[elambo]

Serious question. My last car (Alfa Romeo Giulia QV) was risky when it came to jumping. I'd heard several horror stories of electronics getting fried after an owner attempted to jump another car, and I don't think it was due to incorrect procedures. It was just a frail car in several ways.

So that has me just a little nervous about my car, which is arguably more susceptible to electronics snafus. The other day, someone approached me at a gas station and asked for a jump. I respectfully said that my car is a sort of hybrid (a "mild hybrid" but I didn't want to open that can of worms) and that I don't know if it's safe to jump another car. Then, of course, I felt like a jerk for saying that and not helping out, but the statement was true and my concern was real. If my dashboard got zapped I'd feel like sh!t, but so would the person I was helping, so I passed and decided to do my homework, hence this thread.

[TiMSport]

I can't imagine why not. As for the Alfa, well maybe that can be chalked up to the fact it's an Alfa? Lol.

The question is whether the "other" car has a completely dead or almost dead battery or not. If it does, don't bother. That is the reason I invested in a dedicated jump starter (Hulkman Alpha 85 2000 amp). Impressive what a relatively small electronic brick can do.

BTW, there's a reference to jump starting in the Owner's Manual. Page 365 talks about the battery terminals for jump starting. One thing I realized is the location of the negative(black) terminal is in a weird location, far away from the actual battery itself. There isn't even any description of what it is but it's a dedicated terminal for jumping. The positive(red) terminal is clearly marked though but it's also located a bit outside of the compartment that contains the battery. I've never seen anything like this layout before.

I've attached a couple of photos for reference. As you can see, the negative pole is in an unusual location and I see no marking anywhere, but this is in fact the negative terminal for the battery. The other photo is self-explanatory and you can see the clearly marked red "+" terminal.

NOTE: I just realized you were talking about the M440i, but I don't think there would be a difference with the battery and layout I described. Maybe a fellow M440i owner can chime in.

[HighlandPete]

I see there is a risk with any of our BMW models with advanced power management.

Voltage spikes are my concern. I'm aware of fried electronics, due to jump starts, and some 'jumps' aren't straight forward. I personally won't use my car, explaining there are too many expensive electronics which could be damaged.

[TiMSport]

I agree ultimately. This underscores the advantage of carrying a dedicated electronic jump starter.

[elambo]

Good lord I completely forgot that I have a jump starter in my trunk... Geez, I'm a mess.

Thanks for posting the pics -- I actually looked under my hood after the gas station event and easily spotted that positive terminal (and remember it from the manual, which I'd read long ago), but couldn't find an obvious negative. Now I know where it is. And maybe I'll remember that I have that jump charger somewhere underneath all those shopping bags. It was expensive, too. I loaned my previous one to a neighbor and it came back bulging and non-operational. I guess he left it in the sun?

Anyway, thanks for the info!

[TiMSport]

No problem man. Yeah some of those jump starters can be pricey but the one I got was around $125 or so and well worth it. Packs a nice punch for a fairly small footprint.

[jlapicki]

Originally Posted by TiMSport

I can't imagine why not. As for the Alfa, well maybe that can be chalked up to the fact it's an Alfa? Lol.

The question is whether the "other" car has a completely dead or almost dead battery or not. If it does, don't bother. That is the reason I invested in a dedicated jump starter (Hulkman Alpha 85 2000 amp). Impressive what a relatively small electronic brick can do.

BTW, there's a reference to jump starting in the Owner's Manual. Page 365 talks about the battery terminals for jump starting. One thing I realized is the location of the negative(black) terminal is in a weird location, far away from the actual battery itself. There isn't even any description of what it is but it's a dedicated terminal for jumping. The positive(red) terminal is clearly marked though but it's also located a bit outside of the compartment that contains the battery. I've never seen anything like this layout before.

I've attached a couple of photos for reference. As you can see, the negative pole is in an unusual location and I see no marking anywhere, but this is in fact the negative terminal for the battery. The other photo is self-explanatory and you can see the clearly marked red "+" terminal.

NOTE: I just realized you were talking about the M440i, but I don't think there would be a difference with the battery and layout I described. Maybe a fellow M440i owner can chime in.

I believe that these posts are to jump start your car....not another?

[TiMSport]

Originally Posted by jlapicki

I believe that these posts are to jump start your car....not another?

Hmm. What would the difference be?

[SpeedyATL]

Just be aware that some of those little jump boxes/bricks are only to be used on cars with engines under 4.0L. Not sure the issue, but that's what mine says.

It jumped my 3.8 Genesis and our 3.6 Jeep no problem, bu t I have not tried anything with a larger displacement motor.

[TiMSport]

Originally Posted by SpeedyATL

Just be aware that some of those little jump boxes/bricks are only to be used on cars with engines under 4.0L. Not sure the issue, but that's what mine says.

It jumped my 3.8 Genesis and our 3.6 Jeep no problem, bu t I have not tried anything with a larger displacement motor.

Mine is capable of jumping a 8.5L gas engine or 6L diesel. It also has a quick charge feature which is nice though I may not actually need it since I don't intend to be jump starting cars all the time.

[elambo]

Yes, most jump box sites will list the engine types that their products are capable of jumping. My first jumper (circa 2010) was underpowered for my car and did nothing for the jump. When I started asking other owners of that car they said that these engines required far more amps than typical V8s, and lo and behold the manufacturer had a chart (albeit buried on the site) which explained that. I swapped it out for a more powerful model and bingo!

I'm also curious to know why the charging posts under the BMW's hood wouldn't be ideal for jumps. I didn't think they were unidirectional.

[Seaford]

As an aside, in about 1982 my 1977 Hillman Avenger (older UK readers will know what this was) got a flat battery overnight (as cars were prone to do in cold English weather in those days), chap a couple of doors down offered to jump it from his Cortina…upon connection there was a massive bang with bits of plastic and acid flying everywhere.

Motto of the story = if you are going to jump a car make sure you put the leads on the right way round.

My battery must have been the better of the two as it was his that blew up.