Battery Service in Redwood City: Battery or Alternator
If your car cranks slowly, needs a jump, or the electrics behave oddly, the battery is the first thing to test, and it may not be the battery at all. Five Points Tire diagnoses the battery and charging system, recommends the correct battery for your vehicle if one is needed, and installs it.
Battery service at Five Points Tire, in short
Five Points Tire diagnoses battery and charging faults in Redwood City rather than assuming the battery is the problem, because fitting a new one when the alternator is at fault just flattens it again. We recommend the correct battery for your vehicle, install it properly, and keep you informed through the service.
Almost everyone's first move when a car won't start is to assume the battery.
It's the right guess more often than not. It's also wrong often enough that fitting a battery without testing is how people end up stranded twice in a month.
The battery starts the engine. The alternator recharges the battery and runs everything while the engine is going. If the alternator is the problem, a new battery just gets flattened the same way.
Battery or alternator: reading the symptoms
Testing is the only reliable answer, but the pattern of failure usually points one way before anyone connects anything.
The question to ask is what happens after it starts.
| What happens | Usually points at | How urgent |
|---|---|---|
| Jump starts fine, then dies while driving | Alternator not charging | Urgent |
| Starts and runs fine, dead again next morning | Battery, or a parasitic drain | Soon |
| Cranks slowly, worse on cold mornings | Battery near end of life | Soon |
| Clicks rapidly, won't crank | Very flat battery or a bad connection | Soon |
| Headlights dim at idle, brighten when revved | Charging system output | Soon |
| Dashboard lights flicker while driving | Alternator or a loose belt | Urgent |
If it dies while you're driving, stop suspecting the battery.
Check the terminals before anything else. The powdery build-up around a post adds resistance, and it can produce every symptom of a failing battery on a battery that is completely healthy. It is also the cheapest fix in the car.
Signs you need battery service
- The engine cranks slowly before it starts, especially on cold mornings
- You have needed a jump start recently
- Headlights dim noticeably at idle and brighten when you rev
- The battery or charging warning light is on
- Electrical items behave strangely, or the clock and radio reset
- A clicking noise and no crank when you turn the key
- The battery is more than three or four years old
Telling a battery fault from a charging fault
| What happens | Usually points at | How urgent |
|---|---|---|
| Starts fine after a jump, then dies while driving | The alternator | Urgent |
| Starts and runs fine, dead again next morning | The battery, or a parasitic drain | Soon |
| Cranks slowly, worse on cold mornings | A battery near the end of its life | Soon |
| Clicks but will not crank | Very flat battery, or a bad connection | Soon |
| Headlights dim at idle, brighten when revved | Charging system output | Soon |
| Powdery build-up on the terminals | Corrosion adding resistance | Book it in |
Testing is the only reliable answer. This is the rough guide it usually confirms.
What our team does for battery service
- 01Diagnose the battery fault rather than assuming the battery is the problem
- 02Recommend the correct battery for your vehicle if replacement is needed
- 03Install the battery properly
- 04Look for signs of other problems visible during the work and tell you about them
- 05Keep you informed through the service so you understand what is being done
Why voltage alone doesn't tell you much
A battery can read a healthy 12.6 volts sitting still and still fail the moment you ask it to turn an engine over.
That's because voltage measures potential, not capacity. What matters is whether it can deliver enough current under load, and plenty of failing batteries look fine until they're asked to work.
That's what a proper load test does, and it's why a voltmeter reading from a parts store isn't the whole picture.
Slow cranking is your warning shot
Batteries rarely die without notice. They get gradually lazier over a few weeks first.
That extra half second of cranking on a cold morning is the warning, and it's worth acting on while it's still just an inconvenience.
Cold weather is when a marginal battery finally gives up, because cold reduces the current available at the same time as it thickens the oil and makes the engine harder to turn. Two things working against you at once.
Check the terminals before anything else
Corrosion on the battery terminals can produce every symptom of a dead battery, on a battery that's completely healthy.
That crusty white or blue powder around a post adds electrical resistance. Enough of it and you get slow cranking, dim lights, and a car that won't start.
Cleaning it is the cheapest fix on the entire car, and it's regularly missed. Worth a look before you spend anything.
Also worth ruling out before replacing a battery:
- Loose terminal clamps: You shouldn't be able to twist them by hand.
- A corroded ground strap: The return path matters as much as the positive side.
- A slipping or glazed belt: The alternator can't charge if it isn't being driven properly.
- A parasitic drain: Something staying awake after you lock the car, pulling it down overnight.
- An aftermarket accessory: Dash cams and trackers wired to constant power are common culprits.
Heat kills batteries faster than cold. Cold weather is when a weak battery finally fails, which is why people blame it. Heat is what shortened its life over the preceding summers.
Want it checked? Describe what the car is doing and Five Points Tire will tell you whether it needs battery service or something else. Call 650-365-0280, or send the form and someone calls you back. Request an appointment
How long should a battery last?
Usually three to five years, and the thing that shortens it isn't what most people assume.
Heat is harder on a battery than cold. Cold is simply when a weak one finally fails, which is why everyone blames winter for a battery that was killed by the preceding summers.
Short trips shorten life too. Starting the engine takes a big draw, and a five minute drive doesn't give the alternator time to put it back. Do that repeatedly and the battery lives in a permanently part-charged state, which is what wears it out.
Newer cars need the battery registered
On a lot of modern vehicles you can't simply swap a battery and drive away.
The charging system adapts its output to the battery's age and condition, so it needs to be told a new one has been fitted. Skip that and the car keeps charging as though the battery were four years old, which shortens the life of the new one.
Worth mentioning your year and model when you call so nobody is caught out by it.
Common battery mistakes to avoid
- Fitting a battery without testing the charging system. If the alternator is at fault, the new battery goes flat the same way.
- Trusting a voltage reading. A battery can read fine at rest and still fail under load. The load test is the one that counts.
- Ignoring slow cranking. It's usually a few weeks of warning, and it's much cheaper to act on than a tow.
- Skipping the terminals. Corrosion produces every symptom of a dead battery on a healthy one, and cleaning it is free.
- Assuming cold killed it. Heat did the damage. Cold just found it.
- Not registering a new battery on a modern car. The charging system keeps treating it as an old battery and shortens its life.
The bottom line
The question isn't whether your battery is dead. It's why.
If it dies while you're driving, look at the alternator. If it starts fine and is dead by morning, look at the battery or a drain. If it cranks slowly on cold mornings, you have a few weeks.
And check the terminals first, because it's free.
A battery that keeps going flat is usually a symptom. Where the charging system is suspect, diagnostics finds the drain, a check engine light alongside it changes the picture, and dim headlights are often the first thing anyone notices. Replacing a battery before it strands you belongs on the maintenance schedule.
Five Points Tire tests the battery and the charging system at 2115 El Camino Real before recommending anything, because a battery that keeps dying is often not the battery. Call 650-365-0280.
Battery service questions we get asked
Question not on the list? Ask us directly.
How long does a car battery last?
- Usually three to five years. Heat is harder on a battery than cold, and a pattern of short trips shortens life further because the alternator never fully recharges it. Cold weather is simply when a weak one finally fails.
Is it the battery or the alternator?
- Testing is the only reliable way to tell, and it matters, because fitting a battery when the alternator is at fault just flattens the new one. A rough guide: if it starts fine after a jump and then dies while driving, suspect the alternator. If it starts and runs fine but is dead again next morning, suspect the battery or a drain.
Why does my car click but not start?
- There is usually enough power to operate the starter solenoid, which is the click, but not enough to turn the engine over. That normally points at a very flat or failed battery, though a corroded or loose connection can do the same.
Can a bad battery cause other electrical problems?
- Yes, and it is a common source of confusion. Low or unstable voltage can make electronic modules behave strangely, produce warning lights that have nothing to do with the battery, and reset settings. Testing the battery first is worth doing before chasing anything more complicated.
Does a new battery need to be registered to the car?
- Many newer vehicles do need the battery replacement recorded to the charging system, so it charges the new battery correctly. Worth mentioning your vehicle when you call so we know what is involved. Five Points Tire registers a new battery where the vehicle requires it, because skipping that step shortens the life of the battery you just bought.
Related services
Diagnostics
Modern vehicles record faults across dozens of electronic modules, and a proper diagnosis reads that data and then tests to confirm the cause rather than guessing from the code.
Check Engine Light
A check engine light means the engine management system has stored a fault code, and the code narrows down where to look rather than telling you what to replace.
Headlamp Replacement
A headlight that has failed, or a lens so clouded it is throwing away most of its light, is both a safety problem and something you can be pulled over for.
Preventative Maintenance
Preventative maintenance is servicing components on a schedule so they are replaced while they still work, rather than waiting for the failure and the damage that comes with it.
Roadside Assistance
If your car will not start, has a flat, or will not make it to the shop under its own power, call us and describe what happened before arranging anything else.
Vehicle Tune-Ups
A tune-up replaces the ignition and filter parts that wear out: spark plugs, ignition coils, air and fuel filters, and the PCV valve.