# Jump start X250



## namder (Sep 20, 2006)

Is there any truth that jump starting another motorhome with my X250 can damage anything. During a tour last year I had battery probs and a number of people I asked to jump start me refused stating the damage it could do to a modern engine. I did receive a jump start from another X250 and it didn't appear to cause a problem to the donor vehicle. If there could be a problem, what is it and is there any way of avoiding this as it seems churlish to refuse to assist another motorhomer whos battery has let them down. I suppose disconnecting the battery from the donor vehicle prior to connecting to the receiving vehicle could get round any problems.


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## tude (Feb 9, 2008)

*jump start*

i think what they are probaly thinking of is spikeing the ecu.if you jump start any vehicle you should put the lights or heater on full as soon as it starts this stops the alternator throwing a large spark down to the ecu.
tude


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## Stanner (Aug 17, 2006)

namder said:


> I suppose disconnecting the battery from the donor vehicle prior to connecting to the receiving vehicle could get round any problems.


Given modern electrics I think that might actually be worse than leaving it connected. I think if you look in the relevant section of the owners manual it explains what you must and must not do to safely start another vehicle.

It's what the AA imply in their advice.
http://www.theaa.com/motoring_advice/breakdown_advice/using-jumpleads.html


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## namder (Sep 20, 2006)

*Re: jump start*



tude said:


> i think what they are probaly thinking of is spikeing the ecu.if you jump start any vehicle you should put the lights or heater on full as soon as it starts this stops the alternator throwing a large spark down to the ecu.
> tude


Thanks. Would this apply to the donor or receiving venhicle?


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## Paddy7 (Aug 22, 2012)

I have previously been told a similar thing regarding modern cars, that jump starting can cause spikes to blow the electronics in the donor or receiver. The advice i was given, as stated by Tude, was to ensure that the main headlights on the donor vehicle are on full, when using my merc to start another car i made sure that both vehicles had the lights on and the jump start caused no issues.

Paddy.


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## steco1958 (Mar 5, 2009)

*Re: jump start*



namder said:


> tude said:
> 
> 
> > i think what they are probaly thinking of is spikeing the ecu.if you jump start any vehicle you should put the lights or heater on full as soon as it starts this stops the alternator throwing a large spark down to the ecu.
> ...


Namder, Read your vehicles documents, as long as you stick with that detail you should be ok.

Steve


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## namder (Sep 20, 2006)

Stanner said:


> namder said:
> 
> 
> > I suppose disconnecting the battery from the donor vehicle prior to connecting to the receiving vehicle could get round any problems.
> ...


Unfortunately my owners manual only advises on receiving a jump start and I'm interested in the possible damage to my vehicle when assisting another vehicle. The AA advice makes no mention of a possible spike from the alternator damaging the ECU so could I assume that it's an old wives tale. :?


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## namder (Sep 20, 2006)

*Re: jump start*



steco1958 said:


> namder said:
> 
> 
> > tude said:
> ...


My vehicle docs don't give advice on possible damage to either vehicle so as mentioned in my reply to Stanner it's probably an old wives tale.

I'm still not convinced though due to conflicting advice to the contrary.

John


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## Jeannette (Aug 7, 2012)

Yes, its an old wives tale that jumpstarting can damage either vehicle. The alternators in modern cars and vans have voltage regulators built into them that is specifically designed to prevent voltage spikes occurring. The battery is also designed to be a 'sump' for electrical spikes and can handle voltages in excess of twice the rated capacity in spikes.

Most owners handbooks will have a procedure for connecting jump leads. This usually relates to where you put the cables, on my RCZ for example you don't connect the neg to the battery, it has a separate post because you cant get to the neg on the battery.

There is plenty of capacity in the two vehicles systems to be able to absorb any potential spikes, although the likelihood of any occurring is very small indeed.


regards
Steve


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## namder (Sep 20, 2006)

Jeannette said:


> Yes, its an old wives tale that jumpstarting can damage either vehicle. The alternators in modern cars and vans have voltage regulators built into them that is specifically designed to prevent voltage spikes occurring. The battery is also designed to be a 'sump' for electrical spikes and can handle voltages in excess of twice the rated capacity in spikes.
> 
> Most owners handbooks will have a procedure for connecting jump leads. This usually relates to where you put the cables, on my RCZ for example you don't connect the neg to the battery, it has a separate post because you cant get to the neg on the battery.
> 
> ...


Thank you Steve for a positive reply

John


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## steco1958 (Mar 5, 2009)

*Re: jump start*



namder said:


> steco1958 said:
> 
> 
> > namder said:
> ...


I carry a mobile charging unit around with me one similar to THIS.

You can then help yourself and others without the worry of spiking or other such problems.

Steve


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## brynric (Oct 17, 2009)

I have an X250, if its left too long in store I have to jump it from the car, and then on occasions I've had to use it to jump start the car when it's collected at the end of a long tour. The only problem I had was in the early days when my jump leads were too flimsy and they started to melt. I now have heavy duty ones which are fine. 
I do have a battery booster box but it won't start the engine if the battery is too far gone.


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