Soliciting Non-AGM Battery Experiences

[GreaseMonkey]

I admire the intellectual curiosity. However, wouldn’t it be safer to play with cheaper toys first? You’re gambling with a $50,000 gadget which also happens to be your means of transportation.

Sponsored

 

[GreaseMonkey]

I've noticed the first part: the 12V battery voltage doesn't drop for a good little bit after locking, so clearly the HVB doesn't disengage right away. Which confuses me because accessory mode does not have the HVB engaged, right? But anyway - the supercap thing - I've heard this before but it makes little sense to me. If the 12V system is fully offline, sure, the supercap can fire the actuator once to unlatch the door. But it can only do that if the access module is alive enough to authorize the entry from a key or phone, right? So presumably there's a rather narrow valley of usefulness where the 12V battery is too weak to fire the actuators, but strong enough to authenticate a key.

Anyway regardless of all of that, if I can open the frunk of a fully dead car to access a jump pack, that basically guarantees success. Even if the jump pack didn't work, that's enough access to fully replace the battery roadside and avoid a tow.

Works only if unlocked. So no authentication required

 

[alexw]

I admire the intellectual curiosity. However, wouldn’t it be safer to play with cheaper toys first? You’re gambling with a $50,000 gadget which also happens to be your means of transportation.

Honestly one of the cheaper gadgets I've hotrodded, and certainly the one with the most documentation and support.

 

[alexw]

Works only if unlocked. So no authentication required

That makes much more sense but then, truly, what is the utility!? Maybe if your car spends most of its sleep time unlocked in your garage, it's useful. But 1/3 of the average car's time asleep is locked in a business parking lot, and I daresay most people have this car set to auto-lock so it spends the other 2/3 of its life locked as well. How often does a battery die in the 60 seconds between when the car turns off and when it gets locked?

 

[GreaseMonkey]

That makes much more sense but then, truly, what is the utility!? Maybe if your car spends most of its sleep time unlocked in your garage, it's useful. But 1/3 of the average car's time asleep is locked in a business parking lot, and I daresay most people have this car set to auto-lock so it spends the other 2/3 of its life locked as well. How often does a battery die in the 60 seconds between when the car turns off and when it gets locked?

It’s a doctored workaround to react to complaints and issues over the past 6 years.

 

[RonTCat]

There is only an AGM charging strategy built into the car. If you can find another battery that is happy enough with that strategy, it will work.

 

[Jimrpa]

I've noticed the first part: the 12V battery voltage doesn't drop for a good little bit after locking, so clearly the HVB doesn't disengage right away. Which confuses me because accessory mode does not have the HVB engaged, right? But anyway - the supercap thing - I've heard this before but it makes little sense to me. If the 12V system is fully offline, sure, the supercap can fire the actuator once to unlatch the door. But it can only do that if the access module is alive enough to authorize the entry from a key or phone, right? So presumably there's a rather narrow valley of usefulness where the 12V battery is too weak to fire the actuators, but strong enough to authenticate a key.

Anyway regardless of all of that, if I can open the frunk of a fully dead car to access a jump pack, that basically guarantees success. Even if the jump pack didn't work, that's enough access to fully replace the battery roadside and avoid a tow.

There was a change made a while back to prevent children trapped in the car. Originally, the HVB was disengaged when the car was powered down and, if 12V was unavailable AND doors were locked, there was no way to open them. Hence, the HVB isn’t actually disconnected for a short period of time (I think 12 minutes).

I believe the idea behind the supercapacitors is that the doors wouldn’t be locked if the 12V was dead, so no authentication would be necessary. I don’t know enough of the design to be able to speak authoritatively. Perhaps @Mach-Lee could offer some insight?

 

[Jimrpa]

That makes much more sense but then, truly, what is the utility!? Maybe if your car spends most of its sleep time unlocked in your garage, it's useful. But 1/3 of the average car's time asleep is locked in a business parking lot, and I daresay most people have this car set to auto-lock so it spends the other 2/3 of its life locked as well. How often does a battery die in the 60 seconds between when the car turns off and when it gets locked?

Remember, under the old design, the doors wouldn’t lock if the 12V system was flat. The idea with the change is that the 12V system is being powered by the HVB for a short period of time, allowing you to open doors (including authentication, if it were required). But, for authentication to be required, you’d have to go far enough away for the auto-lock to engage, then stay away long enough for the HVB to be disengaged. At that point, if you don’t have 12V, you’re using the jumpers. That is a very extreme edge case to worry about. Hence why I always made my snarky comment about a rock whenever any of the Helen Lovejoys would implore me to “think of the children”

 

[NY_Cade69]

Hence why I always made my snarky comment about a rock whenever any of the Helen Lovejoys would implore me to “think of the children”

30 Helens agree!

Sponsored