Exchange alternator or DIY

If it's 13V with the headlamps on and the engine off at this time of year then your meters miles out :-)

It was around 12.5v to just under 13v - memory. That is with no lights on or engine running. The car had done an 85 mile trip the evening before and the reading was around 11:00 a.m.

I forget what kind of car you have, but an 80 amp alternator seems like more capacity than your car needs, which might explain the high rate of charge.

Many "sealed" and "low maintenance" batteries do have access covers.

It tried an analogue AVO meter and found it read 0.4 v less than a the digital. The digital was reading 14.85v with engine running and no lights on. The AVO read about 0.4 to 0.4v less, which was around 14.34v. I don't know which is out, or maybe both are.

After an 80 mile trip the battery was warm on the top of the cells - more nearer the positive pole.

Thanks. I'll check properly. The car is a 1.8cc Avensis with the 7AFE engine.

Sounds like it's fine

Yup, that's normal. What's the battery?

Varta, maintenance free. Size? I find out.

There is no easy way to determine which meter is more accurate. If one is a Fluke, I'd trust it more.

It is not unusual for the top of the cells to be a little warm after it has been charged.

I'd bet that your engine displacement is 1.8 liters, not cc.. 80 amps for a

1.8 liter engine does seem like a lot, unless you have a lot of electrical accessories like electric heated seats, rear defogger and heated mirrors, fog lights, entertainment system, etc.

no.

yes.

yes.

no.

yes.

alarm, central locking, ecu, electric sunroof.

The size of the alternator (within reason) doesn't make any difference to the charge rate. That's controlled by the regulator according to the state of the battery. Alternators are large these days to balance the load when running - not to charge the battery faster.

Buy a single zinc carbon cell - AA, etc. Not a Duracell or other long life type. Tescos sell them under their own brand. You might have to buy a pack, though.

They're pretty consistent at 1.7v when new and unused. A fairly cheap and basic check on a meter.

Heated front screen? Air con with aux cooling fan?

=A0 London SW

The replacement alternators for the 2004 Ford Focus 2.0 litre engine is 105 A.

The newer Ford Focus can come with heated seats, mirrors and rear window defogger. The heated seats won't work unless the engine is running (I assume to prevent the battery from discharging). Not sure about the rear window defogger. It also has a stereo, but I doubt that takes that much energy. And don't forget the ubiquitous computers to run the ignition, OBDII, etc.

Jeff

Good point.

When I said that I thought that 80 amps is more than the car needs, it was because I think that the factory spec is somewhere around 60 amps.

[...]

Pah! Puny!

V10 Touareg's have a water cooled alternator rated at 190A continuous,

300A short term. It is driven via a two-speed gearbox to allow full output at low engine speeds.

None of which is of any help to the OP's problem with his Toyota, of course :-)

The heated front screen of the Focus only comes on when the engine is running.

Chris

Not necessarily. For my 2004 Mondeo, there's a selection of 4 different alternators all based on what options it has.

The engine size doesn't make much difference to the electrical load. & I haven't seen a car without a rear demist, interior fan & ICE made in the last two decades.