Fried my ecm with battery change

[Dorsey]

just sent off my 2015 mx52 to be repaired. never got a warning that any spark while changing battery will fry the module. it will cost around 3000.00, and there is no shielding or fuse to help this not happen. full of hate today

 

[mikester]

Bummer. Are you sure it's the ECM?

 

[RBsingl]

It is uncommon because an ECM does have some protection against voltage spikes but it isn't 100% protection.

This is a good reason why you don't want to jump start a piece of modern equipment that has a defective battery (i.e. open cell) because the equipment battery also serves to limit the maximum voltage spike on the bus. If the old battery has an open cell (or battery with extremely high internal resistance) then the act of disconnecting the jumper cables/battery can cause an extremely high voltage transient.

Changing batteries normally doesn't cause the issue but when you are first making contact with the negative connector, it instantly "charges" the DC voltage bus and if the connection is broken as you continue to put the connector fully on then a high voltage spike will occur with no battery to limit it.

Rodger

 

[GreensvilleJay]

kinda curious as to WHY it 'sparked' and..
so....the 3,000 dollar question...
just HOW does Kubota install the battery at the dealership and NOT fry the ECU ???

 

[RBsingl]

Jay,
It is a pretty rare and random event. Normally the transient created is small and the protective devices built into the electronics protect it but sometimes you roll snake eyes.

The most likely (and somewhat controllable reason) is that once the connection is being made it must be done instantly and surely. Seeing a spark and hesitating often results in multiple transient/spark events which greatly increases the odds of damage.

For the same reason, jump packs that have a connect switch are a bit safer electronics wise. The clamps are securely connected and then the switch is thrown to supply power avoiding the possibility of multiple arc/transient events while trying to make a good connection with the negative clamp.

Rodger

 

[GreensvilleJay]

I've designed/built/installed a lot of 'hot swap' computer/telecom gear and never had any 'computer' fried in 3 decades. Most systems were in 'industrial' environments, some connect to 5-10-15 miles of Bell copper wires. One client 'lost' all their terminals(10-12) due to a nearby lightning strike, I never lost the 22 units I had ,some sitting next to the other guys terminals.
So I KNOW that equipment can be properly designed. Why the Kubota ECU fries ,is inexcuseable.... we have the technology, and it only costs pennies per unit to use. Kubota should cover the cost,it's THEIR fault. Changing a battery...yeesh....

 

[lmichael]

Any possibility wrong polarity by mistake?

 

[GreensvilleJay]

That might not be possible if cables are 'just' the right length and ECU 'should' have reverse polarity protection.....

 

[jyoutz]

I just bought a battery disconnect switch for my MX6000. It installs on the negative terminal. Any recommendations about the installation to avoid this issue?

 

[cthomas]

Yeah, make sure the key is in the off position, therefore the ECM is not getting power.

 

[Vlach7]

"Key in the off position", I'm going to tattoo that somewhere, so I don't forget when my time comes.

 

[JohnDB]

It is uncommon because an ECM does have some protection against voltage spikes but it isn't 100% protection.

This is a good reason why you don't want to jump start a piece of modern equipment that has a defective battery (i.e. open cell) because the equipment battery also serves to limit the maximum voltage spike on the bus. If the old battery has an open cell (or battery with extremely high internal resistance) then the act of disconnecting the jumper cables/battery can cause an extremely high voltage transient.

Changing batteries normally doesn't cause the issue but when you are first making contact with the negative connector, it instantly "charges" the DC voltage bus and if the connection is broken as you continue to put the connector fully on then a high voltage spike will occur with no battery to limit it.

Rodger

Is there some way to tame that spike, like temporarily hooking a resister in parallel with the connection that's going to be broken or made, so the resistor dissipates some of the spike energy?

 

[mikester]

Is there some way to tame that spike, like temporarily hooking a resister in parallel with the connection that's going to be broken or made, so the resistor dissipates some of the spike energy?

As RBsingl said there are some internal protections and frying an ECU doing a battery swap is rare. Taking the keys out of the ignition switch before a swap is always a good idea.

 

[The Evil Twin]

Is this a common thing with K? I can't say I've ever had that happen to any equipment. I hook up a tender every time I put something away. Motorcycles, pleasure vehicles, boats, etc. If it actually needs a charge, then I just hook it up too.

 

[Runs With Scissors]

I've replaced hundreds of automotive batteries over the years and the only problem I have ever had is the damn alarm going off, and scaring the sh!t out of me...

 

[GreensvilleJay]

ain't got no alarm but dang radio loses all MY stations and the time goes to 12:00.......

btw, resistor won't work, you need something like MOVs, transzorbs, NE2s.
One possible is to plug a small 12 volt battery into the 'accessory socket' to feed power to the tractor, then remove big battery, install new one. Have seen that used to keep silly radios alive....

 

[chim]

Could someone explain where a HV spike comes from when a 12V battery is the source voltage?

I'd grasp the concept if there was a coil involved.

 

[Chanceywd]

ain't got no alarm but dang radio loses all MY stations and the time goes to 12:00.......

btw, resistor won't work, you need something like MOVs, transzorbs, NE2s.
One possible is to plug a small 12 volt battery into the 'accessory socket' to feed power to the tractor, then remove big battery, install new one. Have seen that used to keep silly radios alive....

I have done that to keep from having the ecm do a reset/ clear codes.

I always have a heavy glove I put over the positive cable end and secure it with a squeeze clamp until I am ready to put it back on.

Bill

 

[RBsingl]

A common mistake many people make in replacing the battery in current vehicles is a lot of them are an AGM type installed in an enclosed compartment with a vent tube for the battery. The owner transfers the vent tube from the old battery to the new battery but forgets to transfer the plug in the other side of the battery from the old to the new which results in hydrogen venting into the compartment via the path of least resistance.

One of my colleagues had his BMW SUV in for a recall several years ago and the shop had a BMW with a damaged trunk. The tech told him the owner changed his own battery and left the plug out. Under normal conditions an AGM won't vent but under heavy charge or discharge, the catalyst in the top cannot convert the amount of gas produced quickly enough so some vents and the owner apparently managed to create his own mini hydrogen bomb.

The other, humorous to all but the owner, mistake is closing the trunk of a trunk mounted battery while it is out of the car. My Cadillac ATS has this setup and the trunk is electronic release only with no key release. I have the premium trim level so if I made the mistake I could use the fold down rear seat back to get to the trunk and use the emergency release handle but economy level trims don't have folding seats. For those owners, if they screw up it is crawl under the vehicle and temporarily apply 12 volts via the starter solenoid terminal.

Rodger

 

[fried1765]

ain't got no alarm but dang radio loses all MY stations and the time goes to 12:00.......

btw, resistor won't work, you need something like MOVs, transzorbs, NE2s.
One possible is to plug a small 12 volt battery into the 'accessory socket' to feed power to the tractor, then remove big battery, install new one. Have seen that used to keep silly radios alive....

"plug a small 12 battery into accessory socket to feed power"........
That is apparently how it works with my 2014 MB E350.
Loose all 12V supply, means.....tow it to dealer,.... for complete reset.