Car Battery

Bigwheels1111

New cars with stop start and needing coding or bmi resets.
Or even location of battery make changing at home very difficult.
My AGM replacement will be about £200.

Goudy

Bigwheels1111 said:

New cars with stop start and needing coding or bmi resets.
Or even location of battery make changing at home very difficult.
My AGM replacement will be about £200.

Yes, some modern vehicles with energy management/smart charging systems often require "telling" a new battery has been fitted.
It's called battery matching and if it's not done the car will continue to charge the new battery like the old battery.
This can cause increased mpg/emissions and can shorten the life of the new battery.

This can be a particular problem if the original battery is no longer available and a suitable alternative has slightly different specs.

Modern cars have been built to strict emissions regs and every little saving adds up, so if they can accurately work out a batteries charging needs and only give it what is needs when it needs it, it can save fuel and improve emissions.


There are different types of lead acid batteries used on cars.

The standard flooded type.
Loose acid sloshing around between plates inside.
Some were unsealed and you could measure the acid concentrate and top up with de ironized water in needed or replace the acid completely.
Some use a calcium alloy on the plates to help prevent sulphur building up plates and were usually sealed and maintenance free.
The CCA is usually a bit lower than other types.

Advanced flooded batteries (AFB).
These use a mat or scrim covering the plates along with a tin alloy.
The acid is still loose.
They are often sealed and maintenance free, a little more powerful and tend to last slightly longer than flooded types, though with some maintenance a normal flooded type can last a long time.

Absorbent glass mat (AGM).
As the name suggests, the acid is absorbed into a glass matting between the plates.
There's no acid sloshing around inside and no real acid maintenance.
They are more powerful which is handy in saving weight as quite often a smaller but powerful battery can be used, they tend to have a higher CCA rating and usually have a much longer life cycle.

AFB's and AGM's are usually fitted to the latest cars as they tend to deal with the demands of stop start, EPAS, smart charging etc much better but that comes at a cost, prices aren't cheap.

Arunmor

The simplest way of course would be to change the battery like for like then the car shouldn't need recoding.  

quantum173

In my experience vehicles need to be used.
A drive of about 20 miles maybe enough.This is important for battery and engine,
Every week minimum.
Or use a trickle charger if possible.
m

Middle_of_the_Road

cymruchris said:

Cloth_of_Gold said:

35har1old said:

Lorian said:

As above they often don't last past 5th/6th winter reliably.

Have had a car for 12 years same battery only 36000 on the clock

Our current car is 7 years old but has only done 20k miles and nowadays we only do about 1000  - 1500 miles per year, the vast majority of which are short, local journeys of about 2 - 4 miles each way. Our previous car was 13 years old when we replaced it and it had only done 50K miles. We've never had a battery problem with either but I wonder if we've just been lucky. I'm concerned now that we might have a problem this winter but on the other hand I don't particularly want to drive around nowhere in particular for 20 odd miles every week just to keep the battery topped up - especially as we live in a large city so driving is, frankly, a bit of a pain nowadays.

Different cars with different batteries consume different amounts of power when parked up. Some cars use a lot less/more than others - some cars can stand for weeks on end and start at the turn of the key - others can be left a week and be nearly as flat as a pancake. I happen to drive one of the latter, renowned for batteries being drained when not driven. I'm lucky that at the moment I have a garage, and can keep a top-up charger plugged in

Not a Jaguar by any chance?

A lead acid battery can be on a float charger for its entire life without issue. That's the short industry standard answer given for reasons of convenience and practicality. The longer answer is that a battery will last longer if it is not subjected to a constant trickle charge for reasons of plate corrosion. Best case is to periodically cycle a battery and bring it back up to full charge then leave it disconnected until the next usage. Batteries last decades if treated this way, but unless you're just storing them it isn't very practical hence the theory of 'just leave them on float charge'.

cymruchris

Middle_of_the_Road said:

cymruchris said:

Cloth_of_Gold said:

35har1old said:

Lorian said:

As above they often don't last past 5th/6th winter reliably.

Have had a car for 12 years same battery only 36000 on the clock

Our current car is 7 years old but has only done 20k miles and nowadays we only do about 1000  - 1500 miles per year, the vast majority of which are short, local journeys of about 2 - 4 miles each way. Our previous car was 13 years old when we replaced it and it had only done 50K miles. We've never had a battery problem with either but I wonder if we've just been lucky. I'm concerned now that we might have a problem this winter but on the other hand I don't particularly want to drive around nowhere in particular for 20 odd miles every week just to keep the battery topped up - especially as we live in a large city so driving is, frankly, a bit of a pain nowadays.

Different cars with different batteries consume different amounts of power when parked up. Some cars use a lot less/more than others - some cars can stand for weeks on end and start at the turn of the key - others can be left a week and be nearly as flat as a pancake. I happen to drive one of the latter, renowned for batteries being drained when not driven. I'm lucky that at the moment I have a garage, and can keep a top-up charger plugged in

Not a Jaguar by any chance?

A lead acid battery can be on a float charger for its entire life without issue. That's the short industry standard answer given for reasons of convenience and practicality. The longer answer is that a battery will last longer if it is not subjected to a constant trickle charge for reasons of plate corrosion. Best case is to periodically cycle a battery and bring it back up to full charge then leave it disconnected until the next usage. Batteries last decades if treated this way, but unless you're just storing them it isn't very practical hence the theory of 'just leave them on float charge'.

Not a Jaguar - an old mid 2000's Mercedes. Yes - I 'condition' the battery regularly as well as keep it on the trickle charge. The charger has an option to recondition as well as keep topped up. 

forgotmyname

A lot of these trickle chargers are rubbish.  They will give a float voltage at low amperage but not a higher spike every now and then

to keep the plates clean.

Sometimes the plates need a fairly high discharge and charge to keep the plates clean.

HillStreetBlues

Can a trickle overcharge, is a smart charger better?

forgotmyname

You will be hard pushed to find an old school dumb charger these days, I think every branded item on sale reduces
the charge rate as the battery reaches a full charge.

Some may just monitor the voltage and nothing else where better ones may also test the resistance as it charges.

Some will say they condition the battery but read into that with a large dose of salt... Tested a few and they just cycle
the battery to charge / off / charge / off to keep the voltage within a set range.

Good healthy battery then just buy the cheapest branded charger, if the battery is weak or has been discharged and left
to sit then put your money into a new battery rather than an all singing and dancing charger.

sevenhills

quantum173 said:

In my experience vehicles need to be used.
A drive of about 20 miles maybe enough.This is important for battery and engine,
Every week minimum.
Or use a trickle charger if possible.
m

I had a new alternator put in, but it hasn't changed the charging rate. He said the battery was good, at 70%, what ever that means.

It hasn't let me down since, as long as I do some longer runs it should be ok.