12v battery problems - again

[tchavei]

I recently installed a bluetooth voltage meter and plan to measure this as well once I won't drive the car for awhile.. would be good to know how long it can last from 12.5v as the dropoff may be steep.

Ah, so silly the recharging is limited to 8 times Please Porsche, make it 50 times or more with an OTA !!

C-tek sense by any chance? ?

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[800v]

C-tek sense by any chance? ?

Ha ha, I saw that But ever since I got a Ctek charger that would overheat I am a bit down on that brand. I got an Ancel BM300 battery meter instead.. just got it so I'll report later how well it works

It has nice graphs though:

(The peaks are me putting the car on, not an automatic recharge)

 

[tchavei]

Ha ha, I saw that But ever since I got a Ctek charger that would overheat I am a bit down on that brand. I got an Ancel BM300 battery meter instead.. just got it so I'll report later how well it works

It has nice graphs though:

(The peaks are me putting the car on, not an automatic recharge)

Wow that looks awesome. I should have researched more before I bought mine I guess. Oh well. I hope it works anyway. Your buffer is 15 days max? Where did you hook it up?

 

[simcity]

Nice table! Where did you get this from? Is this specific to the Taycan or for LiFePo4 In general?

It’s LiFePO4 generic but as the 12v battery in the Taycan is the exact same chemistry it’s applicable.

I’ve lost track of how many of these on bikes I’ve ruined over the years if parasitic drain gets the better of them before you can get a tender on them. They definitely don’t handle parasitic drain anywhere as well as lead-acid as the voltage cliff is so brutal. A real downside I’m afraid.

 

[timc3]

Got a proper number of faults now:

Perhaps I should visit workshop as advised ;-)

 

[tchavei]

At this point, it would be more useful if the car just displayed what's still working.

I suppose that's consequence of the dead battery? Wow. I remember one time my MB going nuts like that. It even rebooted by itself mid drive. Luckily I pulled over, turned off, turned on and everything was OK again. Never happened ever since. This was like 4yrs ago

 

[timc3]

Yeah, turning off and turning back on hasn't helped so far. Going to wait a bit and see if it clears, and if it doesn't I am going to call breakdown out.

 

[800v]

Wow that looks awesome. I should have researched more before I bought mine I guess. Oh well. I hope it works anyway. Your buffer is 15 days max? Where did you hook it up?

Well, I think the C-tek can do this as well in the app, no worries.
The bm300 can supposedly keep 31 days of data -- it's just the app displaying at most 15 days I think. A bad thing is that if the bm300 loses power for even a second it loses all data :-( Not sure how the C-tek fares in this case.

I hooked the bm300 to an always-on fuse so it's hidden in the passenger fusebox compartment. I went a bit overboard and soldered nice MT30 3-wire connectors on the dashcam and bm300, and created a y-splitter so i can easily hookup dashcams etc.

 

[ciaranob]

Well, I think the C-tek can do this as well in the app, no worries.
The bm300 can supposedly keep 31 days of data -- it's just the app displaying at most 15 days I think.

I hooked the bm300 to an always-on fuse so it's hidden in the passenger fusebox compartment. I went a bit overboard and soldered nice MT30 3-wire connectors on the dashcam and bm300, and created a y-splitter so i can easily hookup dashcams etc.

Any chance you could share the fuse location (pic) and advice re hooking up a Ctek sense to the same always on fuse selection (for the electrically challenged !) ?

 

[800v]

It’s LiFePO4 generic but as the 12v battery in the Taycan is the exact same chemistry it’s applicable.

I’ve lost track of how many of these on bikes I’ve ruined over the years if parasitic drain gets the better of them before you can get a tender on them. They definitely don’t handle parasitic drain anywhere as well as lead-acid as the voltage cliff is so brutal. A real downside I’m afraid.

Thanks! I think the Porsche 12V will be ok though as it has a relay preventing it to drain completely -- you just have a "dead" car

 

[tchavei]

Well, I think the C-tek can do this as well in the app, no worries.
The bm300 can supposedly keep 31 days of data -- it's just the app displaying at most 15 days I think.

I hooked the bm300 to an always-on fuse so it's hidden in the passenger fusebox compartment. I went a bit overboard and soldered nice MT30 3-wire connectors on the dashcam and bm300, and created a y-splitter so i can easily hookup dashcams etc.

Are you my long missing brother? ?

That's exactly how I'm planing to do it myself... Woah.

 

[f1eng]

If that table is accurate it means the car should trigger a charge whenever the battery hits 12.9V at rest (8A left)... 8 times before it gives up.

That also means that the voltage sensors in most dashcams (11.5V,12V,12.5V) are all useless. Battery will be long dead before it hits 12.5v

Most dashcams probably assume they will be powered by lead-acid batteries in all cars so probably not suited to a Taycan.

 

[tchavei]

Most dashcams probably assume they will be powered by lead-acid batteries in all cars so probably not suited to a Taycan.

Yeah. Still better then nothing. Gotta catch that old lady bumping into my car early morning and pretending nothing happened. ?

 

[f1eng]

Yeah. Still better then nothing. Gotta catch that old lady bumping into my car early morning and pretending nothing happened. ?

Presumably the reassuringly expensive Porsche dashcam is compatible.

I have never owned a dashcam.

 

[800v]

Any chance you could share the fuse location (pic) and advice re hooking up a Ctek sense to the same always on fuse selection (for the electrically challenged !) ?

Sure, but.. I would not generally recommend this; you don't want to have a short or something so be careful. Use low amp (3A or 5A) fuses for dashcam etc, and use wires that are thick enough and well insulated (I used 20awg for the splitter and 16awg from the fuses; Blackvue dashcam wires are usually 24awg which seems rather thin..).

Anyways, on the passenger side fusebox, the top row is always on, and the bottom is on when the car is "on":

Since those slots are empty these are perfect to tap as those will not connect to any device in the car.

For a Blackvue dashcam, the top row (yellow) is for the yellow wire (always on, main power), and the bottom row (red) (on when car is on) is for the red wire (to trigger parking mode). (and black is ground of course). (and again, I don't generally recommend hardwiring a dashcam as of yet since it is unclear inhowfar that would drain the 12v battery; maybe it is ok if you can set a 48h time limit on parking mode and a 12.5V or higher voltage cutoff. I enjoy this though ).

To connect to a C-Tek or bm300 just connect the yellow (top row, always on) to the "red" connector/wire (+) since we want to see the battery power always (and the black (-) to the ground screw (see below)). (I think this is fine to hardwire as these devices use almost no electricity).

Make sure to use the top slot of the fuse-tap and leave the bottom one empty.
Also, the top of each fuse row is powered, so install the fuse tap with the wire going down, e.g.

Ah, the ground screw: you can remove the side panel on the passenger side from bottom to top with a plastic tool:

and connect the ground wire to the screw there with an M8 hex nut so you don't have to touch the screw that holds the dashboard:

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