12v battery

[Waspie]

Hi guys. I have a 2010 Vellfire eith a 60ah battery. It looks like the battery is not taking a full charge. It stays at a charging voltage of 14.4 volts no matter how long the car is driven. I've checked the alternator ac volttage which is well below the voltage to indicate a faulty diode.

 

My question is, if I change the battery to one recommended on this forum eg Bosch 70ah, does the car ecu need to be reprogrammed for the new battery. Advice would be much appreciated.

[BigNev]

Hi there!

Just to put a bit extra thought to the equation - are you driving with the headlamps on? And other electrical load items? 

Obviously the fuel system is a rather unavoidable one, fuel pump, injectors and ecu.

If you are, then possibly that's why it never gets completely "off charge" / fully charged, maybe?

 

My Subaru Outback has a clever alternator that regulates the charge voltage, not just on or off, but even without lights in the summer, it didn't often drop down to 12.5 volts. There was always something drawing on it, radio/CD/music player, phone chargers, wipers (it's Britain!) etc.

 

But from what I've read, these Toyota's aren't daft, or more realistically not a pain in the posterior, unlike many cars nowadays!

Not like those that have got to be told parts have been changed cos they're too stupid to work it out themselves.....

Progress, ha.

Or manufacturer / dealer profits on labour, perhaps?

 

So changing a battery shouldn't be a headache.

[Waspie]

Hi BigNev. Thanks for the reply. No I don't drive wjth headlights on, except at night obs. The only thing I know is on apart from what's necessary is the head unit which is an after market replacement for the original Japanese fit.

 

The main problem I have is after a couple of days the battery voltage drops to about 11.8v or less, so there is a parasitic draw somwhere. Yet when I check the current draw on the battery, it's about 90 to 100 milliamps, which should not drop the battery voltage so quickly as far as I know. Which makes me question the battery which is a 60ah.

[Rojie]

5 hours ago, Waspie said:

Hi BigNev. Thanks for the reply. No I don't drive wjth headlights on, except at night obs. The only thing I know is on apart from what's necessary is the head unit which is an after market replacement for the original Japanese fit.

 

The main problem I have is after a couple of days the battery voltage drops to about 11.8v or less, so there is a parasitic draw somwhere. Yet when I check the current draw on the battery, it's about 90 to 100 milliamps, which should not drop the battery voltage so quickly as far as I know. Which makes me question the battery which is a 60ah.

I think 60 A is OK, but it is essential for all Alphie owners to ensure their batteries remain fully charged for the colder nights and winter journies.

 

All that current load on short journies can ask too much of the alternator. 

I maintain a spare battery on charge at home, just in case, and carry jumper leads for when not a home.

[Waspie]

When a battery is replaced is it necessary to reprogramme the ecu, which I have heard you have to do with some modern cars

[smurf]

Some modern cars, and I know VAG cars need this, have to have information from the battery programmed into the ECU when the battery is changed. I haven't heard that a 2010 Toyota would need this.

 

If you have a working alternator (which it sounds like you do), no significant parasitic drain and your battery volts is dropping below 12V after a couple days, then your battery is on it last legs. A bit of cold weather might just kill it off. I'd just replace it with whatever the recommended replacement battery is. You could buy an increased capacity battery if you like, but there is no need if you have no actual use for the increased capacity, such as leaving it for long periods unused.