46

The symptoms all point to a faulty battery, and an incorrect test result for the Autozone battery test. Starting with this: Hitting brakes: Brake lights come on and interior lights dim: a good battery should have no problem driving both the brake lights and interior lights without dimming. The same goes for many of the other tests you've done. If ...


39

From an electrical perspective, it doesn't matter. However, a lead-acid battery that is charging or discharging rapidly will give off hydrogen, which is highly explosive. Since you generally make the ground connection last, there's a good chance that you'll get a spark, which is enough to ignite the hydrogen. So while it's unlikely that you'll have ...


35

I think your guess will be correct. The clamp has probably been over-tightened in the past, has stretched and is no longer giving a good tight connection. The copper will have been added to act as a shim to make a tight connection.


22

Fuses do not need to be replaced unless they have blown, so it's not a regular maintenance thing. In terms of checking them, depending on your vehicle, many only require a visual check to see if the metal is present or missing. If you do have fuses where their status is not obvious, a good multimeter is only a few dollars (probably cheaper than replacing ...


19

The reason I would connect the positive cable first (in a negatively-earthed car) is that while tightening the positive connector with a spanner (wrench), if I were to touch the body of the car with the spanner at the same time, nothing would happen and I would be OK. However if the negative was already connected to the battery and I shorted the positive to ...


19

Your question is difficult to answer without you knowing the inner workings of an alternator. The basics. If you move a magnetic field near a coil of wire the electrons in the wire get excited and electricity will be made. The amount of electricity made depends on the size of the magnetic field and its speed. The bigger the field and the faster it's moving ...


19

Heat and thermal stress, even at engine bay temperatures, is not generally the cause of copper wire failure. There is "hydrogen embrittlement" for copper but that only really comes into play at 400C+ in hydrogen-rich environments, usually during annealing. Also, the 20-30C higher range from your hotter climate is pretty negligible from copper's point of view....


18

Corrosion on the terminals is due to hydrogen gas being released from the acid in the battery. It mixes with other things in the atmosphere under the hood and produces the corrosion you see on the terminals. Generally, if the corrosion is occurring on the negative terminal, your system is probably undercharging. If on the positive side, it is probably ...


18

These are some general guidelines when working with electricity on vehicles: Always remove any jewelry, to include rings, necklaces, watches, etc. If one of these items should come in contact between a hot and ground, it will instantly go hot (if there's enough amperage flow) and will burn into your skin requiring surgery to remove. These are a "no matter ...


18

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 recipient vehicle, there should be no issue.


18

Unless you touch both battery posts, your body isn't completing the circuit from - to + The voltage is not high enough to overcome the resistance of your body (under most circumstances) The most dangerous aspect of automotive batteries is that they give off hydrogen gas. If you create a spark close to the battery, its possible to ignite the gas, causing the ...


17

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 always mean you have the jumpers on backwards. Never trust what the covers on the battery says. Check what the battery says to be sure. If there is no way to see ...


17

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 the smaller car's battery as the one on the right. When you connect jumper cables, you connect the positive terminal on the bigger car to the positive terminal ...


16

Chris makes a very good point regarding the hydrogen given off by the battery. There's also another reason, especially on older cars. Ground straps to the engine on most cars are notorious for corroding, so by hooking up the negative terminal to the engine you'll increase your chance of getting the maximum current flow when you're trying to crank the engine.


16

No, you don't have to rely on wire colors to figure out what's what. With nothing more than a decent multimeter and premix flame (blowtorch or gas stove), a two-test sequence can reveal the identity of each wire, assuming the O2 sensor is fully-functional: Determine the heater wires This should be done first. These wires serve to heat up the O2 sensor to ...


16

Yes, the others face it as well. It depends on the pants and shoes you wear, as well as the material of your seats - static charge builds up between the different fabrics when you stand up because of the triboelectric effect. When you first touch a large metal body (such as the car frame), it immediately discharges, giving you the unpleasant sensation. ...


16

It's one of the Heated Windscreen connectors. They have a reputation for breaking off on the Ford Focus, because the wipers hit them if they're not routed correctly. It's common for replacement glass companies to not notice that the car has a heated screen, so don't spend any money fixing it until you've confirmed that it still has a heated screen. This ...


15

The biggest thing to look at for me is the gauge of the wire. The reason I bring this up is, the higher the gauge (numerically) the thinner the wire. Thinner wire will require your jump-start procedure to take more time, as it takes a while to charge the battery before you'll have enough juice to get it running. Thinner wire cannot pass enough amperage to ...


15

When disconnecting a clamp from a car battery, there is a danger of creating a short circuit with the tools that are in contact with the battery terminal. So a tool in contact with the positive terminal can cause a short circuit if it touches any piece of grounded metal. Starting with the negative terminal removes this danger; now you only need to ensure ...


15

Sure you could put a bigger battery in .What may happen is that the total proposed draw is too much for the dynamo and it will go flat.Even if it does not go flat because your appliance usage patterns are intermittent you will get a lower battery life because of the constant cycling .If dealing with the charging system is too hard or too expensive then ...


15

This engine is equipped with a voltage regulator. Depending on the exact construction of the regulator a reverse current would be disastrous, especially the high current from a starter battery


15

All symptoms point to a dead battery, but as you have already attempted to rule that out, the next thing I'd check would be bad connections or cables. Turn on the headlights or something else that consumes a fair amount of power - this makes the results of these tests clearer. If the battery is fine, the voltage at battery terminals should stay close to 12 ...


14

You should be able to sneak a clamp on to the positive terminal, and there's an auxiliary negative (ground) terminal lug nut to clamp onto right in front of the coolant fill tube and power steering fluid reservoir. Otherwise if you really want more room, you need to remove the intake tube (nothing to do with exhaust) by disconnecting it at the rubber ...


14

Most modern diesel engines (ie: engines after mid-80s) require some electricity to run because they are electronically controlled. This is due to computers controlling the fuel charge and monitoring of the engine itself. Without this, the diesel engine has no control. They also require electricity to power the primary fuel pump, to move the fuel from the ...


14

Yes, as everyone is stating, a spark igniting hydrogen gas could cause an explosion, causing injury from small parts, sulfuric acid or both. Very nasty. Hydrogen gas is a byproduct of electrical energy created from a chemical reaction of lead plates submerged into the acid and water. Sparks can happen internally, too. Like when the lead plates warp from ...


14

Yes its possible to start a car with Ultra capacitors. These caps don't appear to have a cycle life that the traditional lead acid batteries have. The ability of these caps to provide starting current is very good. There are a couple of snags: The caps at present are more pricey than the best lead acid batteries. The caps are strung in series to get the ...


14

You don't need to solder them, clean the terminals really well and apply some dielctric grease or buy some battery terminal protector, this is a spray that you can spray on the terminals and this will keep the battery form corroding. I personally use heavy duty bearing grease to apply over and around the terminals, this helps really well keeping the ...


14

The purpose of the fuse is to limit the current in the wire to prevent it from overheating. That could cause the insulation to melt or even start a fire. The other components in the circuit will (should) also selected to handle the same load. So, for example, the accessory outlet should also be able to handle a 20A load. The bottom line is that nothing in ...


13

If the battery dies whilst driving, but you can jump it off another car, you want to look at the alternator first (possibly followed by the battery, the wiring and any large loads, because either your battery is not charging or something is draining it faster than the alternator can charge it) An alternator should give somewhere over 13 volts (often 14.5) ...


13

Yes it can be easily done, but based on your scenario it's not necessary unless you want to sit for extended periods without running the engine. If you are going to leave the vehicle running for Air Conditioning for instance then you don't need to do anything it should work fine as equipped from the factory. Here are some things to consider If you still ...


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