28 votes

Why is gas around a car battery only at risk of ignition from jumper cables?

This is going to get a bit technical but should still be understandable even if you slept through chemistry classes. When is hydrogen dangerous? Just as with the fuel-air mixture in an engine, ...
  • 2,827
25 votes
Accepted

Can one slightly charge a dead car battery with a portable battery jump kit?

As Miracle Max would say, there's two kinds of dead batteries, and there's a big difference between them. Mostly Dead This is the most common kind of dead battery. Let's say your battery is rated for ...
  • 376
21 votes
Accepted

Why do cars die after removing jumper cables?

It's because of a couple things: The battery is very dead and the alternator cannot put out enough power at idle RPMs to run the whole system and charge a battery. This leads to a lack of power which ...
  • 2,859
20 votes
Accepted

No electrical to the dashboard after attempting jumpstart with Schumacher charger

Turns out I didn't read the instructions right (heh). It says to plug the charger in then set to "jump start" wait a couple minutes till it goes from "On" to "RdY" before cranking. https://www....
18 votes
Accepted

Can I jump start one car with two other cars in parallel?

To answer your question, it will not cause any issues as long as the cables are connected correctly. If both donor cars are connected in parallel (negative to negative/positive to positive) to the ...
17 votes
Accepted

Lots of sparks and heat when jump starting a car

With the description you give, I'd say you connected them backwards with about a 99%+ assurance. Large amounts of sparks followed by heat are both VERY BAD SIGNS (as you soon figured out) and almost ...
17 votes

Can I jump start one car with two other cars in parallel?

When you jump start a car, you are always putting the cars in a parallel circuit. Here's an illustration of parallel vs. series: Source Think of the bigger car's battery as the one on the left and ...
  • 5,225
15 votes

Why should I connect the red/positive terminal first when jump starting?

I don't know the actual justification, but to me it makes sense to always attach positive first because it is easy to accidentally touch the lead to something else while installing. If the negative ...
  • 1,193
15 votes
Accepted

Can I jumpstart a non-hybrid car from a hybrid or full electric car?

There are two power systems on all electric cars (fully electric and hybrids alike). This is in conjunction with the much higher voltage battery packs which normally power the electric motors. The ...
12 votes
Accepted

Portable jumpstart kits: why aren't regular car batteries this small?

The two biggest disadvantage of lead acid batteries compared to the newer types like Li Ion are that they are heavier, and that they contain liquid acid. Another possible issue is that they can ...
  • 1,536
12 votes
Accepted

Can a conventional car be used to charge an electric car?

No, you cannot. Well, you might be able to, but not in a feasible way in any likely manner. Electric Vehicles commonly have two separate electric circuits. One running at the normal 12V, which ties to ...
  • 464
12 votes

Using an Anderson plug to jump start a vehicle

Anderson supplies a whole range of connectors with varying current ratings. Also, current ratings tend to be conservative: these are steady-state ratings. So a 50-amp connector can handle 50 A all ...
  • 4,412
12 votes

Can one slightly charge a dead car battery with a portable battery jump kit?

Those types of chargers are designed to provide short bursts of power to start a car, most do not have a battery charging mode. Once the car is started the alternator will complete charging the ...
  • 15k
11 votes
Accepted

Why should I connect the red/positive terminal first when jump starting?

Conventional lead acid batteries produce hydrogen gas as a byproduct of the charging process. This gas tends to collect in and around the battery. As you are aware making the final connection can ...
  • 19.8k
11 votes

Jumping car with too many amps?

The starter circuit should only draw whatever current it needs so the excess shouldn't cause any problem.
11 votes

2 Volts on Car Battery

Lead sulfate crystals form on the battery plates as the battery discharges. As the battery becomes more discharged the crystals go from being soft and fluffy to much harder. Recharged in time, the ...
11 votes
Accepted

Why is gas around a car battery only at risk of ignition from jumper cables?

I am no expert in this topic, but I don't think a "cloud of gas" forms around the battery. Hydrogen gas is the lightest gas of them all (0.089 g/l) and won't pool up if leaked. It will simply rise as ...
10 votes

Can I jumpstart a non-hybrid car from a hybrid or full electric car?

The other answers failed to emphasize an important point: the 12V battery on hybrid cars is not designed to start an engine, being much smaller than typical automotive starter batteries. Thus, it may ...
  • 13.9k
10 votes
Accepted

Jumping car with too many amps?

Those numbers are the max that they can supply. Your starter will "automatically" use as much as it needs up to the max. If the starter needs more than those units can supply, the jumper will only ...
10 votes
Accepted

2 Volts on Car Battery

Since you have a battery which isn't that old (most batteries have about a five year life span), I'd suggest you put it on a charger and try to recharge it. This will allow the battery to come back to ...
10 votes
Accepted

What is the safest way to jumpstart a car surrounded by snow, ice and water? Can I get electrocuted?

There are no special safety issues related to snow and ice. In general, voltages up to 48V are considered safe for the human body. You can touch both contacts of a 12V battery, even with wet fingers. ...
  • 7,017
9 votes
Accepted

How do I know if a jump starter is suitable for my car?

It sounds like you need a trickle charger or battery maintainer - this is a small charger than monitors the charge on the battery, and keeps it charged. Most modern cars have electronics that have a ...
  • 2,578
9 votes

Jumping car with too many amps?

The amp count tells you the maximum amount of current that the equipment can supply. Eg. Your car needs 600 amps to start: The 1000 amp jumper can handle it. Your car needs 1200 amps: The 1000 amp ...
  • 340
8 votes

Can I jumpstart a non-hybrid car from a hybrid or full electric car?

Lots of good answers, but will clarify something for what it is worth: All hybrid cars do have a 12V and a high voltage system. In my Prius (2009, 2003-2009 model), the 12v battery is in the boot. ...
  • 81
7 votes

When jump-starting a car, won't there be a huge back current into the dead battery?

I think you have an issue with the way you are thinking. You are describing the issue as if the batteries are hooked up in series. In that case, yes there'd be a huge back current going on. Both ...
7 votes

Can hooking up jumper cables incorrectly cause one to have to replace the throttle body?

There's a joke in electronic engineering about transistors being invented to protect fuses. Basically, it means that transistors blow faster, and so a fuse is practically worthless for that purpose. ...
  • 492
7 votes

Can a lithium-ion battery really start a truck?

I also doubt the numbers they claim on the package but the real question is ... can you start a truck with it? Yes you can! What you seem to forget is that the car or truck you connect this battery ...
  • 171
7 votes
Accepted

Can a lithium-ion battery really start a truck?

Yes, Lithium Ion batteries are capable of delivering the power required to turn over an engine. The thing I am most experienced with is the kind of batteries you put in remote controlled devices, so I ...
  • 282
6 votes

Does a jump starter with lower amperage than your car battery work?

The cranking amps required to start an engine are not the same as the cranking amp rating of a battery. I don't know the amps required to start your car's engine, but if it is less than 400 amps, then ...
  • 1,193
6 votes

Portable jumpstart kits: why aren't regular car batteries this small?

I have seen "jump starters" like this everywhere. I was given one to evaluate by an Autoelectric importer. I thought it was rubbish. I warned him and he didn't import them. How they work is by using ...
  • 2,053

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