[Gr8 Ape]

Originally Posted by bloozemanAZ

If you have a M8 (only Lithium) than you want a CTEK 56-926 LITHIUM. The Ctek MXS 5.0 technically is wet cell (including AGM). With a M850i with both lithium and AGM I played the "dance" with several chargers including the CTEK lithium model as well as a NOCOS Genius 10 (AGM and Lithium).

As others have stated you only ever connect to the "jump start" terminals under the hood. The catch-22 when reading the M850i manual is to switch from AGM to Lithium only a certain voltage is allowed and that killed the NOCO (as in I returned it). Bought the BMW OEM'd CTEK as it appears to be a unique animal, i.e., not a consumer version available.

It's a few $ more ($40) than either the MXS, Lithium or NOCO. But it's guaranteed to work on the only hybrid (loosely stated) aspect of the M850i. I'm trying to determine if the wife's new LCI X5 is a similar config or just a single lithium/AGM. Either way same part number so I'm golden.

I’m a bit confused. When I tried to source the BMW OEM CTEK (part no. 61432408594), BMW parts suppliers’ websites (including BMW dealerships) consistently said it would not fit an M850ix coupe. What am I missing here? TIA

[bloozemanAZ]

Originally Posted by Gr8 Ape

I’m a bit confused. When I tried to source the BMW OEM CTEK (part no. 61432408594), BMW parts suppliers’ websites (including BMW dealerships) consistently said it would not fit an M850ix coupe. What am I missing here? TIA

Odd but it indeed appears they pulled it for some unknown reason. Same part # for my M850i and the wife's LCI 40i. Did a search and fcpeuro (have bought from them in the past) have it in stock and validate it's compatible with the M850i.

[TupperBMW]

Wow, who “garage queens” a BMW? I know that the 8 series is special and all, but if any car is meant to be driven, it’s a Bimmer

No better way to keep it charged. And especially if you have the M850i or M8, just drive it for fun. Nail that throttle on some backroads, that’ll give your battery all the juice that it needs

[Moopai]

I was going to purchase a charger as I don’t drive much (2-3 times a week about 30-40 minute drive). Last time I was in service, the shop forman took my car for a spin to check something with the brakes. I asked him if it’s a good idea to purchase a charger. When I told him how often I drive my M850, he said that’s plenty to keep the battery in good health and no need for a charger even when at times I’m out of town on business 3-5 days per trip.

I drove my 2016-750ix for almost five years the same way and never had any issues with the battery and the 750 had more electronics than the M850.

[Gr8 Ape]

Originally Posted by bloozemanAZ

Odd but it indeed appears they pulled it for some unknown reason. Same part # for my M850i and the wife's LCI 40i. Did a search and fcpeuro (have bought from them in the past) have it in stock and validate it's compatible with the M850i.

Thank you.

[Gr8 Ape]

Originally Posted by TupperBMW

Wow, who “garage queens” a BMW? I know that the 8 series is special and all, but if any car is meant to be driven, it’s a Bimmer

No better way to keep it charged. And especially if you have the M850i or M8, just drive it for fun. Nail that throttle on some backroads, that’ll give your battery all the juice that it needs

Garage queen, no. Out of town for extended periods, yes.

[TupperBMW]

Originally Posted by Moopai

I was going to purchase a charger as I don’t drive much (2-3 times a week about 30-40 minute drive). Last time I was in service, the shop forman took my car for a spin to check something with the brakes. I asked him if it’s a good idea to purchase a charger. When I told him how often I drive my M850, he said that’s plenty to keep the battery in good health and no need for a charger even when at times I’m out of town on business 3-5 days per trip.

I drove my 2016-750ix for almost five years the same way and never had any issues with the battery and the 750 had more electronics than the M850.

I could have told you that. 30-40 min 2-3 times a week is ample to keep a car charged.

Most of my driving is 25 min, twice a day, 4 days per week. That has always been ample and I have not had a battery issue so far

[KingB_O]

living the life

[darwin080]

Reading the above posts, I'm just curious: what is the difference between a direct battery connection and the Jumper/charger posts up front. If the charger posts are connected to the battery via a + positive bus and a - negative bus, they both end up in the same place: the battery. If I connect the charger to the posts under the hood and measure the current on the battery leads I'll record a current. If I connect the same source at the battery end of the leads I'll still record the same current under the hood. The + bus and the - bus end up at the battery and are continuous, so intuitively a charge placed anywhere along the bus will simply be additive to the entire bus.

I used to charge my 335i in the winter with a battery tender attached directly to the battery for years with no ill effects. In fact I hard wired it onto the battery terminals and only had to plug it in to use it.

Any BMW techs or EE's here who can answer this question as to the safey of direct battery connection on the M8?

[ViO]

Just a word of caution here. ⚠️

There’s two types of CTEC BMW Chargers for two types of BMW batteries.

One charger is for the AGM / Standard Battery and the other one is strictly for the Lithium Battery. The Lithium battery is sensitive to charging voltage.

Make sure to purchase the correct charger for your application. The battery will have either an AGM or LITHIUM tag on it.

As far as I know “most” (if not all) M8’s come with the Lithium battery. Regardless, just check the battery. It takes two seconds. 😊

[BostonBlueBMW]

Originally Posted by Seaford

Definitely leave it on a conditioner….you MAY find some stuff will not be working when you go to use it such as stop/start, comfort access.

a good conditioner won’t do it any harm and it takes an awfully long run to recharge the battery fully - I use this https://no.co/genius5

I got the exact same charger and am getting ready for my first winter storage of the m850i. Have you ever tried charging it with the Genius 5? It has AGM and Lithium settings but nothing that automatically switches between the two.

I am assuming I keep it on AGM for battery type and charge it for the ports under the hood. Thoughts? Please let me know what you do and your experience. Thank you!

[Seaford]

Originally Posted by BostonBlueBMW

I got the exact same charger and am getting ready for my first winter storage of the m850i. Have you ever tried charging it with the Genius 5? It has AGM and Lithium settings but nothing that automatically switches between the two.

I am assuming I keep it on AGM for battery type and charge it for the ports under the hood. Thoughts? Please let me know what you do and your experience. Thank you!

My 840 only has an AGM battery so that is the setting I use.