Answered

Renogy Gel 100AH Settings with Rover 40A MPPT

Posted by Newbie 2.0

Sep 6, 2018 at 5:39pm

Hello everyone. I'm new to the solar hobby and I wanted to make sure that the parameters I set for my Gel battery are correct. From what I'm reading, Gels are very easy on maintenance but are temperamental if charged incorrectly. Please check the image

Posted by Newbie 2.0

Sep 6, 2018 at 5:40pm

Posted by tattoo

Sep 6, 2018 at 6:00pm

It would help if we knew what battery you have not just that it's a gel... They make more than one type gel battery... In all kinds of ah etc.....

Posted by bupkis

Sep 6, 2018 at 6:43pm

www.renogy.com/template/files/2014/06/RNG-BATT-GEL12-100.pdf

maybe admin will fill you in on how long to charge @ that voltage


The effect of temperature on cycle charge voltage: -4 mV / °C / Cell

Posted by Newbie 2.0

Sep 7, 2018 at 8:53am

It's the 100AH Gel Battery from Renogy

Posted by Newbie 2.0

Sep 7, 2018 at 8:55am

bupkis Avatar

Sep 6, 2018 at 6:43pm bupkis said:

www.renogy.com/template/files/2014/06/RNG-BATT-GEL12-100.pdf

maybe admin will fill you in on how long to charge @ that voltage


The effect of temperature on cycle charge voltage: -4 mV / °C / Cell


so instead of -3 it should be -4? Thank you for responding

Posted by bupkis

Sep 7, 2018 at 9:04am

right, that's what the linked pdf shows, I see eq time is zero? ya might consider setting boost charge time to 30 minutes during months of storage and longer than 120 mins if heavily discharged.

Your boost reconnect is ok for usage, that 14.2 means it stays in boost all the time.
Set it below float, 13.2 reference or 13.0, that means it takes a load on the battery while in float to go back to 14.2 boost charging.

Posted by Newbie 2.0

Sep 7, 2018 at 9:38am

eq time is zero because my understanding is that I should not equalize Gel batteries. My plan is to have this setup in constant use day to day so is 120 mins boost adequate?

Are you saying I should set my boost reconnect to 13.2 or 13.0? Or if I use the battery constantly then 14.2 is fine, I don't completely understand how this effects the battery.

Also my SOC percentage reading seems off on the Rover MPPT, I'm assuming 12.1-12.2 is 50% charge for this battery but the % actually reads much lower, more like 13.2v = 50%. Should I completely disregard SOC % and only look at voltage?

I apologize for all of the questions, I really don't want to damage the battery so I want to make sure I'm understanding you correctly. Thank you so much for the help!

Posted by tattoo

Sep 7, 2018 at 10:08am

Yes the SOC means nothing, forget it's even there....

What kind of battery do you have?? I know it's Gel...

Posted by Newbie 2.0

Sep 7, 2018 at 10:20am

tattoo Avatar

Sep 7, 2018 at 10:08am tattoo said:

Yes the SOC means nothing, forget it's even there....

What kind of battery do you have?? I know it's Gel...


Renogy 12v Gel 100AH

Posted by Admin

Sep 7, 2018 at 10:39am


Sep 7, 2018 at 9:38am Newbie 2.0 said:

eq time is zero because my understanding is that I should not equalize Gel batteries. My plan is to have this setup in constant use day to day so is 120 mins boost adequate?

Are you saying I should set my boost reconnect to 13.2 or 13.0? Or if I use the battery constantly then 14.2 is fine, I don't completely understand how this effects the battery.

Also my SOC percentage reading seems off on the Rover MPPT, I'm assuming 12.1-12.2 is 50% charge for this battery but the % actually reads much lower, more like 13.2v = 50%. Should I completely disregard SOC % and only look at voltage?

I apologize for all of the questions, I really don't want to damage the battery so I want to make sure I'm understanding you correctly. Thank you so much for the help!



You are correct, we don't equalize the Gel batteries. We would set the Boost reconnect voltage to 13.2V and also perhaps change the low-voltage disconnect to something lower than 12.2 since it might be disconnecting from your battery constantly under load. We would suggest 11.1V.

In regards to SOC%:

The SOC% visible on the charge controller’s screen is not a measure of the remaining capacity of the battery, but instead simply uses the voltage going into the battery to determine SOC% at that moment. The charge controller uses the voltage-method, but the reading quickly becomes distorted due to factors like discharge rate, temperature, and loads connected to the battery which “excite” the battery and change the surface charge on the battery. To get the most reliable SOC% for remaining capacity, your batteries must be at rest for 2-3 hours (sometimes longer!) with no load by which you can measure the voltage with a multi-meter.

-Renogy Team

Posted by bupkis

Sep 7, 2018 at 10:59am

hi Newbie 2.0, you have a BLANK for Eq, is that the same a zero minutes?

Posted by tattoo

Sep 7, 2018 at 11:08am

You do realize people can't just turn off there load for 2 to 3 hours a day just to check SOC?


I say forget about it, it relates to nothing...

Posted by Newbie 2.0

Sep 8, 2018 at 6:14pm

bupkis Avatar

Sep 7, 2018 at 10:59am bupkis said:

hi Newbie 2.0, you have a BLANK for Eq, is that the same a zero minutes?


yes that is correct

Posted by Newbie 2.0

Sep 9, 2018 at 9:56am

Admin Avatar

Sep 7, 2018 at 10:39am Admin said:


Sep 7, 2018 at 9:38am Newbie 2.0 said:


eq time is zero because my understanding is that I should not equalize Gel batteries. My plan is to have this setup in constant use day to day so is 120 mins boost adequate?

Are you saying I should set my boost reconnect to 13.2 or 13.0? Or if I use the battery constantly then 14.2 is fine, I don't completely understand how this effects the battery.

Also my SOC percentage reading seems off on the Rover MPPT, I'm assuming 12.1-12.2 is 50% charge for this battery but the % actually reads much lower, more like 13.2v = 50%. Should I completely disregard SOC % and only look at voltage?

I apologize for all of the questions, I really don't want to damage the battery so I want to make sure I'm understanding you correctly. Thank you so much for the help!


You are correct, we don't equalize the Gel batteries. We would set the Boost reconnect voltage to 13.2V and also perhaps change the low-voltage disconnect to something lower than 12.2 since it might be disconnecting from your battery constantly under load. We would suggest 11.1V.

In regards to SOC%:

The SOC% visible on the charge controller’s screen is not a measure of the remaining capacity of the battery, but instead simply uses the voltage going into the battery to determine SOC% at that moment. The charge controller uses the voltage-method, but the reading quickly becomes distorted due to factors like discharge rate, temperature, and loads connected to the battery which “excite” the battery and change the surface charge on the battery. To get the most reliable SOC% for remaining capacity, your batteries must be at rest for 2-3 hours (sometimes longer!) with no load by which you can measure the voltage with a multi-meter.

-Renogy Team


Thank you for recommending the boost reconnect change, I have updated that parameter. In regards to LVD, are you saying that when the battery reaches 11.1v under load (well below 50% DOD), if the load was disconnected for 2-3 hours from that point, the true voltage would return to 12.0-12.3 (50% DOD)? I am aiming for longevity in cyclic life for this battery.



Posted by tattoo

Sep 9, 2018 at 12:52pm


Sep 9, 2018 at 9:56am Newbie 2.0 said:



Thank you for recommending the boost reconnect change, I have updated that parameter. In regards to LVD, are you saying that when the battery reaches 11.1v under load (well below 50% DOD), if the load was disconnected for 2-3 hours from that point, the true voltage would return to 12.0-12.3 (50% DOD)? I am aiming for longevity in cyclic life for this battery.



If you let your batteries get down to 11.1v even under a load you won't have to worry about them they will be dead in a very short time... 11.9 is pushing it...

If they are that low I'd bet with no load for 2 to 3 hours you would be lucky if they got up to 12.0v

I'll bet your batteries are suffering now...

Posted by Newbie 2.0

Sep 14, 2018 at 7:32am

tattoo Avatar

Sep 9, 2018 at 12:52pm tattoo said:


Sep 9, 2018 at 9:56am Newbie 2.0 said:




Thank you for recommending the boost reconnect change, I have updated that parameter. In regards to LVD, are you saying that when the battery reaches 11.1v under load (well below 50% DOD), if the load was disconnected for 2-3 hours from that point, the true voltage would return to 12.0-12.3 (50% DOD)? I am aiming for longevity in cyclic life for this battery.



If you let your batteries get down to 11.1v even under a load you won't have to worry about them they will be dead in a very short time... 11.9 is pushing it...

If they are that low I'd bet with no load for 2 to 3 hours you would be lucky if they got up to 12.0v

I'll bet your batteries are suffering now...


I lowered my LVD from 12.2 to 12.0 not 11.1. I didn't feel comfortable lowering it to 11.1 even with the admin's recommendation. I guess I should bump it back up to 12.2

Posted by bupkis

Sep 14, 2018 at 8:12am

it's up to you, any load reduces battery voltage, small loads and you may not notice it, big loads will therefore a small load removed won't have much battery voltage recovery but a big load would.

load testing is on method of testing batteries!

Posted by tattoo

Sep 14, 2018 at 10:05am


Sep 14, 2018 at 7:32am Newbie 2.0 said:


I lowered my LVD from 12.2 to 12.0 not 11.1. I didn't feel comfortable lowering it to 11.1 even with the admin's recommendation. I guess I should bump it back up to 12.2


12.0 will be just fine, But like I said before 11.1 will kill your batteries..


Do you have a Kill A Watt meter? If not you need to buy one..... You need to know for sure what your using.... If your using more than your system can produce you need to back off on your load or get a bigger solar system...

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