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drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
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Hi folks, I don’t know about the rest of you, but I have never come across any vehicle electronics that have been damaged by voltage spikes, even when the vehicle’s regulator is stuffed and the voltage runs riot.
All electronics in vehicles have spike protection built-in and to further this point, I have never come across a vehicle that has spike suppression built in to either the starter motor or the starter motor solenoid ( haven’t had a look at my D3 yet ) and there few things that can cause huge spikes like that when the starter solenoid is de-energized ( turned off ).
Just make sure you don’t drop the positive lead when connecting jumper leads to another vehicle.
Cheers 2008 TDV8 RR Lux + 2009 D4 2.7
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 21st Jul 2006 3:04 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
  
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Well.... I agree about the starter solenoid switching spikes but i've personally changed a fair few ECU's, mainly Bosch units on Merc's and BMW's that have suffered meltdown, the only common factor was having previously suffered flat batteries - some, but not all, could be attributed to incorrect polarity but other systems were OK and no blown fuselinks to indicate as such
Charge alternators were OK too - no blown main or aux. diodes and regulators in spec. That said, i've seen more boiled batteries than blown ECU's as a result of 'runaway' charge alternators....
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| 21st Jul 2006 3:20 pm |
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drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
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10forcash, could agree more about problems stemming from both overcharged batteries and polarity reversal problems but neither of these have anything to do with power spikes.
One of the products I make is a range of battery control and power distribution panel for use in motor homes and caravans.
The most common cause of returns ( about 75% ) for repairs is because the panel has suffered a polarity reverse. We have designed the PCBs to have a fail-safe point that blows rather than have the whole device damaged.
We can always tell it’s a polarity reversal situation that has caused the problem by asking the customer “ How is your 240 AC battery charger “ ( we don’t supply those ) and we get the usual answer “ It’s not working either “.
The most common time that this polarity reversal occurs is when people take their motor homes or caravans to a battery dealer to have house batteries checked and / or replaced and the staff doing the work, put the leads on back to front.
The poor customer can never prove who did the damage, so they wear the cost. our panel are simple to repair but the motor home battery charges start at $800, to replace.
Again, just make sure you take care as you hook up jumper leads and you shouldn’t have any problems. 2008 TDV8 RR Lux + 2009 D4 2.7
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| 21st Jul 2006 9:04 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
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There was an instruction issued to Jaguar dealers & recovery agents in the Mid 90's relating to boost / jump starts, apparently the voltage regulation was 'lazy' and could result in spikes of over 50v for up to 200ms, the instruction was issued, not for the protection of the vehicles (although a few refused to keep running after a jump start) but for the protection of the operatives involved.... apparently one chap with a pacemaker was hospitalised after holding the jump leads on!
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| 21st Jul 2006 9:57 pm |
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lee01277
Member Since: 06 May 2005
Location: Shed
Posts: 821
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Jamo wrote:I flattened my battery sufficently so that the car wouldn't start, by leaving the coolerbox on for two days.
I started the car using a portable battery pack (regulated). The 400km drive home was sufficient to completely recharge the battery.
not switched off my cooler box in over 12 months ???? seems to sort its self out ok.. ..............Somewhere in-between my old D3 and what's to come next .........
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| 22nd Jul 2006 3:18 pm |
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THUB
Member Since: 10 Dec 2005
Location: West Berkshire.
Posts: 717
 
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In the last three months I have had two experiences of flat battery. In April I left the ignition switched on the night before driving to Gatwick. LR assistance on the spot in 20 minutes. A rather clever piece of kit did the job. Looked like a samll but very heavy battery with two large metal prongs or spikes. Stuck them straight on the the "flat" battery terminals key turned and the D3 fired up,
Much more weird was the situation in Germany about 6 weeks ago whilst on a caravan rally. 20 vans on the rally and about 6 or 7 radio hams with their caravans at the other end of the field. Had not used the car for three days. Tried to start up, battery absolutely flat, all info lost. The chap next but one to me had the same problem with his 2004 Rangie. Both started with conventional jump leads. By the way where is the special earth point that is mentioned in the hand book. If it is the shiny silver bracket just by the battery well it does not work. Well not on my D3 any way. Further enquires seem to sugest that some sort of transmitters can cause problems to modern cars. But on the 2 Land Rover vehicles were involved. Everyone else fired up first time. Does anyone have any theories on this? The guy with the Rangie had the problem last year and even had the situation where something (someone?) kept switching on the radio although the car was locked and the key in his pocket!!
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| 22nd Jul 2006 3:40 pm |
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PSC
Member Since: 01 May 2006
Location: Johannesburg
Posts: 255
 
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drivesafe wrote:I have never come across a vehicle that has spike suppression built in to either the starter motor or the starter motor solenoid ( haven’t had a look at my D3 yet ) and there few things that can cause huge spikes like that when the starter solenoid is de-energized ( turned off ).
That would be back EMF from those devices which will only reach the power supply via arcing in the contacts (we are opening the circuit), in addition it will be of an opposite polarity to that applied and is typically sunk by the battery (that which does make it back via the opening contact).
-- Paul
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| 22nd Jul 2006 4:16 pm |
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drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
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Hi PCS, the very thing that happens to any negative or positive spike. The battery acts like a large suppression capacitor.
Although not really relevant these days but it is the same principle that operated when the old point contacts opened and again even though the electronics were no where as sophisticated, they still didn’t get destroyed.
Whether it be a negative or positive spike, the end result would be a much large supply voltage, in other words, during a spike event, theoretically, the vehicle voltage goes from 12 volts to 50 plus volts and if there was no suppression built into ever electronic device in the vehicle, then everything would be damaged.
Now in all fairness to vehicle designers, this is an over simplification of what goes on but between the vehicles battery and the suppression built into all electronics, it is extremely rare that damage is caused by voltage spikes or surges.
While on the point of surge protection, the sale of so called surge protectors is, in my opinion, nothing more than snake oil because if a spike were to be large enough to circumvent the vehicle’s battery and the suppression already built into electronic devices in the vehicle, it will have little problem doing the same to one of these devices, but that’s just my 2 cents worth. 2008 TDV8 RR Lux + 2009 D4 2.7
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| 22nd Jul 2006 10:10 pm |
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dylansdad
Member Since: 04 Apr 2006
Location: Solihull
Posts: 745
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as it was explained to me...... if the battery has enough power to light the dash lights, turn the starter but not start the d3 then chances are the ECU will be ok with jump leads, however the absolute no no is if the battry is totally dead it is at this point the battery provides n protection of powerspikes to the ecu. Dont know if this is tru just repeating guidance of the LR recovery guy and dealership. 2004 TDV6 HSE Auto Zambezi Silver
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| 23rd Jul 2006 5:23 pm |
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drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
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Hi dylansdad, over the years I have heard a lot of different reasons given for not jumper starting and I’ve heard how someone heard how someone else had the computer destroyed when this third person jumper started their vehicle, the problem is that I have never spoken to anybody that has actually had THEIR computer screwed when they jump started.
This is not to say it is never going to happen but I think you will find that there are other mitigating circumstances that have contributed to the problem of the flat battery and are probably responsible for the stuffed computer in the first place.
Now as to trying to jump start with a totally flat battery and being likely to screw ecu. Wouldn’t removing the flat battery and replacing it with a fully charge battery have as much chance of doing the same damage and why doesn’t connecting a battery charger to a flat battery cause damage to the ECU.
Furthermore, if you were to jump start, the battery in the other vehicle would act in exactly the same manor as if that battery was in the vehicle with the flat battery, because you are taking power right at the other battery’s terminals.
When ever I have jump started any vehicle, I have always connected the power source to the flat battery and then given the battery time to get some charge in it before trying to start the motor. If you were to connect the jumpers and then try to start the vehicle straight away then MAYBE this might cause some problems or connecting to the vehicle with the ignition still switched on would not be the best way to do it.
The biggest potential problem with jump starting with a totally flat battery is if the jumper leads were connected in revers. In this case, as the battery is totally flat, it will give almost no protection against the reverse polarity and the vehicle would cop the lot.
If one was to believe half the stories put fore ward about the supposed evils of jump starting then everybody would be getting the vehicle towed to the dealers every time they had a flat battery. There are correct ways to jump start a vehicle that will allow you to do so with the minimum chance of doing anything more than just starting the vehicle. 2008 TDV8 RR Lux + 2009 D4 2.7
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| 23rd Jul 2006 10:51 pm |
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Tony
Member Since: 20 Apr 2006
Location: Adelaide Hills
Posts: 183
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The manual contains some very detailed instructions for jump starting, and there are no warnings or even a mention in mine concerning the need to use jumper leads with inbuilt suppression.
And on the subject of Ham radios interfering with the car's electrics, this is very unlikely indeed. My onboard ham and commercial transmitters run the maximum power allowed (100 watts) at a wide range of HF and VHF frequencies - if there was a possibility of trouble being caused, it would have shown up by now.
Some vehicles built years ago had difficulties with remote locking failing when in intense RF fields, but this only occurred when parked very close to something like a TV transmitter, which outputs power levels many thousands of times greater than any civilian mobile transmitter. This is unlikely to happen with modern vehicles.
I wonder why the Urban Legend Factory keeps churning out these tales of Doom and Disaster; it's seldom that you hear a good positive story happening to a mate of a friend of a mate's cousin.  Ex Defender 110 200Tdi owner.
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| 23rd Jul 2006 11:49 pm |
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Mossy
Member Since: 01 Jul 2005
Location: Hollyoaks, UK
Posts: 2682
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Hi Tony, re. the rf and electrics, I run a Yaesu ft-857 100 watts though the car and have not had a single glitch. D3 HSE V8...
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| 23rd Jul 2006 11:55 pm |
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Tony
Member Since: 20 Apr 2006
Location: Adelaide Hills
Posts: 183
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G'day Mossy,
Yes, I would be surprised if there were any problems. We have mostly Icom ham gear and a couple of CODAN commercial units for voice and data. ( I am involved in some wildlife research - in the bush, not round the local pubs  ) Ex Defender 110 200Tdi owner.
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| 24th Jul 2006 12:16 am |
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Mossy
Member Since: 01 Jul 2005
Location: Hollyoaks, UK
Posts: 2682
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Tony wrote:G'day Mossy,
Yes, I would be surprised if there were any problems. We have mostly Icom ham gear and a couple of CODAN commercial units for voice and data. ( I am involved in some wildlife research - in the bush, not round the local pubs )
Mine's a M.A.R.S mod jobby for CB, PMR and Ham - I run through an ATAS 120, which, I have to say is brilliant, although I'd be keen to know how you've mounted the antenna. Mine's run from the rear ladder through the boot using a ptfe linkage, but I get considerable loss, depsite it being well grounded for tuning.
Isn't all Bush wildlife research?  D3 HSE V8...
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| 24th Jul 2006 12:30 am |
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drivesafe
Member Since: 23 Feb 2006
Location: Gold Coast, Australia
Posts: 867
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Hi Tony, it’s not the power of a transmitter but the frequency that causes the problem.
This is one I have had and still have problems with.
I have a set of Sennheiser Wireless Headphones and they play havoc with all sorts of vehicle remote keys.
I had a D2 and not knowing about the headphones, tried for two hour, with both remotes, to get into the Disco, including calling the dealer because the previous dealer had put the wrong security key code in the owners manual.
Arrangements were made by the deal to have a tow truck come and get the Disco, but in the mean time, as I had to now go out, I turned the TV off which after a short delay the headphone transmitter turned off and BINGO, remotes now working.
I still can not lock or unlock my MkIII Range Rover it it is within 30 metres of the headphone transmitter and the range on the D3 is severely effected, so it the range on my daughter’s Mazada.
I have always had the idea of taking an inverter and the headphone transmitter with me to a shopping centre car park and see what sort of mischief I can get up too, but that’s another story.  2008 TDV8 RR Lux + 2009 D4 2.7
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| 24th Jul 2006 12:55 am |
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