Last night Teddy, my Standard Poodle and I went shopping at COSTCO in the ol' 993 for the annual Holliday feed-the-family-Holliday-guests shop.
When I returned to my car my starter, in the parking lot, seemed to be encountering a hard time turning over the engine and the alarm/Ignition immobilizer system seemed to be acting strangely with the fob icon in the clock flashing. This alerted me to the thought that the battery needed attention. It is odd that a 993 among all the dials and gauges provided does not have a system voltmeter anywhere on the dash. However, I theorized the maintenance-free battery was supplying too low a voltage and suddenly had reduced start capacity and I wanted to remedy it if possible before the battery failed completely. I was looking at it as an opportunity to save the battery so it may live another day.

Modern "maintenance free" batteries are actually ordinary wet cell batteries with the cell servicing ports designed to be somewhat hard to remove. In many cases, a so-called "maintenance free" battery suddenly dies when the electrolyte has evaporated off one of the cells to the point where that one cell fails and the battery stops functioning. When a cell runs low on fluid the available voltage and cranking capacity of the entire battery declines sometimes suddenly.

The solution is to pry off the battery cover and top off the cells with distilled water. There usually is a fill ring that the fluid touches about 3/4" below the top of each cell opening which is a reference as to the cell being completely topped off. In any event, if you look in each hole with a bright flashlight and you see that you have filled each cell to the point where the plates in the cell are completely submerged in fluid the cell is adequately filled.

I found one of the cells to be very low (dry) with the plates exposed and used a large 4 oz. syringe purchased from a pharmacy to add water. Once topped off and with the covers reinstalled I plugged in my trickle charger and let it charge the battery overnight. In the morning I check the battery voltage it was at 12.8 volts once unplugged from the charger. I then started the car and while running the system showed 13.9 volts and all is well.
That was a solid $120 well saved.
The takeaway is for folks to check their battery fluid levels especially during the cooler holiday season where due to the cold car batteries have reduced capacity, to begin with.
Andy

 

Keep a eye on it as when the plate gets "exposed" the battery doesn't last much longer.

 

Correct. Once the plates start to sulfate, it becomes harder to hold a sufficient charge. I covered the subject of checking electrolyte periodically some years ago. Sadly, I noticed that the new design of Interstate lead-acid batteries sold by COSTCO and others is a true, maintenance-free, sealed battery with no provision to check electrolyte level.

 

Good advice Andy. My 993 has a 2013 Diehard with screw caps and I top it off annually. Load tested last month as good as new.

The 997 battery was new in early 2016. An Interstate brand with a very difficult to remove center cover. I managed to remove it last week for the first time and found several cells quite low on electrolyte. Topped off with distilled water as you suggested. I don’t get why these wet batteries are advertised as “maintenance free” and why they make it so difficult to service them.

On the 997 the battery probably would have had to be replaced in another year or so without servicing.

 

I have a lot of batteries. (6 in the golf cart, 3 in the boat and 4 in cars). I try to check them at least once a month. The battery water boils when it is on the charger and you need to stay on top of them. I use a turkey baster and distilled water.