House Battery Problem

[Scalf77]

No, your diagram is correct. Adding a wire directly between the two would bypass the shunt and its purpose. While you appear to have an active shunt (Some control logic mounted on it) in reality the actual shunt part is just a precision resister. As we pass current through the shunt we can measure the voltage drop from the battery side to the loads side and thus calculate current. Just look at it as piece of wire. If we give current a path around the shunt, we can't measure it.

What brand battery monitor is it?

[CDACamper]

The monitor is a cheap one off amazon. I installed it a couple of years ago so maybe it's dying (link below). Everything is stable and working as normal now so troubleshooting is going to be harder. I turned on the fridge last night to see what the voltage drop looked like. It barely moved, so I am fairly confident the battery is ok. I guess I will double check my connections by dropping the battery. I'll also double check my ground connection to the wheel well. Are you aware of a better place to ground under the goucho in a 2001 EB50 build? Are the bolts for the goucho seat a good ground location rather the the wheel well?

AiLi Voltmeter Ammeter Voltage Current Meter Voltmeter Ammeter 100V 350A Caravan RV Motorhome 999 AH

[posplayr]

Originally Posted by CDACamper

The monitor is a cheap one off amazon.

AiLi Voltmeter Ammeter Voltage Current Meter Voltmeter Ammeter 100V 350A Caravan RV Motorhome 999 AH

I have one of those that I used a fair amount for testing LiFe cell performance including matching cell capacities.( I used the 100 Amp shunt rather than the 350 amp version)

Unless you think yours is broken, I would not worry about it giving a problem. There is not any way for it to affect your battery performance unless you have corroded bolt connections which would be the same potential issue you have at the battery terminals.

[Scalf77]

Originally Posted by Scalf77

The other question is where do you get the voltage for the reading for the battery monitor. Not a huge fan of the wheel well connection, but it works. Looks like possibly the monitor has a 3 wire power connection Common ground, Positive to power the monitor, and a positive to read the battery voltage.

I was is wrong, that connector is just for communication port for the display. That battery power/reading connection on the green terminal block.



Were you using that monitor for your bad voltage reading?

[CDACamper]

I was reading voltage on the monitor. I have a feeling that the monitor just glitched but I'm still going to take the opportunity to drop the battery, check connections and add a ground buss bar under the seat to clean up the wiring.

[kbeefy]

I don't think thats how shunts work. A shunt has to have the current passing thru it. That shunt is wired in parallel. So the current can travel around it.


Maybe there are other types of shunts and I don't know what I'm talking about.

[posplayr]

Attached is the diagram for the AiLi Battery Monitor.

All the negative ground return currents (P-) should enter from the right into the shunt and return to the battery (B-). I don't recall the shunt sensitivity but we can imagine it might be something like 1 mV per amp for the 100Am meter yielding 100 mV at 100 amps.

This is not enough to power the display or any conditioning circuitry on the shunt so there is a screw terminal B+ for the low current positive battery connection.

B+ is used to power the display and sample the battery voltage for power measurements.

While I did not modify this diagram, there should be P+ and P- busbars to the right-hand side of the diagram.

You should use some type of a terminal treatment for any high current terminals (> 10 amps)

At DIY Solar there are some recommendations for contact grease. This product from MG Chemical may not get the best but is certainly better than base metal.

https://www.amazon.com/MG-Chemicals-.../dp/B00SMRNSR0

This is recommended for PV solar and battery (not specific to PV solar) connections.

Gardner Bender OX-100B Ox-Guard.
https://www.zoro.com/gardner-bender-...caApMbEALw_wcB


Some of those connections look a little old. I would personally recommend using some Deoxit to cut through and treat some of the existing oxidation, let it dry and then apply the grease as a double layer of protection.

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

[posplayr]

Originally Posted by CDACamper

1der, yes, the battery is connected to the battery neg. side of the shunt. Here is a diagram and picture of what I have.

Do you recommend a better location to ground a buss bar that is inside the van (under the seat area? Would one of the bolts that bolt down the goucho seat be better?

That picture exemplifies why it takes so long to do wiring. I spend a lot of time dressing the wiring and organizing and sometimes having to remake cables to avoid such a mess.

However, I could never make money doing that type of work commercially.

[CDACamper]

Originally Posted by posplayr

Attached is the diagram for the AiLi Battery Monitor.

All the negative ground return currents (P-) should enter from the right into the shunt and return to the battery (B-). I don't recall the shunt sensitivity but we can imagine it might be something like 1 mV per amp for the 100Am meter yielding 100 mV at 100 amps.

This is not enough to power the display or any conditioning circuitry on the shunt so there is a screw terminal B+ for the low current positive battery connection.

B+ is used to power the display and sample the battery voltage for power measurements.

While I did not modify this diagram, there should be P+ and P- busbars to the right-hand side of the diagram.

You should use some type of a terminal treatment for any high current terminals (> 10 amps)

At DIY Solar there are some recommendations for contact grease. This product from MG Chemical may not get the best but is certainly better than base metal.

https://www.amazon.com/MG-Chemicals-.../dp/B00SMRNSR0

This is recommended for PV solar and battery (not specific to PV solar) connections.

Gardner Bender OX-100B Ox-Guard.
https://www.zoro.com/gardner-bender-...caApMbEALw_wcB


Some of those connections look a little old. I would personally recommend using some Deoxit to cut through and treat some of the existing oxidation, let it dry and then apply the grease as a double layer of protection.

https://www.amazon.com/gp/product/B0...e?ie=UTF8&th=1

@Posplayr Thank you for the info. I'll look into the grease and compare it to the dielectric grease I have.

My system is wired like the diagram you included. I am unclear if I should also ground the load side of the shunt (the side connected to the load negative) to the a chassis ground. It doesn't specify this in the diagram. I currently have this side of the shunt connected to the top of the wheel well.

[CDACamper]

It looks like this stuff (Gardner Bender OX-100B Ox-Guard.) is the opposite of the dielectric grease I have been using. The dielectric is an insulator and this is a conductive connection enhancer. I have never seen it before but it looks like a great idea to use. I am going to put some on order for the chassis ground.