While messing around the battery searching for a parasitic draw, it came to my attention that the battery is a little over 4 years old. It seems to me that I just bought the battery a year or 2 ago. I have not kept up with checking the liquid level. I popped one of the two caps(that I could get to) and sure enough the liquid was barely covering the plates. I added quite of bit of distilled water to bring up the level in the 3 cells on the negative side. Well you can't get to the other 3 cells without removing the battery from the car. I must have spent at least 2 hours trying to figure how to do this without removing the battery. I was going to forget it, but the issue got under my skin . After fretting about it for a couple of days I decided just do it. In the end, it took about an hour or so --- much less time than the fretting and trying to find a way around it. I find myself amused at my own behavior. Taking the battery out of this car is a pain, but if I don't take care of it, I'm going to have to take it out anyway ,to replace it. I would estimate that I used 20-25oz. or more of distilled water to fill it. The car is driven a little less than 3000 miles a year. So if you do the math, a battery on a lightly used Corvette is boiling off about 1 oz.of liquid/ per cell/per year. Hope this helps some of you.

 

Thanks.
Adding that much water will dilute the battery acid and you might not be able to start the engine without a jump or bump. You should connect a charger and get it up to voltage before reinstalling. Don't charge the battery while it's attached to the cables.

 

What year C4 ? My 94 coupe takes about 10-15 minutes, remove top 2 bolts loosen bottom bolt of fender, remove holddown bolt and cables, neg first then pos pull it out. If battery needed that much water it's probably toasted.

 

My 94 ----3 fender screws, bottom bolt loosen, top bolt remove, hold down bolt, neg. cable, and pos.cable. Take out, put back, takes me at least an hour. The plates were still covered barely. Some white stuff on some of the plates which I assume to be sulfation. Adding water to battery raises freezing point until charged, so have to careful with that.. Battery reads 12.8 volts now after sitting in a 20 degree garage for a couple of days. Removing #1 Maxi fuse reduces draw to near zero which has made a big difference.

 

Disconnecting the negative cable or putting in a battery cutoff cuts that draw to 0.

 

Yup! And, many do just that - install a disconnect switch: has other advantages too - mainly safety against something shorting and causing a fire/melt-down!

ON THE OTHER HAND...

The battery electrolyte (H2SO4)
will react with the lead forming lead-sulfate which left undisturbed will coat the plates. This (chemical) sulfate action slowly robs the battery of the charge, which is reflected in both the output voltage and load capacity.

Initially, the lead sulfate is in solution (a thick slime-like substance) is quickly removed from the plates every time the battery is being charged, i.e., normal day-to-day or weekly driving is usually enough to keep the plates free of sulfate build-up.

However, if the battery is left over extended periods, e.g., over winter, the lead-sulfate will begin to crystallize and spread like frost on a window pane.

This crystallized form acts like an insulator and is not as easily removed (by normal charging).

As this crystalline layer spreads over the plates, the net result is there is less plate surface area for the normal chemical reaction to take place: the battery capacity to produce electrical power is slowly reduced, more and more.

The sulfate can be removed and kept at bay if the battery is periodically subjected to a full charging. As the battery is charged, the voltage slowly returns to full potential. At that point, further attempt to charge the battery will only cause the electrolyte to "boil" away. For this reason, a trickle charger cannot be left connected to a battery indefinitely; it will continue to boil the electrolyte away to eventually expose the plates and reduce the battery capacity. (Under extreme over-charging, the electrolyte can be completely boiled away until the battery is dry!)

A "smart charger" e.g., Battery Tender (for one...there are many) has voltage sensing ability and circuitry designed to stop the charging process. After which, these smart chargers will just "pulse" the battery to verify charge level and keep the sulfate at bay. If it detects the battery has become discharged even slightly, it will return to charge mode and bring the battery to full charge before reverting to monitoring mode.

The "argument" for the mechanical cut-off switch is that after using them all winter, (not charging the battery) "...the battery is still charged, and the car starts right up!. So, why use a 'Battery Tender' or whatever?"

That may be true in some cases. Regardless tho, sulfating WILL occur. The question is: Once spring has arrived and (assuming) the car is returned to normal weekly exercise, will the sulfate be removed sufficiently to reverse any long term ill effects? Maybe so. But, if left for extended periods, say storage for 6-9 months or more, what will result then?

If left for 3-4 months over winter before being returned to regular use, it seems that is sufficient to restore the battery - according to the experience of those using a mechanical cut-off switch.

Me? I will continue to use a Battery Tender and maintain all my pre-sets and ECM mem-cals. U decide!

 

 

I didn't mention it because it wasn't part of the original question, but in addition to disconnecting the battery I like to run the cars every month or so when in storage. If it's crappy out, they stay in the garage and I'll run them long enough to get the engine up to operating temp. If there's no ice or snow on the streets and alley (assuming there's not a lot of salt down on the streets), I like to take them out for a couple of miles just to stretch their legs a little. Keeps seals etc. in good condition over periods of inactivity plus you can check the general condition of the vehicles at that time. In fact just did that a week ago with the Vette and T-Bird.

I've been doing that for about 40 years now with multiple vehicles and never had a battery issue that could be brought back to inactivity of the vehicles nor seals etc. drying out and causing issues from inactivity.

I recommend whatever someone is comfortable with and works for them, whether a battery tender, disconnecting the battery or something else then that's their best solution.

 

But, I think it is to preserve my sanity...going through Vette withdrawals is a bitch! So, I too take 'em out for a little spin on warm sunny winter days - using your arguments as justification!