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· Seek to understand,^Value
25,378 Posts
Discussion Starter · #41 ·
There is good information today from cn90 and QSilver7 about fitting an elbow into an aftermarket battery, over here ...
> E39 (1997 - 2003) > DIY: Autozone H8-DL Battery
Just purchased an autozone H8-DL battery to replace my autozone 49-DL that was on its last legs. Battery fit perfectly and is in fact a few mm taller than the 49-DL. I did not need to use the shim that I had with the old battery. My biggest issue is that the vent hole is smaller than what was on the 49-DL and so I couldn't use the old fittings. I asked at autozone if it comes with a vent kit or even if I could buy one and the clerk had no idea of what I was talking about. I went to Home Depot to try to buy an elbow like that mentioned in this thread but they did not carry such a piece. So for now I don't have the vent tube connected. I left the battery uncovered so any hydrogen will hopefully vent into what is the large area of the trunk and tomorrow I will see if I can get an elbow that fits either at the local bmw dealer or another auto parts store. Anyone using this battery should make sure they have a proper fitting elbow first!

See also:
- How to test a BMW battery & alternator (1) & the most often recommended diagnostic procedure to test for overnight parasitic battery drain (1) & one user's attempt to locate, describe, and photograph all fuses and relays in the BMW E39 with a picture of every fuse & relay (1) & how to choose a good aftermarket battery (1) and a simple battery replacement DIY (1) & Cn90's explanation of where to get alternator rebuild parts (1) & how to troubleshoot a bad FSU final stage unit (1) and how to build a test jig for your FSR final stage resistor (1) & how to repair solder cracks in your blower motor resistor (1) & how to replace your HVAC blower motor control (1) (E46) & what FSU is the right one to buy based on user experiences (1)

· Seek to understand,^Value
25,378 Posts
Discussion Starter · #42 ·
This thread today has information about the venting:
> E39 (1997 - 2003) > After Market Battery

See also:
- Complete DIY for how to test a BMW battery & alternator (1) & a diagnostic procedure to test for overnight parasitic battery drain (1) & how to find all the fuses (1) & how to choose a good aftermarket battery (1) and a simple battery replacement DIY (1) & where to find the battery explosive charge emergency quick disconnect (1) (2)

· Seek to understand,^Value
25,378 Posts
Discussion Starter · #43 · (Edited)
As a related aside, sometimes the battery terminal cable clamp is bent such that it won't tighten properly and just spins, as shown today...
> E39 (1997 - 2003) > Negative battery cable stuck on terminal?
Hey guys, so last week I had a slight fender bender on the way to work, long story short I somehow ended up "sitting" on top of the hood of an 8th gen Civic. After everything was said and done I got back in my car turned her back on and "Check Turn Signal" message popped up (Somehow the force of the accident blew out my passenger side angel eyes).
In my attempts to find that small issue I ended up trying to pull the battery to see if the error would go away. So my issue goes, the negative cable on my battery will spin (with a small amount of force) on the terminal but seemingly will not lift out. I'm fairly confused as to what could have happened to my negative terminal?
It is extremely common and has been happening to batteries and battery cables ever since they invented the things.

It's soft lead.

People torque the bolt clamp too tightly (I've done it myself).

Lead bends.

All you need to do is expand the terminal once it's off. Twist a wide screwdriver in there to open it up a bit.

Sometimes (rarer because batteries are almost always younger than the cable clamps which are as old as the car) the battery terminal itself has been scraped clean by a mechanic such that it's a bit smaller than stock.

Anyway, just pry the thing up any way you can. I think they even make a puller tool, but, I don't know anyone who uses it.

Please snap a picture of your issue and how you solve it so we can use your experience to help others.
Since you had a fender bender, also check the BST...but you didn't mention any codes...
- where to find the Battery Safety Terminal BST explosive charge emergency quick disconnect (1)

Sometimes the positive terminal melts in an accident...

So, it helps if you can please snap a picture of the problem.

· Registered
15,785 Posts
Some update/tricks on battery...I have done this many times and still swear at the

- Factory is Battery L5 but from my epxerience you can fit L3 w/o issue.
If you use L4 (94R) (BTW, E46 3-series uses 94R), then place a piece of cardboard
on the fore section of the battery to account of the small 1.5 inches of empty space
in front of battery.

- Exide L5 (Home Depot) is now $159! In 2018, it was $119.
In the span of 4 yrs, it has gone up way more than CPI.
Approx. 7% per yr!!!

- Anyway, I have been happy with Exide L5.

- For the battery vents plastic elbows...if yours is broken, go to local O'Reilly auto
parts store, they will give you the elbows for free (they just take off from the batteries
on the shelf).

- To protect the battery metal tray, you can cut some cardboard or a piece of floor mat.
Just cut a hole for the bracket long bolt.

- The Carpeted Tray Cover: once you pry away the 3 plastic clips: (wear goggles!!!),
just store the 3 plastic clips in the trunk, I don't reinstall these clips bc the Carpeted Tray Cover
fits fine w/o these 3 clips. Also, it makes future access easier. These 3 clips are

- The bracket itself: I find the hole to be tightly machined...if you are not careful, you
can cross-thread the female side (on the battery tray). The trick: I drilled the hole on
the bracket a bit bigger, mostly on the fore/aft directions. It is more forgiving this way.
All you need is 1-2 mm enlargement on the fore/aft directions. Once done, the hole
will look a bit ovoid in shape. This trick has helped me a lot.

- Tuck the terminals away using shoe lace, Scotch tape or something non-metallic
for obvious reasons. When the terminals are tucked away, you life will be MUCH EASIER.

- Lastly, don't stand outside the car and bend the back (the battery is heavy and
you can injure your back). Place your left foot inside the trunk, now you can easily lower the battery into its place.

- The metal bracket the notch faces down to match with the notch on the battery itself.

Motor vehicle Hood Bumper Automotive exterior Automotive design

· Registered
15,785 Posts
Another topic people don't talk about is the vent plug.
I usually vent on both sides but this is overkill.

You can simply vent from one side.
But the unused side should be plugged to prevent acid fume from venting inside the trunk.

I took a random photo from the web to show what the vent plug looks like...

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