Car DVM

[WTP Pepper]

Hi
I am looking to buy a simple LCD type DVM module to attach to a 12v lead acid battery (not the main battery) in my car running a few circuits. I would like it as a simple module without a backlight and draw minimum current as it will be permantely powered across the separate battery.

However I would be willing to have a push switch to power the module for a small period to show the voltage if it didn't get fried having an input voltage without a supply voltage.

Any ideas pls?

 

[MrAl]

Hi,

There are a million of them on Amazon. Quality varies, color varies, backlight varies, you name it they got it

 

[crutschow]

Just make sure you buy one designed to be powered by the same voltage it is measuring. Some panel DVMs require an isolated power supply and are thus unsuitable for the task. If it has separate ground pins for the power and input signal, that is a likely sign that it won't work to measure its own voltage.

 

[WTP Pepper]

Just make sure you buy one designed to be powered by the same voltage it is measuring. Some panel DVMs require an isolated power supply and are thus unsuitable for the task. If it has separate ground pins for the power and input signal, that is a likely sign that it won't work to measure its own voltage.

This is what I found. The ones that do are for car cig lighter sockets and therefore have nice electro-luminescence displays which will draw more current that I would like.

 

[crutschow]

How about one like this? It does have a backlight but draws little power.

 

[WTP Pepper]

Nice, but No International Sales. I am in the UK.

 

[crutschow]

Nice, but No International Sales. I am in the UK.

You can't buy internationally in the UK?

 

[WTP Pepper]

You can't buy internationally in the UK?

Apparently No from this dealer.

 

[crutschow]

Sorry, I missed the obvious. Perhaps one of these will work.

 

[debe]

Sorry, I missed the obvious. Perhaps one of these will work.

I have used several of these & they work well. They only draw 4Ma if you disconect the back light, as they are quite readable in daylight. For night time i use a switch for the back light if required.

 

[WTP Pepper]

Just ordered a couple. Will feedback when I get them.
TVM

 

[WTP Pepper]

Well two of them delivered in the UK from China via ebay. Cost £3.00 each with free postage, I have ordered another three. Apart from one being 10mV out compared to a calibrated source, which was just a tweak of a pot on the PCB. I cannot fault them. Without the backlight (a simple cable cut) they draw 3mA so can happily sit across my 17Ah lead acid batteries I keep for testing bit and bobs without deeply discharging them.
They retail at over £25 here.

Buy of the year to me.