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Volt Meter Issue
Posted: 06 Jun 2014, 18:50
by Verne
Sometime in his previous life, Keif had 2 volt meters fitted. One for the main battery and another for the leisure battery.
Unfortunately, they are on permanently and therefore always taking power. Can anyone point me in the right direction to sort it so that they only indicate the power in the batteries when the ignition is on.
TIA
Re: Volt Meter Issue
Posted: 06 Jun 2014, 19:15
by itchyfeet
A manual switch is whats needed
Re: Volt Meter Issue
Posted: 06 Jun 2014, 19:26
by CovKid
Also depends what kind of voltmeter. My digital one draws so little it doesn't matter.
Re: Volt Meter Issue
Posted: 06 Jun 2014, 19:31
by nicq
I fitted one of these
http://www.ebay.co.uk/itm/RS-12-miniatu ... 43ca414c51" onclick="window.open(this.href);return false; wired it to the ignition and the supply to each meter switched seperatly. Works bril.
Re: Volt Meter Issue
Posted: 07 Jun 2014, 20:10
by Mocki
Simple relay ........
Re: Volt Meter Issue
Posted: 09 Jun 2014, 08:10
by ghost123uk
Verne wrote:Can anyone point me in the right direction to sort it so that they only indicate the power in the batteries when the ignition is on.
Aye, but bear in mind, when the ignition is on (and motor running) the two batteries are connected together and so the readings will / should be the same on both. However, you may well want to know the state of the leisure battery when the ignition is OFF, ie when actually using it
If your meters are pulling too much current (and as Ralph says, some don't) then, for the leisure one, a simple "push to make" button type switch (Maplin/Ebay etc) would be a good idea.
And for the main battery one, simply find a wire that "comes live" when the ignition is on. The feed to the headlight switch could be used, though it could read a bit low when the lights are on. Or, as Mocki says, you could fit a little relay, and if you are careful where you take the feed to the meter from (separate wire from battery is ideal) then that would give the most accurate reading
Re: Volt Meter Issue
Posted: 09 Jun 2014, 08:23
by CJH
I've used one of
these from RS.
In position 'I" it shows the starter battery, in position 'II' it shows the leisure battery, and in the middle ('0') position it's off.
Re: Volt Meter Issue
Posted: 09 Jun 2014, 08:52
by ghost123uk
That is very good
But, Verne has two meters already fitted, so the wiring of such a switch does not lend itself (easily) to such a set up
(unless removing one of the meters is an option ?)
Re: Volt Meter Issue
Posted: 09 Jun 2014, 08:53
by nicq
ghost123uk wrote:Verne wrote:Can anyone point me in the right direction to sort it so that they only indicate the power in the batteries when the ignition is on.
Aye, but bear in mind, when the ignition is on (and motor running) the two batteries are connected together and so the readings will / should be the same on both. However, you may well want to know the state of the leisure battery when the ignition is OFF, ie when actually using it
If your meters are pulling too much current (and as Ralph says, some don't) then, for the leisure one, a simple "push to make" button type switch (Maplin/Ebay etc) would be a good idea.
And for the main battery one, simply find a wire that "comes live" when the ignition is on. The feed to the headlight switch could be used, though it could read a bit low when the lights are on. Or, as Mocki says, you could fit a little relay, and if you are careful where you take the feed to the meter from (separate wire from battery is ideal) then that would give the most accurate reading
If you wire it as I suggested,
With ign on but not started. You get both bat voltages as they are not connected together no split charge connection
With engine running. You are checking both batts are charging
Re: Volt Meter Issue
Posted: 09 Jun 2014, 08:55
by CJH
ghost123uk wrote:
But, Verne has two meters already fitted, so the wiring of such a switch does not lend itself (easily) to such a set up
Oops - missed that!
Re: Volt Meter Issue
Posted: 09 Jun 2014, 08:56
by ghost123uk
nicq wrote:
If you wire it as I suggested,
With ign on but not started. You get both bat voltages as they are not connected together no split charge connection
With engine running. You are checking both batts are charging
This is true, but you would not get a reading from the leisure battery when you most need it, ie when parked up camping.
Re: Volt Meter Issue
Posted: 09 Jun 2014, 12:27
by Verne
Thanks guys, I like the push button option for the leisure battery, so may try a combination of relay and button - if I can get it right in my head
Re: Volt Meter Issue
Posted: 20 Jul 2014, 23:03
by ScienceBoy
Just to verify the relay idea, it's there so the meters only get powered when the ignition is on? And this to eliminate any power consumption when laid up?
Re: Volt Meter Issue
Posted: 20 Jul 2014, 23:05
by ScienceBoy
Are folks using two wire or three wire versions? The Chinese translation didn't really explain the third wire clearly :s
Re: Volt Meter Issue
Posted: 21 Jul 2014, 05:33
by ghost123uk
The 3 wire ones are for when the meter is going to be asked to read voltages well away from 12 Volts. The main power wire supplies 12 Volts to run the circuits, the other wire monitors the voltage you wish to read, which can be say 3 Volts, or maybe 30 Volts etc.