Battery

[Guest macca]

I have a battery from a 1.8 BMW 3 series. Got it from a mate who left his lights on and flattened it, he went and bought a new 1

 

It has sat in my garage for about a year. Anyway I charged it and have tested the lighting etc with it. I left it on charge overnight last night and checked it tonight with the multi meter. It is showing about 12.3 volts. Is this correct?

 

Should it be more like 13-14 volts??? Should I stop being a tight sod and buy a new 1????

 

Macca

[Guest Kieran]

I thought that when a 12 v battery showed low 12 or below readings, it was either flat or had a duff cell. A fully charged 12v normally shows about 12.7 me thinks??

 

Kieran

[geoff shep]

Take it to Halfords or somewhere similar and have it tested. They can read 12V but have no umph. Or connect it to the car and see whether it will turn the starter. I had a similarly old batt, charged all day, drove for 30 mins or so but would still not re-start the car.

[Guest Battery Bill]

Should I stop being a tight sod and buy a new 1????

 

Yes

[Snapperpaul]

Oh i love the web, found this under "car battery nominal voltage"

 

Lead acid batteries for automotive use are not designed for deep discharge and should always be kept at maximum charge, using constant voltage at 13.8 V (for six element car batteries). Their capacity will severely suffer from deep cycling. Specially designed deep-cycle cells are much less susceptible to this problem, and are required for applications where the batteries are regularly discharged.

 

Quiescent(open-circuit) voltage at full battery: 12.6 V

Unloading-end voltage: 11.8 V

Charge with 13.2-14.4 V

Gasing voltage: 14.4 V

Continuous-preservation charge with max. 13.2 V

After full charge the terminal voltage will drop quickly to 13.2 V and then slowly to 12.6 V.

 

thats at the battery Bill you might loose a bit if it's a long way from the starter

[Guest chris brown]

It is reading a bit low try cycling it a few times i.e. connect it up and do as your mate did leave the lights on until its about flat. You may find this won’t take long the first time you do it but after 3 or 4 full charges it should get better if not then yes you will have to let the moths escape and get a new one. The problem is they sulphate up with standing particularly if left flat all batteries should be cycled as they last much better in constant use.

[Guest Battery Bill]

thats at the battery Bill you might loose a bit if it's a long way from the starter 

 

[Guest macca]

thats at the battery Bill you might loose a bit if it's a long way from the starter

I turned Bills advise down, mines in the Front!!! Its helping to counteract the understeer!!!!!

 

Bill must have a few inline 'AA' duracells to keep the voltage up. I can see it now thousands of little electrons packing their bags to treck all the way to the front of the car. With inline duracells acting as service stations along the way.

[Guest chris brown]

With inline duracells acting as service stations along the way.

[Guest macca]

Chris

 

Imagine being an electron in Bills car, you travel all that way to the starter, then up in to the loom and to the column, only to be told that you are on Brake light duty, Bummer

[Guest FIRSTBUILD]

batteries really dont like being left flat for to long , if you store one it must be fully charged when you leave it --- I would say charge it flatten a couple of times and see if holds its charge.

[Guest Battery Bill]

Imagine being an electron in Bills car, you travel all that way to the starter, then up in to the loom and to the column, only to be told that you are on Brake light duty, Bummer

 

 

Ps its Joeys car

[Guest chris brown]

Ps its Joeys car

So it is (I stand corrected). But as I understand it you are going to make the same mistake again on the current (poor little electrons again) build.

[Guest Battery Bill]

Oy

So it is (I stand corrected).

 

How on earth can you "Stand corrected" ?

 

It was not you who said it was Bills car

 

 

[Guest chris brown]

Because if I had thought I would have pointed it out on my last fit of mirth. Just can’t get the thought out of my mind of all those little electrons going down that long wire wondering how long it will be before they can take a short way home