Renogy Rover 100 Charge Settings

[jhallprot]

The system consists of 8 Absolute GP 100G21 VRLA Batteries, I have them wired series-parallel, two sets of 4 in series in turn wired in parallel for a 24v system.


Q1: Assuming these are 1200ah batteries and the Rover has 'Nominal Battery Capacity' parameter between 0-9999 do I set it to 1200? Default for autodetecting 24v it is setting a value of 200.

Q2: All the defaults for charging limits seem too high. It is currently around 105 degrees f here so the manual for the batteries says 2.20 is the lower limit VPC. The batteries are 3 cell so my math puts the maximum charge voltage at 26.4 or 13.2 x 2, however the Renogy charge controller is defaulting up to 14v. What should I use for float/max/equalize settings for these batteries?

 

[sunshine_eggo]

Q1:

From here:

https://www.exidegroup.com/eu/sites/default/files/2017-08/Absolyte%20GP%20Constant%20Current%20Specifications_1.pdf

Unless I've missed something, these have a C8 rating of 1000Ah, but they also list a C24 rating of 1152. Since C24 is more consistent with a C20 rating, I would use that value.

If you have 8 6V bateries in a 4S2P configuration, you have 1152 * 2Ah or 2304Ah.

I would be very surprised if the set battery capacity has any significant meaning operationally.

Per the attached datasheet, I would also ensure you are complying with:

https://akkutron.at/wp-content/uploads/pdf/Absolyte-GP_Gebrauchsanweisung_E.pdf

Sections 11-15 in particular.

Q2: Proper temperature compensation is required. If your controller is not capable of temp comp, then it should be replaced. A temperature sensor must be ON the battery. The controller can't just rely on ambient temperature for compensation. Battery temperature is what matters. See 11.1 in the manual.

 

[jhallprot]

Thanks yes I have the temperature probe inserted into one of the battery frames. I hadn't considered that it would be lowering float voltage based on high temps, had only assumed it would cut off with very high temps.

I just lowered from 13.8 to 13.2 to be safe until I understand this better. Thanks for the links I have some pdf manuals but I will check those as well.