Problem with OVD error on RENOGY ROVER 100amp CC

[Andrewko]

When I'm getting peak solar production for the half hour between 1130 and noon, my charge controller turn on and off about once every 10 seconds, it's really annoying because the because it beeps and the inverter shuts off and the whole cabin loses power briefly. The charge controller shows error E2 battery over voltage. I have the charge controller settings in manual mode to what the battery manufacturer (TIME USB) suggests OVD @15.0v and CHARGE LIMIT VOLTAGE @ 14.6v. I contacted RENOGY and they suggested that I set the charge controller to the factory LFP settings but those parameters are much higher than the battery manufacturer suggests. RENOGY stock settings can not be altered which is why I had in in manual mode to start with. The RENOGY stock OVD is 16.4v and the CHARGE LIMIT VOLTAGE IS 15.5v. Any advice much appreciated. I have a 24v system with 2.4kw solar panels and eight TIME USB 12v-200ah batteries wired 4s-4p.

Thank you,
-AK

 

[seneysolar]

You need to adjust the charge limit voltage on the MPPT down to 28.4 for your 24V nominal system (14.2 for a 12V battery). You are likely overcharging a cell and the battery BMS doesn't like it.

Does the Rover only read in 12V nominal and you have to multiply the figures for 24V/48V? Some of the cheap stuff does this, Id be shocked if a $600 MPPT was set up like that..

You only have 2 batteries in series for a 24V system right?

You will need to be in "USER" for battery type.

Equalization needs to be turned OFF or set to 0 minutes

 

[Andrewko]

thanks, what about he boost charge time? its set to 120 min now, and the OVD? the manufacturer says 15.0v, leave at at that or make it even with the charge limit voltage?

This CC registers 12-24-36-48 as 12v batteries and multiplies it.

 

[Andrewko]

Have I damaged the batteries by overcharging them or has the BMS protected them?

Thanks,
-AK

 

[Andrewko]

I have 4 pairs in series and then those 4 pairs are in parallel.

 

[seneysolar]

thanks, what about he boost charge time? its set to 120 min now, and the OVD? the manufacturer says 15.0v, leave at at that or make it even with the charge limit voltage?

I believe "boost" is just the time spent at Absorb V level. With 400 AH of battery, you will probably want that closer to 4 hours. the OVD shouldn't really be used/needed but you could lower it to the 14.6. Wont hurt.

This CC registers 12-24-36-48 as 12v batteries and multiplies it.

Another reason I dislike Renogy... Aside from their lousy tech support. I had a few Rovers in 12V systems I thought I remember reading that about the display only as 12V nominal. For a $600 dollar MPPT it ought to properly display voltage! I have talked to their tech support numerous times, no help at all but they are always very certain its not their fault. I swear the guy just reads from que cards.

Have I damaged the batteries by overcharging them or has the BMS protected them?

No they are probably just fine, thats what the BMS does. They may be way out of balance though. In a perfect world you should disconnect all batteries and top charge each one, then reconnect.
That may be an Annual event anyways with LFP batteries in series. Premature BMS overcharge and reduced capacity are balance issues 90% of the time on here.

 

[Andrewko]

Its an 800ah battery bank, does that change the amount of time Boost should be set to?

 

[seneysolar]

Its an 800ah battery bank, does that change the amount of time Boost should be set to?

Oh sorry i see that now.
Possibly but i would monitor it for now and see if the batteries are still taking charge after that 4 hours. With fixed panels, you will likely run out of daylight hours anyways during this phase.

 

[Andrewko]

Great, thanks for the help!

 

[mikefitz]

The RENOGY stock OVD is 16.4v and the CHARGE LIMIT VOLTAGE IS 15.5v.

These are 'emergency' settings not normal charge values. These settings only act as safety limits if the control process gets confused.
The settings that determine changing are,
Boost voltage, equilisation voltage, boost duration and float voltage temperature compensation, boost recovery.
Suggest, set boost and equilisation to 14.2 volts, boost duration 2 hours, float to 13.4, temperature compensation off, boost recovery 13.2volts. The unit will x2 for the 24 volt system. If you still get cell overvolt, reduse boost to 14.0 or down to 13.8
.

inverter shuts off

It possibility shuts off because one or more of the batteries is shutting down the charge path, leading to a voltage spike at the charger output.
Does the BMS report protection events?
It's also possible the batteries have become unbalanced between the series pairs, resulting in one battery being charged more than the other. Measure each battery voltage as they near full.