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Solutions for Auto Frunk 12V Battery Drain

dogchauffeur

New Member
Jan 21, 2021
2
0
Emeryville, CA
Hi everyone - long post but hoping for some guidance on troubleshooting "12v battery needs service" issues I'm experiencing with my auto frunk system.

I'm using the Hansshow kit, I believe it's version 2, in a 2018 Model 3D.

I've done a ton of research both through Google and this forum but haven't found a lot of consistent leads, in particular from folks experiencing this issue when tapping directly to the positive terminal of the 12v per the instructions. Most of what I've seen are people who tried using VCLeft/VCRight, or posts related to other aftermarket accessories that don't require switched power run to under the frunk.

Here's what I've tried so far:
  • First time this happened I took the car to Tesla service and they replaced the battery (out of warranty since the issue was due to power drain from an aftermarket accessory). Brand new battery started throwing the same error again within a couple of weeks.
  • Hansshow support recommended driving around for about a week to clear the error, which is bogus since the error will persist without a tech clearing it or a full power cycle.
  • Power cycling (based on these instructions) cleared the error and will usually keep the error away for a week or more, depending on how much I drive the car. The error comes back if the car stays parked for a few days.
I'm aware that this is likely related to the additional drain from the control unit tapping the 12v directly, but am surprised that more people haven't posted about this especially with increased working from home and having cars sitting idle.

So far, the only other solution I've heard of is to replace the battery with an after-market battery such as the Ohmmu which may be able to better handle the extra drain. I'd love to have a solution that doesn't require me to hard-reset my car every week or two or spend another $500 just to make this work.

What's the likelihood that I have a faulty control unit? Or is there a way to run a wire from the frunk to a switched power source in the car? I love the convenience of the auto frunk but am considering removing the kit entirely, so any other suggestions would be greatly appreciated.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
8,088
8,960
Riverside Co. CA
Welcome to TMC. Your first post got sent to moderators to approve, and I have approved it. Sorry your first visit and post here is such a problem.

the last thread I remember reading on this kit was a user who had a ton of problems with it and getting support from hansshow):

Problem with Hansshow Support

Here is another troubleshooting thread, but I havent read it:
Hansshow Power Frunk Trouble

Good luck, and hope you find a solution
 

tlr1000

Member
Jun 14, 2018
820
588
Vancouver
Buying an Ohmmu seems like a drastic thing to do to resolve the issue and even if the battery replacement solves the problem, you wouldn't know for certain it was the frunk kit. If there any way to disconnect the power to the frunk kit and close the frunk, try that. Then run your car for a couple weeks with no power connected to the control unit to isolate the issue that it is in fact the control unit. If after some time with no power connected to the control unit and you still see the error code then it's back to Tesla. If no error, then for sure it's the control unit. I have the TeslaOffer kit and have never had a battery issue so if it is your control unit maybe it's electronics pull too much current or something in the firmware of the kit. If not too many people have reported this as an issue, maybe you just have a faulty frunk control unit and Hansshow should send you a replacement. For a longshot if you know anyone with the same frunk kit, see if they are willing to swap control units with you to see if the problem follows.
 

KenC

Active Member
Sep 4, 2018
3,462
3,149
Maine
Hi everyone - long post but hoping for some guidance on troubleshooting "12v battery needs service" issues I'm experiencing with my auto frunk system.

I'm using the Hansshow kit, I believe it's version 2, in a 2018 Model 3D.

I've done a ton of research both through Google and this forum but haven't found a lot of consistent leads, in particular from folks experiencing this issue when tapping directly to the positive terminal of the 12v per the instructions. Most of what I've seen are people who tried using VCLeft/VCRight, or posts related to other aftermarket accessories that don't require switched power run to under the frunk.

Here's what I've tried so far:
  • First time this happened I took the car to Tesla service and they replaced the battery (out of warranty since the issue was due to power drain from an aftermarket accessory). Brand new battery started throwing the same error again within a couple of weeks.
  • Hansshow support recommended driving around for about a week to clear the error, which is bogus since the error will persist without a tech clearing it or a full power cycle.
  • Power cycling (based on these instructions) cleared the error and will usually keep the error away for a week or more, depending on how much I drive the car. The error comes back if the car stays parked for a few days.
I'm aware that this is likely related to the additional drain from the control unit tapping the 12v directly, but am surprised that more people haven't posted about this especially with increased working from home and having cars sitting idle.

So far, the only other solution I've heard of is to replace the battery with an after-market battery such as the Ohmmu which may be able to better handle the extra drain. I'd love to have a solution that doesn't require me to hard-reset my car every week or two or spend another $500 just to make this work.

What's the likelihood that I have a faulty control unit? Or is there a way to run a wire from the frunk to a switched power source in the car? I love the convenience of the auto frunk but am considering removing the kit entirely, so any other suggestions would be greatly appreciated.
I'd ask them to send a second control unit for you to test.
 

TKOGUY

Member
Sep 2, 2019
64
14
Corona
I installed a trickle charger to my battery, sometimes the car sets for a month without me driving it. I also have the Power Frunk installed. Never had this problem.
 

dogchauffeur

New Member
Jan 21, 2021
2
0
Emeryville, CA
Thanks everyone for the suggestions! I messaged Hansshow to see if they will send a replacement unit or at least a firmware update. Fingers crossed but I've heard Hansshow support is pretty bad, so not keeping my hopes too high.

I'd be surprised if it wasn't the control unit, since that's the only accessory I have hooked up and the error only started after I installed it. I'll have to see if the frunk latch will engage without power to the control unit given the weaker spring.

Will report back if I have an update!
 

Pcm888usa

Member
Aug 27, 2015
7
2
Irvine, CA
Hi, I am new to this. What is Hansshow? I had 12V battery replaced after 14 months I took delivery. Tesla said it was due to my dash cam and if the battery fails again, they won't cover it. I am baffled by this since I have dash cam installed on my Audi and Odyssey and never had the same problem granted the 12V socket on the M3 is always hot. The the camera is hot all the time. I know Tesla has its own cam but the resolution is not high enough. Is it really that much power use will kill the 12V. I changed the dash cam to motion detection only. Hopefully that will cut down the power usage when the camera is sleeping when parked. Anyone had the similar issue?
 

tlr1000

Member
Jun 14, 2018
820
588
Vancouver
Hi, I am new to this. What is Hansshow? I had 12V battery replaced after 14 months I took delivery. Tesla said it was due to my dash cam and if the battery fails again, they won't cover it. I am baffled by this since I have dash cam installed on my Audi and Odyssey and never had the same problem granted the 12V socket on the M3 is always hot. The the camera is hot all the time. I know Tesla has its own cam but the resolution is not high enough. Is it really that much power use will kill the 12V. I changed the dash cam to motion detection only. Hopefully that will cut down the power usage when the camera is sleeping when parked. Anyone had the similar issue?
Hansshow is a company that makes various Tesla aftermarket accessories and in the case of this thread the reference is to their power frunk kit which may have caused 12v battery errors. So this thread is not so much about battery issues per se but more to do with possible problems with their power frunk control units. If you search the company in this forum you will get an idea of the items they make as well as the overall customer experience provided.
 

Pcm888usa

Member
Aug 27, 2015
7
2
Irvine, CA
Hansshow is a company that makes various Tesla aftermarket accessories and in the case of this thread the reference is to their power frunk kit which may have caused 12v battery errors. So this thread is not so much about battery issues per se but more to do with possible problems with their power frunk control units. If you search the company in this forum you will get an idea of the items they make as well as the overall customer experience provided.
Thank you for the info. It is interesting to know Tesla will void the 12V battery warranty if after market device/s is using the battery, yet, it include a 12 V socket under the armrest. Certainly not a cigarette lighter. It is for ?????
 

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