all about M8 battery

dan boines · 10-23-2022, 01:05 PM

I use the BMW trickler charger that has a Lithium Ion setting whisch limits charging voltage to 13.5v. Part#CEC400 40127M15W3001063

bloozemanAZ · 10-23-2022, 05:11 PM

Quote:

Originally Posted by RJC-1

Just as I suspected, the question remains why does the M850 get additional batteries and the M8 not? Weight could certainly be an answer but then how did they make up all that missing power...thinking a much more powerful Lith for the M8?

Checking the owners manual for my 2020 M850i it has literally zero information on the number of batteries, where located, etc. Does indicate that if the battery is replaced that it needs to be registered to the car to enable comfort access, etc. Only terminals it calls out for charging or jump starting are under the hood.

bloozemanAZ · 10-23-2022, 05:14 PM

Quote:

Originally Posted by Tethys

Good question but lithium batteries are way more powerful than AGM so why do an AGM at all in the 850?

Because the AGM powers my B&W audio.

Obviously, just kidding and there is truly no explanation why.

RJC-1 · 10-23-2022, 08:41 PM

Quote:

Originally Posted by bloozemanAZ

Quote:

Originally Posted by RJC-1

Just as I suspected, the question remains why does the M850 get additional batteries and the M8 not? Weight could certainly be an answer but then how did they make up all that missing power...thinking a much more powerful Lith for the M8?

Checking the owners manual for my 2020 M850i it has literally zero information on the number of batteries, where located, etc. Does indicate that if the battery is replaced that it needs to be registered to the car to enable comfort access, etc. Only terminals it calls out for charging or jump starting are under the hood.

There's two for sure, Luther under hood and AGM in trunk

bloozemanAZ · 10-23-2022, 08:44 PM

Quote:

Originally Posted by RJC-1

There's two for sure, Luther under hood and AGM in trunk

And AGM powering the B&W audio.

m3_08 · 11-01-2022, 01:21 PM

Had my break in service done today so I asked master technician the same question.
'M8 has only one battery, it's LiON, cost $1200+, located under the trunk floor and if you don't drive enough to charge it recommended to put on LiON charger using under the hood connect points'

Qsilver7 · 11-02-2022, 03:51 PM

BMW warns against using the 12 volt (cig lighter sockets) because they are on a relay and will shut down after a few minutes. If you're using the 12v sockets to charge...then the charger will also be cut off from doing it job.

The car will have a dual battery setup (aux battery) based on options. The aux battery usually is installed if you have active integrated steering or its used to helpw with EPS (electronic power steering). If you have an auxiliary battery, it is maintained by either a PCU (power control unit) or a charging controller.

Use the dedicated jump start terminals in the engine bay for maintaining the car's main battery. The PCU or charging controller will take car of the aux battery.

Dr Thrillride · 03-11-2023, 12:02 PM

All great info here. This battery is 2500 CND so Canadians not driving in winter be aware. I start mine every two to three weeks, but she’s dead this morning. Trying the charger route first.

Dr Thrillride · 03-11-2023, 02:05 PM

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Got her going. Around the block a few times.

These pilot alpines not too bad

m3_08 · 03-12-2023, 09:17 AM

Trying to drive 10-20 miles per week when weather is nice enough. So far battery keeps up nicely and I'm pleasantly surprised by BMW engineering specially when compare with horror stories from new SL R232 forum. Also the JBV1 app shows battery voltage and it really helps to monitor battery status.

RJC-1 · 03-12-2023, 10:51 AM

BMW established and provided a protocol on how to keep the battery and the car healthy during the peak Covid. It applies here as well

Here’s the UK version, can’t seem to locate the US one, but they’re similar I’m sure. https://discover.bmw.co.uk/help/owne...nt-Coronavirus

DionH · 12-11-2023, 10:45 AM

I believe the second battery is a requirement for the driver's assist package to steer the car in an emergency situation where the main battery fails.

eldyf93 · 02-18-2024, 10:05 PM

Quote:

Originally Posted by Tenac

Oh another interesting find on the BMW M8 breakdown of the battery system it says the Lion can be replaced by an AGM battery that follows same ratings. So if that can be located you could buy an AGM.... thought that was interesting. US Spec F91.

Do you know if anyone has tested the weight savings over the 70 Ah Li-ion and a 70 Ah AGM BMW would use?

Tenac · 02-19-2024, 08:56 AM

Quote:

Originally Posted by eldyf93

Do you know if anyone has tested the weight savings over the 70 Ah Li-ion and a 70 Ah AGM BMW would use?

Not that I have seen. But the location of the battery is a good spot to have some heft, very low and just past the rear end. Good for traction there.

10-23-2022, 01:05 PM	#45
dan boines New Member 73 Rep 21 Posts Drives: 22 M8 vert. 24 GLS600 Maybach Join Date: May 2022 Location: Delaware iTrader: (0)	I use the BMW trickler charger that has a Lithium Ion setting whisch limits charging voltage to 13.5v. Part#CEC400 40127M15W3001063
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11-01-2022, 01:21 PM	#50
m3_08 Lieutenant 603 Rep 532 Posts Drives: 2023 M8 conv, IX M60, model Y Join Date: May 2015 Location: ATL iTrader: (0)	Had my break in service done today so I asked master technician the same question. 'M8 has only one battery, it's LiON, cost $1200+, located under the trunk floor and if you don't drive enough to charge it recommended to put on LiON charger using under the hood connect points'
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11-02-2022, 03:51 PM	#51
Qsilver7 Major General 4442 Rep 7,484 Posts Drives: F06 650ix GC / F15 X5 50i Join Date: Oct 2016 Location: Indiana, USA iTrader: (0)	BMW warns against using the 12 volt (cig lighter sockets) because they are on a relay and will shut down after a few minutes. If you're using the 12v sockets to charge...then the charger will also be cut off from doing it job. The car will have a dual battery setup (aux battery) based on options. The aux battery usually is installed if you have active integrated steering or its used to helpw with EPS (electronic power steering). If you have an auxiliary battery, it is maintained by either a PCU (power control unit) or a charging controller. Use the dedicated jump start terminals in the engine bay for maintaining the car's main battery. The PCU or charging controller will take car of the aux battery. Attached Images __________________ 2015 F06 650ix Gran Coupe`(Moonstone/Cohiba Brown)\| 2014 F15 X5 50i MSport (Space Gray/Mocha) Become a BMW CCA member! Click HERE to join and feel free to use my BMW CCA member #191509 as a referral. Last edited by Qsilver7; 11-02-2022 at 03:58 PM..
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03-11-2023, 12:02 PM	#52
Dr Thrillride Major 1399 Rep 1,070 Posts Drives: 2022 M8cs Join Date: May 2016 Location: Canada iTrader: (0) Garage List 2022 BMW M8 comp coupe [0.00]	All great info here. This battery is 2500 CND so Canadians not driving in winter be aware. I start mine every two to three weeks, but she’s dead this morning. Trying the charger route first.
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03-11-2023, 02:05 PM	#53
Dr Thrillride Major 1399 Rep 1,070 Posts Drives: 2022 M8cs Join Date: May 2016 Location: Canada iTrader: (0) Garage List 2022 BMW M8 comp coupe [0.00]	Got her going. Around the block a few times. These pilot alpines not too bad Last edited by Dr Thrillride; 03-11-2023 at 02:45 PM..
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03-12-2023, 09:17 AM	#54
m3_08 Lieutenant 603 Rep 532 Posts Drives: 2023 M8 conv, IX M60, model Y Join Date: May 2015 Location: ATL iTrader: (0)	Trying to drive 10-20 miles per week when weather is nice enough. So far battery keeps up nicely and I'm pleasantly surprised by BMW engineering specially when compare with horror stories from new SL R232 forum. Also the JBV1 app shows battery voltage and it really helps to monitor battery status.
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03-12-2023, 10:51 AM	#55
RJC-1 Lieutenant Colonel 1290 Rep 1,658 Posts Drives: 2019 BMW M850XI Join Date: Dec 2019 Location: Florida iTrader: (0)	BMW established and provided a protocol on how to keep the battery and the car healthy during the peak Covid. It applies here as well Here’s the UK version, can’t seem to locate the US one, but they’re similar I’m sure. https://discover.bmw.co.uk/help/owne...nt-Coronavirus __________________ 2019 M850i xDrive Coupe (06/19 Production) Mineral White/Black, HP Cooling/Tire/M-Technology Pkg/Extended Shadow/Etc., Anthracite Headliner, Carbon Roof, DAx2, Display Key, Various Accs'. Topic permitting, I try to be objective as possible
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12-11-2023, 10:45 AM	#56
DionH Registered 0 Rep 1 Posts Drives: 2021 M850I Grand Coupe Join Date: Dec 2023 Location: California iTrader: (0)	I believe the second battery is a requirement for the driver's assist package to steer the car in an emergency situation where the main battery fails.
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