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Renogy charge controller battery over-voltage alarm

mpickus

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Renogy Rover 100 charge controller periodically sounds a "battery over-voltage" alarm. While the alarm is sounding, the Renogy BT app displays voltages as high as 17V (for a 12V LiFePO4 battery) and I get the same reading when I use a voltmeter on the battery terminals. But after a few minutes, the alarm stops, the BT app and voltmeter both show battery at 14.6V. If I disconnect then re-connect the 6 solar panels when the alarm is sounding, everything also returns to normal. The batteries have internal over-charge protection so I am fairly sure they are never actually charged to 17V. This issue seems to happen particularly on a partly cloudy day when panels are suddenly hit with full sun. Renogy tech support has not been helpful so far. Two questions: 1) should I be highly concerned about damaging the batteries?? 2) is there any way to prevent this error alarm??
 
Sounds like your charge controller is not working properly. The 17V you measured at the battery terminal was probably after the battery overcharge kicked in and there was no load. I would not trust that charge controller.
 
Did you turn off the Batteries Equalization function?
Is the SCC set to auto detect system Voltage or you manually set to 12V?
 
Did you turn off the Batteries Equalization function?
Is the SCC set to auto detect system Voltage or you manually set to 12V?
Charge controller is manually set to 12V. Not sure what you mean by Batteries Equalization function. "Equalize Charge Volt (V)" is set to 14.4V. I do notice that "High Voltage Disconnect" is set 16.0 V which seems way too high. Also "Charge Limit Voltage" is set to 15.5V and that also seems too high.
 
I do notice that "High Voltage Disconnect" is set 16.0 V which seems way too high. Also "Charge Limit Voltage" is set to 15.5V and that also seems too high.
Seeing how you measured 17V, still looks like the charge controller is not working right, or something is not wired correctly.
 
Charge controller is manually set to 12V. Not sure what you mean by Batteries Equalization function. "Equalize Charge Volt (V)" is set to 14.4V. I do notice that "High Voltage Disconnect" is set 16.0 V which seems way too high. Also "Charge Limit Voltage" is set to 15.5V and that also seems too high.
The battery Equalize function should be turned off, Equalization should not be used on LiFePO4 battery. You need to lower the 'Charge Limit Voltage' to around 14.5 (3.62V per cell), 'High Voltage Disconnect' to around 14.75V.
 
Renogy tech support has not been helpful so far.
Typical
Sounds like your charge controller is not working properly.
Hi guys how do you turn off the equalization??
I don’t know that controller but I don’t think it has a LiFePo parameter.
Typically you’d user select AGM/sealed parameters in the ‘user’ menu - if it allows you set the equalize to the same volts as boost you’d do that, or 0.1 volts higher than charging or ‘boost’ volts. (set the equalization time to 0 or 1 minute if it lets you)

Either way 17V is like too high for anything 12V afaik and something isn’t right.

How many watts of panels?
And does this happen after a high-amp load starts up? One funny thing (that I know see others have experienced occasionally) is that when the batteries are full; bright, full sun is present; and a big load starts up - shop vac in my case- the SCC “sees” the sudden load (and interprets or sees that as low voltage) an mppt SCC can spike its output voltage triggering the inverter and (in my case) the charge controller to shut down according to their over voltage settings.
Just brainstorming- not saying this is your issue but it crossed my mind to mention.
 
Somebody smarter than me needs to correct or confirm these.

Or you could look this up using the search bar for any of the many threads that discuss custom SCC settings for LiFePo cells!

The high voltage disconnect may need to different and still be set higher than the charge limit voltage.
The charge limit voltage is too high
The float voltage may need to lower
The bottom two: over discharge and discharge limit are too low

Not my area of knowledge though
 
I’m having a similar issue. Only happens when in boost. Will briefly surge to 17.5. My loads are extremely low. Connecting more loads solved over voltage but there is still a spike.
 
Well, the overvoltage problem with my Renogy charge controller damaged some of my LiFePO4 cells even with a BMS. I ended up getting my money back from Renogy. Replaced it with a Victron charge controller which has worked flawlessly for months now.
 
Well, the overvoltage problem with my Renogy charge controller damaged some of my LiFePO4 cells even with a BMS. I ended up getting my money back from Renogy. Replaced it with a Victron charge controller which has worked flawlessly for months now.
Wow, how long was it running like that?
How do you know if cells have been damaged?
 
Well, the overvoltage problem with my Renogy charge controller damaged some of my LiFePO4 cells even with a BMS. I ended up getting my money back from Renogy. Replaced it with a Victron charge controller which has worked flawlessly for months now.
What kind of batteries were you using?
What was your experience with the renogy refund did they help with the sells too?
 
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Well, the overvoltage problem with my Renogy charge controller damaged some of my LiFePO4 cells even with a BMS. I ended up getting my money back from Renogy. Replaced it with a Victron charge controller which has worked flawlessly for months now.
How did ya find out about the cell damage? How many days was it doing this? Just yanked out the wanderer 10amp for almost exact same issue. I’m concerned with my battery being brand new system. Curious how to really check the cells on a sealed battery like the ampere time 100ah. My guess is controller went nuts over maybe 5 hours.. not good. But I was checking on it several times a day first 2 days didn’t have the crazy issue.
 
The charge volts are too high. The battery BMS is turning off the charge path and the badly designed controller is going over volts.
Set boost volts to 14.0 and float volts to 13.5.
You don't say what battery, but many pre built batteries do not have well balanced cells. This results in cell over volt at high charge volts.
Add a less than capable controller in the mix and you get unwanted effects.

Mike
 
According to my battery (yours COULD and probably is different) ampere time says boost isn’t suggested on a lipo4
As long as boost is set to an appropriate voltage, it should be fine. Your pic even shows it as the same voltage as float.
 
The terminology used by by Amper time for suitable charge voltages is a strange mix of terms and confusing.

Convension for terminology for chargers developed for lead acid is for the three stages of the charge process.
The first stage where the majority of energy is forced into the battery is the bulk stage. The voltage at the battery during this period will be higher than the battery resting voltage and will rise as the state of charge increases.
The bulk stage will finish when the target voltage set in the charger is reached. This is termed the absorbtion voltage, some chargers based on Epever designs term this boost voltage.
Once the target voltage is reached the charger will hold this voltage constant for a predetermined time or until the charge current falls below a predetermined level. This is the absorption period where the the battery is 'topped up' to full. This period may be called boost duration. For lead batteries this absorbtion period ( boost duration) could be for a significant period, 2 to 8 hours. For lithium batteries this period for most applications can be short, less than 30 minutes. Idealy the absorbtion period should be terminated when the current falls to a predetermined level, some chargers have this feature.
Once the absorbtion period (boost duration) is over most chargers reduce the voltage to a float value, this is a lower voltage than the absorbtion voltage. Lead batteries need this to keep the battery fully charged, lithium batteries do not need this, as the self discharge is low. Since most chargers have a setting for float volts, for lithium using a value equal to the resting voltage is common practice.

Some lead batteries need an equalisation stage to maintain them in best condition. This an Infrequent period were a higher than normal 'target' voltage is applied. For lithium batteries this is not required . If the charger cannot be configured to delete this equalisation, then set the voltage equal to the absorbtion volts and period to zero .

The charge voltages recommended by many battery suppliers and manufactures are related to available chargers . Since all chargers are derived from lead acid chargers, the lithium manufactures have adopted similar charge voltages .
These charge voltages are not ideal and may cause system issues where the battery BMS shuts down the charge path due to high cell volts. Long term high charge voltages may damage the battery. ( this may help to sell more batteries!)

For any charger with a timer based charge termination these are the important values for lithium that determine charge.

For a 12v nominal battery.

Absorbtion volts boost volts = 14.0 or 14.2

Absorbtion period = 30 minutes

Float voltage = 13.4 to 13.6 ( use the higher value if solar is powering loads)

Solar chargers have a 'boost reconnect, or bulk reconnect' voltage, set this to 0.1 volt lower than float volts.
Equalisation set to disable or same as boost volts with zero period.
Temperature compensation set to disable.

Mike
 
Well, the overvoltage problem with my Renogy charge controller damaged some of my LiFePO4 cells even with a BMS. I ended up getting my money back from Renogy. Replaced it with a Victron charge controller which has worked flawlessly for months now.

Oof - this is concerning. Long story short, it looks like the Renogy Rover has a DEFAULT setting of 17v for “High Voltage Disconnect". It's invisible until you install the Bluetooth dongle, which then allows you to change this setting. You must use the outdated RENOGY BT app to change it.

This is concerning. I have a much more detailed post with screenshots on another thread here:

Post in thread 'Renogy 40a mppt Li settings'
https://diysolarforum.com/threads/renogy-40a-mppt-li-settings.46856/post-856546
 
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