TBD-Smart Shunt Notes

[Wiltonh]

I have been using this shunt for a few months now and have a few notes that I have not seen elsewhere on the internet or in the manual.

My system consists of 425 watts of solar connected with a Renology controller to a 200AH LiPO4 battery.

1. The battery must be fully charged to setup the shunt.
2. You must put in the battery size and full charge voltage into settings.
3. When setting up the shunt there are 3 different resets that can be done. The first one is the zero current which must be done with no connections to the battery.
4. The second one is a full charge synchronize to tell the controller that the battery is full.
5. The third one is the clear history which is in the top left corner of the history page. My shunt came with crazy values stored in history but a clear fixed that.
6. There is some confusion about using a shunt that is connected in the negative lead of the battery compared to one that uses a donut around the positive wires. The donut has access to all power going in and out of the system. The ground connected shunt has access to all power going in and out of the battery. There is a difference. If you are using a lithium battery that has its own BMS it will shut off when full. At that point any power that is being used comes directly from the solar panels and does not get counted in the total energy created. My Renology controller gives me a total amount of KW hours created and it does not match the shunt. If you used a generator or a 120 volt converter the shunt would stop measuring the energy created once the battery was full. On the donut based system it will be accurate as long as all positive wires go through the donut. I do not consider this a disadvantage but it can be confusing when the controller has a different value than the shunt.
7. My system is setup in a trailer in Southern Baja. We get lots of sun in the winter which easily provides all we need. We do get some cloudy weather at times so here is my charging plan. Charge the lithium battery until it is full. Then charge the laptop, cell phones and tablets. By doing it that way the power used for the electronics never gets counted by the shunt but it does show up on the Renology controller.
8. People complain about the short distance the Bluetooth reaches. If you have an old cell phone, download the app and mount it somewhere as a remote display.

 

[sunshine_eggo]

Some questions/clarifications:

1. How does the battery NOT at full charge prevent the setup of the shunt?
2. Same
3. Varies from model to model. Victron offers zero current calibration for sure.
4. This seems to conflict with #1 as one can't setup the shunt if the battery is fully charged.
5. Varies from model to model.
6. MPPT reported kWh created should not match shunt UNLESS the only thing that's happening is charging. The donut (hall effect sensor) can be installed on either with the proper orientation. A shunt/donut placement is what determines visibility of current. Even when a BMS isn't in protection mode, there will be essentially zero flow to the battery - same with lead acid. A properly installed shunt/donut should ONLY show what passes in and out of the battery... because it's a BATTERY monitor, and it needs to reflect the state of charge of the battery.
7. Why is this important to you?
8. Agree.

 

[Wiltonh]

I wrote these tips as an addition to the TBD-Smart Shunt manual which does not cover some of the things you need to know to set it up. I found the app confusing at first until I fully under stood how to set it up. I did a lot of internet searching and could find almost nothing helpful. Now I like the app a lot.

1. If you setup the shunt on anything less than a full charge the percentage full display in the app will be wrong.
2. If the battery full voltage is not set correctly the percentage full display in the app will not be correct.
3. The manual on this shunt and the videos online do not mention the clear or reset for the history page. You have to figure that out yourself.
4. #1 and #4 are the same. If you sync the shunt to anything less than the full charge voltage the percentage display in the app will be wrong.
6. Agree
7. By filling the main battery first and then adding all of the other loads afterwards you are effectively adding capacity to your battery bank. If you have lots of clouds and your main battery bank does not get full you can choose to wait and fill some of those extra loads later. The camp where we are located is chronically low on battery storage so anything you can do to help that issue makes sense. Most people here do not have a generator backup so they are totally dependent on solar. In the past most RV gas refrigerators took 1 amp to run the control board. The newer models take 2.5 amps to run the controls. If you have 3 days of no solar that means you need a lot more battery.