Simple digital Volt Meter 30mA Draw
Submitted: Saturday, Jul 08, 2006 at 16:49
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Harrow
For those who are after a simple permanent digital voltmeter.
2 wire installation. 7-25V (0.1v res) with almost no current draw (30mA)
small size large digits, but no backlight.
Have 2 installed on cab, Main ans Aux, as accurate as my multi meter, then see attached
Nb: only US$25.00 id you can acess US suppliers
A$60-00 from RS components Aus
Site Link
Cheers
Harrow
Reply By: Mike Harding - Saturday, Jul 08, 2006 at 17:33
Saturday, Jul 08, 2006 at 17:33
I _thought_ 30mA was a pretty heavy current for an LCD - it's 3mA maximum consumption :)
And the data sheet is wrong - the resolution should be 100mV not 100V!
A$60 is far too expensive for that although RS and Farnell are always pricey.
Also note that it is only speced. from 0 to 50C which is not even close to automotive temperature ratings - it will probably be OK but keep it out of direct sunlight when you choose a mounting spot.
Mike Harding
AnswerID:
182433
Follow Up By: Mike Harding - Saturday, Jul 08, 2006 at 17:41
Saturday, Jul 08, 2006 at 17:41
It appears Electus (the wholesale arm of Jaycar) also do that Lascar range:
Site Link
You need a trade account to purchase directly from Electus but the Jaycar shops can supply parts from the Electus catalogue on special order - check with them for pricing - ensure you quote the Electus part numbers to Jaycar.
Just checked the Electus price and it's not a whole lot less than RS - by the time the
shop has put it's markup on it'll probably be about the same :(
Mike Harding
FollowupID:
438848
Follow Up By: MartyB - Sunday, Jul 09, 2006 at 18:21
Sunday, Jul 09, 2006 at 18:21
Just looked at Electus & most Lascar equip is listed as temp out of stock.
Marty.
FollowupID:
438970
Reply By: Member - Phil G (SA) - Sunday, Jul 09, 2006 at 18:04
Sunday, Jul 09, 2006 at 18:04
Out of interest, I just measured the Jaycar combined digital voltmeter/temp gauge and it was using 21.3millamps. So I guess that means it would use one AmpHour every 2 days, and would take a few months to flatten a battery.
Also measured a cheap 2" analogue voltmeter, and it used 85milliamps.
AnswerID:
182577
Reply By: geocacher (djcache) - Monday, Jul 10, 2006 at 23:22
Monday, Jul 10, 2006 at 23:22
Why run it all the time. Supply it only when the ignition is on - and add a small push button switch to supply it with 12v from the feed line when you want a momentary reading without the ignition on.
Remember that voltage readings lag the battery state significantly on charge and discharge, so what you see ain't necessarily what you got....
Dave
AnswerID:
182841