Help needed with volt/amp monitor

[havnfun]

I installed a volt/amp/used monitor in the slot that just had 2 USB slots. Being the electrical genius that I am, I need some help. I connected the 2 existing wires and I get a good voltage reading and the USB connection works but the amps show as 00.00. So, okay, whats up? Can I get the amps on that monitor or not? Does it have anything to do with reversing the 2 wires?? Do I need to run another wire form somewhere?
Thanks,
Jeff

Happy RVing.

[JimD]

Not sure what you installed so a picture or model would help. In any event, you will not be able to get an amp reading from what you describe. The 2 wires you hooked up were for measuring voltage only. To get a current reading you need to be connected in series with the supply line not across it.

I have a cigarette lighter power monitor that measures current that is coming out of the USB port on it. Maybe this is along the line of what you have.

I installed a voltage/current monitor in my motor home. It required a shunt be installed in line with the battery's negative cable at the battery. A wire is connected to the shunt, which is basically just a chunk of metal, and this wire is what measures the current being pulled from the battery. It measures the very small voltage drop across the shunt which is translated to amps.

This single wire is routed to the display along with 2 others that measure the battery voltage. Works very well.

Measuring voltage is very easy. Current on the other hand is much more involved.

[havnfun]

Thanks Jim. I'll have to disassemble it and look for 3 connections or wires. I only recall two wires or terminals coming out of it.
I also don't know how to attach pics from my android phone to this forum messaging, either. Maybe someone could show me how to do that.

Happy RVing,
Jeff

[DrSmart]

You might get more replies if you provide what exactly the device is. There lots of folks on here with electrical knowledge. Do you know the make and model or part number or as Jim said, post a photo.

[JimD]

The way I get photos from my phone for posting here is to either use a USB cable to connect the phone to my computer or attach the image to an email to myself where I can download to the computer. Once there you simply attach it by clicking on the paperclip up top and selecting the file. If it is an image file, such as a jpg, it will attach it plus show it in the message.

[havnfun]

Jim- The charger is a "FXC Car Auto USB Quick Charger." Found on ebay or google search. On the back of it there are only 2 terminals, a plus and a minus. It's round and about 3cm.

I attached a jpg file but it won't post on this response. It shows under ADDITIONAL OPTIONS, ATTACH FILES but thats as far as I can get it.

Happy RVing,
Jeff

[havnfun]

Whoa....shows now.
Jeff

[JimD]

That appears to be a nice unit for charging USB devices and monitoring your battery voltage. It is not able to measure the current being pulled from the battery. If it shows current it is what is going out the USB connector.

A voltmeter like you installed is something I say is mandatory when operating a RV, especially if you boondock. If you are hooked up 100% of the time you don't really need to monitor battery level.

Monitoring current draw is sort of an extra item that is not really required. I have the option and although I look at it now and then, I actually rely on the voltage reading more than anything else. Yes I can see how much current is being drawn when I fire up my inverter or turn various lights on but it really doesn't make any difference to me. When the battery voltage starts to drop that is what I watch closely.

If you really want to watch your current draw there are a number of different options available on Amazon. I even saw one that measured the current by using a coil pickup that is placed around one of the battery cables. Not sure how accurate that is with DC voltage. Most units require a shunt be placed inline with the battery cable. DROK seems to make a number of units.

Here is an example of a unit that is a bit fancier than mine. If you will be going with a unit make sure to pick one that can measure the max current you will be drawing. Mine is 100 amp and I have seen almost 50 amps being drawn when running the slide or levelers.

[havnfun]

Thanks for the info., Jim. Looks like I got suckered into buying this cause it has the Amps on the display. I actually thought it would give me the current reading. If had known what you have provided, I'd have gone another route.
I watch the volts pretty closely also but I thought amps would be nice to know so I could see what various appliances draw. But oh well...live and learn.

Guess my amps will always be 00.0! LOL

Happy RVing,
Jeff

[Britt]

New here, but lots of useless experience. I went with one from Amazon and its working great. I had to extend the wiring with a CAT 5 networking cable to get it to my dash. I took a hole saw to the cigarette lighter below the 12v outlet and installed it there. Looks professional and works great.

https://www.amazon.com/gp/product/B07FGFFHC6/