Battery Box Master Switch "Tidy-Up" Project & Some Scope Creep...

[MAX Burner]

We've had the Battery Box on our radar screen since we purchased Casablanca back in March from its PO in TX.  One of the Hull #226 selling points for us was that the PO had recently replaced the AGMs with 3 Battle Borns and added a Victron Smart Shunt.  However, upon learning from the forum, the BB install by the PO was less than optimum - or at least to our understanding at the time.  We were surprised that there wasn't a battery master "shut-off" switch.  This fact was the main driver for this project - after looking into what we "really" had on our hands, the pervasive project "scope creep" showed its ugly head!

Full Disclosure:  Although we've had several RVs over the decades, never have we owned Lithiums.  Thanks to these forums, learning about the nuances and particulars of LiFePOs, specifically, Battle Borns - and even more specifically, their application with the Oliver, has taken some time to digest.  We didn't want to delve into the "fray" of "cleaning up" what was previously installed until our understanding of this particular system was at a high enough level not to screw something up.  So, thanks to the forums, many of y'all's posts regarding the subject, and special thanks go out to @Geronimo John for his patience and guidance with what ended up being a fairly large scale re-design of Casablanca's DC distribution system.

Initial Configuration and Issues: 

1.  A key indicator that there was an issue somewhere within the "DC system" was that the charge controller would never reach 14.4 volts; 13.6 was the max ever observed/measured.

2.  The BBs were stacked in an unusual configuration on the battery tray.  The rear two batts were aligned side-by-side facing left/right and the third "outer" BB was aligned 90 degrees off facing fore/aft.  Several cables were too short not allowing full battery tray extension.  Clearly not a neat/tidy or logical configuration.

3.  The battery bank was not strapped down.

4.  Although likely large enough for intended current, the three BB's parallel connections were made with 1/0 cables versus the 4/0 cables distributing the current into the trailer.

5.  Several positive and negative connections were made directly to the battery bank without the use of any sort of terminal post or terminal bar even though the Smart Shunt was in place.  These connections were bypassing the SS, not good - thus contributing to phantom current within the DC distribution system and not allowing the Victron App to capture all DC power activity.

6.  One cable, a yellow 4 AWG, ran from a negative BB terminal to the wrong side of the Victron SS; this cable essentially paralleled the 4/0 cable from the same terminal to the shunt.  This made absolutely no sense.

7.  As stated above, no battery master switch.  We've always had a master switch in previous campers - handy for longer term storage and eliminating phantom current.  In case of fire, we wanted a "safety switch" located outside the camper and inside the battery box to quickly secure DC power after quickly exiting the rig.

SUMMARY OF WORK PERFORMED:  

The closer we looked at the DC set-up the more questions and issues surfaced.  There were other ancillary DC system "gripes" but the above list really paints the picture of what we were dealing with...

After quite a bit of forum research, thought, and informative and lively discussions with Geronimo John; a clearer project plan developed.  

1.  We made an assumption that the PO didn't upgrade the "lead-acid" charge controller circuit board as part of the BB installation.  This rationale would explain why we never observed more than 13.6 volts on shore power with the controller energized.  Sure enough, after pulling the board, it was clear that the board was doing exactly what it was intended to do - charge lead-acid batteries; as it didn't have the Lithium micro-switch option.  So, we ordered a replacement 45-Amp board from Amazon with the Lithium option - enter "project scope creep."

Above pic shows replacing the LA charge controller with a Li-capable board.  The lead-acid board is 100% functional and will be posted for sale on the forums.  The new Li-board cranked right up and the BBs finally received the charge intended for a Lithium battery bank:

2.  Disconnected and removed the 1/0 cables connecting the 3 BBs, labeled and stacked them sequentially from back to front.  Sized cables to allow full extension of the battery tray and added nylon tie-down straps from Rangley.  Cut, crimped, heat shrunk, and installed new 4/0 color-coded cables in parallel configuration:  

Made a terminal buss-bar from 3/16" x 1" solid copper for the Blue Sea Systems master switch (Amazon) which will be heat shrinked once it arrives.  Contoured a poly board from an old cutting board to mount the switch, like many owners have done.  Mounted a positive (+) terminal bar with the master switch to accommodate DC connections.

In the new configuration, only 4/0 cables are connected to battery terminals - removed the various "added-on" connections and placed them appropriately between the (+) terminal bar and the Victron SS.  Now, all DC (-) connections are made through the shunt so all DC power measurements are captured with the Victron Application.  Peace of mind - priceless.

While we were at it, we added an SAE solar input port for the 200W Renogy suitcase solar modules - more scope creep...  HA!

Not being an EE, I'm sure there's something left out, but in the end, we've got a clean set-up in the battery compartment, fully functional Victron SS, and the appropriate charge controller to manage the BBs.  Time for a cold one.

Cheers!

A & D

[rideandfly]

Very nice installation! Look forward to hearing how it performs for you.

 

[MAX Burner]

32 minutes ago, rideandfly said:

Very nice installation! Look forward to hearing how it performs for you.

 

Thanks, Bill.  It's passed all of the operational checks, so far so good - very happy with the performance of the new configuration.  

Played around with it a bit earlier today and remounted the (+) terminal bar and applied shrink wrap to the copper buss bar.

Final Config:

...and newly installed location of the Renogy portable solar module input:

Cheers!

[ScubaRx]

Nice work.

[mossemi]

On 9/7/2023 at 12:14 PM, MAX Burner said:

Time for a cold one.

Very nice job!  What brand of safety shoes are you sporting?  Don’t think I’ve seen ‘em before! 😂🤣😂

Mossey

 

[Going]

Nice.  This is exactly what I needed.  Earlier this year I had 3 LifePros installed in your final configuration but they did not install an on/off switch.   I supplied all the parts (except an on/off switch) after consulting with BB so I did provide the replacement board with lithium option.  I have been trying to figure out how to mount the switch inside the box.  And Wa La, here it is!  They did thankfully route all the neg connections through the SS so it would work properly.  Couple of questions; 1) Is a 250A bus bar with 3/8" connectors what you used?  2. Did you use a tie down strap on the batteries?  My 3 fit snuggly in the box using an aluminum flat bar on one side on the bottom of the tray to hold them against the other side so they don't move but seems there should be a strap too in case of a bounce.  However, there is no slot on the back of the tray for a strap to hold onto.

[MAX Burner]

12 hours ago, Going said:

1) Is a 250A bus bar with 3/8" connectors what you used?  

We went with he 400Amp busbar for the positive terminal connections needed at the BB battery bank.  The 250Amp one would likely work but we're dealing with a potential max of 300Amp in the bank so that's why we used the 400Amp option with 4/0 cable all around.  The original configuration used 1/0 cables.

12 hours ago, Going said:

2. Did you use a tie down strap on the batteries?

For an unknown reason, the PO did not tie down the  bank.  On our model, the strap hard points are stamped into the fore/aft rails of the battery tray.  We used 1.5" wide 5-foot cam buckle tie downs which worked perfectly between the BBs.  Similar to what you did, we wedged polyboard cut-to-fit in the gap on between the BBs and the tray rails.  Any moderate bumps could likely bounce the BBs around w/o the tie downs - the tie-down arrangement provides an element of "piece of mind."  Let me know if you need a pic of the tie-downs...

We're happy with the mod and a full credit "shout-out" goes to @Geronimo John for his assist in making this mod come to fruition!

Good luck with your battery switch install!  Be sure to post pix of the project....

[Going]

8 hours ago, MAX Burner said:

Let me know if you need a pic of the tie-downs...

 

Sure, a pic would be goo.  I am not following "between" the BBs.  Are you talking front to back or side to side. 

[MAX Burner]

TWO straps fore/aft works well in our config.  The 4/0 cabling holds the BBs as a "unit" the 2x 1.5" straps with cam-locks secures the entire bank to the battery tray.  I'll get a couple pix to illustrate...