[doug_999]

Originally Posted by F87source

Wait really? That's kind of weird and concerning, but I read through the ctek manual and there was no mention of that except snow flake mode was specifically for AGM batteries and cold conditions.


Also note:
You don't charge directly to the battery, you do it via the terminals under the hood otherwise you damage the IBS.

Snow flake mode pushes I believe 13.7V which should be fine with all AGM batteries. The IBS will stop any charging if it's too much and you'll get an error (if done so under hood), that's how you should know if it's over charging.

Plus BMW resells rebranded ctek chargers, and so do pretty much all major car brands. I've used a ctek multius 7002 for 2 years no on snowflake mode without any issues whatsoever.

Believe it or not, Ctek recommends directly connecting to the battery - but I agree, I just go with the terminals up front.

FYI re AGM charging: https://smartercharger.com/faq/#batteryknowledge6

Originally Posted by chris719

All automotive AGM batteries are basically the same, and there are only a handful of manufacturers in the world. I think most BMW AGM batteries are mfg by Varta or Exide. Johnson Controls, Exide, and East Penn (Deka) make almost all the AGM batteries out there. There are some higher end batteries like Odyssey and Northstar which are a bit closer to a deep cycle design, but the fundamental chemistry is identical.

Not according to Ctek...
https://smartercharger.com/faq/#batteryknowledge6

[F87source]

Originally Posted by doug_999

Believe it or not, Ctek recommends directly connecting to the battery - but I agree, I just go with the terminals up front.

FYI re AGM charging: https://smartercharger.com/faq/#batteryknowledge6



Not according to Ctek...
https://smartercharger.com/faq/#batteryknowledge6

BMW doesn't (it's in the manual) advise connecting to the battery, Ctek does because not all cars have IBS sensors. So if you connect directly to the battery the car cannot control the charging itself which could be bad.

[chris719]

Originally Posted by doug_999

Believe it or not, Ctek recommends directly connecting to the battery - but I agree, I just go with the terminals up front.

FYI re AGM charging: https://smartercharger.com/faq/#batteryknowledge6



Not according to Ctek...
https://smartercharger.com/faq/#batteryknowledge6

The Ctek FAQ is vague and who knows who wrote it.

The fact is, that every car AGM battery is the same other than some model-to-model differences like the thickness and purity of the lead plates. Optima are spiral cells but it is the same chemistry. It will be fine in snowflake mode as it is just 14.7V instead of 14.4V. The fully charged voltage of an AGM battery is 14.7V. You won't get a full charge on the normal mode.

[F87source]

In regards to snowflake mode I see, but in the manual it also said that was optimal for AGM, and cold weather conditions and since that's the condition my car is experiencing due to winter storage that's what i'm using. Nothing else really matches the description of my usage scenario so I have to use snow flake mode.

[chris719]

Originally Posted by F87source

In regards to snowflake mode I see, but in the manual it also said that was optimal for AGM, and cold weather conditions and since that's the condition my car is experiencing due to winter storage that's what i'm using. Nothing else really matches the description of my usage scenario so I have to use snow flake mode.

The snowflake mode is for cold weather only when used with a standard flooded SLA battery. For an AGM, you should always use snowflake mode. Maybe not if you're in Death Valley, though.

[F87source]

Originally Posted by chris719

The Ctek FAQ is vague and who knows who wrote it.

The fact is, that every car AGM battery is the same other than some model-to-model differences like the thickness and purity of the lead plates. Optima are spiral cells but it is the same chemistry. It will be fine in snowflake mode as it is just 14.7V instead of 14.4V. The fully charged voltage of an AGM battery is 14.7V. You won't get a full charge on the normal mode.

+1
whoops I see in my earlier post I put 13.7V, yes it's supposed to be 14.7V for a full charge on an AGM. Which is another reason why snowflake mode is the only compatible mode imo.

The ctek manual that came with my mus7002 mentioned this under snow flake mode (copied directly from the PDF - "Mode 14.7V - This setting is recommended for a battery at temperatures
< 41°F. It is also recommended for many AGM batteries like Optima, and
Odysseys. Consult your battery manufacturer when in doubt"

So yeah for sure it will work with AGM, and the OEM charger bmw sells is a relabeled Ctek with snowflake mode too, so it should work without issue.

[F87source]

Originally Posted by chris719

The snowflake mode is for cold weather only when used with a standard flooded SLA battery. For an AGM, you should always use snowflake mode. Maybe not if you're in Death Valley, though.

Yeah I know, thanks for the info I appreciate it.

For a second I though I messed up lol.

[doug_999]

Originally Posted by chris719

The Ctek FAQ is vague and who knows who wrote it.

Uh, it seems to come from CTek

Weird how people get on their website and write strange things

And my comment re directly connecting to the battery comes from them as well.

[doug_999]

Originally Posted by chris719

The snowflake mode is for cold weather only when used with a standard flooded SLA battery. For an AGM, you should always use snowflake mode. Maybe not if you're in Death Valley, though.

I'm cracking up. Ctek says "it depends" and you say "you should always".

That's funny.

[F87source]

Originally Posted by doug_999

Uh, it seems to come from CTek

Weird how people get on their website and write strange things

And my comment re directly connecting to the battery comes from them as well.

You can connect directly to the battery if it is removed, but it's not ideal if it's in the car because you're bypassing the IBS which monitors the battery's health, charge, and is responsible in charging it.

I'm pretty sure there were two batteries Ctek mentioned that may or may not like the snow flake mode, but all other AGM's that utilize the 14.7V charge should be used in conjunction with snowflake mode.

The good thing is that is should be relatively safe if you charge via the underhood terminals because the IBS will prevent overcharging.

[chris719]

Originally Posted by doug_999

I'm cracking up. Ctek says "it depends" and you say "you should always".

That's funny.

Since when is some intern or whatever schmuck wrote that non-answer (at a single battery charger vendor) an authority on anything?

I don’t know what part of my factual statements you have problems with. Perhaps you can do more than 5 seconds of copy paste from a poorly informed webpage before concluding I’m wrong. Maybe you should measure the peak charging voltage of a BMW AGM battery and get back to me.

[chris719]

Originally Posted by F87source

You can connect directly to the battery if it is removed, but it's not ideal if it's in the car because you're bypassing the IBS which monitors the battery's health, charge, and is responsible in charging it.

I'm pretty sure there were two batteries Ctek mentioned that may or may not like the snow flake mode, but all other AGM's that utilize the 14.7V charge should be used in conjunction with snowflake mode.

The good thing is that is should be relatively safe if you charge via the underhood terminals because the IBS will prevent overcharging.

Don’t waste your breath, he’s unable to do any sort of thinking apparently and will only paste partially correct information from the FAQ section of a crappy website.


Bottom line is you’re right and you should charge via the front terminals in a BMW. Snowflake mode may not make much difference but should be safe for all AGMs.

[Twinsturbo]

IBS will notice the new status of the batteri when you hit the ignition after fully charging it when its connected in the car right?

[F87source]

Originally Posted by Twinsturbo

IBS will notice the new status of the batteri when you hit the ignition after fully charging it when its connected in the car right?

No the IBS learns the condition of a preset battery (the one coded to the car) over time, so as the battery degrades and can't hold as much charge over time the IBS factors that in and charges the battery respective to that condition. That's why if you buy a new battery you need to code the car for that Battey to prevent over or under chargining (under when the new battery is more or the same capacity as the original degraded battery as the IBS charges a degraded battery to a lesser extent, and over charge if you buy a light weight battery with a smaller capacity and this can be bad because if you don't code it over charging can cause battery explosions).

[Twinsturbo]

The IBS charges to a point where the battery holds a certain voltage? So you mean that the IBS doesent read the actual voltage of the battery continously? Overcharging should not be possible!? Cant belive that the system would be so stupid...

[F87source]

Originally Posted by Twinsturbo

The IBS charges to a point where the battery holds a certain voltage? So you mean that the IBS doesent read the actual voltage of the battery continously? Overcharging should not be possible!? Cant belive that the system would be so stupid...

From what I read when the IBS is coded to a battery (voltage rating, and amp hour rating) the IBS will charge the battery to that point, but as the battery gets old of course it won't be able to hold the rated capacities anymore and the IBS is able to determine that based on discharge rate etc. So over time the IBS will charge the battery less as it gets older and degrades. This makes it very important to code/register the battery to the car with every battery swap or you risk under or over charging the battery.

Voltage may vary from battery to battery and so may amp hours.

[Twinsturbo]

It does not make sense that a system like this shouldnt be adaptive? Even if you charge your battery full via the battery itself it is full and the IBS will "see it"? Then its still the same battery with the same "health"! It should not be a problem to charge on the battery itself as far as i can see. Just be sure to code your new battery in when changing?

[F87source]

Originally Posted by Twinsturbo

It does not make sense that a system like this shouldnt be adaptive? Even if you charge your battery full via the battery itself it is full and the IBS will "see it"? Then its still the same battery with the same "health"! It should not be a problem to charge on the battery itself as far as i can see. Just be sure to code your new battery in when changing?

This system is actually really smart imo and I like the implementation.

Adaptive how so? It already changes the charging pattern based on battery health. You can't really charge the battery more than the IBS is already doing maybe you could force in a bit more charge than the IBS but probably not more, if you're putting the same battery back in then there shouldnt be an issue.

The issue arises if you put in a different battery, then you must code it. IMO when charging a battery just leave it in the car and charge under the hood using the jump terminals, that was the car always see's what's going on.

[Twinsturbo]

So no problem charging right on the battery as we discussed? I agree with you on coding in when putting a new battery in!

[F87source]

Originally Posted by Twinsturbo

So no problem charging right on the battery as we discussed? I agree with you on coding in when putting a new battery in!

If you unplug the battery and remove it from that car imo I don't think that is too much of an issue. Just take care when doing so.

[Twinsturbo]

Why not in the car as we discussed?

[chris719]

Originally Posted by Twinsturbo

So no problem charging right on the battery as we discussed? I agree with you on coding in when putting a new battery in!

The IBS appears to contain a coulomb counter, so any charging of the battery that doesn’t pass current through it will make it inaccurate, up to you if that matters at all. I’d probably just unhook it but it should really not damage anything unless BMW designed it poorly.