Spewing Battery !
 

Has anyone ever heard of this?

Yesterday, I started smelling something throught the air vents...like a burning smell. So I stopped the car and went hunting. I found the battery was sizzling and venting some fluid out the side. So I replaced the battery right away.

This moring after driving it last night I find a similar situation with the new battery. There was a little adapter and a hose with the battery. The guy at the parts store said that this hose is to attach to some kind of drain that some cars have to vent the battey!

What the heck are they talking about? I have never heard of "venting a battery". But I do know I dont want battery acid spitting on the inside of the engine compartment!

Any clues?

Steve :confused:

I would guess that your alternator/voltage regulator has problems and the battery is possibly overcharging , heating up, and venting fluid. I would have the alternator/regulator checked ASAP

My understanding is that the vent tube you are talking about is normally for venting hydrogen gas which may be produced by batteries under certain conditions. My C230 has a vent tube as it is inside the trunk, and H2 gas could get into the car. My 300E has the battery in a "traditional" under hood location, and doesn't use a tube. Instead, it sits on a tray to catch spills.

Hi again Steve! Don't drive the car until you straighten out the battery problem! The vent hose you mentioned is only for vehicles with the battery in the trunk or under the back seat. It vents the gasses to the outside of the vehicle. Your battery is under the hood so it can vent safely without the hose attached. Your problem sounds like the alternator is overcharging. This could lead to a battery exploding! Have this looked at immediately! The most likely cause is a bad voltage regulator. It's easy to replace and it's cheap too, however there's a small chance the alternator is the culprit. Keep in mind that the acid and gas escaping from the battery is very harmful to the surrounding area. There are several expensive components just inches away from the battery( behind the black plastic cover to the rear ). Get this fixed ASAP! Keep me posted.

Sounds like some sort of overcharging problem. Yes, batteries do emit a gas (a friend of mine pointed out on the top of the battery that the gas was hydrogen - READ 'hydrogen bomb'!!??) I like to connect a long hose from the vent hole in the battery (if it has a single one) and snake it safely through the body & frame and hang it out the bottom of the car to positively vent the battery. I don't know if this helps anything, it's just a theory of mine that if the combustible fumes are far away from any spark, the better (such as a spark that might occur when a battery terminal is loose or slightly corroded and you hit the key and an arc occurs). It is also important to keep the battery full of water to allow less space for gas to accumulate. Soooo... ...in my opinion, connect a good long vent hose and feel safer. Besides possibly averting a bad situation, (an exploding battery) it will save your battery tray, inner fender, etc. from rusting/rotting. First thing I would do is establish that the charging system is not overcharging as I suspect, and remedy that situation.
Does any body agree/disagree with this reasoning. Respond if you think this is bunk, I enjoy learning new things, especially when substantiated by fact, rather than theory; as I have presented above.

Oh Great!
 

Thanks for the info guys,

This little problem sound serious. However, unlike my old corvette where the alernator was 38 buck and took me 1/2 to change, I think I'm in deeper water here!

Interestingly, I get to warning light on the dash to mention anything is wrong, (not that that is the difinitive answer to problems) however, If it was over-charging, which it might be, I would have thought that would trigger the indicator too.

A couple of questions come to mind...

Where is the voltage regulator?
and
My shop is about 5 miles away...The battery in brand new I think I should make it that far, don't you?

I think I'll check on parts prices tonight.

Man, I'll be glad to get this thing straightened out for a while.

This is starting to become annoying and expensive!

Steve

On my 87 300E the voltage regulator is part of the replacable alternator brush assembly. About 5-10 minutes work and probably about $35 - $50 for the part. Enter your year model in Fastlane and see what they charge. Fast shipping and decent prices. (For example, on my 300E, the Bosch unit is $52, while the German aftermarket unit is $14: For my 98 C230, the Bosch unit is $40) They often have a pic of the part as well.

Very Interesting Readings !!
 

Hey Guys,
Listen to this..

I had a brain wave and finally thought of something. I took my volt meter and went out to my car. Turned it on and thouched the battery leads.

12.57 Volts .. not bad

Then I Started the engine, touched the battery terminals

18.77 Volts .. woah!

So I stopped the engine and went and checked the battery again and :

16.35 Volts .. and I kept the contacts on and watched the number descend...

I think overcharging may the correct diagnosis.

I looked down past the exhaust manifod and saw the alternator easliy but getting to it....It looks as though from the bottom qould be better if I removed the panel covering the bottom of the engine.

Am I on the right track? It feels right.

Steve

Had this happen on my W124 last year!

Had windows down and could smell (as well as see) battery vapors being emitted.

Did the voltmeter check and found 17.5 volts with the engine running!

Ended up replacing the alternator on mine...the regulator is internal...:(

You do have to remove the lower panel to get to the alternator.

The 2 19mm bolts that anchor the alternator can be a bit stubborn, and there is little room to move around for the top bolt. Good time to replace the serpentine belt if it's looking aged in any way. ;)

Sorry...I'm talking as if I know what model car you own?

You are Correct!
 

It is a 90 300e.

I am getting 18.77 volts running. I would like to replace the regulator first and see what I get, but we'll see.

If I have to go the entire alternator route, does anyone know off hand if it is a 70 or 80 Amp Alternator?

Steve

Oh by the way G-Benz...If you have experience in changing that alternator out...please please...feel free!!!

Here's my post back when it actually occurred...

http://www.peachparts.com/shopforum/tech-help/23820-battery-venting-excessively-300e.html

and my repair progress (sorry, no pics):(

http://www.peachparts.com/shopforum/tech-help/24350-alternator-serpentine-belt-install-success.html

venting battery
 

Hi guys! Had the same problem when I just bought my C180 1994 Euro version early this year. The battery in the rear boot was venting acid and gas out of the tube and through the hole in the floor under the spare. The tube was ruptured and the stuff spewed around the back and rusted up the steel in the weaker joints and scratched spots which have been fixed now. Got the electrics checked and it was ok and a new battery was installed and it runs very well now. Only use the car once a week and it is still almost fully charged.

Voltage Regulator ???
 

Well, Ive gone and done it now!

I don't have my parts yet but I was curious (you know what that leads to) about the Voltage regulator.

So.. I reached down and undid the two screws that held it in place. No big deal it just fell out in my hand. So, I thought I get a head start and see how it went back in so that I would know when the new parts showed up.

I CAN"T GET THE STUPID THIG TO GO BACK IN!!!!

Ok, calmer now. The part has two contacts on it that touch a spindle on the alternator, I can see that but it wont fit back in.

Q...Are the two contacts on the Voltage Regulator supposed to be different lengths? These are. And when you put these back into the alternator they point towards the center right?

If you have done this and if there are any tricks, please help.

Steve

Brushes
 

Sounds like the carbon brushes. These are spring loaded. You have to hold these back to clear the armature (spindle inside the alternator). I usually use sewing cotton to tie these back, and then cut the cotton and draw it out when assembled.

They can wear unevenly, don't worry about it.

You may need to clean up the armauture (the copper bit), if it is worn or dirty. Use very fine glass paper and clean off all the dust. Do not use emery paper or carborundum paper, or whatever it's called in the States. The dust off this is electrically conductive and may cause you problems!

I hope you aren't going to put the alternator back on when it is clearly overcharging. Spraying boiling hot acid around the inside of your car is not part of the maintenance schedule!

Thanks Neil
 

I will use that tip to put the new VR back into the alternator.

The alternator is still mounted on the car and it won't be driven until it's fixed.

I was just trying a "test fit" to make sure I understood how the new VR would go back it - thats when I was having troubles.

You mentioned "sewing cotton" sorry for the differences in English, but do you mean thread?

Thanks
steve

English as she is spoke!
 

Yes, sewing cotton=thread.

Have fun!

OK .... Help! Help! Voltage Regulator
 

Changing the V.R.

OK I 've got the car up on jacks and am underneath it....

There are two set of screw holes upper and lower on the alternator.

I had alot of trouble using the lower ones but I got the new VR put in on the upper set. It looked OK so I buttoned it back up and reconnected the battery.

Before starting.... 12.45 volts ok

After starting 12.0 ....11.98 .....

then I turned on the lights 11.90 ...11.89...

and dropping.

So I checked my other two cars 13.5 & 14.2 while running.

I think either I had the VR in wrong or something else...

Obviously the system is not charging....but not warning lights on dash either.

Gonna wait for a reply here....

Please If you can help.


Thanks
Steve

Part 2
 

I don't know maybe its right..?

I re-installed the VR and before starting 12.4 V at the battery

While running 12.0 - to 11.98

I let it run for about 10 minutes to see if it would fall further but it seemed to stay right around 12 V

and when I shut it off ... 12.38 from the battery.

maybe its doing what it's supposed to..but I would have thought I get more that 12 V while running.

I only have 2 fords to compare it to.

Steve

Sorry to keep spilling my woes on you!
 

Well I did alot of reading in the archives and it looks as though I am supposed to be getting about 13.5 - 14 volts when running.

So.. It sounds like the alternator is not putting out at all. Just running on the battery.

Looks like new alternator time. $160.00 man!

Does any body have experience changing one of these things?

I can get to it easily from underneath (I've got it up on jackstands) but the serpentine belt ?? ...never messed with one before.

Can the alternator be replaced without jacking with the tensioner?

Are there any tips I should know about?

Thanks
Steve

If the alternator wasn't charging properly before, your battery voltage under load is going to measure a bit low for a while, I believe. If the new battery was damaged by the overvoltage and acid spewing you described, that may be a source of the 'low' 12 volt reading. (My battery reads about 13.5 running, 12 with engine off.) If it were steadily dropping over time, I would say you were running off the battery and the alternator still had a problem. But since it is holding at 12, and may eventually climb up a bit, the alternator is possibly doing OK. You don't have the overvoltage like you did before the brush change, so no (additional?) damage should occur to the battery. Running it for a while and checking the voltage at the battery may be in order to see what the voltage is doing. Running for a while should show if the voltage is going to decrease (running off battery?), increase (battery charging back up), or staying the same (damaged battery and/or faulty alternator?)

Also, if the battery was spewing, did the liquid get replaced? I would have the battery checked out before I popped for a new alternator.

Here is a drawing of the back of my alternator.

http://www.warewolf.net/jelliott/alternator.jpg

The bottom hex bolts 'A' and 'B' were removed to replace the reg/brush assembly. Is your alternator different?

Thanks John ....
 

The Voltage across the battery with the old regulator was 18.7.

The engine ran on the new battery ran for only about 10 minutes before I got home.

It never sizzled like the old one and it's spew was only a drop or two. I really think the new battery is Ok. I will go start the car and let it run for 15 more minutes or so and see what happens.

Here is what my alternator looks like.


http://www.oklahoma.net/~shintze/300e/alt.jpg


It's an 80 AMP Alternator
It looks as thoug there are only 2 bolts holding it in.

Thanks
Steve

Here's what I am getting..
 

This is the place!

Up On Jacks
http://www.oklahoma.net/~shintze/300e/300_0014.jpg

The Back of the Alternator with the new VR installed
http://www.oklahoma.net/~shintze/300e/300_0016.jpg

Voltage NOT Running 12.55
http://www.oklahoma.net/~shintze/300e/300_0017.jpg

Voltage Running 12.02
http://www.oklahoma.net/~shintze/300e/300_0018.jpg

Though I'd show you!

:D

Good News!!!
 

I took some advise and ran the engine for a while and some at higher RMP than Idle.

Now...even at idle I am getting 13.33 V!

Woo Hoo!

I think it will get better with time to.
(I hope)

Here is what the old VR looked like...
note the difference in size of the contacts..


http://www.oklahoma.net/~shintze/300e/VR_0005.jpg

Any thoughs ...please feel free!

(I'll be driving with the Volt meter for a while till I feel better) LOL
:p

VR versus rebuilt unit
 

As an aside, I wonder at the differences in culture UK/US. When my alternator on my 190E went wrong, I bought a rebuilt unit from my local Bosch agent for 38 pounds, say $60. I paid pretty much the same for a rebuilt unit on my beemer.

I've never considered replacing just the VR.

Perhaps this is because Bosch units are used on some very ordinary cars in Europe?

Just an observation

You may be fortunate enough to not have to replace the alternator, but if not, I have replaced mine without too much dismantling.

I got the belt off without messing with the tensioner...I did have to remove the fan for access (3 allen bolts secure it to the clutch). The width of the belt makes install and removal easy. There should be enough slack to pull a bit off near an adjacent pulley, then rotate a free pulley until it works itself off. Did the install in the opposite manner. Hope you have a manual to use as a guide to how it all threads back together!

Two 19mm bolts hold the alternator in place. The bottom on is easy to get to, but the top one requires some effort, as there is little room to move a tool around. This is a knuckle scraping job at this point. I took about 2 evenings to remove the alternator (did the work casually), but it took about 1/2 hour to install everything (alternator, belt, fan) once the alternator showed up at the doorstep.

BTW, your pics show a different unit than the Bosch alternator I obtained. You couldn't replace the regulator as it was internal, so alternator replacement was my only option (Bosch OEM, $160 @ FastLane).

My three-year old battery wasn't damaged by the excess voltage, but I did have to refill a couple of cells with distilled water...