[ducatiti]

Still new to my X7 and browsing this forum every night, just found out it has three batteries, one being a lithium ion. I have a CTEK charger with an AGM option. Do I have to use this AGM option? Would it hurt the battery to use a cheap trickle charger?

[jmciver]

Originally Posted by ducatiti

Still new to my X7 and browsing this forum every night, just found out it has three batteries, one being a lithium ion. I have a CTEK charger with an AGM option. Do I have to use this AGM option? Would it hurt the battery to use a cheap trickle charger?

The main car battery, which is located under the floor in the trunk area, is a standard AGM/Lead Acid type battery (at least it is on my 2020 X7 40i). So just about any decent battery charger will be fine, including your CTek charger. Depending on your X7 options, you may have 1 or 2 auxiliary batteries, which could be lithium. You would need a charger that can handle lithium batteries for those.

However, if all you want is the ability to keep your X7 on a trickle charge for when it sits for extended periods, a standard trickle charger will be fine. The aux batteries in the X7 should not need any type of trickle charge. But aux batteries like this are still not common in cars yet, so knowing how/when to charge them is not really known (unless you have the shop manual for the X7). I have yet to see an X7 owner report a battery related problem that involved one of the aux batteries in the X7 - but time will tell.

That said, if you are buying a new battery charger anyway, buying one that can also charge lithium batteries is a way to help futureproof your equipment. The last battery charger I bought a few years ago is lithium capable, but that was mainly because my M3 came with a lithium battery as the main car battery (no aux batteries like the X7).

[gdurhamski]

I just pulled mine out of 6 months of storage. I just used a basic Battery Tender brand maintainer I got at Costco a few years ago. I connected it to the battery jumping/charging posts in the engine bay. Worked great. No problems with any of the batteries.

[ducatiti]

Originally Posted by jmciver

The main car battery, which is located under the floor in the trunk area, is a standard AGM/Lead Acid type battery (at least it is on my 2020 X7 40i). So just about any decent battery charger will be fine, including your CTek charger. Depending on your X7 options, you may have 1 or 2 auxiliary batteries, which could be lithium. You would need a charger that can handle lithium batteries for those.

However, if all you want is the ability to keep your X7 on a trickle charge for when it sits for extended periods, a standard trickle charger will be fine. The aux batteries in the X7 should not need any type of trickle charge. But aux batteries like this are still not common in cars yet, so knowing how/when to charge them is not really known (unless you have the shop manual for the X7). I have yet to see an X7 owner report a battery related problem that involved one of the aux batteries in the X7 - but time will tell.

That said, if you are buying a new battery charger anyway, buying one that can also charge lithium batteries is a way to help futureproof your equipment. The last battery charger I bought a few years ago is lithium capable, but that was mainly because my M3 came with a lithium battery as the main car battery (no aux batteries like the X7).

Thanks for your post. I would have to read a few times more lol.

So if I plug in my CTEK on the appropriate connection in the engine bay, it will charge all the batteries if I had a lithium capable charger?

From what I understand, if you have an AGM battery you have to select the appropriate mode on the charger, not the lead acid standard mode. Can you confirm this?

That being said, do our 40i's come with AGM or lead acid batteries?

[jmciver]

Originally Posted by ducatiti

Thanks for your post. I would have to read a few times more lol.

So if I plug in my CTEK on the appropriate connection in the engine bay, it will charge all the batteries if I had a lithium capable charger?

From what I understand, if you have an AGM battery you have to select the appropriate mode on the charger, not the lead acid standard mode. Can you confirm this?

That being said, do our 40i's come with AGM or lead acid batteries?

You would charge your battery from the terminals in the engine compartment, just like any other car. Not sure if charging from there will charge the aux batteries in the car though, but I would not worry about them to be honest. My research tells me that the main battery in the the X7 is an AGM type battery.

https://www.realoem.com/bmw/enUS/sho...diagId=61_6169

[MystroX5]

Always the charge point under the hood. Just use the alligator claps. Fast and simple.

[JNasty]

Might as well go all in. It's overkill for the price but hey its branded.

https://www.bmwpartsnow.com/search?search_str=charger

[jmciver]

Originally Posted by JNasty

Might as well go all in. It's overkill for the price but hey its branded.

https://www.bmwpartsnow.com/search?search_str=charger

The BMW charger is just a re-branded CTEK charger so you can do better than that as far as price and there is nothing special about that charger either. There are also other good charger brands as well, like Noco. The charger I mentioned in my post above is a Noco Genius charger and has worked well for me.

[ducatiti]

Originally Posted by jmciver

The BMW charger is just a re-branded CTEK charger so you can do better than that as far as price and there is nothing special about that charger either. There are also other good charger brands as well, like Noco. The charger I mentioned in my post above is a Noco Genius charger and has worked well for me.

When I purchased my CTEK charger a few years ago, I honestly thought that they were one of the better ones. I guess I was wrong lol.

[jmciver]

Originally Posted by ducatiti

When I purchased my CTEK charger a few years ago, I honestly thought that they were one of the better ones. I guess I was wrong lol.

Nothing wrong with the CTEK, it gets the job done. There are also other good options available. Some people get hung up on the BMW being on the label - but in the case of the "factory" battery charger it does not matter. I chose Noco for the additional features over the CTEK/BMW charger - which may not be necessary/desired by other users.

[J_PNW]

So for those of you already trickle charging, do your gizmos show the battery charging to 100%?

I just got the Noco Genius 2 (so the 2Amp version). It showed less than 25% charge when I first connected, and stayed at <50% until I disconnected it 16 hours later.

Pictures of the charger and my connection points in the pictures attached.

Are you all seeing the Noco chargers get to 100% displayed charge?

[ducatiti]

So do you select AGM as default for the X7?

[J_PNW]

Yes, I selected 12v AGM on the Noco - it’s not a “smart” device in the sense that it figures out what the appropriate charging mode is against the battery.

I don’t know that I need a trickle charger in regular usage, but wanted to test this since the X7 will be unused for the next 4 weeks.

Have you guys been able to see the Noco show higher charge levels on the battery?

[thenew3]

Originally Posted by J_PNW

So for those of you already trickle charging, do your gizmos show the battery charging to 100%?

I use the BMW oem charger and it will get to 100% but sometimes takes a couple of days to get there.

[stockguru]

Originally Posted by thenew3

I use the BMW oem charger and it will get to 100% but sometimes takes a couple of days to get there.

There is some serious battery drain on these cars. Even if you charge to 100% it goes down to 30% seemingly in one drive. I have noticed that it stays in the 30-40% range for me having charging it multiple times with oem trickle charger. And it does take more than a day to charge.

[thenew3]

Originally Posted by stockguru

There is some serious battery drain on these cars. Even if you charge to 100% it goes down to 30% seemingly in one drive. I have noticed that it stays in the 30-40% range for me having charging it multiple times with oem trickle charger. And it does take more than a day to charge.

I think that's by design. They don't have the alternator engaged all the time to lessen load on the engine and therefor in theory use less gas. I believe they try to keep the battery around 50% charged.
MB has been doing this for at least the past 10 years. I saw that on my previous MB and usually took 2-3 days to charge it to full.

[FishOuttaWater]

I've been reading this with great interest because we just bought a new Jeep and the X7 sits a lot now. It hasn't been cranked in almost a week. My wife used to use it all the time running errands and picking up the grand kids from school and such and they love the Jeep and have kicked the X7 to the curb. We will be taking another trip out west in January, hopefully, depending on the status of the country by then, and don't want to get out there in the cold weather and have the battery crap out on us. We bought the car in May of '19 and have about 25k miles on it. Should I get one of these chargers and keep it on it for maintenance? We are driving it to Ga. tomorrow but it's only about a 250 mile round trip. Hadn't really thought about this before. Thanks.

[thenew3]

Originally Posted by FishOuttaWater

I've been reading this with great interest because we just bought a new Jeep and the X7 sits a lot now. It hasn't been cranked in almost a week. My wife used to use it all the time running errands and picking up the grand kids from school and such and they love the Jeep and have kicked the X7 to the curb. We will be taking another trip out west in January, hopefully, depending on the status of the country by then, and don't want to get out there in the cold weather and have the battery crap out on us. We bought the car in May of '19 and have about 25k miles on it. Should I get one of these chargers and keep it on it for maintenance? We are driving it to Ga. tomorrow but it's only about a 250 mile round trip. Hadn't really thought about this before. Thanks.

250 mile trip should be plenty to charge the batteries. If you are going to let it sit for a few weeks at a time, it's a good idea to get one of the trickle chargers to keep the battery topped up. Should help extend longevity of the battery.

[stockguru]

Originally Posted by thenew3

250 mile trip should be plenty to charge the batteries. If you are going to let it sit for a few weeks at a time, it's a good idea to get one of the trickle chargers to keep the battery topped up. Should help extend longevity of the battery.

I would recommend a charge before you leave if it's sitting for a month or longer. You don't necessarily need to have it charging at all times. If you do, make sure you get one of the chargers that auto shut off so you don't risk over charging it.

[FishOuttaWater]

Originally Posted by stockguru

I would recommend a charge before you leave if it's sitting for a month or longer. You don't necessarily need to have it charging at all times. If you do, make sure you get one of the chargers that auto shut off so you don't risk over charging it.

Thanks. We usually drive it on the weekends but sometimes we don't get out of the neighborhood really. I will do what you said to be on the safe side. I bought a Noco Genius 5 today. I have an enclosed trailer and a zero turn mower that will benefit form it also.

[RClementTX]

Not so sure about using CTEK MUS4.3 charger with new mild hybrid system. Just took delivery on a 2021 X7 with the 4.0 mild hybrid 335HP engine. Asked the Genius when I got my first briefing about jump starts - advised that they were the same as in the past using 12V pack on the engine compartment positive/negative terminals. Since I was spending hours on configuration decided to put my CTEK charger (in AGM mode) on those terminals. Noted that after 8 hours, the charger never moved beyond "3" - bulk charge which is unusual since my X5 charges fully in about 4-6 hours. At the same time, instrument panel had a warning that I had a charging error; the error message cleared once I started the car and hasn't returned so I figure no harm done. I understand that the 12V battery and the 48V Li Ion battery are connected via DC to DC converter. I presume that the converter is a 2 way unit with 48V charging the 12V and vice versa. But after getting error message and failing to charge beyond build charge I am now on quest for info on how to maintain my batteries when the car's idle for several weeks (due to my travels). Any informed input would be appreciated. By the way, have reached out to Genius and don't have answer to this question yet.

[thenew3]

Originally Posted by RClementTX

Not so sure about using CTEK MUS4.3 charger with new mild hybrid system. Just took delivery on a 2021 X7 with the 4.0 mild hybrid 335HP engine. Asked the Genius when I got my first briefing about jump starts - advised that they were the same as in the past using 12V pack on the engine compartment positive/negative terminals. Since I was spending hours on configuration decided to put my CTEK charger (in AGM mode) on those terminals. Noted that after 8 hours, the charger never moved beyond "3" - bulk charge which is unusual since my X5 charges fully in about 4-6 hours. At the same time, instrument panel had a warning that I had a charging error; the error message cleared once I started the car and hasn't returned so I figure no harm done. I understand that the 12V battery and the 48V Li Ion battery are connected via DC to DC converter. I presume that the converter is a 2 way unit with 48V charging the 12V and vice versa. But after getting error message and failing to charge beyond build charge I am now on quest for info on how to maintain my batteries when the car's idle for several weeks (due to my travels). Any informed input would be appreciated. By the way, have reached out to Genius and don't have answer to this question yet.

That might be normal if it's a freshly delivered vehicle and you haven't driven it much. They don't come from the factory with fully charged batteries. And if it has been sitting in transit (on a train or truck) for some time, it could have drained relatively low.

First time I charged up my X7 it stayed on the 3rd light for over 24 hours. Took a few days for it to reach the 8th light on my charger.

I never turned the car on while the charger was connected so I didn't get any errors.

Also since you have the mild hybrid, that 48v system has I think a 0.9kwh battery, which if has a 12v to 48v DC->DC converter would mean it could take your 12V charger quite a bit of time to charge up that 0.9KWh battery. (Doing some simple math, if you have a 12V 5A charger, that's 60 Wh, 8 hours continuous gets you 480Wh which is about 50% of what the 0.9KWh battery will take. So depending on the state of charge of all 3 batteries, it could take quite a while. My charger is only 12V 2A I believe so it takes much longer).