charge in about 2 hours in a 69 280 SL. There's just to much going on under the hood of these cars when they're just sitting. I know use it more, only 412 miles this past year.

The NNIAL8R

Had to replace the Optimas in both my 1999 C5s today...One was 5 years old, one was 4...My 2005 SSR is still on the original battery as is my 2007 C6Z....I use Battery Tenders on all of them........Last month I had to replace the original battery in my 2004 Silverado...It was exactly 7 years old...I guess it got a seven year "itch"

FWIW, a Battery Tender will only maintain a battery, it wont charge a dead or low battery...also, a battery can have 12 volts, but that doesnt necessarily mean it will have the needed amps (about 200) to start the car...

The best thing to do is pull the battery...have it fully charged using a regular battery charger, then load test it to see how it holds up under load (amps)






.

Kevin_NYC

Good Taste

I have a '68 250 SL; dark olive green, cognac leather, tan canvas

I had a diehard in SL for 9 yrs!

su8pack1

The Battery Tender Jr will charge. Once at 100% it maintains that. From their site about the Jr.

"Perfect for all lead-acid, flooded or sealed maintenance free batteries (AGM and gel cell).

Complete 4-step charging program (Initialization, Bulk Charge, Absorption Mode, Float Mode).

Automatically switches to float / maintenance voltage after fully charging the battery.

If the battery voltage drops too far under load, full charger output power resumes."

madmax4499

did you put a volt meter on it? at 12 volts the battery is only 25% charged, 12.4 is 75% 12.6 is 100%, little more complicated than that but it will give you a good idea of the state of charge.

MKenM

Sulfation may have set in on the battery. Use a good old hydrometer to check the specific gravity of the sulfur in the battery.

The NNIAL8R

If it charges it must take an eternity...I think the Jr is only capable of 1-2 amps at the most.....A regular charger can charge anywhere from 50-200 amps....

The NNIAL8R

Try that on a sealed battery... (which most modern batteries are)

madmax4499

I know what your saying but your terms are off, you dont want to confuse people.

Vette5.5

When a battery drains down to total zero, it's usually a goner, and sounds like what happened to yours. For all the batteries you have, may want to get a Midtronics conductance tester, as gives you a read out of battery plate condition. While not cheap, I have a PBT-200, and better than getting stranded in nowhere land. For new battery, maybe check the Advance Auto site, as running code "ES123" $30 bucks off $100 online purchase now. Their Gold 90T5 is a 100% identical drop in replacement for my car w/vent tube ports, and 3yr free.

FortMorganAl

It's not the car. It's the way you are abusing the battery. Yes, there are more electronics in a C6 than a 52 Buick. You can't let them sit without a tender for 3 weeks repeatedly and expect the battery to last. But take care of the battery properly and they can easily last 7-10 years.

rgauchey

I just sold my '99 Plymouth Prowler. It had the original factory battery. 12yrs on a battery tender in the winter and the battery was still like new.

The NNIAL8R

...Battery Tenders are a MUST on these vehicles if they sit for much longer than a few weeks between drives...The parasitic electrical draw (even with the ignition off) will pull even the best battery down without a tender...

Also, gel batteries (such as the Optima) dont fare near as well as a conventional wet battery....Even with a battery tender the Optima life is about half that of a conventional wet battery....but to me, it's still worth the extra cost of the Optima, despite it's shorter life, when youre talking about a C5/C6 Corvette...Too many expensive wiring and electronics below the battery tray that can be damaged if a conventional battery leaks...

RobVette

I'm seeing a lot battery related problems on this forum. Last year, my battery died after 4-5 days. Since then I've always used a battery tender.

dpigguy

Focus people! The real issue here is not the battery, which is dead and must be replaced. Its the fact that he only drove his car 400+ miles in the last year! Its a car - use it!

su8pack1

You're right I should have had it on sooner. I just didn't drive it enough this year and the battery was weaker than in years past.

Jimmy W1

(1) I don't think this is true at all. (What you are probably thinking about is when the cells go dry) I was an automotive electrician for six years back in the 70s. And we learned that one of the BEST things for a battery was to let it go completely dead and then charge it back up. This recycles the battery and will not harm it in any way. I have a 78 Vette that sits all winter and usually goes completely dead before I get around to charging it back up. (when I want to get it out and drive it) The battery in it is probably 6 or 7 years old and goes dead 5 to 10 times a year. And it's still good. I just charged it back up two days ago. When it sits so long the clock runs it down. I have had it for 20 years and have only had 2 batteries in it. And I have only put about 3,000 miles on it. So, most of the time it sits and the battery goes dead. (2) I didn't think the Battery Tender Jr. was that good of a charger for a car battery. I understood that it was too small and was meant for motorcyles and small boat batteries and would be hard for it to charge up a car battery the way it should from completely dead. At least that's what the guy at O'Reilly's told me. (3) Like someone mentioned, the best way to check and see if your battery is completely charged is with a hydrometer, if you can get to the cells. You need to get the long glass type. Not a cheapo. When you check it, there should be no more difference in the cells than 25 points. Any more than that and your battery is getting weak.

Jimmy W1

Another thing. If you have 15 batteries to maintain, the best thing for you to do is charge them up completely and then take one of the terminals off of the battery. The clock is probably running them down and they should stay charged up if you disconnect one of the terminals. You'll have to reset the clocks and maybe some other memory items, but at least the batteries won't go dead in all of them. So, just charge up the battery and pull the positive terminal off of the battery and you should be better off......

The NNIAL8R

...but from a safety standpoint, pull the negative, not the positive terminal off...You wont get any fireworks if you accidentally short your wrench, ratchet, etc, to the frame, etc...

Larry/car

I had a battery go in my one car this summer. It was on the tender and green lighted, removed the tender used the power top system and put the top down. When I hit the starter, it grunted and that was it. The battery failed. No warning, top motor operated normally, must of shorted when all the amperage was called for to start the engine. The battery was seven or eight years old.