jaycar battery terminal question

[roon_VR]

Hi guys,

Just recently bought a Jaycar battery terminal and it has a black and red wire coming out of the LCD display. Just quickly, where do i connect these wires?

Thanks,

P.S. i have uploaded a picture to show you

 

[1991_Vn2nV]

Being red and black I would say Positive and Negative?

I would assume you would only need to connect on, as surely it would get ground or power from whichever terminal it sits on (meaning the other needs to be connected for the voltmeter).

Most people use it on the positive terminal, so I guess black goes to ground?

 

[azkwazere]

I would assume you would only need to connect on, as surely it would get ground or power from whichever terminal it sits on (meaning the other needs to be connected for the voltmeter).

Youd think that but you'd be wrong!

You need to connect both wires (i did) to both terminals, the LCD is isolated form the terminal for some crazy mofo reason... im sure its valid.

Red = +
Black = -

aZk.

 

[roon_VR]

I just figured it out and i needed to put it on the positive and negative terminal on the battery (as azk said)

thanks anyways!

 

[1991_Vn2nV]

Youd think that but you'd be wrong!

You need to connect both wires (i did) to both terminals, the LCD is isolated form the terminal for some crazy mofo reason... im sure its valid.

Red = +
Black = -

aZk.

lol someone at Jaycar got lazy

 

[Immortality]

lol someone at Jaycar got lazy

you can wire it 2 ways. directly to the positive and negative terminals which means it's always on (possible drain on battery if you don't use car regularly) or wire one of the wires through a excisting relay meaning it's only on when you have the ignition switched on

 

[blueholden]

or wire it through an alarm style bonnet pin so it works when your bonnet is open regardless of the ignition being on it will still work but only when your bonnet is open


thats how i have my civic one wired just connect one of the wires straight to battery and put the other through the pin switch

 

[commsirac]

Doesnt look like it would go under the bonnet? or be durable to last.

How to wire it, depends what you want it for?

Most multimeter displays will stay on for weeks at a time, not even flattening a small 9V battery, but perhaps check if there is a current rating for the device before wiring it to live 12V.

Perhaps just wire it after the ignition switch,(like what is done on all cars that come equipped with voltmeters) ie on the fuse for the radio, or anything else that becomes live when you turn the ignition on....its going to use only a tiny amount of current regardless and wont overload any circuit. (you wont need a relay) Actually the indicator fuse would be good as it would allow you see the voltage while the starter is cranking.

Yes it will read slightly lower than the voltage measured at the battery if your accessory load is high, however, doubt you will be even able to measure this given that the display is only to the nearest 0.1V.

 

[Mike S]

Doesnt look like it would go under the bonnet? or be durable to last.

I might be stating the obvious but dosn't a battery normally go under the bonnet ?

I like the idea of having a bonnet switch to turn it on as you won't be able to see it when the bonnets closed anyway (stating the obvious again .. lol)

 

[commsirac]

Could be right above......my first look at the item and it looked like got dual cigarette lighter type sockets for powering other devices as well, hence thinking it was a voltmeter for inside the car......but those sockets are actually for battery cables?

Strange device, why would you need a permanent voltmeter under the bonnet?, why not have it inside the car so you can see it all the time?