When the load on my alternator suddenly increases and decreases, could it cause a damaging surge

electrical-wiring

#1

When the load on my alternator in my car suddenly changes (such as when jumping someone and they crank their engine) could it cause a damaging surge to electronics or computers in my car? It is fairly new, but I assume it has a surge protector.


#2

The battery acts like a large surge protector…If jumping a car with a completely dead battery great care must be taken as high currant flows are possible and electrical system damage is possible…


#3

If the battery is stone dead or near that point what needs to be done is to connect the jumpers and allow the running engine to idle for about 15 minutes before attempting a start.

I realize most people are impatient and don’t do this. You takes your chances…


#4

+1 for both Caddyman and ok4450.


#5

I do not jump someone’s vehicle and I don’t jump mine. If at home I use the battery charger and if not I call a service with a portable charger. The service fee will be a lot less than repair for fried electronics.


#6

I agree with Volvo. With todays cars and a ton of electronics and many computers, it doesn’t pay to take chances. I’ve seen too many ICs destroyed from a static discharge alone.


#7

I don’t recommend jumping or getting jumped. For the reason stated, potential damage to either or both cars’ electrical systems. I’ve done it quite a bit over the years, both jumping and getting jumped, for the most part w/no problem; but the last time I fried an alternator diode jumping a neighbor’s car. That neighbor’s car had a very dead battery apparently. That was the last jump experience for me.

And it isn’t just high currents during the start-up you have to worry about. When both cars are running and connected together, you got two alternators and two voltage regulators connected in parallel. With computerized charging schemes used in newer cars these days there’s a good chance they’ll each be trying to set the charging voltage to something different. Think about it. Connecting 14.5 volts directly to 13.5 volts, that’s a short circuit and there’s surely going to be some electronic components complaining.


#8

I don’t use jumper cables anymore. I bought a jumper box and it always seems to get the job done. You might get away with a few jump starts but if you do it frequently a fried alternator or worse is possible. The electronics of new cars is so sophisticated, and sensitive that jump starting cars is getting too risky and the repairs are expensive if you do have a problem.

I have a real nice set of heavy duty jumper cables, and I haven’t used them in at least 10 years. I am on my second jumper box over those same 10 years and find it a tool I can’t be without.


#9

I no longer “jump” vehicles, including my own, with/from other vehicles. Yes, damage can occur. The best way to jump a modern car is to use your cell phone… to call the “auto club”.


#10

@Mountainbike I have also stopped jumping on modern cars. I have a battery pack which accompanies us on trips and otherwise sits in the garage ready to help friends and neighbors. The Li-Ion ones are so small they fit in the glove box.