battery voltage...

[purplecrocs]

I had the multimeter out the other day so thought I'd check the voltages on my battery.. the starter battery was giving me a reading of approx 11.8V engine off/no hook-up and about 12.5V with hookup or the engine going... is this a bit low? I seem to remember reading on various posts here it should be around 13.5 - 14V (my leisure batt shows 13.5 with hookup/engine)

and if that is low does it mean the battery is knackered? It doesnt look that old, its a Bosch silver something or other

...on a side note... would it be wise to disconnect my battery if I'm not going to use the van for a couple of weeks at a time.. ie would i just remove the negative terminal to stop the radio etc draining it?

Thanks!

[pocolow]

My starter battery reads around 12v when engine off then around 13.7-14.1v when running and my leisure is around the same. Both batteries are around three years old. I found it useful to fit a voltage gauge to the dashboard then I can monitor both batteries constantly...

[albertramsbottom]

Starter battery should be 12.5v but will be higher after a charge from a carger or alternator and will then drop rapidly to 12.5v

When the engine is running it should be over 13.5v may even 14.v.

Is your v-belt loose?

[albertramsbottom]

My starter battery reads around 12v when engine off then around 13.7-14.1v when running and my leisure is around the same. Both batteries are around three years old. I found it useful to fit a voltage gauge to the dashboard then I can monitor both batteries constantly...

Intresting but htose meters are not very reliable or accurate. A fully charged battery should be 12.65 v. A battery that has a voltage of 12.0v would be only 20% charged.

Your battery is knackered or the digi meter is out

Cheers

[purplecrocs]

hmm.... if I knew what a v-belt was i'd tell you, but I am assuming as I still only get 12.5V when the Westy charger is running while on hook-up its not related..?. I also assume the meter isnt out as the leisure battery give the more 'normal' reading of 13.5V

How long are batteries supposed to last?

[pocolow]

Starter battery should be 12.5v but will be higher after a charge from a carger or alternator and will then drop rapidly to 12.5v

When the engine is running it should be over 13.5v may even 14.v.

Is your v-belt loose?

That photo was taken in the middle of winter when it was below freezing , right now it is reading 12.51v..

[albertramsbottom]

hmm.... if I knew what a v-belt was i'd tell you, but I am assuming as I still only get 12.5V when the Westy charger is running while on hook-up its not related..?. I also assume the meter isnt out as the leisure battery give the more 'normal' reading of 13.5V

How long are batteries supposed to last?

It does sound like a battery issue if your lesure battery is fine and when engine running it reads 13v or more

Cheers

[horns]

How long are batteries supposed to last?

They should last a few years, but it depends how they've been treated. A normal starter battery won't tolerate being completely drained much - do it a few times and its toast...

[purplecrocs]

ok. would i be wise to disconnect the negative terminal when not in use for a couple of weeks to stop the radio memory, clock etc draining the bat?

[horns]

I've never bothered. Mine has sat there for weeks without the clock and radio making much of a dent in it.

[kevtherev]

indeed

modern head units are drawing 0.05A these days.

put a meter across mine with the clock and it barely registered.

[CovKid]

Intresting but htose meters are not very reliable or accurate. A fully charged battery should be 12.65 v. A battery that has a voltage of 12.0v would be only 20% charged.

Your battery is knackered or the digi meter is out

Cheers

Must correct you here, these dash meters can be calibrated exactly and mine is spot on, verfified with a known good professional digital meter.

[AngeloEvs]

mine is accurate but if the reading is low then the chances are that there is a small volts drop in the wiring, as cov kid points out, you can calibrate them to compensate anyway by comparing the reading to a good quality multimeter.

[albertramsbottom]

Intresting but htose meters are not very reliable or accurate. A fully charged battery should be 12.65 v. A battery that has a voltage of 12.0v would be only 20% charged.

Your battery is knackered or the digi meter is out

Cheers

Must correct you here, these dash meters can be calibrated exactly and mine is spot on, verfified with a known good professional digital meter.

Hairy muff mate, what I think I meant is that unless you have a table that reads of the different voltages against the actual battery condition they are very hard to read with any relevence.

[CovKid]

Well thats true and you need to put battery under load to know if its any good or not. The volt meter mod was really to give a visual indication of what alternator is putting out (and that it is actually charging) and what the present voltage reads from one or more batteries when engine is off. My second battery is long overdue for replacement and will quickly drop to around 11v if I have the stereo on for about an hour - a vague indication that its not in the flush of youth (like myself).

If I was putting more demand on it, I'd definately get a new one but for now it saves my starting battery from going flat, a problem that I was plagued with a few years ago. Generally a duff battery won't hold a charge for that long (even if it'll take a charge) and after 3 years most batteries show a greater or lesser degree of deterioration I find.