!@%$ wiring

[elwopo]

Purchased a digital multimeter trying still to get something to work the way it should on this thing of mine...

How do you know the ground is sufficient to get an accurate reading? I put the red probe on what I want to test, but there's not always handy metal nearby to put the black one on.

I've got a junction block inside the electronics locker. When I try to check the power to the screws the reading seems low (4 -7 volts) the radio and vhf work...but shouldn't the power at the screws be 12v? The battery is brand new....put it in last night.

 

[tashasdaddy]

Re: !@%$ wiring

yeap, check your cables from battery to junction box, for corrosion, nicks etc. remove connections and make them shiney. is new battery fully charged?

 

[elwopo]

Re: !@%$ wiring

Yep. Battery went from store to charger to boat, because of all the problems leading up to this. Wanted to make sure the source was as good as possible.

I'll check all the wire I can get to. Some of it is in long runs inside the hull....then it runs through the aluminum tower and into the box.

If I have to replace the whole wire run...what gauge would be best to use?

Is there a device that can check current along a wire and not just end points?

 

[elwopo]

Re: !@%$ wiring

Forgot one thing...
Can the aluminum tower be used as a ground when checking this stuff?

 

[bruceb58]

Re: !@%$ wiring

Make your self a long jumper(length from the battery to whatever you are going to measure) with alligator clips on the ends. Use this to attatch to you battery ground and the other to your meter ground probe. This, you will be absolutely sure you know what you are measuring.

 

[elwopo]

Re: !@%$ wiring

Make your self a long jumper(length from the battery to whatever you are going to measure) with alligator clips on the ends. Use this to attatch to you battery ground and the other to your meter ground probe. This, you will be absolutely sure you know what you are measuring.

Absolute genius idea!
Got 20' 12 gauge wire and clips. Meter alone read 12.7 at battery and with long wire on....read the same.

Now....should everything on the other end read 12.7? I mean switches to anchor light bases to junction box....everything?

Just trying to figure out how O.C.D. to get with this....

 

[jtexas]

Re: !@%$ wiring

T/D: "is new battery fully charged?"
el wopo: "Yep. Battery went from store to charger to boat..."
the correct answer was "Yep....Meter alone read 12.7 at battery"
You won't know it's fully charged until you measure the voltage and get 12.65 or more.

Get real O.C.D with keeping all the connections tight and free from corrosion. A little less O.C. with the measurements. Every switch and connector and even the wiring will drop a little bit of voltage - if it's within half a volt at the socket, call it good.

 

[bruceb58]

Re: !@%$ wiring

Measure the voltages with things turned on so that there is current running through the wires and contacts. This way you can see if there is a voltage drop caused by any bad connections, bad switches....

Another thing you can do is to probe the negative bus bar near your fuse panel with many things turned on. This will tell you the voltage drop between your negative bus bar and your battery. Should be as close to 0V as possible but you will see some voltage depending on the current, the size of the wire and the connections. You make this measurement just like you did before with your long ground probe on the negative side of the meter and probing the negative bus bar with the positive lead.