Have I been doing this wrong years?

[AttheDocktors]

I admit it guys, I am not handy at all when it comes to mechanics - automotive or marine. I decided to read the manual that came with my portable battery charger that I bought for my boat. It stated that you should not connect both the positive and negative clamps to the battery posts. This is how I've always jumped my car's battery. Does this hurt the battery at all? Does it affect the time it takes to fully charge my batteries?

....Have I been wrong for years?

 

[SKEETR]

Re: Have I been doing this wrong years?

It doesn't hurt the battery. I think they say that in the event that alot of hydrogen was produced and someone didn't unplug the charger before disconnecting the clamps at battery. Needless to say you should ALWAYS unplug a charger before making or unmaking connections to a battery.

 

[SKEETR]

Re: Have I been doing this wrong years?

Since yours is portable just make sure it is off before conn/disconn.

 

[brianvolt7]

Re: Have I been doing this wrong years?

Absolutely do not jump a battery like this. I have seen one explode. When jumping with another battery and connecting +to+ and ?to- terminals you effectively double the amperage that the batteries are producing. A basic rule is batteries in series add the volts ( two 12's becom 24), batteries in
parallel are current adding and volts stay the same (tow 12 remain 12). The batteries become one system and the combined amperage travels through both batteries. In other words 600 cold cranking amps become 1200 cranking amps. When you use a reference to ground, like an engine block your are defusing the systems capabilities of combining the amperage. . Because current travels from negative to positive the added resistance of a motor block is enough to stop any accidents from happening.
It is not a myth, you can blow up a battery easily if jumping or charging without using a ground reference instead of the negative term on your battery.

 

[Silvertip]

Re: Have I been doing this wrong years?

Connecting to the engine block doesn't "defuse anything" and if there is any resistance in that connection it needs to be fixed. Connecting the charger away from the battery (using the engine block and the positive lug on the starter solenoid for example, removes the chance of a spark touching off the hydrogen gas since those two points are generally well away from each other. As was mentioned, make the connection before plugging in the charger.

 

[mike64]

Re: Have I been doing this wrong years?

Always a good idea to wear safety glasses when charging/jumping a battery just in case. Waaaay back when I was in high school one of the teachers had a car battery blow up on him. He suffered some burns to his face but fortunately he had glasses on so it could have been worse. Every time I go to charge a battery I think of that and dig out the safety glasses. I'd rather get the nickname "scarface" than "patchy".

 

[joed]

Re: Have I been doing this wrong years?

Absolutely do not jump a battery like this. I have seen one explode. When jumping with another battery and connecting +to+ and ?to- terminals you effectively double the amperage that the batteries are producing. A basic rule is batteries in series add the volts ( two 12's becom 24), batteries in
parallel are current adding and volts stay the same (tow 12 remain 12). The batteries become one system and the combined amperage travels through both batteries. In other words 600 cold cranking amps become 1200 cranking amps. When you use a reference to ground, like an engine block your are defusing the systems capabilities of combining the amperage. . Because current travels from negative to positive the added resistance of a motor block is enough to stop any accidents from happening.
It is not a myth, you can blow up a battery easily if jumping or charging without using a ground reference instead of the negative term on your battery.

A portion of this is incorrect in my opinion. 600 CCA is the available amps not what the battery puts out. Connecting two batteries in parallel gives more available amps but does not supply more amps unless asked for.

When you use a reference to ground, like an engine block your are defusing the systems capabilities of combining the amperage.

Totaly not true. The batteries are still in parallel and draw what ever amps is needed. Could be be dangerous if the cables in between are small. They could burn up.
The battery blows up because of a spark and hydrogen gas. Moving the negative point WHEN CHARGING or JUMP STARTING, moves the possible spark away from the battery and away from the possible hydrogen gas..

 

[bruceb58]

Re: Have I been doing this wrong years?

When you use a reference to ground, like an engine block your are defusing the systems capabilities of combining the amperage.

Completely wrong. Most of this post was just wrong.

The reason you make the last connection to the block is that this is where/when the spark is going to occur as you complete the circuit. It just keeps the spark away from the battery so that it minimizes the chance of ignition of the battery gasses.

 

[brianvolt7]

Re: Have I been doing this wrong years?

I stand corrected; I?m an electrician not a mechanic.

Is there a legal cure for obnoxious?

 

[jlinder]

Re: Have I been doing this wrong years?

The last connection should be the neg. side going to the chassis or block. This is for 2 reasons:

1. As stated, by connecting at the block you are putting any sparks away from the battery and possible explosive fumes.

2. Protection against the clumsy. Consider the condition where you have connected the ground on both ends and the positive on the other good battery side. You now go to connect the last positive and oops, you touch part of the car body. Instant short through the jumper cables and really big sparks.
(It would also mean that your last connection, the one that can cause a spark, would be right at the battery with the possible fumes)

 

[gstanton]

Re: Have I been doing this wrong years?

Lawyers Rule!

 

[fdmsiv]

Re: Have I been doing this wrong years?

Theoretically it doesn't matter if you connect "-" to "-" or connect to the engine block/frame. If you follow the wiring connected to the "-" batt. post you will find a rather large cable that is attached to the frame. Most cars and trucks use the frame as the "return" wiring.

Also, connecting "+" to "+" and so on is connecting in parallel. Connecting "-" to "+" would be connecting in series.

 

[GiMLit]

Re: Have I been doing this wrong years?

Connecting to the engine block doesn't "defuse anything" and if there is any resistance in that connection it needs to be fixed. Connecting the charger away from the battery (using the engine block and the positive lug on the starter solenoid for example, removes the chance of a spark touching off the hydrogen gas since those two points are generally well away from each other. As was mentioned, make the connection before plugging in the charger.

Exactly.
Using the positive post the battery and a ground elsewhere is more than acceptable.
The idea is just to move the possibility of a spark around a battery that is potentially gassing the area and ready to go boom!

 

[bruceb58]

Re: Have I been doing this wrong years?

Lawyers Rule!

Actually...common sense rules...but then again...
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