Completed-Added a 2nd Battery, Victron SmartShunt and 2nd MPPT. 2023 T@B 400

RTWCTS

We have started modifying the DC side of our electrical system by adding a second Battle Born heated battery and a Victron SmartShunt. We didn't feel the need for more peak power but wanted a longer duration of dry camping time. For that reason we didn't mess with the stock inverter.

I had read that someone had issues with the stock angle bracket holding in the battery, so I removed it and installed pieces of birch plywood to create pockets for the batteries. Next I added a birch plywood 'shelf' for the SmartShunt to make it all fit the way my mind saw the project.

 I know there is a myriad to ways to do this. This is how my mind processed the solution. Our next (last for now) electrical upgrade will be to add a Victron solar controller for our ground-based panels.

RTWCTS

We installed a 2nd solar controller for our ground-based panels today.  It is on the passenger side of the trailer, next to the battery cut-off switch. 

On our last T@B, we had installed a connector on the driver's side of the tub. When choosing spots for dry camping we always tend to park so there is more room on the passenger side. We're hoping that having the panels where there is more room will make it easier to 'chase the sun'. We installed an SAE connector to the wiring because that is what we are already using with the main cable on our briefcases.

That pretty much completes the mods we feel we need to get on the road. Thanks for looking...

Robermcm

Old post, I know, but I’m about to do the same thing - add a victron smart shunt and a second 100ah battery. Trying to determine the parts needed. Thinking…

1. A 1-2ft 2ga negative cable. (3/8 connector both sides?)
2, Same thing as #1 on positive side. 

3. A short jumper from shunt to negative connection block. 

Anything else?
Thanks!

RTWCTS

You're on the right track @Robermcm. The length of the battery cables needed will depend on where you put the shunt and second battery. For my install I bought two pairs of 12" cables with 3/8" connectors.

As visible in the first picture in the post:
-negative 12" from the distribution block to the shunt
-negative 12" connecting the two battery negative terminals
-positive 12" connecting the two battery positive terminals
-factory positive from distribution block to positive terminal on battery 1
-factory negative from shunt to negative terminal on battery 2
(one extra 12" positive into the toolbox).

If you are buying a self-heating battery to match what came with your T@B, you need to add a jumper wire to connect the heating terminal screws (also visible in the picture) so it activates when you flip the switch in the cubby. 

The only other wiring to do is connect the power wire from the shunt to a positive battery terminal (supplied with the shunt).

There are some Victron setting to do in the App. You can also synchronize the shunt with the Victron MPPT, but that doesn't require purchasing anything to accomplish.

It was a worthwhile project. Have fun! I'm sure you will get more answers from others...  

Robermcm

Thanks much. That was exactly what I was hoping to get back. Three add on questions:

1. Did you consider using the shunt’s second monitoring port for the midway connection between the batteries - presumably to understand balance of charge between the two? Ports there, might as well use it!

2. That factory negative cable looks like a 2 footer and thicker than the add-ons. Did you buy 2ga cables, which would make the factory a 0 or 00?

3. I see two small red wires, one each going to the positive battery terminals. Figure one is the power to the shunt. The other looks to be coming from the inverter? And it has a Waco extension to the wire. 

thanks. Battleborn earth day sale on through Friday!

Robermcm

In case anyone else needs to sort through what they need to go factory 100ah lithium to twice that plus a shunt to watch it all.  

RTWCTS

Looking at all of this after a good night's sleep, clearly I 'misremembered' my original wiring @Robermcm. What I originally stated as the factory negative (from battery 2 to the shunt) was not the factory cable. The factory cable has a yellow crimp end. The cable you identify as #5 is a 0 Gauge, 18" cable that I pulled from my toolbox to complete this wiring. All the other wiring is 2 Gauge.
My only 'defense' for the error is that I had soon added a third battery to the setup and changed the wires around. 

I never hooked up midpoint monitoring since the 3rd battery was added within two weeks of this original upgrade... where is the midpoint of 3 batteries?
Finally, the second small red wire you mention is the factory wiring going to the switch in the cubby to power the battery heat function. It routes behind the inverter and then through the Alde compartment. You'll easily be able to trace it when you have everything opened up.
Hope I got all the details right this time!

Robermcm

Now i have battery envy!  Thanks for the update. Makes sense. 

I’m thinking 200ah of lithium in a 23m400bd plus some so-so solar can get me 2 full boondock days, or 3 if I get more sun. No fridge or p.t.  fridge, just Alde control, lights, water pump, usb chargers, CO/Fire/sensors. Sound reasonable?

elbolillo

@Robermcm With sunshine you should be able to do fairly well. Especially if you don’t use the fridge. That is the biggest draw on the battery in general.

With 400ah of lithium we took a 3 week trip last August/September through Colorado, Arizona, and Utah and never got any lower than about 55% on our batteries. This was with fridge running and inverter usage to power our Starlink. We had plenty of sunshine to keep the batteries running strong.

RTWCTS

In my opinion, your plan is sound @Robermcm. You should have energy to spare. 
As @elbolillo states, the biggest power draw is the fridge.  We use about 50 Amps a day, 35 of that being keeping the fridge nice and cold. The rest is used up running the roof fan while cooking, lights to read with at night, etc.
The point of 3 batteries for us is to last 5 days (the expected limit of black tank capacity) in a heavily forested area with no real solar input. Everyone has different needs/usage.

Robermcm

Your boondock goals are mine as well. Thanks for sharing real life data. Helps me gain confidence in my assumptions.