Ironhead Digital volt meter

[Andy Hog]

Hi,

I am fitting a digital volt meter to my bike, I am wiring the supply wire direct to the ignition, so when I turn the key it comes on.

Should I be wiring some sort of load transistor or something between the meter & the supply side to protect it in case of a voltage surge?

TIA,

Andy.

[rokytnji]

I.d just wire in a low amp inline car fuse to the hot wire in series and call it a day.
The voltmeter should state specs somewhere so you can figure if 1 or 2 amp is OK.

[Tomcatt]

Originally Posted by Andy Hog

I am fitting a digital volt meter to my bike...

Should I be wiring some sort of load transistor or something between the meter & the supply side to protect it in case of a voltage surge?

No.

[Andy Hog]

A fuse is a great idea, that's on the to do list for tomorrow.

Thank you.

Andy.

[bustert]

the volt meter is a parallel system and not an inline system. if it is a good brand, then it should have all the protection you need. it probably uses less than 1 amp to function.
the only issue i can see is if your system has excessive ac ripple, the a filter capacitor could be used but then again, system on the machine would be affected also like flickering in the lights.

[Tomcatt]

Originally Posted by bustert

..the volt meter is a parallel system and not an inline system...

+1
There's virtually no current flowing thru the voltmeter. It just sees voltage. You can hook the voltmeter directly across the battery terminals with no ill effect. Or across the terminals of your car battery that can supply far more current than your bike battery.

[rokytnji]

Well. My Fluke VOM is internally fused to a 9 volt battery.

Up to you.

[Tomcatt]

Originally Posted by rokytnji

Well. My Fluke VOM is internally fused to a 9 volt battery.

Mine's the same but the OP isn't hooking up a VOM, just a volt meter. The fuse in your VOM keeps you from toasting the meter if you try to do an amperage check using ohms settings or similar.

[RandallM]

Fuses are for current generally. Volt meters pull very little current. Way, way less than 1 amp, miliamps in fact. You don't need a fuse. If there is a fault that somehow pulls that much current to blow a fuse, then your volt meter is going to be the least of your worries.

The fuse in that Fluke is for current, it has nothing to do with the battery or voltage. Well, if you connected to 1Kv maybe, but under normal circumstances, no.

PS. I repair electronics for a living.

[Andy56]

Where will you voltmeter get power from to see the display?

The Fluke and other handheld meters use a battery.