Renogy Rover 30A with LiPo batteries

[hummbug]

I have a bunch of extra e-golf battery modules I'd like to use with my Renogy Rover. They are 4s3p LiPo chemistry batteries from what I can tell, which means fully charged they should be at 16.8 volts. I have a Renogy Rover 30a unit and the bluetooth module, but I can't seem to get the parameters set up to work right with these batteries. Seems they want a 12v or 24v system. Even when I put the controller in USER mode and set the parameters: If I set it on 12v I get a battery overvoltage error, and on 24v the system seems to want to overcharge them. My DC load is just landscape lighting which seems to be ok with the 16.8v output.

I set:
HV Disconnect, Charge Limit Voltage, Equalize charge voltage, boost charge voltage, float charge voltage, boost char return voltage all to 16.8v
Over disc reture volt, low voltage alarm, over discharge volt all to 12v

Am I just using the wrong controller or is it possible to get this to work?

 

[learning all the time]

I have a Renogy Rover 40A. My best recommondation would be contact Renogy although they have not been the most helpful to me.

 

[hummbug]

I cross-posted here: https://support.renogy.com/en/support/discussions/topics/35000017483?page=1
Seems unlikely I'll get support from Renogy.

 

[Ampster]

Verify your chemistry. True Lipo (Lipoly) is the most flammable chemistry followed by NMC then LFP (LiFePO4) . They run at different voltages also.

 

[learning all the time]

Verify your chemistry. True Lipo (Lipoly) is the most flammable chemistry followed by NMC then LFP (LiFePO4) . They run at different voltages also.

Good catch Ampster. I got so hung up on the Renogy and programming I completely missed the LiPo. AKA: The worlds most dangerous battery.

Hummbug, I also have the bluetooth module. I have also had programming issues with it. Renogy now has upgraded modules of the BT1 I think its called. You may have to eliminate the BT module cause I am starting to think it does not play well with the controller for issues that I have had.
If you go with the LiPo batteries wrap them in a flame resistant bag. I use these in RC cars and they can get hot as I'm sure you know. These are also what Samsung tried using in their phones and almost ruined their cell phone business.

 

[Ampster]

These are also what Samsung tried using in their phones and almost ruined their cell phone business.

Thanks for that explanation. I had not heard that detailed explanation before. That problem gave all Lithium batteries a bad name.
@hummbug , can you verify the actual chemistry? It will have a significant bearing in your settings.

 

[hummbug]

They are lithium, but not LiFePO4.

Also perhaps not LiPo but not "pouch" batteries.

 

[Ampster]

I am sure they are Lithium. If not LFP the nominal voltage per cell might be 4.0 volts for NMC or other Cobalt related chemistries. I would try to get several corroborated sources to verify.

 

[hummbug]

They are definitely happy at 16.8v fully charged, they are 4s3p configuration. 4.2v per cell.

 

[learning all the time]

I am sure they are Lithium. If not LFP the nominal voltage per cell might be 4.0 volts for NMC or other Cobalt related chemistries. I would try to get several corroborated sources to verify.

This was the best link i could find: https://parts.vw.com/p/Volkswagen__/Drive-Motor-Battery-Pack-Charger/65137822/5QE915681B.html
Not an exact match but close

 

[Ampster]

Okay the normal range for NMC like chemistries is 4.2 to 3.0. That is the same as my Nissan Leaf modules.
Back to your original question:
I would set;
-HV Disconnect, 16.8
-Charge Limit Voltage,16.6
-Equalize charge voltage, try to disable or set time to zero.
-boost charge voltage, i think this is the same as Charge Limit so try 16.6
-float charge voltage, you want this below the voltage the cells settle at so try 15.8
-boost char return voltage, this should be lower than float and may depend on usage. Try 15.6 for starters you just want this and float settings to avoid micro cycling.
Over disc reture volt, low voltage alarm, over discharge volt all to 12v, i am consrvative, especially with used cells near the bottom so I would start with 14 (3.5 per cell) to make sure you don't have a runner.

 

[hummbug]

Further experience here just shows that the USER mode just doesn't work. It doesn't seem to pay attention to the settings in there. I replaced the battery with 18650 batteries in a 3s6p setup and settings are just ignored. Anyone have a suggestion of a solar controller that really works with Lithium 18650 batteries?

 

[learning all the time]

Further experience here just shows that the USER mode just doesn't work. It doesn't seem to pay attention to the settings in there. I replaced the battery with 18650 batteries in a 3s6p setup and settings are just ignored. Anyone have a suggestion of a solar controller that really works with Lithium 18650 batteries?

So two questions: First, are the lithium parameters not for your batteries? Second, are you using bluetooth for user settings? Manual says user changes have to be done by bluetooth. I'm very curious with this issue as I have the 40 amp model.

 

[hummbug]

The settings I attempted above wear for a different set of batteries I figured the controller was confused between 12 or 24 volts and I put in a 3s setup that was much closer to 12 volts. I am doing the configuration with Bluetooth and it is really not working

 

[gnubie]

I have a couple of Rover 40li (OEM is SRNE, li just means it has a lithium preset) and can program them to suit my own designs via modbus (which is what you are doing with bluetooth). The settings stick and work. The only quirks I have found, and it may just be my lack of understanding of the device based on the rather poor modbus documentation) are:

1) Absorption time must be set in multiples of 10 even though the setting allows single digits. Anything not a multiple of 10 is treated as invalid but no error is produced and the unit will not, at least in my testing, exist absorption charging. It may be using tail current mode in this situtation.
2) Manually setting battery voltage rather than relying on automatic caused a similar issue, seemingly endless absorption charging.

As far as I can see the controller is intended for 12/24 operation without any ability to specify a battery outside of those numbers. Any value outside of those assumes automatic selection from those values. Sure you can manually enter voltages but the battery voltage must be specified as auto or one of those. From the modbus specs it's likely that all SRNE controllers act in this way - specific battery voltages (12/24/36/48/96) with anything else being autodetection into one of those values.

I can't say for sure but if you are trying to do odd-ball voltages with these controllers, you may have made a mistake buying one.

 

[hummbug]

Thanks for the info. I don't see settings for "absorption time". Do you know where I can find this?
How are you setting via Modbus directly? I'm thinking that there is an error in the BT module and it isn't really setting all the stuff right, so if I can do it with Python or Node.js with modbus over serial I'd be glad.

 

[gnubie]

It might call it boost. I have a RS232 USB adapter and some perl scripts that I use to throw commands at it. You could easily do it with python too. If you want the register map, https://github.com/wildmountainfarm...ther/solar/resources/renogy_rover_modbus.docx

 

[hummbug]

'
My settings, set and verified to be set, but controller still claims battery overcharged and past 100%.

 

[gnubie]

There is an option to set the Ah rating of the battery but that only works if the load is on the load output terminals so it can count Ah in and out. Otherwise it falls back to voltage based SOC which as we all know is as accurate as a drunkards game of darts. It will likely be basing the SOC from the nominal battery voltage too, mine does. So if you configure '12v' battery regardless of your charging voltages once it gets to what ever it considers to be fully charged for a '12v' battery that's what it shows on the display - 100%. As you take your battery higher in voltage, it will complain about overcharge, flash the battery LED etc but in reality it's not actually over charged and the charge process will continue on as per normal based on your custom voltages.

This is only from experience with my Rovers.

 

[hummbug]

Well you can see that there is plenty of sun (69.6v on the panels) and battery is at 12.2v but charging is off. Should be topping it off to 12.6v as I have set.