Odd Issue in Renogy System

[germainJpetrov]

TLDR at the bottom. I am just trying to provide as much context as I can.
Hello all. I am new here, and somewhat new to solar power systems.
I have what I would guess to be a pretty general 400 watt 12v system. 4 100 watt solar panels, 40amp MPPT CC, 12v 200ah bluetooth battery, and a 2000 watt inverter. All of these are Renogy brand. All of it is currently installed, wired exactly how Will Prowse shows in his 400 Watt wiring diagram.
During this past winter, due to a roof leak emergency in my motor home currently still under construction, I had to disconnect and completely remove my panels from the roof in order to cover the thing in a giant tarp. So for the next few months from that point, the battery was disconnected from any charging source, while its only draw was the charge controller.
About 2 months ago, I noticed that the voltage had dropped below the under-voltage threshold, which prompted me to disconnect the batter from any and all power loads.
I contacted Renogy about the issue to see why I had under-voltage, which led to them telling me that I should hook it back up to the CC and connect the panels when possible.
I did this, and after a little while it got back above the threshold and everything appeared normal.
During that time, the renogy battery monitor read the capacity above 90%.
Seeing that it didn't take long to get the battery up to 100%, I powered on my inverter for the first time in several months to set up my back-up camera/DVR system.
The following evening I left the inverter on just to see how it would do just being on for 12 hours straight.
The next morning, I check the system and everything is completely dead.
Of course, im like wtf, as my battery monitor showed 96-100% before I clocked out for the day. So why is the system dead.
This prompted me to utilize the bluetooth feature of the battery to investigate what happened. The battery was depleted according to the BT. So I had an over-discharge.
I disconnect and reconnect the negative terminal to get something to happen on the charge controller, luckily the batt had just enough to power the CC, so that I can quickly reconnect the panels.
I have been exchanging emails with Renogy Support since the under-voltage issue. The conversation has now shifted to the question of why my battery monitor was wrong.
As I reset the batt monitor to match what the batt BT was reading, I notice that the batt monitor was trying to indicate that the battery was being charged faster than what the BT in the batt was saying. Also, the CC batt capacity reading has always seemed wildly inconsistent.
TLDR: The capacity differences between the Batt Monitor, the BT in the Batt, and the CC are huge. I am trying to figure out why, and more importantly, if something is wrong with any of my components. Any help with this would be greatly appreciated, as I can't find anything else on the web that helps, and Renogy Support has yet to provide any suggestions outside of just monitoring the system and using a multimeter...

 

[mikefitz]

Ignore the battery capacity readings on the Rover, it's voltage based and inaccurate.

The BMS reports 31.9% and a voltage of 13.2 , the monitor indicates 48% and 13.3 volts.

I think they are all incorrect, assuming the voltages are for a rested battery, 13.2 and 13.3 indicate a SOC above 70%, perhaps inthe high 80% region.

I suggest the following, disconnect the inverter from the battery, fully charge the battery, this will be when the battery voltage has exceeded 14.00 volts under charge for 30 minutes . The resting voltage, no load or charge, should be 13.4 volts +/- 0.5. Confirm all volts with a resionable meter, ( Renogy calibration is sometimes lacking in accuracy).
At this point set the monitor to 100%.

It's possible the shunt in your system is not wired correctly, the battery negative connects to the battery side of the shunt, everything else, loads and charger, connects to the other side of the shunt, possibly via a buss bar.

It will help if a circuit diagram and pictures of the install are provided. This helps identify issues such as poor quality fuses/ breakers and errors in the wiring.

Mike

 

[Tomthumb62]

The resting voltage, no load or charge, should be 13.4 volts +/- 0.5.

Ok, thank you. Not OP, but your comment helps me understand a similar issue. So if I charge it to 14.2V, resting voltage is normal for 13.4V? This is my first LiFePO4 and I didn’t realize the resting voltage drops so much like that.

 

[germainJpetrov]

Ignore the battery capacity readings on the Rover, it's voltage based and inaccurate.

The BMS reports 31.9% and a voltage of 13.2 , the monitor indicates 48% and 13.3 volts.

I think they are all incorrect, assuming the voltages are for a rested battery, 13.2 and 13.3 indicate a SOC above 70%, perhaps inthe high 80% region.

I suggest the following, disconnect the inverter from the battery, fully charge the battery, this will be when the battery voltage has exceeded 14.00 volts under charge for 30 minutes . The resting voltage, no load or charge, should be 13.4 volts +/- 0.5. Confirm all volts with a resionable meter, ( Renogy calibration is sometimes lacking in accuracy).
At this point set the monitor to 100%.

It's possible the shunt in your system is not wired correctly, the battery negative connects to the battery side of the shunt, everything else, loads and charger, connects to the other side of the shunt, possibly via a buss bar.

It will help if a circuit diagram and pictures of the install are provided. This helps identify issues such as poor quality fuses/ breakers and errors in the wiring.

Mike

Thank you for replying. I'll attach some photos of my setup. I know its not very pretty, but I tried to wire it up as close as possible to the set-up done by Will Prowse.
So, the info from the bluetooth could be wrong as well? If so, would that mean that this battery is shot? My biggest fear is that the battery just sucks...

 

[mikefitz]

I don't think there is a problem with the battery, I suspect the internal monitoring system that reports via Bluetooth is a little confused and hopefully will sort itself out after a few charge cycles.
It seems the shunt is wired correctly.
You may have set up the monitor incorrectly, use either the Renogy instructions, ( not very helpful) or 'you tube' for guidance.
Set as follows,
CAP : 0200.0 Ah capacity of your battery
Full V: 014.0 V volts under charge considered as full, 100%
ZeroV: 010.5 V battery considered empty, 0%
PowOff: 012.0 V battery approaching empty, turn off monitor display
Alarm: 012.5 V alarm flash and buzzer, 15 % capacity remaining
Atten: 0.000% not used

Once you have fully charged the battery it should auto sync to 100% SOC.
You can as an option, force 100% SOC by press and hold ^.

I guess you are using the LFP settings in the MPPT charger, not ideal but OK. With experience with your system you may decide to modify the charge volts.

Summary,
Ignore SOC on the Rover, it's very approximate.
Set up the monitor as suggested, regard its SOC as correct.
The BMS readings should become more correct after a few cycles.

Additional comment, the low cost breaker feeding the inverter could cause issues.
Advise replacing with high quality Bussmann breaker or suitable fuse with fuse holder.

Mike

 

[JWLV]

With LiFePo4 batteries, a small difference in voltage can signify a large difference in state of charge (SoC). For example, 100% SoC might be 13.0V. At 50% SoC, the voltage might be 12.8V. The point here is that battery voltage is not a good indicator of SoC. It can only give you a very rough estimate.

Being such a small system, any load can significantly affect the battery voltage. A battery that has been fully charged might drop to 12.4V under a load. Under no-load cases, 12.4V would give you a rough estimate of a nearly drained battery.

Voltage while being charged, voltage at rest, and voltage under load can and will be wildly different.

 

[germainJpetrov]

I don't think there is a problem with the battery, I suspect the internal monitoring system that reports via Bluetooth is a little confused and hopefully will sort itself out after a few charge cycles.
It seems the shunt is wired correctly.
You may have set up the monitor incorrectly, use either the Renogy instructions, ( not very helpful) or 'you tube' for guidance.
Set as follows,
CAP : 0200.0 Ah capacity of your battery
Full V: 014.0 V volts under charge considered as full, 100%
ZeroV: 010.5 V battery considered empty, 0%
PowOff: 012.0 V battery approaching empty, turn off monitor display
Alarm: 012.5 V alarm flash and buzzer, 15 % capacity remaining
Atten: 0.000% not used

Once you have fully charged the battery it should auto sync to 100% SOC.
You can as an option, force 100% SOC by press and hold ^.

I guess you are using the LFP settings in the MPPT charger, not ideal but OK. With experience with your system you may decide to modify the charge volts.

Summary,
Ignore SOC on the Rover, it's very approximate.
Set up the monitor as suggested, regard its SOC as correct.
The BMS readings should become more correct after a few cycles.

Additional comment, the low cost breaker feeding the inverter could cause issues.
Advise replacing with high quality Bussmann breaker or suitable fuse with fuse holder.

Mike

You know, I may have set up the monitor incorrectly like you said. Because, I don't remember setting the Full Volts to 14. I'll check again and report back to be sure, but I am thinking that my mindset at the time was "oh it's a 12 volt system so full voltage must be 12 volts..." I have a feeling that's what I did.
I'll go through your recommended set-up instructions and report back. Should I go ahead and carry out that set-up or wait until it reads %100 charged?
Also, whats wrong with using the lithium setting on the CC? I am currently using that setting as the instructions suggested.
And I will look into the bussmann breaker.
Thank you for your help.

 

[mikefitz]

Fix the monitor set up as soon as possible. If you set Full V to 12 volts , the monitor would report 100% SOC at this battery voltage. 12 volts on a lithium battery is only 10 % SOC. This ties In with your reported issues.

Lithium pre set on your Rover MPPT is; charge voltage , (boost volts) 14.4 volts, no absorbtion period, no float.
Once the charger detects the battery volts have reached 14.4 it stops charging, Further charging that day will not occur until the battery volts fall below 13.2 ( boost return volts is set at 13.2).
This is a good procedure to only charge the battery, ( once the battery exceeds 14.0 volt consider it full with the low charge currents in the system), but this results in no solar helping to power loads until the battery volts fall to 13.2 volts, around 70% SOC.

Setting up a more conventional charge profile could result in using more solar power and result in the battery having a higher SOC by the end of the day.

This is not the most inportant task at the moment. Getting a more consistent SOC reading is number one priority.

There are no details given for the inverter, its AC loads and any DC loads on the battery. Perhaps your battery loading exceeds possible solar input.

 

[germainJpetrov]

Roger that. I'll get on setting up the monitor correctly. I took a look at it just now and saw that I didn't even put any value in for High V or Low V, I just left it at 0 for some reason...
I have had this system installed since March-April 2022. So I have yet to put any significant loads on it either DC or AC. That's why I was so confused when the battery capacity was drained completely over night when I only just left the inverter on.

 

[germainJpetrov]

Fix the monitor set up as soon as possible. If you set Full V to 12 volts , the monitor would report 100% SOC at this battery voltage. 12 volts on a lithium battery is only 10 % SOC. This ties In with your reported issues.

Lithium pre set on your Rover MPPT is; charge voltage , (boost volts) 14.4 volts, no absorbtion period, no float.
Once the charger detects the battery volts have reached 14.4 it stops charging, Further charging that day will not occur until the battery volts fall below 13.2 ( boost return volts is set at 13.2).
This is a good procedure to only charge the battery, ( once the battery exceeds 14.0 volt consider it full with the low charge currents in the system), but this results in no solar helping to power loads until the battery volts fall to 13.2 volts, around 70% SOC.

Setting up a more conventional charge profile could result in using more solar power and result in the battery having a higher SOC by the end of the day.

This is not the most inportant task at the moment. Getting a more consistent SOC reading is number one priority.

There are no details given for the inverter, its AC loads and any DC loads on the battery. Perhaps your battery loading exceeds possible solar input.

So according to the CC and the batt monitor I have reached full SOC. Although the bluetooth app has the cap at 75.5%... The voltage has stopped at 14.3 volts on all mediums, including my multimeter. After my last comment I did reset the batt monitor full volts to 14.0. and zero to 10.5.
I didn't see your edit until just now. I am running a renogy 2000 watt inverter which powers an AC panel that supports 5 different 20amp breakers and a main breaker of 40 amps. I have 9 AC power outlets each 20amps (though I don't plan on using anything close to 20amps very often). The biggest AC load I will have will be my fridge and freezer, but they only draw just over 1 amp when running after the surge load. They are only 2.5 cubic feet, so very small, but I have yet to actually use them on that system (currently using them in my house b/c my house fridge went out). My DC loads consist of 12 overhead LED lights, 4 wall mounted reading lights, two small bathroom exhaust fans (computer fans), and a roof vent fan. I don't remember the specs of the vent fan, but with all of my lights on it only draws somewhere around 12 to 14 watts. I have yet to push the limits of the system, that's why I was so confused that my battery drained after only one night of only leaving the inverter on with no other loads.
In the near future I do want to get a different inverter. I've seen that these renogy inverters don't like surge loads even if the surge is within it's advertised limits.

 

[Renogy Solar]

I am very sorry to have troubled you.
I would like to clarify that the SOC on our CC is calculated according to an algorithm and there is a certain amount of error in the values so it may not be accurate.
If the SOC displayed by DC Home is not accurate, we suggest that you adjust the battery charge voltage to 14.6V in USER mode, and then recalibrate the battery SOC after the battery is fully charged.

 

[germainJpetrov]

I am very sorry to have troubled you.
I would like to clarify that the SOC on our CC is calculated according to an algorithm and there is a certain amount of error in the values so it may not be accurate.
If the SOC displayed by DC Home is not accurate, we suggest that you adjust the battery charge voltage to 14.6V in USER mode, and then recalibrate the battery SOC after the battery is fully charged.

Thank you for your response.
Am I adjusting the charge voltage in the charge controller or in DC Home? Or the battery monitor?

 

[mikefitz]

I assume Renogy expect you to change the charge voltage in the solar charger. Doing this will not help.
It seems the battery SOC is out of calibration.
Your charging stopped at 14.30 volts and the BT reading of 14.3 volts with zero current, this indicates a full battery. With a 200 Ah battery and low charging current, reaching 14.3 volts is a practical 100% charged.
To confirm the battery SOC has reached 100% , with the battery disconnected from charger and loads, after it's been charged, its resting volts should be greater than 13.4 volts. ( say an overnight rest)
Assuming it's confirmed the battery is fully charged, my suggestion to reset the calibration in the battery and leave the default.e setting in the charge controller in the lithium setting.

Mike

 

[germainJpetrov]

I assume Renogy expect you to change the charge voltage in the solar charger. Doing this will not help.
It seems the battery SOC is out of calibration.
Your charging stopped at 14.30 volts and the BT reading of 14.3 volts with zero current, this indicates a full battery. With a 200 Ah battery and low charging current, reaching 14.3 volts is a practical 100% charged.
To confirm the battery SOC has reached 100% , with the battery disconnected from charger and loads, after it's been charged, its resting volts should be greater than 13.4 volts. ( say an overnight rest)
Assuming it's confirmed the battery is fully charged, my suggestion to reset the calibration in the battery and leave the default.e setting in the charge controller in the lithium setting.

Mike

I'll give this a shot. Although I don't know how to reset the calibration in the battery. The DC Home app doesn't really have any where that I can change any settings. It's just a battery or device status display, a store/shopping tab and something like social media.

 

[mikefitz]

I don't have Renogy stuff so cannot advise on resetting the battery to 100%, there is little support Information in the available Renogy manual. The Renogy BT app Indictates a setting option , the cog wheel, have you inversigated that?
As I suggested if the battery reaches 14.3 volts under charge, any shows a resting volts over 13.4, then its fully charged regardless of the battery reading.
More research found the following information,
To make changes in the Renogy products you need Renogy BT app, not Renogy DC home app.
Load and run app, on the screen there is a + sign, top right, select this and enter the password to get administrator rights.
PW is , 135790123
Select the Renogy product and select the the cog wheel to see peramerter and make changes.

Mike

 

[germainJpetrov]

I don't have Renogy stuff so cannot advise on resetting the battery to 100%, there is little support Information in the available Renogy manual. The Renogy BT app Indictates a setting option , the cog wheel, have you inversigated that?
As I suggested if the battery reaches 14.3 volts under charge, any shows a resting volts over 13.4, then its fully charged regardless of the battery reading.
More research found the following information,
To make changes in the Renogy products you need Renogy BT app, not Renogy DC home app.
Load and run app, on the screen there is a + sign, top right, select this and enter the password to get administrator rights.
PW is , 135790123
Select the Renogy product and select the the cog wheel to see peramerter and make changes.

Mike

Okay. I have to let my battery charge up again for a few days. Last week I was running my inverter with no loads to make sure its power draw was normal according to the manual, which turned out to be fine.
Once charged to 100% I'll disconnect the solar panels and check its resting voltage.
I guess it makes sense that I'd have to purchase the BT module in order to change any parameters. I should have investigated the "smart" battery more before investing in it. Another odd thing I noticed is that even when charging and when drawing power, the DC Home app never showed a "present current". That has been sitting at 0 throughout this endeavor...
Thank you for the information. I'll report back in a few days.

 

[mikefitz]

Your battery already has BT built in. Download the Renory BT app, follow the instructions in my post and have access to the battery parameters .
I am not convinced Renogy know what they are doing with their products .
With better technical control of the products they brand label, it should be possible to have easier access to product setup and performance data.

 

[Renogy Solar]

Thank you for your response.
Am I adjusting the charge voltage in the charge controller or in DC Home? Or the battery monitor?

If you wish to change your charging parameters, we recommend that you use the "USER" mode on the controller to do so.
For the calibration of the battery SOC we recommend that you raise this parameter when setting the battery charge parameter, at which point the battery is fully charged to complete the calibration of the battery SOC.

 

[germainJpetrov]

Your battery already has BT built in. Download the Renory BT app, follow the instructions in my post and have access to the battery parameters .
I am not convinced Renogy know what they are doing with their products .
With better technical control of the products they brand label, it should be possible to have easier access to product setup and performance data.

Earlier this week I got the battery back up to 100%. I disconnected the solar panels yesterday and checked the voltage just now. The CC and battery monitor both read 13.4v. My multimeter read 13.39v. Im assuming that 0.01v is accounting for power usage over night by the draw from the batt monitor and the CC...
I downloaded the Renogy BT app. This app has an average rating 1.6 stars, so Im not sure how much confidence we should have in it. I connected my battery to the app and it is not giving me any parameters at all. It knows my battery because it displays the ID number from the label, but it shows nothing else, even after loading it several times. Now for the administrative inputs I am wondering what values to put in most of these categories that are in the pics I attached. I've been searching forums and I can't find anything. Or rather, which one of these categories are actually important?

 

[germainJpetrov]

If you wish to change your charging parameters, we recommend that you use the "USER" mode on the controller to do so.
For the calibration of the battery SOC we recommend that you raise this parameter when setting the battery charge parameter, at which point the battery is fully charged to complete the calibration of the battery SOC.

How do I get to "USER" mode? The manual is not helping in this regard. I mean, it tells me to access this by using the DC Home app, but on the app it has no such function or option, or maybe the place to change battery settings is very hard to find.