12 Volt Power Meters

[2825Matheny]

Hello,
I will be installing two Bayite power meters (Amazon # B013PKYILS). One will monitor the output of the converter. And the other will monitor the power consumed by all loads in the RV. Each meter is a BAYITE-PZEM-101 and each has a 100 amp/75 mV shunt.
My question is about the shunt wiring. The shunts will be installed in the front compartment where both my converter and batteries are located. The meters will be installed inside the RV near the load center. There will be about 25 feet between the shunts and the meters. I plan on using 18/2 speaker wire to connect the shunts to the meters. Is the wire I plan on using appropriate for this distance?
With this post is a schematic of the shunt wiring. Does anyone with more smarts than I see any issues with my plan?
Also, with this post is the complete schematic of my 12-volt wiring.
Thanks in advance for your input.

Here is a link to my Good Drive Folder with info, PDF's, photos, etc. about there meters and installing them.
https://drive.google.com/open?id=1KGD_xFPDWBcqqaHcRSaBk_3x1D8gqMYv

[gbkims]

Hello,
I will be installing two Bayite power meters (Amazon # B013PKYILS). One will monitor the output of the converter. And the other will monitor the power consumed by all loads in the RV. Each meter is a [COLOR=#333333][FONT=Arial]BAYITE-PZEM-101 and each has a 100 amp/75 mV shunt.
My question is about the shunt wiring. The shunts will be installed in the front compartment where both my converter and batteries are located. The meters will be installed inside the RV near the load center. There will be about 25 feet between the shunts and the meters. I plan on using 18/2 speaker wire to connect the shunts to the meters. Is the wire I plan on using appropriate for this distance?
...
Thanks in advance for your input.

Nice Drawing!

I think the wire gauge should be fine. The meters function similar to the battery monitors like Victron or Bogart that use current shunts.
The Victron BMV702 comes with about 30' of 24 gauge wire for its shunt.

The shunt look like they'll depend on the wires to support and hold them in place.

[jkwilson]

What happens if that speaker wire gets a hole rubbed in the insulation? It isn’t fused properly to avoid a fire.

[Cate&Rob]

Hi Jamie,

I installed one of these a couple of years ago. I put mine in the front compartment, fastened to my inverter with two sided tape. I seldom refer to it unless I am diagnosing something electric. It seems to be accurate but the tiny button to reset or page through is kind of difficult to use. I fused the power feed as John suggests . . . I think it is a 1A fuse. The wire that came with this gauge is heavier than the signal cable on the Victron BMV702 . . . but is still just signal transmission without significant current. I have the Victron on my boat and this monitor seems to be just as accurate for a fraction of the price.

Rob

[gbkims]

What happens if that speaker wire gets a hole rubbed in the insulation? It isn’t fused properly to avoid a fire.

For the 18 Awg from the shunt's measuring points, I don't think enough voltage or current can be generated to do much but make the meter not read correctly.
With 100A flowing thru the shunt it creates .075 volts, less amps thru the shunt then lower voltage(drop) generated.

Bogart's Installer Instructions have some good info and a overall drawing on their connections.
Their use of an extra wire on the measuring wires reminds me of RTD wiring in instrumentation to eliminate voltage drop of the wires affecting the measured voltage at the meter.
They show to fuse the +12 that powers their meter, not the measuring wires.
http://www.bogartengineering.com/wp-...2=false&r=wide

[2825Matheny]

No worries. FYI this is for a shunt. Voltage is in the mV range and current is very very low too. And, this shunt is installed on the Negative side of the circuit. It is very common practice to install shunts without circuit protection.
And speaker wire is rated at 30 volts. I'll be well below that at 12 volts. So the dielectric properties of the insulation are OK. And, as typical with any wiring installation and best practices, all wires are protected from abrasion when installed.
Thanks for looking out for me, but all is well.

[howson]

I sure hope there's someone else out there that didn't know the purpose of a shunt. I'm guessing the probability is high. This video explains it well:

BTW--thanks for the schematics, Matheny (Jamey and/or Peggy?). Helped me to understand this new-to-me topic.

[gbkims]

I sure hope there's someone else out there that didn't know the purpose of a shunt. I'm guessing the probability is high. This video explains it well:

BTW--thanks for the schematics, Matheny (Jamey and/or Peggy?). Helped me to understand this new-to-me topic.

Videos good, wish I'd learned electronics with more visuals.
And to EEs, why do we have to have "Conventional Current Flow Theory"?

[Cate&Rob]

why do we have to have "Conventional Current Flow Theory"?

This goes back to the "best guess" by that guy named Ben Franklin .

Rob

[Country Campers]

If my electronics teacher looked like that I may have payed a little more attention.Probably would have not learned more but would have payed more attention.

Brian