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dmwahl

Member
Mar 12, 2021
67
39
Verona, WI
That seems a heck of a lot easier than running a lead all the way to the front. Is there any good reason not to take this approach?

Some people don't like splicing into an existing wire. Personally my reasoning for tapping into the liftgate power wire was that it's already there, fused (30A), and routed safely. Running another wire, especially exposed to the outside, seems at risk of getting torn off/damaged by debris or chewed on by a curious 4 legged friend. The tekonsha module is only rated up to 4A or something, so there's plenty of capacity for it. I used a quick splice sized for 14awg (2.0mm^2) and then wrapped with electrical tape. As long as you use the proper size and keep it far enough away from the connector to avoid tight bends in the wire there's no issue. You can easily find wiring diagrams online for any year/version of the car since they have changed colors a few times. I suspect that even though they change wire colors they don't change the power liftgate module often, so the pin number should be more consistent (that's a guess though not a statement based on any knowledge). I wish I had taken a picture, if I ever have that panel off again I'll be sure to.
 
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Wolfsbane

Member
Aug 29, 2017
48
82
Fleming Island, FL
Some people don't like splicing into an existing wire. Personally my reasoning for tapping into the liftgate power wire was that it's already there, fused (30A), and routed safely. Running another wire, especially exposed to the outside, seems at risk of getting torn off/damaged by debris or chewed on by a curious 4 legged friend. The tekonsha module is only rated up to 4A or something, so there's plenty of capacity for it. I used a quick splice sized for 14awg (2.0mm^2) and then wrapped with electrical tape. As long as you use the proper size and keep it far enough away from the connector to avoid tight bends in the wire there's no issue. You can easily find wiring diagrams online for any year/version of the car since they have changed colors a few times. I suspect that even though they change wire colors they don't change the power liftgate module often, so the pin number should be more consistent (that's a guess though not a statement based on any knowledge). I wish I had taken a picture, if I ever have that panel off again I'll be sure to.
Great feedback and I'm certain I'll follow your lead (no pun intended) whenever a tow bar is released for the refreshed Model X.
 

Jasper7821

Member
Apr 5, 2016
57
18
Tucson
I want to add a hitch to my 2014 P85+, when towing your boat, do you know how many more kilowatts it took to get from point A-B and how far it was.
I know on the level highway it would be much less than taking off at signal lights, just looking for a rough estimate of the increased energy.
 

DayTrippin

Member
Apr 30, 2021
787
804
Park Cities
That would be a difficult question to answer in general. A lot depends on terrain, size of load, how aerodynamic it is, speeds you are running, etc. I can provide input based on my MY LR to put in perspective.

Towing 2 large jetskis, wider than the car itself and taller, my energy consumption goes up by about 20% at 55 mph, about 50% at about 65 mph. Above 65 efficiency plummets like a rock. Despite that, it is still cheaper to tow with than my last gas SUV I used in the exact same way.

Most I could go on a charge at 65 mph, on level roads, was about 160 miles and then I had to slow a lot until I found a charger. Planned on charging sooner but the one I stopped at was totally full so I went on a bit. I found I could drive about 70 mph on the highway, recharge ever 120 miles and do pretty well.
 

Jasper7821

Member
Apr 5, 2016
57
18
Tucson
That would be a difficult question to answer in general. A lot depends on terrain, size of load, how aerodynamic it is, speeds you are running, etc. I can provide input based on my MY LR to put in perspective.

Towing 2 large jetskis, wider than the car itself and taller, my energy consumption goes up by about 20% at 55 mph, about 50% at about 65 mph. Above 65 efficiency plummets like a rock. Despite that, it is still cheaper to tow with than my last gas SUV I used in the exact same way.

Most I could go on a charge at 65 mph, on level roads, was about 160 miles and then I had to slow a lot until I found a charger. Planned on charging sooner but the one I stopped at was totally full so I went on a bit. I found I could drive about 70 mph on the highway, recharge ever 120 miles and do pretty well.
That's perfect. Thank you very much. Was just looking for a rough increase percentage.
 

antdun

Member
Mar 8, 2018
75
102
Utah
I want to add a hitch to my 2014 P85+, when towing your boat, do you know how many more kilowatts it took to get from point A-B and how far it was.
I know on the level highway it would be much less than taking off at signal lights, just looking for a rough estimate of the increased energy.
In the bit of testing I've done with my fishing boat it reduces range by about a third, or you could think of it as the other way around that the energy consumption per mile went up about a third.
 

Jasper7821

Member
Apr 5, 2016
57
18
Tucson
In the bit of testing I've done with my fishing boat it reduces range by about a third, or you could think of it as the other way around that the energy consumption per mile went up about a third.
Thank you very much, I really appreciate it. That would roughly put me at 425 watts per mile for a similar size boat.
 

DayTrippin

Member
Apr 30, 2021
787
804
Park Cities
Depends on how the SC is set up. Some I was able to pull alongside and charge (if not full). One I had to decouple the trailer to charge. That was a PITA. Some I've seen it set up so you could more easily pull up with a trailer. Basically the ones that have been around the longest are the least friendly for towing.
 

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