This probably doesn't fit here but not sure where else to ask. I used my 100 hp Kubota tractor to jump a Case skid Steer off a few weeks ago. The skid started and the tractor stayed running everything seemed normal. Several days later I went to use tractor and it wouldn't start. To make a long story short the shop says boosting the skid fried the Engine Side ECU on the tractor. Has anyone seen this issue on equipment? Both were 12v systems.
Nonsense. Especially since it had the good battery, was running, and was jumping the dead unit. Now the ECU might be dead but the jump start is not what caused it. The most it saw was a slight momentary drop from 14 volts to 13 volts or something.
Now if you decided to try and spark the jumper leads together you could have done some damage to the alternator. But no, proper boosting would not have fried an ECM.
Dead batteries seems to be so common anymore that most of the new equipment comes with a stud to hook your leads up to without having to uncover the batteries.
I have seen people do damage by hooking jumpers up backwards.... even for a split second. I use jumper cables at least 50 times a year and have never (that I know of) seen an ecu get blown from jumping.
Have not seen ECU failure but seen a handful of alternators having the magic smoke released with regulator toasted.
Usually caused by the poor alternator trying to charge the fully dead battery. Running at or above its rating for hours to accomplish this.
Or hooking the cable backwards and frying the diodes/rectifier. When you jump start a completely dead battery, run it close to full speed with no other loads to give the alternator lots of air for several minutes.
I kind of use the opposite approach, I figure the fan moves a lot of air no matter what speed and at lower RPM the alternator is putting out a lot less current which is what gets it hot. Or rather it puts out way more when the RPM rises. But I have not tested this theory. The only one I know for sure is to charge the battery before using it again.
Alternator output is not so much relative to speed as the old generators, they will still crank out amps but maybe not enough voltage at lower speed until you get the field a little more active. I will generally raise speed up SOME but not a lot.
I went to the shop today and they are saying it looks more like a lightning strike. The tractor was in the field with a 15' bush hog hooked to it for about a week during this time. I was building fence and there was 2 double H braces within 50-75' of the tractor. Those brace post were driven 52" into the ground. Maybe it struck a post or the bush hog. I know we have trouble with lightning strikes frying our instruments at work even with a good grounding grid. Who knows, going to be costly though. It ended up getting both computers on the tractor.
I was really careful when I boosted the skid. I had to hook to the tractor battery but the skid has studs for jumping as John C said. It really doesn't matter when it comes to cost what caused the issue but I was having a hard time convincing myself boosting something off fried both computers. I never said anything to the shop about my doubts or about lightning striking, figured I would just let them diagnose it. Thier the experts I just think I know stuff
Sometimes they make things up so they don't get stuck for the repair .
Lightning does weird stuff and it doesn't have to hit something to mess it up. A few years back I was running the shop for a construction company and we had put in a computer card system on the gas and diesel pumps to track fuel in the vehicles. The company that installed it was giving me a hard time because it was in for a week and we had not grounded it, so I had one of the bosses drive a ground rod in that morning and we attached the ground wire to it. That afternoon we had a horrendous thunderstorm and the guys were standing in the back door and saw lightning hit the tower for a high tension line running thru the field 300 feet away. About an hour later one of the crews came in for the day and came into my office and asked why is the card system out, and why is there smoke coming out of the box. I went out and opened it up and the main card inside was fried, and the corner where it was hooked to ground was completely gone. We figure the lightning back fed into the box at the ground and cooked it. Boy did I love calling the company that installed it and tell them that we had a very good ground now, even too good. George
Lightning does do crazy stuff. Up until Harvey hit Houston my area had the most rainfall in TX YTD. It just keep raining and storming (we got 26" in 6 weeks). Kinda why I suspected lightning. I definitely believe they would try to avoid a repair that cost them but no reason for the shop to make things up on this one, pretty sure I'm stuck with the bill....no warrenty
Ground rods mean nothing. They can even be counterproductive. Things need to be BONDED. Where everything metal is connected to everything else with heavy copper. If there is concrete or metal in the ground it gets bonded also. This is 100x better ground connection than an 8' rod in some dirt. I maintain and construct radio sites and we get direct hits from lightning right onto sensitive radio antennas, very seldom any damage. But I am constantly harping, NO INDEPENDENT GROUNDS. Everything solidly BONDED to everything else.
This.
My thinking on revving the engine to save the alternator: the battery will take so many amps at a certain voltage. Say the battery is old and not as efficient as new, it will take 20 amps at 14V for 30 minutes. The alternator will produce 20 amps whether the engine is turning 800 or 2,000 RPM, and 2,000 RPM isn't "lugging" the alternator as much. Now if the engine is idling at 600 RPM, or there's two batteries at a low speed, maybe the voltage will only be 13.5, but the amps will probably still be around 15, or 30 instead of 40A for the two batteries. Raise the speed to 1,000RPM and the output is probably 14V (with two old batteries sucking 40A total), raise the speed to 2,000RPM and the batteries are sucking the same 40A because the voltage is still the same, but the alternator isn't as hot, in my estimation.
I am referring to when the thing is jump started, and the battery is 10 or 11 or maybe 12 volts if you are lucky. The alternator will be operating way outside its rating no matter what you do. It is operating at full field so the RPM is the limiting factor. The current will be high and raising RPM will make it higher fast. Once it starts regulating at 14 volts then you are correct but if the battery got ran flat it can take a while to get there.
I've not long had a Mitsubishi canter , 12 v system with two 12v batteries in parallel , running over the vehicle issues with the agent he said if I ever need to jump start it , keep the connected vehicle connected to it for a while to let the volts rise so not to cause damage to any electrical gear with low volts . Seems to me new vehicles have so much electrical gear still on when the key is off quietly draining power unlike my old gear , off meant meant off .
I don't know about the low batteries and lugging the alternator stuff. I do know what I've been told by the people who repair and rebuild alternators that the two things that kill them early are jump starting with the battery leads reversed and slipping drive belts. Apparently the heat from slipping drive belts goes right into the rotor affecting the lubed for life bearings and sometimes the coating on the windings. As a habit I don't just pull the leads off a battery as soon as the machine starts. I let it stay on for a minute or two to make sure I don't get a spark when I disconnect because of a difference in voltage between the jump unit and the unit being jumped.
This is what I was thinking of, at 1042 Rotor Rpm (less than 500 engine RPM) this 60 amp alternator will put out 33Amps. Pretty level output and my guess is that it will heat up the components faster at the low speed. I don't own a heavy duty enough set of jumper cables that I ever have to worry about that, if the jumped battery doesn't contribute enough, just wait another five minutes. Of course with my own stuff I put the charger on it... but you want a jump, no problem, your battery and alternator. I'll see if I have the appropriate DC amp meter to do some tests. I know I can find a few batteries that will do the trick.
The reason this subject was dear to my heart is I was getting ready to leave a job the other day and the service truck would not start. Found less than 9 volts on the battery. Very shallow downhill and about 6' to roll before fence/cliff. I tried bump starting the normally sluggish starting Ford 351W engine in 3' of slow roll in 1st gear and what do you know, it started. I got out of there and checked voltage, still 9V. Drove it about 10 miles like that but did not have enough power to climb a hill any more, thinking electric fuel pump. Found a shady spot and changed out the battery with a new battery I carry for customer sale. Livened up right after that but still no alternator of course. Picked one up on the way in. Took a different truck. Put the old battery on trickle charge but even after half a day it was not real full. Installed new battery, new alternator and fired it up, noted the much higher charging rate at higher RPM so let it idle about half an hour and crossed my fingers that I would not fry the new alternator on my way to the next job, now it has been a couple of days and everything seems to have stabilized fine. Not enough room in my schedule for mechanical breakdowns.
Finally getting the tractor back today. The Engine ECU, Tractor ECU, and the Digital Dash Panel had to be replaced hope that stuff fixed it.
Had lightning strike a 2 year old peterbilt 579 insurance said total bill was just slightly north of 25000 for all the computers and crap it took out
I got the bill Monday. Just shy of $5,000. I was told they had a guy in several years ago that ran into a hot wire used for cattle and it wiped his computers. That stuff sure is nice until it goes haywire.
Hey guys, have any of your tried one of thes enew super capacitor jump starters on heavy equipment? All the relatively cheaper ones are all 12v but i am wondering if hooking these upto one of the dead bateries would do or do wondering if a better way would be to connect 2 seperate 12v supercap starters so one for each battery in a 24v system?
I had the twenty four volt unit for years. They work great and are a lot cheaper that two 12 volt units.
Hi John Thanks for the reply. I’ve been using a Schumacher 12/24 with the built in batteries for over 5 years now. But that’s units had it now cuz one my guys managed to misuse it somehow! So thinking of getting one of the new supercap batteryless ones. Which one do you use because so far I haven’t been able to find any 24v supercap ones on amazon etc. I found a couple on the internet butvprettt pricey around 1000 usd.hence the reason I was considering a couple of 12v units. Schumacher make a 800A 12v unit which is supposedly pretty good.
I had a 24 volt unit that was probably batteries as it was kind of heavy. It cost $500 from the Napa store and it lasted for years. Bounced around in a pickup, never leaked fluid and I've jumped D9 and D10 sized units three or four times a day. I could charge it by plugging it into the cigarette lighter or with the supplied charger in any 110 volt socket. The company I was working for bought two more of them and still use them today and got rid of their roll around jumper carts. I don't know about the capacitor ones yet. I'm guessing that they are pretty light. Still I think it would have to go a long way before it was better than the 24 volt battery units I've been working with for years.