Sunday, November 2, 2008

Battery Acid Damage

I came out of work one day last week, and noticed a small puddle of liquid under the passenger's suspension console. "That's weird", I thought, "there has been nearly zero humidity today". I knelt down, and dipped a finger into it. It was slightly slippery, so I thought at first that it was transmission fluid. But bringing it close to my nose, I detected the distinct smell of... battery acid.

Last weekend, therefore, I disassembled the rear compartment. I took out the batteries and the boxes so I could both find the leak as well as repair any damage. I believe the leak is actually coming from the *tops* of the batteries. The Zivan charger is apparently notorious for "overcooking" batteries during the equalization phase, which can lead to acid boiling out of the caps. The rear box is a two-piece assembly, using only silicone caulk to try to keep it "acid-tight." Obviously not enough.

As far as damage goes, it was all paint and surface rust (if I had let it go all winter, it would likely have destroyed the suspension console, and possibly the whole car):

I scraped all the paint and rust off the area, washed the battery acid residue off of everything it was on (that's the white stuff on the rack), and spray-painted some rust-coat paint on everything. Three coats for good measure. Next summer I'll do a more thorough job.

As far as resolving the leak - I'm stuck with the Zivan charger for now. But I can at least make the box much more acid-tight. I have some heavy plastic sheeting I use for various things. So, I used it here to make a liner for the rear box. I cut a piece big enough to fill the box with plenty left over for good measure:

I then placed the batteries into the liner and box (this took a little care - although the plastic is heavy, the batteries are heavier, and it is not hard to stretch the liner enough to rip it):

I then cut the top of the liner even with the tops of the batteries, taking care to allow the hydrogen exhaust vent to work properly:

One final note. While I had the battery box out, I took the opportunity to find the tach wire. In my car, for some reason, it was *white* and purple rather than *black* and purple. Whatever. I attached a white 16-gauge wire to it, ran it along the DMOC wiring harness loom (attaching it at many places with electric tape) then hooked it to Pin 25 of the DMOC ampseal connector. Here is the wire in the engine compartment:

Just like Tim's, mine seems properly calibrated at an EE1SpeedoDiv of 70. It's nice to have the tach... but it points out that I, like most people, have pretty serious vibration issues from about 4500 to about 5500 RPM. Not sure what to do about it at this point - I don't drive in that RPM range (other than to test the vibration). Tim had no end of fun fixing it on his car...


onei57 said...

Hey Ross, I was filling my batteries up to the fill ring and was having the same problem. In the DC manual it recemended filling the batteries one inch below this ring. It either doesn't boil out after charging or spills less. Anyway it's alot better. Matt

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