Lithium Ion Batteries, Battery Cutoff Switch, Battery Monitor, Distributor (Bus Bars)

[choied]

Hey folks, I am new to all things solar/battery-related.  So please forgive me for any mistakes/errors.  I welcome and would very much appreciate any comments/suggestions.  I am about to replace my AGM batteries with Lithium Ion (LI) equivalents, specifically Battleborn (100 Ah 12V GC2 LiFePO4 Deep Cycle Battery).  These LI batteries have the same/similar footprint as the 6V AGMs I currently have, so the battery layout on the tray will be much the same.  In my limited research, there are at least two possible routes to go on the number of batteries and their respective layouts.  One is to go with two or three 12V batteries lined up in a single row (using three batteries would take up the entire depth of the battery tray, leaving unused space along the sides of the tray).  A second option is to go with four 12V batteries that have the same/similar dimensions as the 6V AGMs.  [Note: The battery tray measured approximately 15" wide by 21-1/2".] deep.  The second option uses up the entire battery tray.  I am curious as to what choices others have made with regards to the number of batteries and their respective layouts. 

How have others decided to connect the batteries and with what size/gauge wiring.  I had a chance to take a survey read of Minnesota Oli's LI project (wow!!), but currently I am not considering using a bar to interconnect the batteries.  I am considering connecting the batteries together using 4/0 cables - although I wonder if I using 1/0 cables to interconnect the batteries would be sufficient. Using a smaller diameter cable/wire would certainly make it cheaper to replace in the future and easier to work with as well.  Is 4/0 cable really necessary?

I figured I could add a true battery cut-off switch at this point to simply enable myself to easily cutoff the batteries from all downstream loads, but I am still considering whether this is truly necessary. Seems to me that any parasitic draws may not be material enough to warrant the extra work.  I will take a look at mounting options and make a call on that.

Should I add-on a Victron battery monitor?  I guess it could be fun.  Some more buttons to push and a display to look at.  Again not sure on this one as constant monitoring may not be necessary.

Has anyone used a distributor? I am considering using a distributor to centralize cables/wires.  The distributor would handle all cables/wires, e.g., the mains connecting to the 12V system, the solar panels and the inverter.   I was told that the cables related to the battery temperature sensor would no longer be necessary.  The only cables that would be present in the battery closet would be the cables interconnecting the batteries themselves along with the one entry and one exit cables.

[Mike and Carol]

There are a couple of other recent threads that address some of your questions and concerns.  I asked BB about jumper cables, they recommended 1/0 and sent me two along with my two batteries.  I also had them send a new PD4045 that had a lithium setting.  I have the BlueSky and there were some settings that needed to be reprogrammed.  BB sent me those settings.  I installed a battery cut off switch because BB recommends disconnecting them for periods of storage longer than a month or so.  I have a little over 1AH phantom draw when everything is off and that can add up over a week or so.  They don’t recommend leaving the charger on continuously while in storage more than 2 or 3 weeks.  I was told if it is parked in the open then the solar can keep the batteries charged long term while allowing them to “rest” each night.

 

[choied]

Thanks for the picture - Mike & Carol.  Very nice and clean! 

Was wondering if you used a distributor to consolidate the other cables/wiring, i.e., how did you handle the other connections?  I cannot see any other lines.

And to confirm, the battery connections to and from each other are with 1/0 wiring? Looks to be less than 4/0 gauge on the connections to the cutoff switch as well, correct? Then 4/0 wiring for the mains?

[Mike and Carol]

Yes, the jumper cables are 1/0, provided by Battle Born.  We used the buss bar on the “under the bed” side and the terminal strip (not sure the correct name) on the “under the dinette seat” side.

Under the bed next to the solar controller.  Buss is behind circuit breaker.

 

This is under the dinette seat.

Added this voltage controller for the Maxxfan and bath fan.

 

Edited February 11, 2021 by Mike and Carol

[choied]

In addition to the items above, I am figuring out what I believe others have already figured out 🤪- which is I need to change/upgrade my Progressive Dynamics Converter.  At this time, Progressive Dynamics is recommending that I go with their newest version, the PD4045CSV, which has a switch to allow users to charge Lithium or LeadAcid batteries.  Also, the PD representative pointed out that I would need to upgrade any fuses related to charging the batteries to 60AMP.   

Edited February 12, 2021 by choied

[choied]

Finally finished this project.  Currently, I have two batteries and I have space for four total, two main battery cables & one small gauge wire for the shunt between the battery storage area and the inside areas.  On the inside, I decided on two separate busbars (one for the red and another for the black).  The red-side busbar ended up left of the pantry and the black-side busbar on the right of the pantry.  Had to redo some cables to custom lengths.  The only thing that remains "unfinished" so to speak is the battery monitoring system.  While the unit is connected, I failed to find and snake the cable from the bottom to the top as I was unable to find the hole and do this.  A job for another day I guess...