How long should a 12v Car Battey last?

[Harry Bloomfield]

Some dodgy retailers may still sell them with no vat if you search around: eg https://www.ebay.co.uk/itm/281275825175

SLK, have a terrible reputation.

 

[mattylad]

Back in times of old, when flags were allowed to be flown, snowflakes were white stuff falling from the sky and Gen Z were nowt but a twinkle in Gen X eyes, we used to have turkey baster type testers, battery top up fluid etc.
It was part of the cars general maintenance to top up the battery electrolyte.

Now they are all supposedly sealed maintenance free (although it's usually just a sticker over the same top up bungs.

Would a modern battery not also benefit from the old style test and topup routine?

 

[Harry Bloomfield]

Would a modern battery not also benefit from the old style test and topup routine?

Part of the equation, is that charge rates/voltages are much better controlled and engines start without the lots of cranking that used to be needed, so less wear, tear, and evaporation of electrolyte occurs.

 

[carmanmemoranda]

Back in times of old, when flags were allowed to be flown, snowflakes were white stuff falling from the sky and Gen Z were nowt but a twinkle in Gen X eyes, we used to have turkey baster type testers, battery top up fluid etc.
It was part of the cars general maintenance to top up the battery electrolyte.

Now they are all supposedly sealed maintenance free (although it's usually just a sticker over the same top up bungs.

Would a modern battery not also benefit from the old style test and topup routine?

You assume all batteries are the same. They're not

 

[Ron0z]

I used to own a hydrometer. I found it mildly interesting to measure each cell's specific gravity, but at the end of the day it didn't really matter. While the SG could tell the charge state, another good way was to listen to how the engine turned over as you tried to start it (spinning freely or barely getting the engine to turn over).

I also recall topping up the cells with distilled water. It was so easy to overfill, which was not a good idea. It was a routine activity, doing that. The water evaporates. On the other hand, if the battery is sealed, there will be no evaporation. Therefore, less maintenance, and I'm all for that.

 

[mattylad]

You assume all batteries are the same. They're not

NO I don't.
I asked a question, Harry answered it.

You can go bury your head.

 

[carmanmemoranda]

Now they are all supposedly sealed maintenance free (although it's usually just a sticker over the same top up bungs.

I rest my case.

And he only partially covered it. Evaporation occurs via charging not through cranking.

But crack on

 

[Notch7]

As long as a politician's popularity

That up as long as a whores drawers…..

 

[Harry Bloomfield]

Evaporation occurs via charging not through cranking.

Then, when it has finished cranking, the used up charge has to be put back in it, causing more evaporation.

 

[Justin Passing]

The neighbour's Ford Galaxy (I think) battery died suddenly at about 8 years from new car, and wouldn't "jump" start. Tried leaving the good car running 15mins to charge the dead battery, too. ANd that Ford's battery is not easy to change, it's tucked away..

ALso too as well, I called in a local Toyota main dealer - it's time I got what will probably be my last car.
Two one year old cars - a RAV4 PIHybrid, and a LandCruiser, both had flat batteries. I couldn't even adjust the electric seats so I could get in.
Alarming!
The RAV4 has a remarkably low top to the door aperture. Ugh. The LC was ok, but they've made them look like dump trucks.

 

[robinbanks]

Would a modern battery not also benefit from the old style test and topup routine?

Nope, the electrolyte isn't most often free to slosh around as it's soaked up in a fibreglass matting, or a gel

another good way was to listen to how the engine turned over as you tried to start it

External Temperature also influences this so it may not be a universally reliable test

if the battery is sealed, there will be no evaporation

They aren't sealed to that extent; they still have vents that regulate pressure changes. Blocking those during charging ruins the battery

Tried leaving the good car running 15mins to charge the dead battery, too

This should always be done. So many people connect the jump leads (and potentially to the wrong place like the terminals of the dead battery, and in the wrong order) then go rev the good car and immediately start trying to crank the dead car; far more reliable to use the good car to charge the dead battery some as you describe, and one can even get away with very skinny jump leads indeed with this approach.. Have successfully used a scrap of 2.5mm T&E as jumper before now..

Somewhere I've got a natty set of leads that have a volt meter built into the cable that puts a light on when the discharged battery has sufficiently recovered

both had flat batteries. I couldn't even adjust the electric seats so I could get in

Alas, those batteries are probably now ruined - the longer they were like that the more capacity they've lost.. If it keeps happening and resolving the parasitic drain is on the todo list, it may be worth paying through the nose for a Li-Ion battery that will withstand the deep discharge

Hopefully though the electrical systems of the car were controlled by a BMS that shut everything down when the voltage dropped too low rather than it truly being the battery getting down to sub 10v..

 

[blup]

Back in times of old, when flags were allowed to be flown, snowflakes were white stuff falling from the sky and Gen Z were nowt but a twinkle in Gen X eyes, we used to have turkey baster type testers, battery top up fluid etc.
It was part of the cars general maintenance to top up the battery electrolyte.

Now they are all supposedly sealed maintenance free (although it's usually just a sticker over the same top up bungs.

Would a modern battery not also benefit from the old style test and topup routine?

Bring back the crank handle

 

[robinbanks]

And manual window winders. Very handy for getting out of submerged cars with failed electrical systems!

 

[carmanmemoranda]

Then, when it has finished cranking, the used up charge has to be put back in it, causing more evaporation.

That can be the case yes.

But the car can start perfectly and suffer charging system error, which is much more likely.
Or the wrong battery type fitted etc.

The point being there are various battery types and systems.

 

[Harry Bloomfield]

This should always be done. So many people connect the jump leads (and potentially to the wrong place like the terminals of the dead battery, and in the wrong order) then go rev the good car and immediately start trying to crank the dead car; far more reliable to use the good car to charge the dead battery some as you describe, and one can even get away with very skinny jump leads indeed with this approach.. Have successfully used a scrap of 2.5mm T&E as jumper before now..

Correct!
My leads are homemade, from coax, containing lots of copper screening, with croc clips much smaller than the usual monsters, on the ends. The heavy duty, manufactured leads, just are not necessary.