Where are the F30 (N55) engine ground points

yusufm786 · 03-04-2019, 10:47 AM

Hey ppl

My f30 335i (N55) is experiencing an issue with a fairly new battery where the battery seems to not be charging properly so the voltage remains pretty low (11.5V). Every now and then the start stop will deactivate as a result, and also once in a while I'm getting a long crank followed by a low battery error.

The battery is still fairly new so I suspect it's something else. The voltage with the car switched on is around 14.8V so that seems to be fine, so I'm wondering if my engine ground is possibly corroded so presenting a high impedance.

Can someone point me to exactly where the engine ground strap is located, with pics if possible? Also, is it possible to see it from the engine bay without getting under it?

Billfitz · 03-04-2019, 12:11 PM

Did you register the battery when you installed it?

yusufm786 · 03-04-2019, 02:52 PM

It was installed at BMW so I believe they did. Installed an original bmw battery too.

Billfitz · 03-04-2019, 03:25 PM

I don't think the engine ground strap would cause the battery to not take a charge. You can read the alternator output and the battery charge at the charging posts under the hood. If it reads 14.8v there when the engine is running and only 11.5v when it's not that indicates either a bad battery or a bad voltage regulation circuit that's preventing the battery from fully charging.

Rebound · 03-04-2019, 04:37 PM

The battery's in the trunk, so you aren't going to see it from inside the engine compartment.

Billfitz · 03-04-2019, 05:04 PM

And that would be why there are charging posts under the hood.

Rebound · 03-06-2019, 11:53 AM

Quote:

Originally Posted by Billfitz

I don't think the engine ground strap would cause the battery to not take a charge. You can read the alternator output and the battery charge at the charging posts under the hood. If it reads 14.8v there when the engine is running and only 11.5v when it's not that indicates either a bad battery or a bad voltage regulation circuit that's preventing the battery from fully charging.

Bill, I also own a Prius, which has a 12v battery in the back, and an owner had body work. The body shop hadn't tightened the battery ground strap to the frame, and it caused all sorts of issues until it was detected and secured. So... yes, I think it's possible.

Billfitz · 03-06-2019, 12:17 PM

Anything's possible, but the charging posts are electrically past the point where the ground strap is likely to be a problem.

03-04-2019, 10:47 AM	#1
yusufm786 Private 26 Rep 72 Posts Drives: 323i Join Date: Apr 2011 Location: South Africa iTrader: (0)	Where are the F30 (N55) engine ground points Hey ppl My f30 335i (N55) is experiencing an issue with a fairly new battery where the battery seems to not be charging properly so the voltage remains pretty low (11.5V). Every now and then the start stop will deactivate as a result, and also once in a while I'm getting a long crank followed by a low battery error. The battery is still fairly new so I suspect it's something else. The voltage with the car switched on is around 14.8V so that seems to be fine, so I'm wondering if my engine ground is possibly corroded so presenting a high impedance. Can someone point me to exactly where the engine ground strap is located, with pics if possible? Also, is it possible to see it from the engine bay without getting under it?
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03-04-2019, 12:11 PM	#2
Billfitz Lieutenant General 8245 Rep 16,089 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	Did you register the battery when you installed it?
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03-04-2019, 02:52 PM	#3
yusufm786 Private 26 Rep 72 Posts Drives: 323i Join Date: Apr 2011 Location: South Africa iTrader: (0)	It was installed at BMW so I believe they did. Installed an original bmw battery too.
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03-04-2019, 03:25 PM	#4
Billfitz Lieutenant General 8245 Rep 16,089 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	I don't think the engine ground strap would cause the battery to not take a charge. You can read the alternator output and the battery charge at the charging posts under the hood. If it reads 14.8v there when the engine is running and only 11.5v when it's not that indicates either a bad battery or a bad voltage regulation circuit that's preventing the battery from fully charging.
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03-04-2019, 04:37 PM	#5
Rebound Second Lieutenant 153 Rep 258 Posts Drives: F33: The 435i Convertible Join Date: Dec 2017 Location: Oregon iTrader: (0)	The battery's in the trunk, so you aren't going to see it from inside the engine compartment.
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03-04-2019, 05:04 PM	#6
Billfitz Lieutenant General 8245 Rep 16,089 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	And that would be why there are charging posts under the hood.
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03-06-2019, 12:17 PM	#8
Billfitz Lieutenant General 8245 Rep 16,089 Posts Drives: '15 328iX GT Join Date: Jan 2015 Location: New Hampshire iTrader: (0)	Anything's possible, but the charging posts are electrically past the point where the ground strap is likely to be a problem.
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