Welding on a jk
08-06-2017, 04:58 PM
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Welding on a jk
Im planning to do some welding to my jk. When researching the topic for my ford f250 I came across conversion companies that make ambulances, and other conversion types talking about how every module needs to be pulled and without they where super easy to fry even if they were careful.
Most of the information on jeeps I've dug up seemed worded very general. And I want to be reasonably sure I'm not about to fry my jk.
From searching the web, I've heard a recommendation to disconnect the battery. I feel like jeep's parts Dept is on commission and has secretly spread bad information. Considering how well the HVAC system in my wrangler has functioned compared to every other brand car or truck I've owned. I never had a HVAC system go full on Fukushima meltdown smoke and everything till I owned a jeep. I honestly doubt jeep has considered a person welding on a jeep when designing the electronics. I can see how disconnecting the battery can be a important step as microcontrollers are alive 24/7 in the jeep, I'm sure some voltage spikes would echo ripples through the can bus Bricking modules. That's before even considering some microcontrollers if left unprotected are susceptible to high voltage programming. And specific voltage requirements. The internal trace gaps of a uncapped ic are tight tolerances it would not take much of a voltage boost to create a spark gap.
Maybe you own a 4x4 shop, maybe your a welder, maybe you work at a 4x4 shop, maybe you welded once or twice on your own jk. Please share what method you used to protect your jk, experience, and did anything fry.
Most of the information on jeeps I've dug up seemed worded very general. And I want to be reasonably sure I'm not about to fry my jk.
From searching the web, I've heard a recommendation to disconnect the battery. I feel like jeep's parts Dept is on commission and has secretly spread bad information. Considering how well the HVAC system in my wrangler has functioned compared to every other brand car or truck I've owned. I never had a HVAC system go full on Fukushima meltdown smoke and everything till I owned a jeep. I honestly doubt jeep has considered a person welding on a jeep when designing the electronics. I can see how disconnecting the battery can be a important step as microcontrollers are alive 24/7 in the jeep, I'm sure some voltage spikes would echo ripples through the can bus Bricking modules. That's before even considering some microcontrollers if left unprotected are susceptible to high voltage programming. And specific voltage requirements. The internal trace gaps of a uncapped ic are tight tolerances it would not take much of a voltage boost to create a spark gap.
Maybe you own a 4x4 shop, maybe your a welder, maybe you work at a 4x4 shop, maybe you welded once or twice on your own jk. Please share what method you used to protect your jk, experience, and did anything fry.
08-06-2017, 08:06 PM
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Relief
When I first heard about it on jeeps I started to wonder if I was going crazy. I'm sure more welding is being added to a average jk verse a f250. With f250's I've heard of them pulling at least 3 modules out. Luckily on my f250 I was able to figure out a bolt on method for the task.
I know ground clamp close is important. In my mind I debated battery connected or not
On one side I see the battery leveling out the voltage spikes, on the flip side I can see voltage ripples entering the can bus and a microcontroller might interpret those to change or reset some random value essentially leaving a unwanted result or failure of that module
Then with the battery disconnected voltage spikes could more easily exceed the rated trace gaps inside those same microcontrollers frying those same ic's. The trade off is those mcu's wouldn't be on long enough to get to watch the can bus and start changing variables stored on them.
It's a catch 22, maybe jeep did really did design this right and it wasn't just luck. If you welded with the battery connected you had several modules powered on waiting to talk to each other. Wireless control module is one, if that failed it could brick your jeep, requiring a tow to a dealer. Maybe I'm wrong but even if you swapped in a new one, it would need to relearn the keys chip.
Maybe I need to ask if anyone fried a module welding to their jk and what if any prevention steps they tried that didn't work.
I know ground clamp close is important. In my mind I debated battery connected or not
On one side I see the battery leveling out the voltage spikes, on the flip side I can see voltage ripples entering the can bus and a microcontroller might interpret those to change or reset some random value essentially leaving a unwanted result or failure of that module
Then with the battery disconnected voltage spikes could more easily exceed the rated trace gaps inside those same microcontrollers frying those same ic's. The trade off is those mcu's wouldn't be on long enough to get to watch the can bus and start changing variables stored on them.
It's a catch 22, maybe jeep did really did design this right and it wasn't just luck. If you welded with the battery connected you had several modules powered on waiting to talk to each other. Wireless control module is one, if that failed it could brick your jeep, requiring a tow to a dealer. Maybe I'm wrong but even if you swapped in a new one, it would need to relearn the keys chip.
Maybe I need to ask if anyone fried a module welding to their jk and what if any prevention steps they tried that didn't work.
08-07-2017, 01:20 AM
#4
JK Super Freak
2 things happen, voltage differential from high current flow and RFI/EMI.
With high currents during welding you want the ground as close to the arc as you can get it, but often will still get current running a weird path which can cause a voltage to develop between two ground points. Also the arcing itself generates EMI which can induce current flow in conductors. With integrated circuits it doesn't take much to fry them which is why you want to disconnect them if possible and if not then disconnect the pos and neg batt cables.
I've seen it happen welding on frames before at as low as 90-115 amps
With high currents during welding you want the ground as close to the arc as you can get it, but often will still get current running a weird path which can cause a voltage to develop between two ground points. Also the arcing itself generates EMI which can induce current flow in conductors. With integrated circuits it doesn't take much to fry them which is why you want to disconnect them if possible and if not then disconnect the pos and neg batt cables.
I've seen it happen welding on frames before at as low as 90-115 amps