Jmup Start - Is It Bad For The Car?

[Bix]

I haven't started my car for about 6 to 7 weeks. My car is an E46 330Ci. I called the mechanic yesterday but he somehow didn't turn up. BlackCat then gave me an idea to seek help from AAM by asking if I was a member of the said association. The first AAM crew came over around 20:00 and listened to the sound of the engine and said it's not the battery. They said that it needs to jump start cos it has to do with the engine. They said the name for it but I can't recall it at the time of writing this post. I was advised to call AAM again and ask for a mechanic to jump start the car because they don't have the tools. I did as advised and the mechanic from AAM came and said that it's the battery. He wanted to sell me a low maintenance battery for around RM500. I agreed but I asked if he was entirely sure if it's the battery and nothing else can be done. He then tested with a smaller size battery and it didn't work. He then opened the largest battery he had in his van (which is the one that he wanted to sell to me) and it simply didn't fit in the battery compartment. I then saw the notice (sticker) on my original BMW battery and it explains on the colour of light / indication. Green is if it's good, black says that it needs to be recharged and yellow says that it needs replacement. Mince clearly indicates black.My question is - Is it bad to jump start the car? What are my options to recharge the battery? The AAM mechanic didn't want to take the risk to jump start the car cos it might damage my computer system - Is this true? Does anybody know the market price for an original BMW battery?Thank you in advance for your replies. I really need some advice. Cheers...

 

[jarance]

I don't think it bad to jump start a car. If is not recommend, then BMW would mentioned it in the user manual.

The AAM mechanic do not want to take the risk which is quite normal considering that they don't want to take the responsibilty.

Sometime, if you have not use your car for about 6 weeks, there is a possibilty that the battery is drained to a level where you just cannot crank the engine.

Even when you have stop your car, there is still some electronic devices like alarm system, radio, clock and other accessories that you have installed which will slowly drained the battery over a period of six weeks. Some people tends to disconnect the battery terminal in order to perserve the battery power when they know that they will leave the car idle for a long time.

Coming to your question about the risk of jump start a car. I think there is minimum risk as most of the car nowadays are using alternator which basically will prevent overvoltage. Overvoltage can only happen if you jump start from a car which have a faulty alternator/voltage regualtor or you jump start from a lorry which used 24VDC i.e 2 X 12 VDC.

Do not replace your battery with any battery size. The user manual will tell you the correct AH (Amp Hour) rating to use. Using a too low AH battery will not give you enough reserve power to crank the engine and using a too high AH battery will put addition load on your alternator.

 

[astroboy]

If its a manual car, then can push start...

There's a jump start terminal built into your engine compartment.. look for the RED color plastic cap that has a "+" logo. That's your positive jump start terminal. For negative, normally JDM cars will ask u to clamp the engine hoist bracket near the spark plugs.. for my E90, there's a dedicated -ve behind the driver's side headlight.

If jump start is not recommended, these terminals would not be there..

It takes some knowledge for jump starting a car.. which terminal to clamp first, which is the best ground lead to clamp, should u leave the "donor" car's engine running, during the clamping of terminals, what to pay attention to.. any fault in the procedure can potentially fry your ECU.. or explodes one of the battery!!

Just like taking medicine, take the recommended dosage will be fine... if u empty the entire bottle hoping for a more speedier recovery.... good luck!!

 

[Bix]

I don't think it bad to jump start a car. If is not recommend, then BMW would mentioned it in the user manual.

The AAM mechanic do not want to take the risk which is quite normal considering that they don't want to take the responsibilty.

Sometime, if you have not use your car for about 6 weeks, there is a possibilty that the battery is drained to a level where you just cannot crank the engine.

Even when you have stop your car, there is still some electronic devices like alarm system, radio, clock and other accessories that you have installed which will slowly drained the battery over a period of six weeks. Some people tends to disconnect the battery terminal in order to perserve the battery power when they know that they will leave the car idle for a long time.

Coming to your question about the risk of jump start a car. I think there is minimum risk as most of the car nowadays are using alternator which basically will prevent overvoltage. Overvoltage can only happen if you jump start from a car which have a faulty alternator/voltage regualtor or you jump start from a lorry which used 24VDC i.e 2 X 12 VDC.

Do not replace your battery with any battery size. The user manual will tell you the correct AH (Amp Hour) rating to use. Using a too low AH battery will not give you enough reserve power to crank the engine and using a too high AH battery will put addition load on your alternator.

Thanks a lot Jarance for the explanation. I supposed that the AAM mechanic didn't have much knowledge for BMW and he simply didn't want to take the risk. Following your reply, I have just called my mechanic at German Mechanics and I asked for a better option with no risk and the answer is to disconnect the battery and send it over to the garage to recharge it. He also said the same thing that it's ok jump start the car. However, the best possible way is to recharge it separately.

I didn't know that I was going to be away for such period of time. Even if I did, I still didn't know that it would be best to remove the battery. lol...

Anyway, I appreciate your response. Cheers... :top:

If its a manual car, then can push start...

There's a jump start terminal built into your engine compartment.. look for the RED color plastic cap that has a "+" logo. That's your positive jump start terminal. For negative, normally JDM cars will ask u to clamp the engine hoist bracket near the spark plugs.. for my E90, there's a dedicated -ve behind the driver's side headlight.

If jump start is not recommended, these terminals would not be there..

It takes some knowledge for jump starting a car.. which terminal to clamp first, which is the best ground lead to clamp, should u leave the "donor" car's engine running, during the clamping of terminals, what to pay attention to.. any fault in the procedure can potentially fry your ECU.. or explodes one of the battery!!

Just like taking medicine, take the recommended dosage will be fine... if u empty the entire bottle hoping for a more speedier recovery.... good luck!!

AstroBoy, if it were a manual car, yes, I would like the idea to push it, just like in the movies. Haha... :laugh:

Yes, I agree that it takes some knowledge to jump start the car. Very good metaphor on explaining how to jump start a car with the medicine story. :hahaha:

Thanks mate!

Oh by the way, I'm glad that the battery that the AAM mechanic wanted to sell to me didn't fit my car cos I just found out that an original BMW battery cost around RM500, which is the same price as the one I almost bought from him and a normal low maintenance battery cost around RM300 only. Mate, what a waste would it be for me if it did fit.