Just sharing a battery drain solution. I'm posting because you always hear about the most complex fix to a problem and there is not that much out there that requires a pretty simple fix. 98 C5 was keeping a charge from Sunday to Thursday (with a slow start). Come Sunday to Sunday nothing when I turned the key. So I cleaned all the grounds, tested the battery and alternator. All came back fine and the still the same thing. Called the Vette Dr's to schedule a visit due to all the short issues you read about on the forum. He asked me a few simple questions:
1) How old is the battery - 4 years and I let him know that it was rated for 7.
2) How often is the car driven. - 6 months out of the year.

Resolution - Buy a new battery. Regardless of it being on a charger, batteries need to be cranked.

Purchased a new battery - Issue completly gone. No ripping the car apart no anything. Left the car for 2 weeks, started right up. Just a heads up - Even if battery and alternator test fine, it's not always accurate. I will just have to come to terms that the car will need a new battery every 4 years.

 

I second this, use a battery tender. I use an AGM Battery (to avoid the leaking acid problem) and they do not respond well to being deeply discharged, it shortens their life.

A battery tender does NOT overcharge a battery.

 

I'd certainly second the suggested use of a battery tender. Anyone purchasing a new one should check its charge rate carefully at first. I know first hand of three battery tenders/minders that were defective and overcharged their batteries. Won't mention any names. And I don't see why tenders/minders (at least the ones I've had first-hand experience with) take the batteries above 13 volts--some to near 14. I know that is about the level that an alternator will provide, but it seems excessive for a static tender. Why don't they cut off and hold around 12.7 volts?

 

GM Factory Experts said that C5 batteries should be rated at 120 minutes Reserve Capacity (this is the number of minutes a battery can maintain a useful voltage under a 25A discharge).

Very few batteries have this much reserve capacity, which is why people have trouble when they leave their C5 sit.

 

Hmmmm......you coming to terms with that is great for the battery manufacturers.

I drive my car about the same as you (great Chicago weather), and have every expectation of getting better than 4 years from a battery. Did anyone ever audit the current draw, or did they just change out the battery?

 

They don't cut off at 12.7 volts because a battery is not fully charged until 12.9 volts. A 12-volt battery will measure at about 12.9 volts when it’s fully charged and about 11.4 volts when it is fully discharged.

Most Battery tenders cut off at about 13.2 volts, well below what will damage a battery.

 

Thanks for all of the advice and that is what I was considering going forward so I can get more than 3-4 yrs out of a battery. However, when I suggested a tender to a tech he said that is will help though it's the cranking which really helps with the life of the battery. I guess the cranking takes the most power and it's that charging and discharging that maintainns the life of the battery. A battery tender is a minor cost to at least give it a try. I really apprciate all of the ideas and I am just psyched I did not have to rip my car apart to find out I onlly needed a battery. Last question is how could the battery test ok on the machine and not start a car after a week?

 

Oh Oh, did this happen to your NEW battery in your car?

If so, you have a battery drain problem ! Some parasitic drain is draining your good battery. Before testing batteries, they usually charge them up.

Check for drain by putting an amp meter on car and waiting 10 minutes. Then pull fuses, one-by-one, until your drain goes down, that is the circuit giving you problems. Check lights on mirrors and power seats (often a cause).

GOOD LUCK !

PS: Your battery expert does NOT sound like much of an expert. IF a battery passes the Load Test, it is good period ! Sounds like you got rid of a good battery !

 

Where would someone place the amp meter? I'm having the same issue- just bought a NEW optima yellow less than a month ago, and it's dead already. I drove the car last weekend and it was fine, went to start today, nothing. I didn't have the tender on it for the past week, but it only sat for a week.

Not to hijack the thread, but could any of the following cause an unusually high drain?
- LED Halo Taillights
- Aftermarket HIDs on low beams
- Aftermarket HIDs on fogs
- XM Commander
- Window Valet
- Hardwired V1 to rearview mirror
- 3rd brake light flasher

 

See post #590

http://forums.corvetteforum.com/c5-t...n-long-30.html

 

Sorry for the confusion. This happened with my 4 yr old batter. Ever since I had the new battery in, holds a charge and works like a champ.

 

I used a Battery Tender Plus on my '00 for seven years and it kept my battery in top shape. Am using one on my '03 now since I don't drive it every day.

 

Awesome. Thanks for lettinng me know. I will be getting one this season. Can you please let me know which one you have?

 

My dad just had a battery drain issue with his 1999 Corvette. He came home from a vacation and drove around like usual on his 7 year old battery. The next day the battery was dead. He installed a new Optima battery and it drove fine. Next day it was dead. Charged it up and next day dead.

He took it to the dealer for repair. 4 days of working on it later they fixed it with a new fuse panel. He said they had suspected all kinds of modules and practically took the thing apart chasing the problem.

It cost him $700 but the repair is guaranteed for life under Mr Goodwrench.

We were trying to figure out what would wear out on the fuse box. The new one came with all relays and fuses in it. They gave him the old fuse box and it had all the old fuses and relays still in it.

I told him after all that work they probably found a bad $10 relay but changed the whole fuse box to jack up the price to pay for all the labor that went into the repair.

 

 

I agree,a simple test and change of a relay in that fuse block probably would have fixed it!

 

glass mat batteries like the red top don't tolorate sitting idle w/ a 30ma drain. For wet batteries you can get away with simply unhooking the negative cable..... not so with a glass mat type.

 

Grab a CTek charger. A little pricey but they work very well.

Peter

 

Post 590 is what I posted a LOOOOOOONG time ago.

I will tell you,,, that I had a 1998 Coupe and the OEM battery was 7 years old when I took it out of service because I was afraid it would leak. The battery NEVER died even after sitting idle for 2,3, 4 weeks during the winter. It would sit idle for almost 1 1/2 MONTHS and still have the ***** to crank the car. No charger, tender or jumping. It still cranked.


IF,,,,,,,,,, you have a GOOD battery and the correct parasitic current draw,,, sitting for two months is doable. HOWEVER,,,,, running the battery down to that level isn't good for it. IF,,,, you plan on letting the car sit for an extended period of time, just disconnect the damn battery and reconnect it when your ready to put it back on the road. Its that simple. It does NOT hurt anything to leave the battery disconnected for that long PERIOD!

Testing and knowing what the parasitic current draw of your C5 is important. If your having issues, test it. It takes 20 min.

richieice

If you have a BRAND NEW BATTERY,, sure,,, its going to allow you to have the car work normally for a LONGER period of time cause the battery has a lot more reserve power. IF,,, the parasitic current draw is excessive, you will soon be in the same boat as with the old battery.

Measure the current draw and post what it is.

BC

 

I talked to a friend who owns a hot rod shop and specializes in electrical problems. He said 2002 and new cars can be tested by a device that is hooked up to your OBD port. The device will tell you where your electrical drains are coming from. I guess 01 and earlier have a different computer.

My dad says his Corvette is working fine with the new fuse panel. Also the seats and interior lights were acting funky before the panel was replaced now everything is working like new. He thinks maybe several of the relays were getting tired after 11 years in the AZ heat.

He never had a battery drain issue until this September and never had it on a tender.

I can't find the part number but I remember the same fuse box was used on Cadillac, GMC, Buick and Pontiac.