Renogy Rover 40A controller does not charge battery

BobSD

New Member
I'm hoping someone can help with this mystery.

Background: I tested the voltage on an existing 3 Renogy 100W solar panel system. I also purchased a new Renogy 100W panel. I was not able to test the currents.

The Renogy Rover 40A controller is correctly set for 12V and Li. No errors are shown in the indicator lights or throwing an error code.

The combined voltage for all 3 solar panels was about 58V, as measure by the Renogy box. Each panel had a roughly 19V output.

The voltage for the new panel was 19V also.

With all 3 panels hooked up in the system, only the 2nd, from the top, of the 4 led indicators lit on the Renogy box.This indicates that there are no issues with the battery. However the battery does not charge.

Periodically the top led of the 4, that indicates “charging", would light for ~2 seconds and then go out. When lit, the voltage, as measure at the Renogy controller, would appear to drop steadily from around 58V to roughly 20V, then the top led light would go out, charging would stop, and the voltage would return to 58V.

I unhooked all 3 panels and re-hooked up only 1 single panel. The voltage listed on the controller was 19V. The same sequence would occur as with the 3 panels hooked-up.

I then hooked-up only the new out-of-the-box solar panel. The voltage listed on the controller was 19V. The same sequence would occur as with the 3 panels hooked-up and also the single older panel.
 

Substrate

Solar Addict
Are you making sure to connect the batteries *first*, and the panels last?

I see that in the Rover manual, and is something I had to do with scc's in the past. If you hook up a panel first, either the controller would smoke/fail, or revert to a default safe float-only mode.

These types of controllers REALLY don't like to have only panels connected to them with no battery attached first. Easy to forget this if you are swapping batteries or making infrastructure changes.

If this is the case, my hope is that the Rover is just confused, and not damaged.

(Although with today's liberal return policies, the chance of a previous owner damaging stuff is high and merely passed on to the next buyer.)
 

BobSD

New Member
Hi, thanks for the reply. You may have been on to something regarding the battery. The whole situation has been fraught with complexity (see below), but thankfully it has been resolved. Last week I disconnected the battery from the controller to do a hard reset. The system worked fine after that.
Read on if you want more details on the history that led to this issue!
About 1 month ago the lithium batteries drained down possibly to their minimum and shut off. I noticed the inverter had been on for awhile without my knowledge and assumed that this caused the batteries to drain, due to the inverter current leakage. I turned off the inverter and plugged in the system and recharged it. A few days later I went for a previously arranged appointment to install a roof rack. The installers found a bad panel... and then remounted the system differently using only 3 of the 4 panels. It was after this event that I noticed the solar was no longer charging. Lots of confounding factors here.
I ordered a new panel. And went about debugging the system as described above.
Rebooting the controller by removing the connection to the batter, and thereby turning off the power, solved the problem.
We can only speculate on what caused the problem in the first place.
 

Substrate

Solar Addict
Glad that got sussed out!

It's kind of a catch-22 when controllers either fry or go dumb if the bms of an LFP battery hits the dead-man switch and basically creates an open-circuit / no battery condition for the controller.

Rather than letting your inverter or bms become the LVD, if the project is critical, consider investing in an external programmable LVD which will shut off the loads, rather than disconnect the battery from the controller. These of course draw a tiny amount of power themselves.
 
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