The ALMOST perfect- Inexpensive Battery Monitor -Entry Level Upgrade

[norty1]

I'm currently using the original setup to include a shunt and I'm not particularly fond of having a shunt hanging off of my battery since it's subject to contamination.

[/QUOTE]

Do you have a pic of your shunt installation on the first installation? I’m just getting around to the install and was wondering the shunt could be protected some way.
Maybe I should post this in the original thread?

[Mustang65]

The easiest way to mount the shunt is to get a 6" battery cable from the Auto Parts Store.

- Measure the size of your Shunt resistor and order a PVC project box (or electric box) on Amazon and drill a hole at each end for the cable/lug.
- Mount the shunt inside the plastic box. If the shunt is over 4" then you could do a 4x4 PVC electrical box and put the shunt in diagonally.
- Remove the existing ground cable at the frame.
- Connect the 6" cable you just purchased to the chassis ground point and one end of the shunt resistor
- Mount the plastic box on the frame next to the existing chassis ground point.
- Connect the existing ground cable (Negative) from the battery to the other side of the shunt resistor.
- Run in the CAT5 cable to where you want the Display
- Connect the CAT5 to the shunt resistor and the display.
- POP the top of a cold one, sit back and enjoy a job well done!

Don

My Registry

RVing with SOLAR

[hoppers4]

Originally Posted by norty1

Do you have a pic of your shunt installation on the first installation?

Here's my setup. I fused the power to the meter. Also used some phone wire I had hanging around rather than CAT5 cable. Also used alligator clips on everything except the shunt where I crimped on a couple of connectors.

[norty1]

Originally Posted by hoppers4

Here's my setup. I fused the power to the meter. Also used some phone wire I had hanging around rather than CAT5 cable. Also used alligator clips on everything except the shunt where I crimped on a couple of connectors.

Thanks, I'm on it.

[01tundra]

Originally Posted by Mustang65

The easiest way to mount the shunt is to get a 6" battery cable from the Auto Parts Store.

- Measure the size of your Shunt resistor and order a PVC project box (or electric box) on Amazon and drill a hole at each end for the cable/lug.
- Mount the shunt inside the plastic box. If the shunt is over 4" then you could do a 4x4 PVC electrical box and put the shunt in diagonally.
- Remove the existing ground cable at the frame.
- Connect the 6" cable you just purchased to the chassis ground point and one end of the shunt resistor
- Mount the plastic box on the frame next to the existing chassis ground point.
- Connect the existing ground cable (Negative) from the battery to the other side of the shunt resistor.
- Run in the CAT5 cable to where you want the Display
- Connect the CAT5 to the shunt resistor and the display.
- POP the top of a cold one, sit back and enjoy a job well done!

Don

My Registry

RVing with SOLAR

If the shunt lug is large enough (8mm or larger) I believe that I can connect one end of the shunt directly to the battery post (Lifeline GPL-27T) and the existing ground cable lug to the other end. Is it OK to connect the shunt directly to the battery instead of placing a jumper between the battery and shunt? I was thinking that this way the shunt is protected inside the battery box.

[Mustang65]

Originally Posted by 01tundra

Is it OK to connect the shunt directly to the battery instead of placing a jumper between the battery and shunt? I was thinking that this way the shunt is protected inside the battery box.

The problem with enclosing the shunt in the battery box is that the chemical fumes from the charging battery will eventually deteriorate the shunt and its connections. The fumes play hell on any metal that gets exposed to them. It may cause a problem with the connection, affect the charging of the battery and if you have a large load on the shunt it may over heat. Not a good idea.

Don


My Registry

RVing with SOLAR

[lonestarrpm]

Originally Posted by 01tundra

If the shunt lug is large enough (8mm or larger) I believe that I can connect one end of the shunt directly to the battery post (Lifeline GPL-27T) and the existing ground cable lug to the other end. Is it OK to connect the shunt directly to the battery instead of placing a jumper between the battery and shunt? I was thinking that this way the shunt is protected inside the battery box.

As long as the shunt is from the GND terminal to chassis ground -- I can't see a problem. The voltage across it is minimal such that even if it shorted out, there would be no concern other than not providing information for the meter.

I went the HALL Effect route. As long as my cable fits. I should be good to go.
Advantages as I see it.

+ No need for an additional cable interface. (source of resistance, source of failure, reduced cost)
+ Can measure current in both directions -- so I can monitor charging and discharging.

I have no idea if it will be more or less accurate?
- The shunt will have some variance with resistance and will change with temperature to some extent.

Mike

[BrentB]

I found this link about various ways to sense current: https://e2e.ti.com/blogs_/archives/b...e-which-to-use

[Mustang65]

Originally Posted by BrentB

I found this link about various ways to sense current: https://e2e.ti.com/blogs_/archives/b...e-which-to-use

I was using the Arduino and sensors to monitor my current (.001 volts), but in RVing that type of monitoring is not needed, although it can be used to start to identify when something is going south in the electrical circuits.

The inexpensive Chinese products do just fine for RVing.

For the home... I installed a nice unit with CT's in the service panel.
My Energy Monitor Installation

Don
My Registry

RVing with SOLAR

[PlayersZ28]

Originally Posted by Mustang65

I was using the Arduino and sensors to monitor my current (.001 volts), but in RVing that type of monitoring is not needed, although it can be used to start to identify when something is going south in the electrical circuits.

The inexpensive Chinese products do just fine for RVing.

For the home... I installed a nice unit with CT's in the service panel.
My Energy Monitor Installation

Don
My Registry

RVing with SOLAR

I have 2 Arduino units monitoring my system with a touchscreen in the trailer for display. Also a Pi that logs information.

Only because I can code it all myself.

[nighthawk87]

Originally Posted by BrentB

The only thing I don't like about the Bayite unit is that it doesn't keep a running total of the amp hours going in and out of the battery. I was looking for this type of "fuel gauge" for my battery.

It keeps track of watt hours in the bottom right. Just reset it every morning And have a calculator near to convert to amps by dividing by 12.

Another option is just convert your battery amp hr rating by multiplying by 12 to get its watt hr rating and use that. I plan to make a chart that tells me what my 100,90,80,70,60,50,40% charges are of my 210 amp hr or 2,520 watt hr is.


Sent from my iPhone using Tapatalk

[mammut]

Any issues with using the wireless version? Seems like an easy solution without having to run another wire into the my trailer.

https://www.amazon.com/gp/product/B01M5CWR2P

Based on my limited knowledge, it appears it would need to be hooked between the wires going from the battery to the to the battery positive and negative terminals. Is that right?

[01tundra]

Originally Posted by Mustang65

The problem with enclosing the shunt in the battery box is that the chemical fumes from the charging battery will eventually deteriorate the shunt and its connections. The fumes play hell on any metal that gets exposed to them. It may cause a problem with the connection, affect the charging of the battery and if you have a large load on the shunt it may over heat. Not a good idea.

Don


My Registry

RVing with SOLAR

How hot can the shunt get under normal operation? Putting it in a PVC electrical junction box with a cover could pose a heat issue as well, no?

[BrentB]

Mammut,

I have that wireless unit. The problem with it is that the wireless signal is very weak. It will not penetrate through a metal walled RV. It might be able to penetrate fiberglass, but the range is usually 10 feet or less. As for the wiring, you just have to connect the shunt between the battery negative terminal and the negative cables running to the RV.

[Mustang65]

Originally Posted by mammut

Any issues with using the wireless version? Seems like an easy solution without having to run another wire into the my trailer.

https://www.amazon.com/gp/product/B01M5CWR2P

Based on my limited knowledge, it appears it would need to be hooked between the wires going from the battery to the to the battery positive and negative terminals. Is that right?

The shunt is mounted between the Batteries NEGATIVE terminal and the CHASSIS ground connection.

Don

My Registry

RVing with SOLAR

[Mustang65]

Originally Posted by 01tundra

How hot can the shunt get under normal operation? Putting it in a PVC electrical junction box with a cover could pose a heat issue as well, no?

Under "NORMAL" operating conditions, the shunt resistor will not heat up. The difference between each end of the shunt is only a few mV's. The problem arises when the shunt connections become contaminated if stored in a battery box or exposed to the elements. The connection of the special metal between the outer ends of the shunt eventually will become affected and will no longer have a 100% connection with the other metals. That is where the heat will be generated. Otherwise the shunt temperature will be the same as the battery cable's temperature.

Don

My Registry

RVing with SOLAR

[01tundra]

Originally Posted by Mustang65

Under "NORMAL" operating conditions, the shunt resistor will not heat up. The difference between each end of the shunt is only a few mV's. The problem arises when the shunt connections become contaminated if stored in a battery box or exposed to the elements. The connection of the special metal between the outer ends of the shunt eventually will become affected and will no longer have a 100% connection with the other metals. That is where the heat will be generated. Otherwise the shunt temperature will be the same as the battery cable's temperature.

Don

My Registry

RVing with SOLAR

So corrosion = higher resistance = higher amp draw = higher temperature. Got it.

Placing shunt in a dedicated electrical junction box w/ cover reduces the corrosion chances at the electrical connection points.

Thanks for the clarification.

[Bassdogs]

Originally Posted by 01tundra

So corrosion = higher resistance = higher amp draw = higher temperature. Got it.

Placing shunt in a dedicated electrical junction box w/ cover reduces the corrosion chances at the electrical connection points.

Thanks for the clarification.

Making sure I am understanding this correctly. Should I use a standard pvc electrical junction box to house the shunt? The box s/b attached to the tongue frame and then the negative lead that is attached to one end of the shunt is reattached to the frame?

Also thinking down the road, what are the warnings that a shunt has or is in the process of failing? Should this be something that would be high on the trouble shooting list if I have a 12v system failure?

[Bookemdanno]

Here's a battery for all the battery & solar geeks. Pretty cool idea.

https://www.youtube.com/watch?v=g_cC0NKvCDY

[Vasquez Kid]

Originally Posted by Bookemdanno

Here's a battery for all the battery & solar geeks. Pretty cool idea.

Thanks for sharing this very interesting video Danno. Fasinating stuff. I love it.

Jeff