Volt meter current drain

[Pete4]

Hi,

My van doesn't have a volt meter, just a red light to tell you the battery's about to die.

I'm putting a voltmeter in the kids playhouse though as it's solar powered and I'd like to see the state of the battery as it's got a number of electrical devices that they leave on.

My question for the people with volt meters in their 'van is; is the volt meter on all the time or do you push a button to see the battery status? I',m not sure if the current taken to run the volt meter is significant.

Pete

 

[Icemaker]

ive had three coachmans and now an ace and all the vans have had volt meters that continually show the battery condition whenever the power switch is set to "van". if i set the switch to car the meter then shows the condition of the car battery, and obviously if set to off then nothing is displayed. as far as i am aware the meter would take years to drain even an 85 amp battery.

 

[Icemaker]

ive had three coachmans and now an ace and all the vans have had volt meters that continually show the battery condition whenever the power switch is set to "van". if i set the switch to car the meter then shows the condition of the car battery, and obviously if set to off then nothing is displayed. as far as i am aware the meter would take years to drain even an 85 amp battery.

 

[Pete4]

Thanks John. I did have an old voltmeter in there that drained the battery overnight. I've got a new swanky one now and I thought it would be a small current drain but then again, I thought the old one would too.

 

[Rayc1]

Pete, the voltmeter is in parallel with the battery ( across it) and not in series as a current meter would be. The only drain would be the meter coil which is very high resistance giving minimal current drain. To get an accurate reading you will need minimum 2.5mm cables directly to the battery terminals kept as short as possible. It would be sensible to put a 10A fuse in the positive feed. If you don't want accuracy you could get one that shows green / yellow / red, which will give an indication, and take the feed of the nearest 12v termination.

 

[Pete4]

Thanks Ray,

I'd wired it up as you described and all working OK, I was just worried about the current drain.

One point you raised, and I'll do it as soon as possible is the fuse. I have no fuse in line at all as the electrics kind of evolved from a single light to the thing it is now.

Thanks for that.

Pete

 

[Brian_5062637]

Hi

If you connect a milli-ammeter in series with one of the voltmeter leads you will see what current it is using. A pocket multi-meter will do the job. Don't forget to get the polarity correct! Beejay

 

[rayc]

Thanks Ray,

I'd wired it up as you described and all working OK, I was just worried about the current drain.

One point you raised, and I'll do it as soon as possible is the fuse. I have no fuse in line at all as the electrics kind of evolved from a single light to the thing it is now.

Thanks for that.

Pete

Pete, Have a look at the meter, sometimes they have the full scale detection resistance stamped on them. If it has then divide the voltage (say 14v) by the resistance to get the current.

I think you need to fuse the supply from the battery to the van electrics asap if there is no fuse anywhere. Is there no supply fuse in the DC distribution panel? If not suggest a 20A fuse in line with the positive supply.

 

[Pete4]

Ray, It's a playhouse mate. My 'vans got a zig unit etc. The playhouse has three lights and a TV.

 

[Pete4]

Hi

Intrestingly, the battery is dead flat after a week with the volt meter connected. The battery is only a small thing at about 15 amp hour but it goes to show the cost of having a volt meter to look at in the caravans...

Pete