Renogy Rover 40A Li acting weird?

[CrispySonOfA]

I have a Renogy 40A Rover charge controller with 600w of panels installed. This unit has worked for about a year and 6 months without issue with this setup. I have a 200AH lithium battery from renogy as well. What I was experiencing is that the controller would start with a high amperage going to the battery and then slowly drop down to almost nothing. Nothing has changed and I checked all the connections. I am curious if this is something commonly experienced with a bad controller or other. Any insight is appreciated. Renogy tech support is awful so I figured I'd ask here before subjecting myself to that. I am a licensed electrician and have a good clamp/multimeter. I am more curious if this is a common issue with these rovers. I noticed the controller senses the SOC at 100%but says this is a reference only. The battery thinks it's at 86% so I'm not sure where the disconnect is with the two. I appreciate the insight very much.

 

[Dynoman]

I have a Renogy 40A Rover charge controller with 600w of panels installed. This unit has worked for about a year and 6 months without issue with this setup. I have a 200AH lithium battery from renogy as well. What I was experiencing is that the controller would start with a high amperage going to the battery and then slowly drop down to almost nothing. Nothing has changed and I checked all the connections. I am curious if this is something commonly experienced with a bad controller or other. Any insight is appreciated. Renogy tech support is awful so I figured I'd ask here before subjecting myself to that. I am a licensed electrician and have a good clamp/multimeter. I am more curious if this is a common issue with these rovers. I noticed the controller senses the SOC at 100%but says this is a reference only. The battery thinks it's at 86% so I'm not sure where the disconnect is with the two. I appreciate the insight very much.

Renogy sells value priced equipment which is not top of the line. With that being said my Rover 40 amp solar charge controller has been going for about 3 years now and works well, but one does need to know its limitations. The Rover is actually manufactured by SRNE.

As you said the Rover SOC indicator is not accurate and is not to be used. If the battery has a SOC indicator that would be the SOC to look at.
Also a good battery shunt monitor such as the Victron Smart Shunt is a very good way to know the SOC of the battery.

https://www.amazon.com/dp/B0856PHNLX

It is very possible that after 1 1/2 years of use the Renogy battery has lost its Top Balance of the individual cells inside the battery at full charge. Problems occur when the battery approaches full charge similar to what you describe. What can happen is one cell in the battery will go over voltage and the BMS will shut down charging to the battery causing problems like described. One thing to try is to set the Boost Charge Voltage lower and extend the Boost Charge Time in an effort to balance the cells in the battery. If the battery still shuts down lower the Boost Charge voltage more until the BMS no longer shuts down charging to the battery and will remain in boost. Run the boost for 2 hours or more in an effort to balance the cells before going to float mode. Over days or weeks try and slowly increase the Boost Charge voltage in an effort to get a higher state of charge from the battery.

Typically when all is working properly the Rover will go from MPPT charge mode into Boost charge mode and the current going to the the battery will slowly decrease to about 4 or 5% of the AH of the battery while in Boost and then go into Float mode. Adjust the Boost Charge Time Minutes at the desired Boost Charge Voltage to accomplish this scenario. So with a 200AH battery x 5% = 10 amps before going into float mode. Use the DC clamp meter on the Rover output to the battery to measure as the Rover Amp output is not very accurate although much better than the Rover SOC indicator which is worthless.

Don't know what settings are being used in your Rover and not familiar with the Renogy 200AH lithium battery. Assuming it is a 12 volt Lifepo4 battery that charges to max of 14.6 volts a suggestion would be to click the link below and read this message and then read the entire thread. There is significant information on the Renogy Rover MPPT solar charge controller.
Hope it helps...

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...

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