# car battery terminals



## ajaye (May 19, 2019)

On my BMW, the battery is in the back, but it has JUMP / CHARGER terminals in the engine bay.

It is recommended to ONLY charge or jump from these 2 points. The PROBLEM is both terminals in the engine compartment, have gotton some surface rust and it's getting worse.

A while ago they were a bit "manky" so did use some sandpaper on them, so not sure if I made this worse. Not sure if there was some coating on these ?

The BMW charger I was using started ok, then stopped dead, I think the rusty terminals might have caused this. IE not making proper contact

So,, I can sand the rust off, BUT I want to do something to keep the terminals rust free, but I'm worried anything I put on them may interfere with the operation/contact of the terminals,, anyone voice any advice on the below thoughts, to stop corrosion and allow good contact

1> Vaseline/petroleum jelly on the terminals
2> Rust/inhibitor converter (turns rust black)
3> I have a small spray of battery terminal maintainer
4> Dielectric Greece 

txs


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## ChuckTin (Nov 17, 2014)

#3 is what I've used. Yes you may have removed an anti-corrosion coating. Get some baking soda and an ear swab. Paint damp baking soda on the terminals, cuts acid. Clean them throughly after and apply the battery terminal spray.


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## ajaye (May 19, 2019)

yeah , thats what I was thinking, had my car for say 5 years, 18k on the clock when I got it, engine bay was like new, I noted some "aly" time build up so put some fine grade sandpaper and since then both term's, when to rust rather quickly.

they are easily changeable I believe, but with current crisis not sure I wanna mess with replacements

txs on the advice I have all the above, maybe not the dilectric greese
I'll give it a try, 

of course unless anyone else disagrees ?
next couple of days I wanna attempt it


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## Dave Sal (Dec 20, 2012)

I have a 2000 model year BMW E39. The battery is in the trunk like yours and I have the jump terminals under the hood. I keep my battery charged and topped off weekly with a Deltran battery tender. There is an optional cigarette lighter adapter that I use that makes it super convenient. The Deltran can be purchased at Amazon or Walmart for about $49, and the cigarette lighter adapter goes for about $6.75. While the comments about the jump terminals are good, it's much easier to use a battery tender to keep the battery fully charged.

Looks like the prices went up a bit since I purchased mine. 

https://www.amazon.com/Battery-Tend...=deltran+battery+tender&qid=1587244642&sr=8-6

https://www.amazon.com/Battery-Tender-BATTERY-MfrPartNo-081-0069-5/dp/B003CJ927I/ref=sr_1_1?crid=5WJ4BUI8R95O&dchild=1&keywords=battery+tender+-+081-0069-5+-+deltran+cigarette+lighter+adapter&qid=1587244675&sprefix=deltran+battery+tender+cigarette%2Caps%2C172&sr=8-1


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## de-nagorg (Feb 23, 2014)

I am proud to say that I am not rich enough to own a BMW, but those under hood terminals should be a lead material, not ferrous metal, and should not RUST, tarnish or oxidize yes, but RUST, never.

They make a terminal cleaning brush to be used to clean battery terminals, and since the under hood terminals are not near the battery, they won't have acidic residue to need a baking soda cleaning. 

The spray that you have should be fine, after cleaning the oxidation from them.


ED


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## ajaye (May 19, 2019)

txs dave, 
my car is parked on a drive, my BMW charger, which I think is a Celtek basically was around 100 and something odd bucks, it did or can come with ring adaptors, to fit on the battery terminals, but all the research I know is it's not a great idea to charge or jump from the battery

On the newer models they use IBS (intelligent battery system) and you could cause problems.

Looking at the neg terminal, it is integrated into a "black box" with a whole heap of wires, so I suspect there is a reason for doing this, certainly on the newer cars.

Also it does NOT look easy to simply replace thoes 2 terminals. 

I luckily OR unluckily do an 80km daily trip (but not that working from home)

so the odd time in winter or now, is the only time I need to give it a trickle, so this works for me 



Dave Sal said:


> I have a 2000 model year BMW E39. The battery is in the trunk like yours and I have the jump terminals under the hood. I keep my battery charged and topped off weekly with a Deltran battery tender. There is an optional cigarette lighter adapter that I use that makes it super convenient. The Deltran can be purchased at Amazon or Walmart for about $49, and the cigarette lighter adapter goes for about $6.75. While the comments about the jump terminals are good, it's much easier to use a battery tender to keep the battery fully charged.


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## ajaye (May 19, 2019)

Thinking about it , your right, that's why I used some very light fine sandpaper originally as I thought it was just oxidization, bad form really on having battery terminals with what really is a steel material.

One of the advantages of a rear battery is no problems with being in an exposed engine bay.

Problem, is there is no oxide now, there is rust, 



de-nagorg said:


> I am proud to say that I am not rich enough to own a BMW, but those under hood terminals should be a lead material, not ferrous metal, and should not RUST, tarnish or oxidize yes, but RUST, never.
> 
> They make a terminal cleaning brush to be used to clean battery terminals, and since the under hood terminals are not near the battery, they won't have acidic residue to need a baking soda cleaning.
> 
> ...


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## ajaye (May 19, 2019)

a video I took a while ago on the tender, showing the terminals, they were at the time in good shape


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## ajaye (May 19, 2019)

looking at the terminals today, the positive, looks like it's just scoured and underneath is a "copper" or "brass" looking material

but the neg is rust


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## Old Thomas (Nov 28, 2019)

Is this a car that you hardly ever drive or a daily driver? On my daily drivers I can’t remember the last time I had to charge a battery. I have left them for months and they start. Why do you have to charge it? Don’t BMWs have an alternator?


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## ajaye (May 19, 2019)

So the car to me is 5 years old. Battery was replaced by dealer when I bought it so it's been years.

No, I don't have any problems, but when the weather is VERY cold, I would get a battery/charge alarm which goes after driving it.

Also we do a lot of shuffling of cars and as you know a start/stop to move the car 10ft so the other can get out, does not do a battery a lot of good. BMW's also stay in whats called a "stand-by" mode for 20 minutes after after start-up, so the battery stays in low power energized mode.

Even with this, I do 80kms a day and no problems, but recently has I said in the beginning, I have been working from home, and the car has not had any long drives, just a few up the roads and an occasional shuffle. BUT I have had no "alarms" on the car at all. As a precaution I have put the tender on it once a week for a day or so, just to keep the charge up.

BM's tend to be very reliant on good battery operation, as most of the car is a selection of computer modules. I could replace the battery but it's not needed yet.

So in short, was a daily driver and now since Covid not LOL

HTH


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## Old Thomas (Nov 28, 2019)

I have not had a car or truck in the last 40 years that wouldn’t do what you said many times over, even in sub zero weather. Buy a Ford or a Chevy, they start every time.


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## Dave Sal (Dec 20, 2012)

What year and model of BMW is this? I had one of those BMW battery tenders that I bought at the dealer many years ago. It looks exactly like the Deltran I have now except it had the BMW Roundel on the front. It died after I tried using it on my son's Saab. 



And Ed, you can definitely afford a BMW. My model year (2000) can go from $1k to about $8k, depending on condition. I'm not planning on getting rid of mine any time soon, as I planned to keep it for many years when I bought it and I still love the car.


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## MTN REMODEL LLC (Sep 11, 2010)

I have a 528XI/E60.

When the car is used for repititive short trips, it drains the battery. It is a known problem for at least 2008-10 models. The car has so much electrical/security systems, you can hear it finally shut down 15 minutes after you have locked it. It's been that way since new.

No problem if it is used for normal driving allowing it to recharge.

My wife was using it for very short repititive trips just down and up our hilly street.

Charging it was getting to be a PIA. So I just ran a short charging pigtail from the battery into the trunk. Put a female 3 prong plug on the pigtail and a male on the charger (so it can't get wrong polarity). All my wife has to remember, if necessary to charge it while I'm out of town, is to plug the charger into 120 LAST.

We just leave charger in the trunk

It's a Shumacher that just goes to trickle after reaching full.


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## ajaye (May 19, 2019)

Txs man, 
I'm not some youngster either  I'm mid 50's
wrenching since I was about 20, owned 3xFord's (and 1 company car), a Porsche, 3 Vauxhall's (GM in US) company , 1 Vauxhall private 2, VW's (company) 1 Dodge (canada), wife has had 2 dodges 

My dad and 2 Austin 1100's a wolesley 1300, and a host of others LOL

Some were good some were not, all had there problems, I can tell you bad stories on all of them and on new cars. The point is I stay away from pissing contests on makes, albeit luxury cars or not, they all end the same. 

I would have kept my 944, but immigrated to Canada, the BMW was the best bang for the buck 4 seat convertible. BMW have done some God awful stupid stuff, Dodge/Chrysler have done worse... not putting a 2c grommet in a car steering lock, to prevent the key pulling out while driving, and willing and knowingly to handle lawsuits for death, as it was cheaper than recalling millions of cars LOL 

Please keep to the point, I get it, been there done than and on car forums for many many years, :vs_smirk:



Old Thomas said:


> I have not had a car or truck in the last 40 years that wouldn’t do what you said many times over, even in sub zero weather. Buy a Ford or a Chevy, they start every time.


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## MTN REMODEL LLC (Sep 11, 2010)

Dave Sal said:


> What year and model of BMW is this? I had one of those BMW battery tenders that I bought at the dealer many years ago. It looks exactly like the Deltran I have now except it had the BMW Roundel on the front. It died after I tried using it on my son's Saab.
> 
> 
> 
> And Ed, you can definitely afford a BMW. My model year (2000) can go from $1k to about $8k, depending on condition. I'm not planning on getting rid of mine any time soon, as I planned to keep it for many years when I bought it and I still love the car.


YES>>YES>>>YES ^^^^^^^^^^^^^^^^^^^^^^^^


ED.... My wife was a realtor for many years....so we have had to have many "nice" cars...2 Audi's and 2 Lexuses.

That BMW is by far the finest car to drive I have ever had by far.....it is a pleasure on long trips...it is the first car that I actually love.

Try it and you'll be hooked ...especially if you have extended driving...(both kids in Cali).


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## ajaye (May 19, 2019)

hey Dave, '12 128i E88 (vert) M-sport package :smile: bought is on 22k in 5 years it's up to 110k



Dave Sal said:


> What year and model of BMW is this? I had one of those BMW battery tenders that I bought at the dealer many years ago. It looks exactly like the Deltran I have now except it had the BMW Roundel on the front. It died after I tried using it on my son's Saab.
> 
> 
> 
> And Ed, you can definitely afford a BMW. My model year (2000) can go from $1k to about $8k, depending on condition. I'm not planning on getting rid of mine any time soon, as I planned to keep it for many years when I bought it and I still love the car.


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## ajaye (May 19, 2019)

This>>>>>>



mtn remodel llc said:


> when the car is used for repititive short trips, it drains the battery. It is a known problem for at least 2008-10 models. The car has so much electrical/security systems, you can hear it finally shut down 15 minutes after you have locked it. It's been that way since new.
> 
> No problem if it is used for normal driving allowing it to recharge.


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## ajaye (May 19, 2019)

I LOVED my 944, there was a tear in my eye when the new owner drove her away... I could not bear to buy another, I love German cars, so the BM was next obvious..

I had also been looking at MB's CL's but the cheaper the benz the more money pit they are... plus, the verts, look like boats and into old man territory. 

The 1 series vert, did it for me, styling and marque, ok, mid age crisis.
whatever floats a persons boat.. but yeah your right, also with verts/cabs
once you have one, you never get over them.... 

Would have gone 3 series vert, except for no trunk space



MTN REMODEL LLC said:


> YES>>YES>>>YES ^^^^^^^^^^^^^^^^^^^^^^^^
> 
> 
> ED.... My wife was a realtor for many years....so we have had to have many "nice" cars...2 Audi's and 2 Lexuses.
> ...


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## Dave Sal (Dec 20, 2012)

MTN REMODEL LLC said:


> I have a 528XI/E60.
> 
> When the car is used for repititive short trips, it drains the battery. It is a known problem for at least 2008-10 models. The car has so much electrical/security systems, you can hear it finally shut down 15 minutes after you have locked it. It's been that way since new.



Same thing happened to my E39 when I first bought it. I had a company car at the time and didn't drive the BMW for days at a time. Within the first two years I had to jump start the car a few times, and then the repeated low charge state must have damaged the battery and I ended up buying a new one. It was at that point that I learned that you have to drive these cars regularly or the batteries will die an early death. That, or use a trickle charger.


I find my Deltran (same as the BMW model) trickle charger the most convenient to use. I roll down the drivers side window about an inch, put the charger on the floor, plug the end into the cigarette lighter socket, and then feed the electrical plug of the charger through the window into the outlet on the front of my workbench in the garage. I then close the door and peek in the window to make sure the red light on the charger is on and walk away. Usually by the next day the light is green and the battery is fully charged. Simple.


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## de-nagorg (Feb 23, 2014)

MTN REMODEL LLC said:


> YES>>YES>>>YES ^^^^^^^^^^^^^^^^^^^^^^^^
> 
> 
> ED.... My wife was a realtor for many years....so we have had to have many "nice" cars...2 Audi's and 2 Lexuses.
> ...


The finest long distance driver that I ever had the pleasure of driving was a VOLVO sedan.

That was one smooth ride, even over some not so smooth roads through the S. Dak black hills. 

But back to the OP, There is a better way.

Get it out on the road and go to a neighboring town once daily, like take SWMBO out to dinner every day.

It keeps the car charged, and who knows might spice up your night life .


ED


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## ajaye (May 19, 2019)

<<<<<<hey guy's UPDATE>>>>>>>>>>>

OK I got a better result. I followed advice and did the following

1> I used a worn scourer green pad, to rough up and clean the pos terminal
2> The same on the neg, but had a bit more work to get rid of the surface rust
3> I have a battery kit, so used the battery cleaner I guess is acid based
4> Let it dwell, wiped it off then used the battery preserver spray a red liquid, which smelt of a petroleum product

Put the charger on, and for the first time after an overnight, the charger actually stayed in the "battery" icon, which I think is the maintainer part of the charge.

So the red liquid coating didnt seem to impede the charging and I hope now it will save the terminals

thanks ALL !


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## ajaye (May 19, 2019)

.......



de-nagorg said:


> The finest long distance driver that I ever had the pleasure of driving was a VOLVO sedan.
> 
> That was one smooth ride, even over some not so smooth roads through the S. Dak black hills.
> 
> ...


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## ajaye (May 19, 2019)

Swmbo

Found this under my Christmas tree one morning, how could I resist but to obey ! LOLOL

She was my exgf, she was DEF a swmbo !

I'm married now :sad: 

I'm not sure how low I could have cut the photo, it's not a nude, (just lingerie)
but err'd on the side of caution in order not to garner the rath of the mods LOL


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## DallasCowboys (Jan 30, 2017)

ajaye said:


> Thinking about it , your right, that's why I used some very light fine sandpaper originally as I thought it was just oxidization, bad form really on having battery terminals with what really is a steel material.
> 
> *One of the advantages of a rear battery is no problems with being in an exposed engine bay.*
> 
> Problem, is there is no oxide now, there is rust,


There might be an advantage to that, no excess heat etc...

I had a 2005 325i / E46. 
I had the impression that they did it for weight distribution.
The battery must weigh 50 pounds. Adding 50 pounds to the rear and removing 50 from the front, is an easy way to distribute the weight.
I think the car had a weight ratio of 51/49.
I miss the way it drove and how it made me feel when I climbed in the car. It was the first car I ever owned that actually made me feel like I was driving it, and I was in control, as opposed to just riding in it. 

I think most manufacturers should put the battery in the rear. It would free up more space in the engine bay and do a better job of distributing the weight and improve handling.


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## ajaye (May 19, 2019)

Yeah, I had heard that, even my 944's battery was in the back,

I'm not sure howmuch offset 50'lbs of battery makes compared to 350lbs of engine and another 300lbs of front weight.

but def better to have it in the back.
* less destruction from heat
* less destruction from luctuating temps
* no road spray splash

my battery looks brand new, and I've had the car 5 years LOL



DallasCowboys said:


> There might be an advantage to that, no excess heat etc...
> 
> I had a 2005 325i / E46.
> I had the impression that they did it for weight distribution.
> ...


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