Now I have to check what model I have. I've had it since at least 1992 I think, this year I had to buy new leads for it as the old ones finally gave up at the solder joint inside the plastic housing I keep mine with the battery out of it when not in use.

 

Yikes! $56 for that contraption? It's just a switch with a cable! I think this $5 battery disconnect switch would do the job just as well:
https://www.ebay.com/itm/Car-Battery...item26075dbb01
Install the switch, set up the car as previously described, put your multimeter across the switch (set up for 250 mA or less), and then open the switch. Easy peasy!

I still like PatternDayTraders technique the best. Cost: Zero!

 

There is no doubt in my mind that you could make that switch work perfectly.
One big disadvantage of using the jumper wire, is you cant start the car for a road test or maybe to let it hot soak at idle or something, and that has a way of screwing you over when you are looking for an intermittent problem.

 

Contraption? If you knew that every car that came in the shop with a suspected 'parasitic' issue was tested using the same technique and devices I'd think you'd have a very different opinion. Fabricate your own? No doubt not an issue but keep in mind this original had to pass hands in shop environment and be considered 'reliable'!!! Reliability maybe considered important feature as well as quality meters. Your Chinese 'fabrication' and what you choose for cabling might miss on maybe the reliability!!

 

I'm sorry, but I do not understand what "Chinese fabrication" you are referring to. It looks to me like the Kent Moore tool is a fabrication of a "top-post" battery cut-off switch to adapt it to a "side-post" application. If you like the same green **** as the Kent Moore tool, here's another link:
https://www.ebay.com/itm/Auto-Batter...7WY:rk:17:pf:0

No "Chinese fabrication" required.

 

Got the battery tested at autozone and firestone. Both places said it was good. Re tested with the jump wire and multimeter and came out at 0.02. So i guess ill hook it all up and let it sit a few days and see what happens.

 

You don't have a draw problem at .020

 

Ya we will see what happens. I have a bunch of stuff unplugged so ill put one thing back at a time and see. If i leave the car over winter can i take the battery in the house or does the c4 need a batter connected for the computer?

 

You can if you want. I don't. The battery might last longer if you do.

 

Are you still seeing this strange problem? Something is apparently staying turned on after the lights go off, but what? Keyless entry system?

 

Latest test showed no problem so im going to just let it sit a few days and see if the battery drains.

 

If you're only seeing a 20 mA drain, you don't have a problem, except that we haven't fixed anything! That's the same 20 mA results you told us about in your original posts, #3! Has something changed?

This has been a fun, educational exercise, if nothing else!

 

I was getting 200ma. Not sure what i did to get it to 20ma.

 

I would expect a good, fully charged battery to last at least 3 months with a 20 milliamp draw and maybe 6 months. My 95 has sat from November to March and started up fine.

 

That really depends on the type of battery you are using. In your 1995 do you have a Absorbed Glass Mat battery (AGM) or a flooded lead acid battery (FLA). A FLA battery has a much higher self discharge rate than an AGM battery. Maintenance free batteries are really just a FLA battery with limited access to the electrolyte. And now you can even buy a Lithium Iron battery for your car or RV, they are not cheap but they have potential.
Age has an added effect as a battery that is two or three years old will self discharge faster than a new one might.

A 20 mA parasitic loss is considered within the "Normal Range" for a C4.

Being a Battery Expert, I am getting a bit concerned with all the "flavors" of batteries available today. Our cars are designed to operate and charge a 12 volt FLA battery, the set-points in the alternator are set for a FLA battery. If you install a AGM cell you want different settings if that battery is going to last. Charging it up to 14.7-15.0 volts will cause the AGM battery to open it's vent and release hydrogen or electrolyte. This is why I still use the FLA batteries in most of my vehicles, their cheap, reliable and recyclable and my cars were designed to use them with the proper settings in the alternator. Then you look at these Red Top and Yellow Top Optima Cells, they are being sold as a "regular battery" and in some places they work just fine.
On my Cadillac Seville STS the Red top lasted 18 months before it died. The high charge rates and the electrical draw that Cadillac's have was too much for it. I removed it from service and played with it. The folks at Optima told me to use a second battery in parallel and charge it through the second battery to reclaim the battery. I tried until the battery started emitting this green smoke while being charged at a 5 amp rate through a second battery. The Optima batteries have special requirements for charging properly, technically it is an AGM spirally wound cell and it should be charged more carefully. They do not like AC ripple in the DC Battery charger and I suspect that is why they asked me to use a second battery in parallel as it removes most of the AC ripple.

I installed a AGM on my Ford V-10 in my RV and it does hold a charge well into spring without any help. Since I don't use the RV as often this is handy. In both of my Corvettes are Interstate batteries. And this time of year they are on a charging bench where they will spend their winter getting ready to power my toys in the spring.
Gone are the days of the simple FLA battery I am afraid. My 2004 VW Passat had it's first battery change at 153,000 miles and it almost fourteen years old. What I REALLY want to know is why do original batteries last 5 -6 years and all the replacement batteries last 3-4 normally?
Best wishes with your Corvette!

 

Well that explains why every Optima battery I've ever bought, fails in less than two years.
I've always had good luck with plain lead acid batteries. I might consider somthing different if the battery is in the passenger compartment somwhere. But on the c4, that isn't the case.