Hot answers tagged

7

The "9/16" marker (at Walmart, at least) is the nominal date of manufacture - the actual date may be a few weeks earlier. It's used for warranty replacements. Walmart batteries are often on a 3+2 warranty - if it fails within the first three years, you get a completely free replacement battery. If it fails in years 4 or 5, you get a pro-rated discount on a ...


7

No, these are not sell-by dates or expiration dates. If batteries expired within a couple of months of manufacture, they'd be useless for their intended purpose. Getting a battery that's been manufactured in the same month you bought it would be unlikely. Batteries are big and heavy, and in many cases are manufactured overseas. A month or two one way or the ...


7

That year of RAV 4 uses the alternator to tighten the belt. It may not be adjusted properly and the belt is slipping. . .


6

This is a bad idea. There's a very good reason why ECU's default to running on the rich side when they are unable to get a valid reading from the O2 sensor and that is because running an engine too lean can cause quite substantial amounts of damage. If you were able to (somehow) simulate the fluctuating readings within the "acceptable" range the ECU ...


6

More than likely the problem is either your serpentine belt is worn out, or the tensioner pulley isn't providing enough tension to keep the belt in place. Belt slippage accounts for the low amount of voltage output. Because it's the easier of the two, I'd suggest replacing the belt first. I'm not sure on your RAV4 whether there is an indicator on your ...


5

OK, so this turned in an unexpected direction - when I loosened the bolts of the starter some water started running out I when I completely removed it I found this: Somehow water got into the starter area and the pinion rusted in the extended position. That of course explains why I couldn't hear or feel the solenoid engaging. I took it in to bench test it ...


4

The work that a battery can do is measured in watt-hours. You observe that a high or low voltage across the terminals somewhats reflect the state of charge of the battery. That is true, but it's not a reliable measurement of anything else. Batteries of different ages, or with different chemistries and internal surface areas will perform differently (and nor ...


4

Best guesses: One or more cells of the battery is low on water or the plate is collapsing. How old is the battery? Near end of lifespan? A battery can read full voltage, but under load will drop voltage. Are you taking the voltage directly off the battery itself or the cable clamps? Drops to voltage off the battery itself would indicate the need to ...


4

I see two possibilities here: The battery is weak The battery terminals are corroded enough to cause voltage-drop issues, so both battery and alternator are fine but the charging system isn't able to provide full voltage to the battery likewise the starter motor isn't getting the expected voltage from the battery Given that the battery and alternator ...


4

This is much simpler than its being made out to be. The easiest way to do this is to get a simple "clamp meter" that reads electrical current, and clamp it around the positive battery cable while all the accessories you need are turned on. You already know the voltage is 12-14v, so you don't need to measure that. The meter will give you a reading, in Amps,...


4

Or will each appliance receive exactly what it asks for? Yes Conversely, if I connected this fuse tap and cigarette lighter instead to a lower amperage, like 10, what would happen if the cigarette lighter asked for 15 amps? It does not ask, it takes, so it would burn the wire supplying the 10 amps, unless it is fuse protected somewhere else. Safest bet is ...


3

Given your driving history, I would guess this isn't a "parasitic draw" problem at all. If you have had the battery continually undercharged for 6 months, it may have lost a lot of capacity. If you measure the voltage immediately after the end of a drive, it should be more like 13.2, and drop to 12.7 within a few minutes as the chemical reactions in the ...


3

I think your battery is okay. You are getting 12.7 volts after driving, which means that it is fully charged. It's the charge after sitting a few days that concerns me, 12.2 volts is generally considered 50% charge, 12.0 is 25% charge, so after a few days your battery is dropping below 50% charge. That's actually fairly normal as modern cars have battery ...


2

Just my thought, but I have a similar issue on my race car trailer, which has a huge inverter which runs lights, an air conditioner, a microwave, a refigerator (frozen burritos and healthy hydration liquids) and the DVD player. (These things are essential when racing a vintage car. Say nothing!) My actual point is, I have a bank of 3 deep-cycle batteries ...


2

I assume you're looking for something like this? The key to this is you're looking for a remote starter which happens to provide a low battery protection option. You must have remote start to do what you're asking, and honestly once that's addressed it really isn't a big stretch to add low-voltage protection.


2

Did more research on this and the consensus seems to be that Tacoma's electronics detect the additional current (of the accessory), and drop the voltage automatically as some sort of safety/precaution mechanism. No alerts/lights/errors as a result of this, though. I ended up using an add-a-circuit fuse tap to tap a switched fuse in the engine's fuse block.


2

Remote start is not a separate starting system. It is an electronic control that triggers the existing system to start the engine. Since your car starts by key without issue, I suspect the problem you are having is not related to the car battery or starter itself. Likely what is happening is the battery in your remote is low or dead causing no signal. ...


2

A frayed wire could definitely be the cause. What is the, "wire to the remote starter" and what is it's function? Starting a car, remotely or otherwise, requires a large wire to provide power from the battery to the starter motor, usually through a relay. If you have a bad connection such as wire that's not large enough, wire that is damaged or frayed, or ...


2

I'd say that 16.8 VDC is a bit too high to call "safe." Now to answer the primary question, obviously it depends on the exact vehicle. Different computers and different wiring designs will result in different characteristics. As an example, if your battery is very dead, then putting a 15 VDC trickle on it will read something like 8-10 VDC. You know it's ...


2

It's much cheaper to fix an O2 sensor issue than the consequences of unsuccessfully trying to spoof it, and you will be unsuccessful. Don't do it. If you run an engine too lean it can cause detonation in cylinders, which is the uneven explosion of the fuel-air mixture. Detonation sends shock waves through your cylinder, piston rings, head gasket, valves, ...


2

The answer is that yes, it can be, to some extent, according to battery university. However, the battery should rest for 24 hours, which may be impractical. Note that most cars have a low continuous current drain on the battery. So, ideally, the battery should be disconnected from the car, meaning you lose your radio stations. The other difficulty is ...


2

Yes, a bad regulator will cause your motorcycle battery to be overcharged. This is a common failure because of the way motorcycle alternators work. Measure the battery voltage while the engine is running. It should be between 12V and maybe 14.8V max. Now rev up the engine and see if the voltage shoots above that. If it gets to 15 Volts or more, it is ...


2

I wouldn't worry too much. You can go a little deeper in checking the system. But you will need a load tester. I wouldn't worry about 0.4v. You could turn on as many loads ad you can. Head lights/hi and low beam, a.c., blower motor, and radio. And check the voltage.


2

To get this off the unanswered question list: There was an intermittent break in the wiring harness near the MAP sensor. I removed the damaged section and lineman-spliced it, and this particular problem disappeared.


2

That is a lot of spark advance. It looks like its sitting at 5-7ish degrees, then pulls up to almost 30 suddenly. Thats way higher than any normal adjustment I've seen. I added my own line onto your graph, and it looks like the voltage drop coincides with the start of the spark advance. Based on this, the fact that the MAP is suddenly blown, and the ...


2

Use a voltmeter across the battery and an ammeter in series (as mentioned a clampmeter - accurate hopefully) and get the values with all the things running you want. Power is then volts * amps ... Better yet is to have a second battery with a split- charge system - caravaners do this and so do vehicles with electric winches... Edit : added based on ...


2

My car is doing the same - and it's because the demands of lights, heater etc plus the effects of the cold are making the regulator charge the battery more. I have put a multimeter on mine and have seen 15.3V - checked the detail 2 winters ago as i had to replace the original battery (which had a date stamp showing it was 10 years old). In the summer the ...


2

So from what I've found, the ECU handles voltage sensing and determines if there is a fail state for the charging system. From what I understand, there are low/high thresholds, and from what I was able to find quickly, they are typical 13.6~15v. If that's the case for your car, you should be within range, but it could be slightly different. From my ...


2

When you follow the wiring diagrams, the alternator is directly connected to the battery (if that connection fails the the alternator can be damaged) and the battery is connected to the vehicle electrical system. The common point is usually the battery positive terminal or the other end of the battery positive cable. Removing the battery still leaves the ...


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