Battery plugs not removed and not holding charge

[Mikesalem]

Hi everyone, I hope someone can help me.

I bought a new VARTA battery for my Ssangyon Kyron a few months ago and it is not holding charge. Nothing on the car has changed and it is rarely used, maybe twice a week for a short trip. I have tried longer runs and charging the battery but it only lasts a day or two. Although saying that, the main battery charger doesnt seem to be adding any juice to the battery now whereas it did before and lasted a week or two.

I have removed the negative while running and the engine continues. The battery was tested as being ok recently by a garage but just a quick test. Now while checking it today I did notice that I had only removed one of the two transport plugs, but assume that should not be the problem. I have checked all lights etc and nothing is left on and as I say nothing has changed with the car since the new battery. It is going into the garage but would be great if I could find a solution beforehand,. Thank you in advance for any help :-)

[Scrump]

By transport plugs, I presume you are referring to the vent plugs. Normally a length of tube is connected to one of the vent holes and the other plug is left in. There are two plugs so the pipe can be fitted to either end depending on the particular car.
Leaving one vent plug in is normal and is not a problem.

If you are using the car infrequently and doing mainly short journeys then that will be causing issues with a discharged battery.

[Mikesalem]

Hi, thanks for your help, I shall leave the one plug in, There are no pipes etc in the car or on the last battery. Yes I had assumed it was because of short trips etc so have made a point of doing a few 1 hour drives and the battery does last a few days but only a few days.

[LunarOne]

If the engine runs with the battery disconnected, then the alternator is obviously working, but that doesn't mean it's working well enough to charge the battery. Will the car rev without the battery? For petrol (gasoline) engines, you need more battery power to rev the engine, for diesels it usually doesn't matter so much. Do you have a voltmeter? You can get a very cheap multimeter online if not.
Reconnect the battery and measure the voltage when the engine is not running, when it's idling, and with the engine at above 2000 rpm. Ideally you want the voltage to be above 12.5V when the engine is off, and above 14V with the engine running, although it might not be at idle.

I have a few cars but do very little mileage since I work from home. None of them get driven more than once or twice a week, and then only for relatively short trips. Because of that I am susceptible to battery issues, so I bought one of these for each of my cars:
https://www.amazon.co.uk/dp/B08VHMJYXY

It's a little voltage datalogger that connects to your car battery and records its voltage over time. You can then display the data in an app on your phone. It will show you instantaneous battery voltage, and measure cranking voltage and also display a graph of how the voltage varies over time. Highly recommended.

[liner33]

It needs to be checked for a drain but i suspect you have a faulty alternator

[GreenV8S]

You need to get somebody competent to check the charging system and residual drain. It's easy to do. Without that, you're wasting your time trying to guess whether there's a problem or what may be causing it.

[Mikesalem]

Thank you thats very helpful. Its a 2L diesel and does seem to be very heavy as it were to turn over, battery has to have a pretty good charge. The garage checked the voltage when running and not and said the battery was fine and that maybe something is drawing on it but as I said nothing has changed and it was okay to begin with. I think it may have to be a garage job unfortunately. Its already going in for something else anyway. Again thank you :-)

[Mikesalem]

Hi GreenV8S, yes I think that's what I will have to do, thank you.

[Mikesalem]

liner33 said:

It needs to be checked for a drain but i suspect you have a faulty alternator

Thank you, it is an old car so quite likely the alternator, I will get the garage to check :-)

[Chris32345]

Scrump said:

By transport plugs, I presume you are referring to the vent plugs. Normally a length of tube is connected to one of the vent holes and the other plug is left in. There are two plugs so the pipe can be fitted to either end depending on the particular car.
Leaving one vent plug in is normal and is not a problem.

If you are using the car infrequently and doing mainly short journeys then that will be causing issues with a discharged battery.

It's very rare for modern battery's to have a vent tube not seen one for a long time on car

[Hereward]

My battery has a vent tube (see black corrugated tube on left). The battery is mounted under the front passenger seat so you don't want nasty gases in the cabin.

[LunarOne]

Hereward said:

My battery has a vent tube (see black corrugated tube on left). The battery is mounted under the front passenger seat so you don't want nasty gases in the cabin.

Nasty gases? it's only Hydrogen, which is 2/3rds of that stuff you drink when there's nothing else available. It's not like people set fire to dead plant material rolled up in paper these days!

[Chris32345]

That's the first one I've seen for about 10 years
Thought they was all sealed now and only vented if there excess pressure w.g meaning there's a fault

[Hereward]

LunarOne said:

Nasty gases? it's only Hydrogen, which is 2/3rds of that stuff you drink when there's nothing else available. It's not like people set fire to dead plant material rolled up in paper these days!

Ah, I didn't know that, I thought Hydrogen Sulphide was released if overcharged.

So what is the purpose of the vent tube - presumably simply to handle pressure / liquid expansion as Chris said?

[E-bmw]

LunarOne said:

Hereward said:

My battery has a vent tube (see black corrugated tube on left). The battery is mounted under the front passenger seat so you don't want nasty gases in the cabin.

Nasty gases? it's only Hydrogen,

Which is EXTREMELY flammable.

[GreenV8S]

E-bmw said:

Which is EXTREMELY flammable.

And potentially acidic.

[E-bmw]

GreenV8S said:

E-bmw said:

Which is EXTREMELY flammable.

And potentially acidic.

That too.

[TwinKam]

Where a battery is in the habitacle, it must either be a sealed type or, if vented, then vented to the exterior by means of a tube. This includes batteries located in the luggage space. This is not only to avoid the build up of Hydrogen (which is not only flammable but also explosive...) or H²S if it's being over charged, but also to prevent acid spillage if you invert the car.

[donkmeister]

E-bmw said:

LunarOne said:

Hereward said:

My battery has a vent tube (see black corrugated tube on left). The battery is mounted under the front passenger seat so you don't want nasty gases in the cabin.

Nasty gases? it's only Hydrogen,

Which is EXTREMELY flammable.

So are farts, and they are produced in much more prodigious quantities than the hydrogen off a lead-acid cell... Certainly after curry night, at least.

[Mikey G]

E-bmw said:

LunarOne said:

Hereward said:

My battery has a vent tube (see black corrugated tube on left). The battery is mounted under the front passenger seat so you don't want nasty gases in the cabin.

Nasty gases? it's only Hydrogen,

Which is EXTREMELY flammable.

Seen a battery go bang, was about 30 years ago when a neighbour borrowed my car to jump start his 2CV, he put the leads on his battery and up it went. Was probably faulty anyway. But there is a reason why it is advised that the last connection you make is the earth and you do it to a metal body part or engine away from the battery...