Max Power

well, i bought my car used . . its a 98 honda civic ex coupe.

the engine and transmission are fine, they've pulled excellent and havent done me wrong since day one. the cars got almost 35k miles.

but the electrical system doesnt seem very good. my driver side headlight doesnt shine as brightly, and i've already had to replace the alternator. and this cruddy stuf always forms around my positive battery terminal . . . . .

any guesses? thanks

Nelson

Battery Corrosion... use either baking soda or actual coca-cola and that will loosen up the corrosion, take a steel brush and scrub it down...

Sounds weird, but check out the thread on using newspapers to wipe windows...

Max Power

hehe, that wasnt really the point i was getting at.

even after i wash it off its still there. . . . does anyone know whats causing it?

flappy188

Good question! answer this man!

Nelson

Caused by:
A bit of battery physics and chemistry.
The electrolyte in batteries is potassium hydroxide, or KOH. This is actually a quite corrosive substance. It usually stays safely inside the batteries but under certain circumstances it can leak. Batteries are designed to permit outgassing, which usually occurs when the battery is reverse charged (a condition that often occurs in battery packs containing several cells connected in series, when they are deep discharged.) Sometimes, however, it appears that old batteries can also leak electrolyte, in the form of gaseous KOH.

The good news is that KOH readily reacts with carbon dioxide (CO2) found in air, forming harmless potassium carbonate (2KOH + CO2 => K2CO3 + H2O). No wonder you see all that white crystalline stuff near battery terminals! This stuff can easily be removed with a small brush, and it rarely leaves behind any residue. Sometimes the crystal appears wet; as far as I know, that's ordinary water that's bound to crystalline K2CO3.

The bad news is that air contains very little CO2. When there's only a limited amount of air available (such as when your calculator is safely stored inside a box or case for a long period of time) eventually all CO2 will be exhausted. If additional KOH is leaked from the batteries, it'll do its corrosive best, attacking both metal and plastic parts inside your calculator. The result is often black corrosion, appearing for instance on solder joints; this type of corrosion is especially difficult to deal with because when it mixes with solder, it makes the contaminated solder difficult to melt or remove. Because gaseous KOH can penetrate just about anywhere, corrosion can appear in insulated wires, even inside chips that are not in hermetically sealed cases.

So much about black stuff and white stuff... what about the blue or green stuff? That stuff, believe it or not, has almost nothing to do with batteries; it has everything to do with the presence of voltage (whether from a battery or another source) in a damp environment (that's my theory anyway.) If there's a sufficient amount of moisture in the air, electrolysis can take place involving any circuit traces, wires, or leads that are connected to a voltage source. Most circuit traces are made of copper; the result of the reactions taking place here is probably copper oxide (with its characteristic greenish-blue color), and perhaps other copper compounds. This problem can be compounded by the fact that a byproduct of the reaction between the KOH electrolyte and carbon dioxide in the air is water; so the small amount of air trapped inside a calculator can get quite damp even if the machine is stored in a dry, but not well ventilated place.

Conclusion: leaving a power source inside an electronic device for very long periods of time is probably not a smart idea. If the voltage source is a dying NiCd battery that can release corrosive gases, or if the device in question is stored in a humid environment such as a damp basement or an unheated storage room, things get worse. Vintage calculators can be worth a lot of money these days, so it pays to take good care of them!

-The Intermet :thumbup:

Cliff Notes:
It's science MAN!

Solve:
Buy anti-corrosive spray available at a Pep Boys near you! (or any automotive place)

Max Power

hehe ic

wonder why it isnt on my parents batteries tho . . . . i ask this question cuz they give me lectures on the first problesm they see.

this time they blamed the corrosion on my intake h:

ill check out pep boys tomm. thanks:thumbup:

CivicHatch

Jus' pour a 50cent Coke on it. :thumbup:

Fujiwara Takumi

there is a red paint htey make for anti corrosion, you scrub that battery down and put the paint on and it helps a lot. it may mean your battery is going, but im not sure.

as far as the dim light...have you replaced the bulbs? tried switching sides? it may be that theyre different brands.

what is the non-running voltage out of oyur battery?

running voltage?

should be 10.2-11.5 and 13-14.5 respectively i believe.

Jkan2001

mmm acid....it eats battery acid and yet we're still drinking it by the 2liter IT BURNS IT BURNS

Fujiwara Takumi

try eating some stomach acid once and tell me that coke is more acidic. not too quick on the uptake eh pal?