[yourbrokenamp]

So I recently hardwire my dashcam to my fuse box with a battery discharge prevention device: https://www.amazon.com/Lukas-LK-290-.../dp/B01D11EMZI

I set the device to cut power to the dashcam when the battery falls below 12.4 volts, since I read that should be the cut off voltage to prevent the battery from deep cycling: https://dashcamtalk.com/battery-discharge-prevention/

The problem is that when I view the voltage (unlocking the dash menu:

) after the car has been off for a while, the voltage read out is 12 volts.

This causes the device to cut power from the dashcam (which is exactly what it is suppose to do) because it goes below the 12.4v cut off.

As I understand the battery voltage should not be 12 volts when idle/off because it is new (just replaced it a few days ago).

Might this be the alternator not charing it fully?

I should note that the dashcam stays on for a while after I drive and completely shut the car off. The car starts up fine with no problems. A new fully charge battery should not be draining pass 12.4v in less than a day, right?

[kkasson]

Did you register the new battery? The car might not be charging it all the way if not.

It's also possible that it just needs a few days to recharge....if the battery sat for a while before it was installed, the voltage may have dropped a little. The voltage isn't actually an accurate measure of how much charge is in the battery, but it's a decent indicator of it.

Since it's starting the car fine, and if the battery was registered correctly, then I'd just wait a few more days and see what happens.

[Three_thirty_I]

Nothing wrong with using the hidden menu for this, but remember that the car's electronics are awake and drawing power off the battery. If you have a proper multimeter, set it to DC volts and connect it to the jump points in the engine bay (the red plastic covered point and one of the strut nuts). If the car has stood for longer than 30 min (or 60 min if your car has factory phone connectivity installed) with the doors closed and the key fob out of the ignition, it is supposed to be in full sleep mode and therefore drawing the minimum current. So I would start by taking a base rest voltage reading at this point. You can have someone start the engine while still taking this reading and it really should behave much the same as in the vid above. At worst, it might show ~12v for a few seconds before it starts to climb to ~14.4v.

Since the battery was replaced, are you certain that it was registered so that the IBS charging knows there's a new battery fitted? I would think that regardless, it should be charging above 14v irrespective of that, but I would make sure that this was done, and if not, have it done as soon as possible.

Also, if you have good smart battery charger, you could just give it a good charge in the meantime, and then see how it goes.

[yourbrokenamp]

Originally Posted by kkasson

Did you register the new battery? The car might not be charging it all the way if not.

It's also possible that it just needs a few days to recharge....if the battery sat for a while before it was installed, the voltage may have dropped a little. The voltage isn't actually an accurate measure of how much charge is in the battery, but it's a decent indicator of it.

Since it's starting the car fine, and if the battery was registered correctly, then I'd just wait a few more days and see what happens.

Yes, it should be registered since I took it to a local indy BMW mechanic and he said he coded it.

Also, I should note that I've only driven the car about 6-7 times for about 20 min each time since I got it installed. I was wondering if that would have something to do with it not being ample driving time for it to fully charge.

[Three_thirty_I]

Originally Posted by yourbrokenamp

Yes, it should be registered since I took it to a local indy BMW mechanic and he said he coded it.

Also, I should note that I've only driven the car about 6-7 times for about 20 min each time since I got it installed. I was wondering if that would have something to do with it not being ample driving time for it to fully charge.

I can't think that this would cause a problem, that's more driving than my car sees typically, and I have an intermittent battery drain that I have not yet been able to solve, but it can handle standing a week at a time provided it has a good half hour uninterrupted drive each week, or if I cheat and connect the battery charger of course. My battery is OEM and was newly fitted September last year. Fully charged with my battery charger it shows around 13.3v, slowly drops to below 13v and then gradually settles around 12.5v for days thereafter. From normal driving it typically sits around 12.68v and slowly works its way down to around 12.36v after roughly a week of standing.

[yourbrokenamp]

Originally Posted by Three_thirty_I

I can't think that this would cause a problem, that's more driving than my car sees typically, and I have an intermittent battery drain that I have not yet been able to solve, but it can handle standing a week at a time provided it has a good half hour uninterrupted drive each week, or if I cheat and connect the battery charger of course. My battery is OEM and was newly fitted September last year. Fully charged with my battery charger it shows around 13.3v, slowly drops to below 13v and then gradually settles around 12.5v for days thereafter. From normal driving it typically sits around 12.68v and slowly works its way down to around 12.36v after roughly a week of standing.

Interesting...

the other odd thing is when the car is on and driving the highest I've seen the voltage with the new battery (from the dash menu) is 13.9v. It goes back and forth between 13.7-13.8v generally, which seems low to me. Any idea if this is indicative of an alternator problem?

I will try measuring the voltage with a multimeter this weekend too.

[Meeni]

If the car is off, the battery should read 13.4 or around immediately after you turn off the engine.

The, it will slowly decrease as the battery discharge powering the "sleeping" computers, and you dashcam.

You should take a measurement to see the rate of discharge with and without your cam, and see if the cam is what is draining you battery very quickly, of something else.

Is the new battery acid-lead or is it AGM ? The rate of charge you report is what is appropriate for an acid-lead, but it is low for an AGM. There is a setting in the battery coding software to change the battery type, it should match/