Battery tender threw Cel?

[M4_85]

So I had my m4 on the ctek lithium battery tender for 3 months. Drove the car and cel
Came on. Codes were high voltage and valvetronic sensor. First I wonder if the too are related, and i wonder why if the tender is not suppose to over charged. Anyone have this issue?
Thanks

[ElectroThermal]

Was your tender connected directly to the battery? When wiring mine up I came across information that grounding to the battery directly will cause CEL's and other issues. Apparently wiring a tender through the jump points under the hood allows the ECU to monitor the incoming current, whereas going direct to the battery bypasses the sensing circuits and that causes issues when the battery voltages change.

[M4_85]

Originally Posted by ElectroThermal

Was your tender connected directly to the battery? When wiring mine up I came across information that grounding to the battery directly will cause CEL's and other issues. Apparently wiring a tender through the jump points under the hood allows the ECU to monitor the incoming current, whereas going direct to the battery bypasses the sensing circuits and that causes issues when the battery voltages change.

Originally Posted by ElectroThermal

Was your tender connected directly to the battery? When wiring mine up I came across information that grounding to the battery directly will cause CEL's and other issues. Apparently wiring a tender through the jump points under the hood allows the ECU to monitor the incoming current, whereas going direct to the battery bypasses the sensing circuits and that causes issues when the battery voltages change.

No, it was through the hood like you said you do.. maybe the tender no good.

[M4_85]

Anyone deal with this? Thinking of just selling it if it's going to through a cel…

[icegrill]

No. No issues with the ctek lipo charger.

[rkyan661]

So I also have the CTEK charger and have the quick connect under the hood. I've been using it for two years but last month it threw the check engine light and the valvetronic was failing. This is a 2018 one owner car with only 4000 miles. Since I'm in NYC I used the charger for the winters and just warmed up the car and drove it every other weekend for a bit.

Per the mechanic the valvetronic actuator rusted due to condensation and it's worse if the car doesn't get driven frequently or warmed up enough.

After googling "valvetronic actuator" it seems that it could be CTEK related as it sends charge through and not sure if it triggers this piece

[M4_85]

Originally Posted by rkyan661

So I also have the CTEK charger and have the quick connect under the hood. I've been using it for two years but last month it threw the check engine light and the valvetronic was failing. This is a 2018 one owner car with only 4000 miles. Since I'm in NYC I used the charger for the winters and just warmed up the car and drove it every other weekend for a bit.

Per the mechanic the valvetronic actuator rusted due to condensation and it's worse if the car doesn't get driven frequently or warmed up enough.

After googling "valvetronic actuator" it seems that it could be CTEK related as it sends charge through and not sure if it triggers this piece

Funny you say that, when I took my car out of storage with the tender I got cel for high voltage and my valvetronic sensor went, wonder if they are related. Cost me $1500

[rkyan661]

Originally Posted by M4_85

Funny you say that, when I took my car out of storage with the tender I got cel for high voltage and my valvetronic sensor went, wonder if they are related. Cost me $1500

Yea I think it may be. Cost me around the same price which is the going rate

[lucius]

I've had mine on a tender for approximately 4+ months due to New England winter.
I was not aware that you are not supposed to hook it up directly to the battery.
Maybe I was one of the lucky few who did not get hit with a cel.

This is the tender I have:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[rosemont83]

So, if storing the car, sounds like it's probably a better idea to take the battery out, and charge it separately..

[TDotBMW]

This valvetronic failure seems to be a major issue with drivers who don't put a lot of miles on their car. There is a new service/puma bulletin fix that requires the valvetronic motor, eccentric shaft, and dme programming to be done when you get the CEL. You should also hear the infamous ticking noises occasionally when you open the door. That apparently is related to those above mentioned parts.

There is some sort of correlation to the battery. What that is, I am not exactly clear.

BMW was able to goodwill my repair for the valvetronic/eccentric shaft replacement. It helps if you have some sort of history with this issue.

[M3orbust]

That sucks I feel that you should be able to put your car on a tender and not have to worry about ruining/shorting out electrical control modules.

I store my car as well being in the Midwest, during winter it doesn't get started for at least 3 to maybe 4 months and I can't even put it on the correct lipo tender and not have a problem what a joke. My garage is heated, I don't know if that would help with this potential storge problem and or maybe just putting it on for a 2 week span in the middle of the storage time frame so you don't (blow) your valvetronic assembly idk

[TDotBMW]

Originally Posted by M3orbust

That sucks I feel that you should be able to put your car on a tender and not have to worry about ruining/shorting out electrical control modules.

I store my car as well being in the Midwest, during winter it doesn't get started for at least 3 to maybe 4 months and I can't even put it on the correct lipo tender and not have a problem what a joke. My garage is heated, I don't know if that would help with this potential storge problem and or maybe just putting it on for a 2 week span in the middle of the storage time frame so you don't (blow) your valvetronic assembly idk

I had it on a CTEK BMW tender in the winter and it didn't help. I think the car just needs to be driven and not just a couple miles here and there. It's appears to be a design flaw of the entire system by BMW.

Maybe disconnecting the entire battery and keeping/charging it inside would help

[Fat Goose]

Originally Posted by icegrill

No. No issues with the ctek lipo charger.

Same. lipo.. Lithium tender is a shall. Zero issues

[M3orbust]

Originally Posted by Fat Goose

Same. lipo.. Lithium tender is a shall. Zero issues

How many months do you leave it on the ctek and how many seasons have you done it ?? just curious

[Fat Goose]

Originally Posted by M3orbust

How many months do you leave it on the ctek and how many seasons have you done it ?? just curious

2 years, 12k miles

[icegrill]

Originally Posted by Fat Goose

2 years, 12k miles

Same I've used it on and off for 3 years no issues. I know there are other threads about the ctek with zero issues. Seems suspicious if it's related to your problem. Did you check all the wiring and ground under the hood for tightness?

[M3orbust]

Originally Posted by icegrill

Same I've used it on and off for 3 years no issues. I know there are other threads about the ctek with zero issues. Seems suspicious if it's related to your problem. Did you check all the wiring and ground under the hood for tightness?

I don't have one yet and no issues. I just don't want to buy it and have problems, seems like some people are

[Fat Goose]

Originally Posted by M3orbust

I don't have one yet and no issues. I just don't want to buy it and have problems, seems like some people are

Better replace that crankhub as well