oldjohnt Posted July 11, 2023 Report Share Posted July 11, 2023 (edited) Hey you Solar Equipment Experts and users, I have a question: I have a Renogy Rover 60 Amp MPPT Solar Charge Controller feeding my SOK 412 Amp Hour 12.8 Volt Lithium Battery Bank, has worked perfect two years using the Renogy FACTORY lithium charge parameter setting which charges around 14.4 Volts. I want to add a second Renogy Rover 20 Amp MPPT Charge Controller fed by another new panel ALSO SET at its same factory Lithium 14.4 Volt charge. QUESTION with the outputs of both controllers,,,, identical other than size,,,, each at same factory charge rate of 14.4 Volts,,, feeding the same battery bank,,, WORK OKAY AND EACH ADD CHARGING AMPS AND NOT FIGHT EACH OTHER ???? The reason I asked is I've seen 2 or even 3 charge controllers feeding a common battery bank and they worked TOGETHER and added charging amps, however I've been told by someone (supposed to know??) NOT to do this ????? I could series up panels, but my Renogy may not be capable of either the new total higher voltage or all the charging amps capacity my panels could deliver grrrrrrrr A new single bigger Volts and Current MPPT ??? PS I could bump up EACH controller to 14.6 charging voltage but that's NOT my issue/question, Im concerned if they will work TOGETHER add charging amps and not interfere with each other ??? Thanks yall John T Edited July 11, 2023 by oldjohnt Quote Link to comment Share on other sites More sharing options...
Randyretired Posted July 11, 2023 Report Share Posted July 11, 2023 I have 2 Epever controllers and an Outback controller. On occasion I will add the inverter/charger. It works great. Since the controllers are voltage regulated these keep the voltage needed or as high of voltage as the solar will support. On occasion I have seen one controller working a little harder than another but I don't see that as a problem. Each controller has different panels and the panel voltages vary significantly. Quote Randy 2001 Volvo VNL 42 Cummins ISX Autoshift Link to comment Share on other sites More sharing options...
Randyretired Posted July 11, 2023 Report Share Posted July 11, 2023 I would also like to add that as long as the charge controllers combined are within the total amp capacity of the batteries I cannot think of a reason that this isn't a good idea. With LifeP04 it would take a really powerful charger or solar array to push to many amps. The controllers I use are all different sizes. Quote Randy 2001 Volvo VNL 42 Cummins ISX Autoshift Link to comment Share on other sites More sharing options...
GlennWest Posted July 11, 2023 Report Share Posted July 11, 2023 (edited) I have 2 all in one units. So two different mppt controllers feeding same battery pk. Works fine. Also both units have dual mppt controllers so I could have 4 feeding same pk if more solar added. Edited July 11, 2023 by GlennWest Quote 2003 Teton Grand Freedom towed with 2006 Freightliner Century 120 across the beautiful USA welding pipe.https://photos.app.goo.gl/O32ZjgzSzgK7LAyt1 Link to comment Share on other sites More sharing options...
oldjohnt Posted July 12, 2023 Author Report Share Posted July 12, 2023 UPDATE I finally had a good bright day to pull the RV out into the sun to see what happens. With BOTH the 60 Amp Renogy hooked to 4 panels and the 20 Amp Renogy hooked to its own new separate panel (for necessary reasons) ALL TO THE SAME LITHIUM BATTERY BANK.......BOTH set at the same factory lithium charging voltage and parameters....... BOTH were pumping charging amps into the battery,,,,,Neither changed + or - of what charging amps they were contributing together versus if one or the other was shut off.............. NOTE it was Renogy Technical Support that told me doing that was NOT recommended... I can envision the case where if two controllers had different charging algorithms there could be conflict issues, none appear in my case.. For now Im leaving things as is, its not broke (for now) so Im NOT gonna fix it lol Thanks gang John T Quote Link to comment Share on other sites More sharing options...
Chad Heiser Posted July 12, 2023 Report Share Posted July 12, 2023 As you found, there are no issues running multiple charge controllers in parallel to a single battery bank. I currently have three charge controllers going to my single battery bank. I prefer controllers that can be networked to talk to one another to better coordinate charging, but this isn’t required. The only thing you have to pay attention to is the battery max charge rate. Every battery manufacturer has a recommended charge rate (how many amps the battery can accept). You do not want to exceed this number or you could damage the battery (if AGM/Lead Acid) or cause the BMS to kick in and shut down charging (if Lithium). Quote 2009 Volvo 670 with dinette/workstation sleeper - Walter 2017 DRV Mobile Suite 40KSSB4 with factory mods, dealer mods and personal mods - now in the RV graveyard 2022 DRV Full House MX450 with customized floor plan 2018 Polaris RZR Turbo S (fits in the garage) 2016 Smart Car (fits in the garage or gets flat towed behind the DRV when the RZR is in the garage) My First Solar Install Thread My Second Solar Install Thread & Photos and Documents Related to the build My MX450's solar, battery and inverter system - my biggest system yet! chadheiser.com West Coast HDT Rally Website Link to comment Share on other sites More sharing options...
oldjohnt Posted July 12, 2023 Author Report Share Posted July 12, 2023 (edited) 14 hours ago, Chad Heiser said: The only thing you have to pay attention to is the battery max charge rate. Thanks Chad, I'm good as far as that, my max charge rate is 100 Amps and I don't anticipate over 75/85 amps max. I had seen multiple controllers used before and didn't anticipate problems, especially with my two matched controllers, but when Renogy Tech Support recommended NOT to do this I was concerned which prompted my post. However, as an attorney and engineer I understand why the corporate lawyers insist on such things in manuals with big caution warnings like CONSULT AND FOLLOW NEC GUIDELINES etc. etc. fills a page lol I'm good to go and felt better after todays experimenting John T Edited July 13, 2023 by oldjohnt Quote Link to comment Share on other sites More sharing options...
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