Reviving an old thread here but did anybody ever come up with clarity on this?
Let me start by saying much if the below is not directly related to this thread but you guys seem to know more than most on the alternator and BMS.
I’ve been looking into the start stop (aux) factory battery system in conjunction with adding an auxiliary battery for the traditional dual battery set up...and to be honest my head is spinning a little bit.
Does anyone know what the factory BMS charging sequences between the main battery and the start stop battery is?
By that I mean does the system charge the main battery first, the charge the start stop (aux) battery? Does it simply charge them both at the same time? Any idea what the input voltage is when it is charging?
It appears from some posts I read on other forums that the starter itself does not run off of the start stop (aux) battery but rather the main battery. And that the start stop (aux) battery only provides power to ancillary systems such as brakes, fans, radio, and other parts of the electrical system while the engine shuts down. Is anyone able to confirm that?
My assumption is that the start stop module and entire battery setup and design is already inclusive of a dual battery charging system set up. Such that the start stop (aux) battery is isolated from the main? And that the system will call for voltage when the BMS reads either of these batteries being below their thresholds. Seems from what you guys are saying however the entire system is being undercharged as is. (To which removing the “smart” function of the charging system potentially fixes said issue and makes sure the main and the start stop aux stay fully charged.)
My initial thought was to replace the start start battery with a bigger AGM one (much like would be done in a pre start stop model LR). But with the start stop module and related connector in the way there isn’t room. I had an LR mechanic tell me that I may be able to just unplug the start stop control module, secondary plug in that same area, remove the battery, and disregard the entire system as it wasn’t on the 2015 model with the same motor (SCV6) and he believed those components where the piggyback to the original system. However I don’t think this is possible, as I believe the system is built to look for both batteries and completed circuits, etc. I assume it will throw codes and confuse the ECUs. (However I am very tempted to just go disconnect the two plugs and see)
To throw it out there, I don’t care about the ECO light being on, I just want a solution to dual batteries. I also have a GAP tool if needed.
So as a secondary solution I have considered is replacing the start stop (aux) battery with a lifepo4 Battery. I know they do not like heat, but from my understanding the BMS system that is installed on a lifepo4 has thermal shut off’s for both hot and cold, and that the main issue with heat is plating which simply shortens battery life span (say from 8years to 4 or something) Since the start stop aux battery is smaller, the cost of a lifepo4 battery is not near as much as a full size. You can build them for even less. If possible I may also be able to get more capacity out of the battery as lifepo4s are smaller and can be packaged many different ways. While there is limited space for the start stop (aux) battery, there is some room in the box that isn’t used by the current factory battery and the start stop module may be able to be loosens and moved or have new bracket made to inch out a bit more space. (This assumes the LR BMS system looks for voltage only and not capacity)
So, I am now wondering if the battery management system for the Land Rover will play well with the lifepo4, and I’m not sure if the LR battery profile should need to be reset? Does it matter to the system if it’s lifepo4 or AGM connected to it , and does it matter to the battery (since the lifepo4 has its own BMS)?
My goal was to run a switch controller (trigger 6 shooter) off of the start stop battery to run some floodlights, rock lights, and maybe some small LED light strings under the tail gate and awning. By using a lifepo4 battery I can get more run time, and less likely hood of hurting the battery should I run it down. If the start stop (aux) battery is isolated from the main, then I also don’t have to worry about waking up to a dead battery. Further I was thinking I would run 100 watt hood solar panel to provide some additional power while stationary. (This would be a secondary step and if not needed I would use the solar to recharge the third battery.)
Yes I just said 3rd battery (As if the first issue wasn’t enough.....)
I need more power than what that start stop (aux) battery can handle. My goal is to run a fridge, recharge a few phones and iPads, and charge a dewalt battery as needed (probably rare but when needed it’s needed). Looking for 2 solid days off grid with the stretch to 3 days being possible with logical and mindful power management.
To do this I have two approaches;
1) I have a redarc BCDC1240d. My thinking (after realizing I cannot so the traditional dual battery set up) was to buy a lifepo4 bank for the rear of the truck and take an otherwise traditional approach with inverter, plugs, etc and use a throw out solar blanket, or even a roof mounted panel, to get some assistance form solar when sitting or driving, and otherwise go the traditional route with this half the system.
2) use a solar generator that has everything built in, charge it at home, and just plug it into the rear 12v power plug. Then plug the fridge and other items needed into it. When I shut the car off, the bank will power everything, and I can plug in the solar. (Can’t really run dual inputs on smaller 1000-1500w solar generators)
I could obviously take option 1 and run everything off the second battery in the back, but due to the limited space I have I am not sure I can make all the connections in that area for. Installing the switch controller, bcdc, battery, inverter, switch panels, etc takes up a lot of space and since I have the DVDs, rear air, and surround cameras I don’t think I have much space in the rear side panels.
Any input you guys have would be appreciated.
