renogy 40a mppt charge controller shuts down when it reaches boost voltage

[darkowl]

I put a new 12v 200ah Litime battery on a renogy charge controller into a van build. I initially configured the renogy with the following settings:


High Voltage Disconnect: 14.2 V
Charge Limit Voltage: 14.1 V
Equalize Charge Volt: 14 V
Boost Charge Volt: 14V
Float Charge Volt: 13.6 V
Low Voltage Alarm: 12.1 V
Over Discharge Volt: 11.1V
Discharge Limit Volt: 10.6 V

TODAY: The voltage on the controller was set to boost with v= 14, but the victron monitor read 13.2, so the battery was not charging and was also only half charged. I rebooted the system. It started acting weird. I took a video of the problem today (FF to 16s):

I believe the error message that displayed was E1, battery over-discharged, and maybe i even saw E2 show up, battery under voltage.

with USER profile programmed settings, the batteries voltage increases quickly once pv is connected, and then the system shuts down. The "true" battery voltage right before the PV system was turned on was about 13.2.

UPDATED SETTINGS:
I changed the settings from USER to LI today, the Renogy native profile. I haven't monitored this new profile too closely, but issue hasn't reoccurred yet, possibly because the charged voltage on the LI profile is higher, at 14.4. When the battery voltage approaches the charged voltage at 14.4 will the same shut down will re-occur?

I didn't charge the battery to full before installing in the van. Was that necessary? Thanks for your help in letting me know what happened and how to fix.

 

[MisterSandals]

High Voltage Disconnect: 14.2 V
Charge Limit Voltage: 14.1 V

Are these your SCC settings or your BMS settings? I have never seen an SCC that disconnects the battery instead of terminating charge.

 

[darkowl]

Are these your SCC settings or your BMS settings? I have never seen an SCC that disconnects the battery instead of terminating charge.

Those are the settings on the renogy SCC. I dont have access to the Litime BMS which is sealed up in the battery box.

 

[MisterSandals]

Those are the settings on the renogy SCC.

Ok, let me refresh my memory on the SCC settings, its been a couple years since i got my friends Rover setup.

What does your array look like? Can you describe panel watts, Voc and configuration.

 

[MisterSandals]

I am seeing these as the available settings, no sign of an high voltage disconnect.

>>
This is an attempt to try and translate what is in the manual if programming using the buttons on the Rover itself.
over-voltage Warning 14.5
Equalization Voltage 14.1
Boost Voltage 14.1
Float Voltage 13.6
Boost Return Voltage 13.2
Under Voltage Warning 10.9
Under Voltage Recover 11
Low Voltage Disconnect 10
Low Voltage Reconnect 11.2
Equalization Duration 0 Hrs.
Boost Duration 1 Hrs.
>>

Informative thread here:

Renogy 40a mppt Li settings

Thanks for the info, I get no heat from the 2 awg wire so that's good for me. Just ordered a 40a circuit breaker to go between the charge controller and batteries plus the Blue Sea 5191 terminal block and 200a fuse today. The 8 guage is less than 2 feet and I did find a little heat when the...

diysolarforum.com

 

[darkowl]

Ok, let me refresh my memory on the SCC settings, its been a couple years since i got my friends Rover setup.

What does your array look like? Can you describe panel watts, Voc and configuration.

Sure. 3 x 100w renogy 12v solar panels, wired in series. Open circuit voltage of each panel is 24.3w (from amazon). I have since set the Renogy Rover to LI Mode instead of manual program. I attached the LI default profile.

 

[darkowl]

I am seeing these as the available settings, no sign of an high voltage disconnect.

>>

I can only program like 5 settings, no BT on this controller. I attached the settings I was able to program with USER mode that were causing the error: Battery Voltage, Equalization Voltage, Boost Voltage, Float Voltage, Over Discharge Return Voltage, Over Discharge Voltage.

So actually I think I entered these:
Equalize Charge Volt: 14 V
Boost Charge Volt: 14V
Float Charge Volt: 13.6 V
Over Discharge Volt: Default (12.6)
Discharge Limit Volt: Default (11.0)

 

[MisterSandals]

I attached the LI default profile.

Great, thanks. Surprised they actually have a "disconnect". It is ungodly high so seems unrelated to charging and likely a safety for the Rover's electronics in case its connected to a 24V battery for example. I dunno, mostly speculating though.

Lets look at the battery. Can you see any of the cell voltages or anything. It kind of looks like BMS disconnect now that i think about it.

Maybe it needs some cell balancing. To facilitate this, i'd drop boost voltage down to 13.8V (lower a smidge if this happens again... 13.75V) and up the boost duration to 2 hours.

13.8V with sufficient absorb stage should get you 100% charge. Run this for half a dozen cycles to see how it goes. If you feel like upping the charge voltage for whatever reason (13.8V is the highest any of my 4 current systems charge), increase by .1V gradually as it allows. We all have our own charging beliefs and preferences.

Hope this helps. You're getting to 13.8V which is not awful. Minor tweaking to dial things in if desired.

 

[darkowl]

Lets look at the battery. Can you see any of the cell voltages or anything. It kind of looks like BMS disconnect now that i think about it.

Cant see cell voltage unless I pull the top of the case, which I may do if needed (or just send it back to Litime).

Hope this helps. You're getting to 13.8V which is not awful. Minor tweaking to dial things in if desired.

Am I though? I mentioned in the original post even though the SCC read 13.8v right before disconnecting in the video, the Victron BMS stayed around 13.2. The battery was at about a 50% SOC from the factory before hooking it up.

Thanks for the suggestions, I can try the boost at 13.8v with the custom user profile (my assumption is it would also shut off at 13.8 just as it did at 14, but I can try it). I can't program boost duration on this model.

 

[MisterSandals]

(my assumption is it would also shut off at 13.8 just as it did at 14, but I can try it)

Yea, i was thinking it was ok at 13.8 and shut off as it inched above. Try 13.78 then.

the Victron BMS stayed around 13.2. T

I was wondering what "Victron monitor" you were talking about. The purpose of a second BMS is to monitor? Or is it a BMV shunt?

You have all the different voltages. Have you tried to figure out which is right or why they are different with a decent meter?

 

[mikefitz]

To add, with this Renogy charger using the lithium profile, there is no float or absorbtion. When the battery reached the charge, boost, 'target' volts it stops charging. It will return to charging when the battery volts falls below 'boost return volts'.
A further complication is that some units are poorly calibrated.
I suspect the strange operation of the charger was due to BMS shutting down the charge path.
Mike

 

[darkowl]

The purpose of a second BMS is to monitor? Or is it a BMV shunt?

Oops! Indeed it was the Victron BMV showing a different V than the SCC.

I suspect the strange operation of the charger was due to BMS shutting down the charge path.

Any ideas what would be triggering this shutdown? And do you think the LI Renogy charging profile would be more stable and compatible with the battery vs manually set params?

 

[MisterSandals]

Any ideas what would be triggering this shutdown?

My wager would be on a single cell triggering high voltage limit.
This is what my previous recommendations were made to address.

 

[darkowl]

My wager would be on a single cell triggering high voltage limit.
This is what my previous recommendations were made to address.

Thanks, I will try to implement some of your ideas over the weekend and measure the voltage independently with my meter.

 

[darkowl]

My wager would be on a single cell triggering high voltage limit.
This is what my previous recommendations were made to address.

I stopped by the van today to check on things. The night time voltage was 13.7 now on the Victron battery monitor, it seems the charge controller put 53ah into the battery today.

Could this mean we are out of the woods, cells are balanced, and it will reach full charge tmrw at 14.4?

 

[MisterSandals]

Could this mean we are out of the woods, cells are balanced, and it will reach full charge tmrw at 14.4?

Are you sure you need to go back into the woods? Having your battery resting at 13.7V is 100% full.

I am an "if it works don't fix it" kind of guy.... maybe thrashing the settings and BMS disconnect is more fun than i thought.

 

[darkowl]

Are you sure you need to go back into the woods? Having your battery resting at 13.7V is 100% full.

I am an "if it works don't fix it" kind of guy.... maybe thrashing the settings and BMS disconnect is more fun than i thought.

We are leaving on a trip tomorrow, although it appears that the SCC charged the battery up to 14.4 volts and was in boost mode, when turning on the fridge, some lights, and the fan in the evening, after about 2 hours and 7 amp hours of discharge, the voltage read 13.23. Is this a normal behavior, or should it be higher? Thinking something it's still wrong, or that the battery didn't charge really after all...

 

[MisterSandals]

it appears that the SCC charged the battery up to 14.4 volts and was in boost mode,

Just because you blast the voltage up to 14.4V it does not mean the battery has a fully saturated charge. Is 14.4V the resting voltage? Any other measurement, especially if you're still charging is fairly meaningless.
Not sure why you're not interested in taking the advice from anybody who has offered good solutions.

after about 2 hours and 7 amp hours of discharge, the voltage read 13.23.

2 hours of what? Letting the battery in a resting state?
The 7Ah of discharge should remove any surface charge but the big unknown is STILL whether you've gotten a full saturated charge.

Sorry I don't have anything useful to help with what you are doing to your batteries.

 

[darkowl]

Just because you blast the voltage up to 14.4V it does not mean the battery has a fully saturated charge...

Sorry I don't have anything useful to help with what you are doing to your batteries.

My apologies, you are right, I thought this problem was over once the SCC stopped malfunctioning and began charging, so I never bothered to really dig deeper.

The battery should have been fully charged by now. It sat getting charged by the SCC for couple of days and had 0 loads connected to it while getting good solar exposure. So unless something is messed up, it should have been fully charged. I will get back to you with more data, resting voltages, etc.

I appreciate your help and patience with a novice!

 

[JPiskun87]

My apologies, you are right, I thought this problem was over once the SCC stopped malfunctioning and began charging, so I never bothered to really dig deeper.

The battery should have been fully charged by now. It sat getting charged by the SCC for couple of days and had 0 loads connected to it while getting good solar exposure. So unless something is messed up, it should have been fully charged. I will get back to you with more data, resting voltages, etc.

I appreciate your help and patience with a novice!

Any updates on the system running equalization and boost at 13.8 for a longer duration to try and balance out the battery? I have a brand new 12.8v lifepo4 that when set to 14.4 on equalization and boost as per the battery manufacturer recommendations, I too would get an E02 alarm for battery over voltage. Once I dropped it down to 13.8 for both settings and a float of 13.5 my SCC would run through all the cycles flawlessly with no more alarms. Just curious if the method stated helped your situation.