Vintage Mustang Forums banner
  • Hey everyone! Enter your ride HERE to be a part MAY's Ride of the Month Challenge!

1 - 11 of 11 Posts

·
Registered
Joined
·
4,800 Posts
Discussion Starter · #1 ·
I looked under the hood for the first time in awhile today and I noticed what looked to be rust around the battery apron. I assume that it is battery acid. There is also a little corrosion on top of the batter terminals. Has even caused some paint to start flaking off. I'm going to mix up some soda to neutralize it but this is the 2nd or 3rd time I had had to do so. What is the cause of this?

Thanks.

J. Boggs
 

·
Registered
Joined
·
1,913 Posts
That is normal for an unsealed battery; most batteries now are sealed, recombinant types.

You may have too much distilled water in your battery, and it overflows out the vent when it is highly charged.
 

·
Registered
Joined
·
916 Posts
Similar to what 2ndNatr said, the battery is probably leaking.
 

·
Registered
Joined
·
3,220 Posts
Dont rule out the charging system overcharging the battery or the battery having a weak or dead cell. If your battery isn't sealed you can remove the caps and watch while the motor is running, if one cell appears to be boiling more vigerously than the others it may be defective...
 

·
Registered
Joined
·
1,770 Posts
In my case one cell didn't boil and the other five did. 10.8 volts was all I could get out of this aircraft battery. Dang things cost $100.
 

·
Registered
Joined
·
10,588 Posts
John,

You can test the electrolyte's specific gravity with a hydrometer and note the levels of the cells, looking for one cell which may be different than the others. Record what you find.

Then fire the engine (battery caps on) and measure the voltage across the battery.

Post what you find.

In an open battery, I've found keeping the electrolyte down about 1/2" from the top (checked cold) and using those little felt washers around the battery posts seems to help.

It's definitely not concours but I also spray a bit of cosmolene-style moisture repellent on the battery terminals after securing them...that seems to prevent weepage of acid into the terminals, bolts and cables...

What fun, eh?? *G*
 

·
Registered
Joined
·
4,800 Posts
Discussion Starter · #7 ·
I tested it with my cheap hydrometer but I got weird results. All the balls went all the way up and stayed at the top. If the battery is sound they should stay at the bottom-right? Mine are so high, they don't register on the scale at all. I know it works, cause I tested another battery that I know is good (and the battery in my Mustang is only a year old and seems to operate well accept for the overflow.)

What would cause and overcharge?

J. Boggs
 

·
Registered
Joined
·
10,588 Posts
At 100% charge, the specific gravity should read around 1.25-1.27 and the voltage should be around 12.75 VDC, all measured with the battery at rest (no load and not just coming off charge unless the charge was tapered)

Although this page deals with off-grid systems, the battery principles are sound...

IME, the floats should not go all the way to the top, although different hydrometers read differently...
 

·
Registered
Joined
·
6,070 Posts
sounds like your voltage regulator is over charging the battery..causing it to cook way too much..I'd change the regulator first thing
 

·
Registered
Joined
·
977 Posts
Clean the terminals up and spray paint on the terminals to seal it up some. Hope that helps.
Brent
 
1 - 11 of 11 Posts
Top