Atego CAN bus failure during electric storm (1 Viewer)

[sallylillian]

On the 15th of September there was a terrific electronic storm at Tavira, Portugal, we were on the Algarve motorhome park there. It took out the site WiFi and a number of electric points. My electric cable had its bollard connector shattered. Not burnt in any way and the house 230 vac and 12 vdc all worked fine. I changed the hook up cable.



2 days later we went to leave and the Atego would not start. It went through its checks, briefly displayed 4 events, dashes for the air tanks and then a warning box about the brakes. The engine would not turnover. The buttons on the steering wheel were inoperable so I could not clear the warning or interrogate the menus. I was eventually taken by breakdown truck to Mercedes Faro. The Atego is 24 vdc. One week later they find 2 fried CAN bus control gateways. They have stated that they must have been damaged in the storm from what they can see. These gateways were hidden well under the dash inside the vehicle. Parts arrive on Tuesday so hopefully we will be on our way.



However I am very concerned as to how the CAN bus was compromised, there is no external evidence of a lightning strike. None of the house systems are damaged that I know of. The only thing I did find was the fuse to the heated windscreen was blown.



Could the electric storm have somehow penetrated the glass and surged through the heating wires and through the ground connection hit the CAN bus? We had the EP jacks down and the slide out. These will be interconnected to the engine, I would have thought, but only through the D+??



I would appreciate any constructive comment, which I appreciate is very difficult without actual hands on examination. Also I would like to understand how I can protect my DC systems in future.



Thank you

 

[Lenny HB]

Flipping heck you are going to be worried now every time there is a storm. As long as there hasn't been a direct lightning strike you would expect vehicle electrics to be able to withstand those conditions.
Have you checked the roof for any damage but even if had been a strike I would expect the electricity to travel around the outer shell and not affect components inside.
If it's transmitted via the cables, ferrite beads with each cable looped through one might help but I would think impossible to do on a vehicle wiring loom. If radiated enclose all devices in a grounded lead box again not practical on a vehicle.
Realistically I can't see what you can do apart from hope it was a one off experience.

 

[sallylillian]

Exactly Lenny. It is the time it takes to fault find, and the 2 parts..... €10,000!! Another story in itself.

The solution was only identified on Thursday at 15:30, subsequent debate revolved entirely around getting the parts, one of which was on extended delivery due to chip shortages. 24th October!! Fortunately as I had engaged with Mercedes 24hr support, (read my post on the RAC linked to this issue) I was afforded special status and on Friday lunchtime they had the parts on the way from Germany. So a big vote for Mercedes, another thing I shall share with the RAC when I get home.

So once the parts had been confirmed en-route it was end of the week and asking what and how was not top of my list. I had been planning a fly home, so I was now relieved. On Monday I will ask for their opinion on routing of the electric charge.

I do not know if the heated windscreen fuse had already blown or was a key indicator to the storms route into the bus. In theory it can happen to any modern motorhome with a CAN bus!!

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[St3v3]

The ehu cable has a connection to the vehicle, so could have been that, or the heated screen. I suspect you've just been unlucky. To go towards preventing it you'd have to fit a surge arrestor on the incoming EHU, and a lightening rod to the top of the truck with a big earth stake!

Quite a big bill though!

 

[funflair]

Hi Michael

I know I am a bit slow but I have only just clocked that your problem was brought on by a lightning strike, I thought it was just a Mercedes issue and I was thinking "that's not good", how can you protect the vehicle and CAN BUS from future similar issues? I doubt if you can to be honest as lightning can take any path it feels like although I am sure it would go for an easy target like something on the roof.

 

[Robert Clark]

Found this article online about RV’s and lightning

What Happens If An RV Gets Struck by Lightning?

Here's how to protect yourself and your RV from a lightning storm.

vehq.com

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[CazPaul]

Well if lightening has struck the van then you have been lucky I think, especially if the insurance is paying the big bill.
Maybe having a quality built Motorhome has limited the potential damage?

 

[martin2603]

Friend of mine ´s IVECO Stralis was struck by lighteygoing through the Dartfofd crossing. Stopped it stone dead.
He did manage to restart it then a trip to the IVECO shop !

 

[tonyidle]

Lightning doesn't have to actually strike anything to cause a massive spike on the incoming mains and that is likely what caused the CANBUS issues. All the van habitation and base vehicle electrics are connected to a common earth and that is the likely source. The best protection is to disconnect from the EHU if you have a warning of a severe thunderstorm nearby. My limited knowledge comes from analysing the effect of lightning on telephone lines. Everyone assumes overhead lines are vulnerable but not once did I experience an overhead line strike: it was always underground cables subject to massive earth currents from nearby ground strikes.

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[tacr2man]

Its possible that the electric screen element acted as a collector for the emp generated by a nearby lightning strike , seeing as how the screen fuse was blown ?

 

[Jamesh]

How about a flag pole some distance from the van with a jumpstart lead bare at both ends taped to it! Wouldn't want to be near it in a strike though!

Cheers James

 

[sallylillian]

Its possible that the electric screen element acted as a collector for the emp generated by a nearby lightning strike , seeing as how the screen fuse was blown ?

That sounds very probable then. I have received some interesting wisdom from a German forum. I quote:-
"for damage to the control units, a strong magnetic field is sufficient even without voltage influence. Often the control units are not finally destroyed but only the software is killed. This does not help you at the end of the day, because the software does not simply be reinstalled, but the control units still have to be replaced. If there has been a lightning strike in the immediate vicinity, the resulting magnetic field can cause this defect."

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[lunarman]

Taran_Las Had a similar experience some time ago at Le Crotoy https://www.motorhomefun.co.uk/forum/threads/le-crotoy.89312/#post-1061870

 

[sallylillian]

Its possible that the electric screen element acted as a collector for the emp generated by a nearby lightning strike , seeing as how the screen fuse was blown ?

As a supplementary I can reduce the risk on the EHU by unplugging, but what about the heated screen. Any ideas?

 

[Taran_Las]

Taran_Las Had a similar experience some time ago at Le Crotoy https://www.motorhomefun.co.uk/forum/threads/le-crotoy.89312/#post-1061870

Thanks for reminding me John.

It was only last month I finished the therapy sessions.

​

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[cmcardle75]

Electromagnetic pulse - Wikipedia

en.wikipedia.org

 

[jongood]

As a supplementary I can reduce the risk on the EHU by unplugging, but what about the heated screen. Any ideas?

Probably a real one off but would an old fashioned static discharger help? like a lightning conductor.

 

[jongood]

Just to add the jacks wouldnt offer such an easy route as the charge would have to get through the oil or seal.

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[DBK]

The blown fuse to the windscreen demister might be a clue to what happened. The fine wires in the glass will act like a winding and could pick up a current from a strong magnetic pulse nearby. The induced current needs to find somewhere to go and it found a way through the earth connection in the EHU.

It's also possible the surge came the other way through the EHU cable. We had a central heating boiler fried a couple of years ago when lightning struck nearby.

The only practical way forward is to learn from the experience. If lightning threatens disconnect the EHU. Your MH standing on rubber tyres is pretty safe proving you don't earth it through an EHU.

A useful lesson though. Something I hadn't though of before.

Commiserations over the cost and inconvenience.

 

[autorouter]

Aircraft electronic control units and systems are subjected to severe electromagnetic pulses, equivalent to a direct lightning strike. They have to survive and continue to function. Typically all the possible input and output wires go through devices that arrest and absorb the shocks, while still allowing normal voltages and currents through. Pilots tend to avoid flying through thunderstorms, but the aircraft will normally survive multiple strikes if they are caught unawares. I'm saying this to point out that the techniques for lightning protection are well-known to electronic engineers.

However this protection, and the testing to ensure it functions, are extra expenses for an automotive manufacturer, so they put in some protection but not comprehensive coverage. The result is that on rare occasions damage can occur.

The description from the German forum in sallylillian's post is true, but not the whole story. What causes the voltage spikes are sudden changes and reversals of extremely strong magnetic fields. These magnetic fields are caused by the rapid increase and decrease of massive electric currents that is what lightning is. A steady magnetic field doesn't cause a problem, it's the rapid increase and decrease in strength that penetrates into structures and causes high voltages.

I wish I could recommend some obvious protection measures, but apart from putting the vehicle inside a garage, unplugging the EHU and retracting any aerials, I can't really help.

 

[Jamesh]

The blown fuse to the windscreen demister might be a clue to what happened. The fine wires in the glass will act like a winding and could pick up a current from a strong magnetic pulse nearby. The induced current needs to find somewhere to go and it found a way through the earth connection in the EHU.

It's also possible the surge came the other way through the EHU cable. We had a central heating boiler fried a couple of years ago when lightning struck nearby.

The only practical way forward is to learn from the experience. If lightning threatens disconnect the EHU. Your MH standing on rubber tyres is pretty safe proving you don't earth it through an EHU.

A useful lesson though. Something I hadn't though of before.

Commiserations over the cost and inconvenience.

Might be worth having an isolator in the demister wiring? Thus an emc will not have the opportunity to frazzle a canbus / emu.

Cheers James

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[tonyidle]

Just to add the jacks wouldnt offer such an easy route as the charge would have to get through the oil or seal.

Lightning that managed to traverse the air gap from cloud to earth (although actually it jumps the other way) will have little difficulty with the few extra mm of an oil seal.

It's impossible to discuss lightning by attempting to use conventional electrical norms. The earth itself, for example, may not be a 'good earth'. Consider a ground strike: imagine then the current dissipated over an area surrounding the strike. As the current dissipates concentric voltage circles can be drawn around the strike: within a metre of the strike there may be a voltage of several million volts between the strike and the circle. Between that and another circle at two metres a lower voltage will exist. Eventually, perhaps after tens of metres, the voltage will have dropped to an acceptable level. Cables in the ground passing through the area will have insufficient insulation to withstand the higher voltages and after insulation breakdown will conduct until they pass an area of increased ground conductivity (or a metallic bearer in a manhole). At this point the still high voltage will again cause the insulation to fail and 'jump' to the conducting object. Now imagine that an electricity supply cable is involved! With consumer devices connected to it. I have handled lengths of telecommunication cable with a single point of entry then 'blisters' every 300mm for tens of metres where earth 'jumps' have occurred. These occurrences are more common where ground conductivity is poor (not much cover over rocky terrain for example).

My point is really that there are few effective steps you can take to guard against lightning damage. The most important step is to isolate the van from the mains. And I cannot think of a second step. Induction into the screen or its wiring is feasible but so is induction into other wiring on the vehicle so little can be done to mitigate against it. Fortunately EMP damage caused by lightning is very rare. Damage to mains connected devices is extremely common.

As an aside lightning conductors aren't put in place to conduct lightning - the current from a strike would explosively melt them. They're there to dissipate the build up of static that precedes a strike thus preventing the strike from occurring at all.

 

[DBK]

Lightning that managed to traverse the air gap from cloud to earth (although actually it jumps the other way) will have little difficulty with the few extra mm of an oil seal.

It's impossible to discuss lightning by attempting to use conventional electrical norms. The earth itself, for example, may not be a 'good earth'. Consider a ground strike: imagine then the current dissipated over an area surrounding the strike. As the current dissipates concentric voltage circles can be drawn around the strike: within a metre of the strike there may be a voltage of several million volts between the strike and the circle. Between that and another circle at two metres a lower voltage will exist. Eventually, perhaps after tens of metres, the voltage will have dropped to an acceptable level. Cables in the ground passing through the area will have insufficient insulation to withstand the higher voltages and after insulation breakdown will conduct until they pass an area of increased ground conductivity (or a metallic bearer in a manhole). At this point the still high voltage will again cause the insulation to fail and 'jump' to the conducting object. Now imagine that an electricity supply cable is involved! With consumer devices connected to it. I have handled lengths of telecommunication cable with a single point of entry then 'blisters' every 300mm for tens of metres where earth 'jumps' have occurred. These occurrences are more common where ground conductivity is poor (not much cover over rocky terrain for example).

My point is really that there are few effective steps you can take to guard against lightning damage. The most important step is to isolate the van from the mains. And I cannot think of a second step. Induction into the screen or its wiring is feasible but so is induction into other wiring on the vehicle so little can be done to mitigate against it. Fortunately EMP damage caused by lightning is very rare. Damage to mains connected devices is extremely common.

As an aside lightning conductors aren't put in place to conduct lightning - the current from a strike would explosively melt them. They're there to dissipate the build up of static that precedes a strike thus preventing the strike from occurring at all.

I agree with you, there really isn't much you can do to prevent lightening damage other than avoid earthing the vehicle. Aircraft can survive direct strikes partly through design but mostly because the current has nowhere to go. Likewise, disconnecting the EHU lead seems a sensible measure when the air is crackling.

This page has an interesting video clip of a lightning strike. It shows the initial flows down from the cloud which create columns of ionized air one of which the main "thunderbolt" exploits.

Why does lightning strike from the ground-up?

The enlightening image below is of a lightning strike slowed down at 10,000 frames per second. It can be seen that the most intense flash produced from the lightening occurs in the direction from...

earthscience.stackexchange.com

 

[sallylillian]

So I need a weather app that specifically warns me of an excessive electric storm; on the case. Thanks for all this discussion and opinion, I am sure it will be an eyeopener for many.

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[funflair]

An eye opener indeed Michael, unplug EHU and lift the jacks and anything else that earths the van is what I take from this.

 

[Lenny HB]

This is what you need Michael, it gives real time lighting maping.

Real Time Lightning Map

See lightning strikes in real time across the planet. Free access to maps of former thunderstorms. By Blitzortung.org and contributors.

www.lightningmaps.org

 

[GWAYGWAY]

The can-bus system has diodes at each end ,if one goes open circuit the whole systems fails. It needs a specialist electrician to chek out the can bus circuit itself.

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[sallylillian]

The can-bus system has diodes at each end ,if one goes open circuit the whole systems fails. It needs a specialist electrician to chek out the can bus circuit itself.

Tell me about it. 2 on mine over 5 days on and off. With Mercedes Xentry and Oscilloscope. Plus online to Mercedes support electrician. Plus finding where Mieir put all the kit.

 

[Catpirate]

Not a MOHO problem but I experienced spike issues at home after a storm. By chance I was testing a spike analyser on my mains, the analyser recorded date /time/amplitude etc of any spikes. My washing machine and computer were affected and after a few emails my electric provider agreed to pay for the damage.

 

[sallylillian]

Interesting, I have written to the site just asking for confirmation of the event as it affected so much of their kit. Just for third party confirmation for the insurers. I have yet to get a reply. I wonder if their installation was suspect and they fear litigation. Not quite the same as electricity suppliers in the UK are legally bound on performance of supply.

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