jump starting 24 volt equipment

[Coaldust]

Remember back in the 90’s when there was an abundance of caution regarding ECM’s? We were going to destroy them with our welders and improper jump starting.

Disconnecting Cat J1/J2’s every time we struck an arc. More ECMs got damaged with bent pins and messed up connections than electrocuted by welding.

The OEM’s have very specific instructions for welding prep. I don’t see folks taking any precautionary precautions today except for common sense ground placement.

Have any one of you fellas ever destroyed a ECM?

 

[John C.]

I’ve welded on dozens of machines and never had an issue.

 

[92U 3406]

I always pull the ground or switch off the disconnect before welding. I know many welders that just strike an arc with it all connected and never saw a failure.

Honestly, I've seen only 2 legit failed ECMs. One was due to water intrusion. The other one simply failed. No outside factors like boosting or welding.

 

[Delmer]

I fried an alternator one time, working long way from the alternator, but it was an AC welder.

Anybody else use the little inverter welders for a battery charger? just turn the amps down to whatever you feel like and hook it up, make sure the polarity is correct first.

 

[Coaldust]

Can’t say that I’ve ever witnessed an ECM damaged from welding or jump starting, either.

I think ECM’s are most fragile during the programing process when something happens to stop the process, like battery voltage dropping below limits or a door on a light vehicle being opened ( turning on a BCM). Then, you end up with a brick that you can’t do anything with.

 

[Tugger2]

All this talk of jumpstarting and such reminded me of what we had at the shop. Not sure if it was accurate but it was always referred to as "The Airplane Starter". This was basically a huge battery charger, think of a 3 foot cube on wheels that on anything other than a flat smooth surface took two men and a boy to move more than few feet. It plugged in to a 440 outlet and as I recall put out 32 volts. Hook that up to a dead 24 volt machine in freezing temps and it would crank over like the middle of the summer after a short lunch break!

I have a feeling it would not be good to connect it to any of these computer controlled machines as I bet it probably did not put out pure DC voltage. It also had at least 200 feet of cord on the input side which might have been one of the reasons if you touched the handle while power was on you would feel a little tingling! Not 100% sure but think it ran off 3 phase and only had a three conductor cord. A few years before I retired company had MSHA inspectors who said it was not to be used unless we converted to 4 conductor grounded cable and that included rewiring all the outlets it was used on, so it got put back in the corner of shop with a "DO NOT USE" tag on it!

Ive seen those rigs ,i think Hobart made some of them and they looked like a welder.
Id be interested to know what the open circuit voltage is on an Sam400 Lincoln running at at idle? Hooked to 24 v for a coupe of minutes and everything turns over fine. However i had more starting problems today so it will interesting to see if the alternator is working or not after a few welder starts.

 

[Bluox]

Ive seen those rigs ,i think Hobart made some of them and they looked like a welder.
Id be interested to know what the open circuit voltage is on an Sam400 Lincoln running at at idle? Hooked to 24 v for a coupe of minutes and everything turns over fine. However i had more starting problems today so it will interesting to see if the alternator is working or not after a few welder starts.

Are the sam machines a CV machine ? A volt meter would answer that question.
Bob

 

[terex herder]

A sam400 is a CV/CC switchable machine.

 

[Tugger2]

Good point.Yes they have both cc and cv . We had been stick welding so it was set on CC

 

[Bluox]

Good point.Yes they have both cc and cv . We had been stick welding so it was set on CC

You can use your welder to charge 24 volts just don't hook up to the batteries .
A short charge would help start easier and not be as rough on the starter.
Bob

 

[Truck Shop]

Remember back in the 90’s when there was an abundance of caution regarding ECM’s? We were going to destroy them with our welders and improper jump starting.

Disconnecting Cat J1/J2’s every time we struck an arc. More ECMs got damaged with bent pins and messed up connections than electrocuted by welding.

The OEM’s have very specific instructions for welding prep. I don’t see folks taking any precautionary precautions today except for common sense ground placement.

Have any one of you fellas ever destroyed a ECM?

Didn't happen at our shop, one of our trailers was having landing gear supports replaced at a shop this was about 10 years ago. Carrier unit--fried the ECM. So I always disconnect the
ground from battery before welding--always have only takes a few seconds. The shop tried to say the welding didn't cause it-well the unit was just shut off about 2 hrs before with no issues.

 

[JD955SC]

Cat guidelines are to shut off master switch or if none then disconnect battery cable. We weld on thumbs, catwalks every day plus use welding to fix brackets and get broken bolts out never had a problem. If I had to dig out every ECM and unhook it it would take a half day to do that to weld one broken bolt out.

 

[suladas]

Always disconnect battery, I don't know why anyone wouldn't take the few seconds to do so. My dad had a flatdeck put on his truck years ago, go to pick it up won't start fuel pump done, shopped admitted they didn't disconnect batteries. It's was from welding, or the 1 in a billion chance it managed to die at the exact same time. I bet after paying for the tow bill and shop bill fixing it they disconnected batteries from now on.

 

[lantraxco]

Depends on the welder, the one we used had a special low amp setting, we hooked the jumpers up to the battery being careful to observe polarity, then with the dial cranked as low as it would go, fired the welder up, it was single phase 220. As long as you have a battery in circuit it will pull the voltage down, we had to crank her up ten or fifteen turns, as stated until the headlights got good and bright. I'll bet if you check most older battery chargers they have fairly high open circuit voltages, they just built the transformers to put out so many amps with a battery load voltage of 13.5 or whatever, no real regulation. As far as electronics yeah, always remove battery grounds and always connect your welder ground as close as physically possible to the weld. Gotta love guys that ground to the frame and then weld on something where the current has to pass through a bearing or two....

 

[kshansen]

As far as electronics yeah, always remove battery grounds and always connect your welder ground as close as physically possible to the weld. Gotta love guys that ground to the frame and then weld on something where the current has to pass through a bearing or two....

I hadn't read much of this thread since Tuesday and just thought about making the comment on how some guys get lazy and on say a front end loader hook the ground lead to the cutting edge and weld where ever else they need to work! Can't say I ever saw a problem related to welding but then I think most of the guys at the shop were pretty smart about keeping the circuit as short as possible!

 

[JLarson]

I always disconnect batteries on customer equipment, don't need a well it worked before....

You should also be mindful of ground placement as far as bearings/bushings too, we've fixed a few things that other people have nuked the bearings on cause they grounded on the other side of a bearing.

 

[JLarson]

As far as jumping a 24v piece if I'm out in BFE I'll hit one batt at a time with cables from the truck. Usually through I just put a 24 v start/charger in the rig and drive over to the dead machine and run the charger off my engine drive.

If it's a reoccurring no start call without an obvious sign, like hey dumb ass you left all the work lights on again, I'm quickly going to start checking batteries and cleaning connections too.