diy solar

diy solar

Is something wrong with my mppt charge controller?

Ghodges

New Member
Joined
Oct 5, 2020
Messages
3
Hi everyone. New here.

I've got an issue with my Renogy Rover 40v mppt.

Here's the pertinent information...
400w PV panel
Rover 40
2- 200aH Renogy pure gel batteries in series (24v)
I'm using the bluetooth dongle with the app on my phone

Here's the issue...
With the mppt set to 24v and gel batteries, the advanced settings seemed to be set for a 12v system. For instance, high volt disconnect showed 16v and float charge 13.8v. You can see more details in this screenshot.

Screenshot_20200928-140550.png

As it is here, I am unable to change any of the settings that have gray cells. I also cannot change them on the unit itself.

Here's what I have done so far...
- I reset the unit per Renogy's instruction
- Under battery type I put it in "User" mode and was able to change the settings, but they all max out at 17v.

Renogy customer service, while being very friendly, have not provided any substantive help.

Any whizz bangs here that might be able to help me? I suspect I might have a defective unit but need to find out what's really going on and then maybe I can convince Renogy to step up.

Thanks in advance, Gary
 
Can you manually specify 24V instead of relying on auto-sense? The manual indicates this is possible.
 
It's normal. The charger is set in terms of a single 12V battery but multiplies it to suit the battery voltage. I have a 24V battery (2 x 12V AGMs in series). The charger is either auto-detect battery voltage or set to 24V. All the status readings are shown as actual battery voltage but the configuration is still represented as 12V. It actually advises this in the foot notes in the manual on the page that shows the voltages for the various battery types.

Here's a few of the config registers from one of my test units configured for a 24V battery.

Code:
150 155   110    141     133    130     126    120
15V 15.5V    11.0V 14.1V 13.3V 13.0V 12.6V 12.0V

The footnotes go on to advise that only Li (if you have a Li model) or user settings can be changed so you can't actually edit the other presets.

*edit*
fixed obviously incorrect voltage
 
Last edited:
Hmm, interesting. Seems that customer service would have told me that
 
I just connected my Renogy Rover 40A Li to my 24V LFP system, and it is not charging. My voltage is above the Boost Char return voltage of 13.2x 2 = 26.4v. Is this normal? Does the voltage have to drop below 26.4 v to start charging?? If that's the case I wish I could change that setting. Beautiful sunny sky today and not able to harvest it.
 
Seems like crummy pre-loaded parameters. It does charge but only when my battery is below 26.4 volts. Which for LiFePO4 the average cell is 3.3 volts and my battery is only about half full. Then it quits charging! I need to increast the "boost char return voltage" but it won't let me do that under the Lithium setting.
 
Hi everyone. New here.

I've got an issue with my Renogy Rover 40v mppt.

Here's the pertinent information...
400w PV panel
Rover 40
2- 200aH Renogy pure gel batteries in series (24v)
I'm using the bluetooth dongle with the app on my phone

Here's the issue...
With the mppt set to 24v and gel batteries, the advanced settings seemed to be set for a 12v system. For instance, high volt disconnect showed 16v and float charge 13.8v. You can see more details in this screenshot.

View attachment 24470

As it is here, I am unable to change any of the settings that have gray cells. I also cannot change them on the unit itself.

Here's what I have done so far...
- I reset the unit per Renogy's instruction
- Under battery type I put it in "User" mode and was able to change the settings, but they all max out at 17v.

Renogy customer service, while being very friendly, have not provided any substantive help.

Any whizz bangs here that might be able to help me? I suspect I might have a defective unit but need to find out what's really going on and then maybe I can convince Renogy to step up.

Thanks in advance, Gary
I found that in these times the best thing to do is simply return it, especially if you are in the window. I try to stay with Amazon as they are very responsive and I have returned no less than a half dozen items while installing my solar system (non-grid used for backup power).
 
Sorry i probably did my posting incorrectly. I found that in these times the best thing to do is simply return it, especially if you are in the window. I try to stay with Amazon as they are very responsive and I have returned no less than a half dozen items while installing my solar system (non-grid used for backup power).
 
For your lifepo4 you probably have to increase the bulk voltage to 29.2 to get it to start charging. At 26.4 its reading a full battery. I don't have the renogy but on my ecoworthy 20a mppt, I notice if I set the bulk voltage too low it charges at very low amps. maybe 1 amp or less. If you have voltage drop from controller to battery you might have to increase the bulk even higher then 29.2 (unless the renogy has a setting to compensate for voltage drop).
Its a waste not to take advantage of available sunlight. Charging lithium is where I discovered how voltage drop affects how much amps the controller sends to the battery. To see if you have voltage drop measure voltage at battery terminals, and compare that to what the renogy controller is measuring. If they are the same then your good, if the battery is lower then you need to compensate by raising the bulk voltage.
 
I had the same thought when I loaded mine up on the phone. Very counter-intuitive. The app is kind or worthless, to be honest.
 
Back
Top