Overview

This page describes the electrical system in our 2020 Sprinter 170, with a 4 cylinder 2.1L diesel engine.

Main components:

The electrical system is located in the garage, on the driver side, running from the rear to the area just above the wheel well. The electrical system is mounted on a plywood panel, currently shown as a cardboard mockup in the photo below.

Second Alternator

It takes a lot of energy to charge a big battery bank. To provide substantial charging power, we have a Nations 280XP alternator with a Wakespeed WS500. Wakespeed and BattleBorn are sister companies now; both are owned by DragonFly. Things to know, based on various conversations with Wakespeed and BattleBorn:

* My installation originally used a SmartShunt. I switched to the BMV-712, which has the same form factor as the Smart-Shunt; if I had room, I would probably have used the Lynx Shunt. It will be potentially handy to have the BMV-712 display near the battery bank.

The Wakespeed website has an excellent Buying Guide and other information; click on Learn and look for the How-to Guides.

BattleBorn is a good place to order from. Be sure to order:

It is generally accepted to not use an under-chassis fuse for the positive run from the alternator, and instead simply fuse that run on the electrical board. In my setup, the long 4/0 run from the alternator goes to the SmartShunt and then to the 4th spot on the Lynx Distributor (where it is fused). This shunt is not technically needed, but I already had it and might as well deploy it -- with it we can see the alternator amperage on the Touch display. A good technical POC at Wakespeed is Matt at x109.

Can be hard to find folks who will install a second alternator, perhaps especially true in the Atlanta area. Monster Customs (just outside of Atlanta) installed ours. We agreed for me to do most of the work to integrate with the Wakespeed and my electrical board.

A detailed (but maybe dated?) install thread is here. Some confusion over 2-belt vs 3-belt installations. More here.

To run the 4/0 wires underneath, some installers have used these " commscope bhd 114" hangers. One source: Radio Gagas.

Batteries

We have 3 BattleBorn GameChanger-3 batteries for total of 810 Ah. These are mounted standing up "tall", with the positive terminals towards the side wall. The batteries are connected together with copper busbars.

Main Fuse, Main Switch, and Shunt

The positive busbar is connected to a 500A ANL fuse block with 4/0 cable, which is then directly connected with a very short busbar (approx 3") to the Blue Sea HD-Series 3000 switch (rated at 600A), which is then connected to the Victron Lynx input using a very short 4/0 cable.

The negative busbar is connected to a Victron SmartShunt 500 with 4/0 cable; the SmartShunt is then directly connected to the Victron Lynx (had to make the hole on the Lynx busbar slightly larger to accomodate the M10 bolt on the shunt).

Charging Rates

BattleBorn asserts that .5C charge rate (135A per battery) will not reduce battery life. Note that 240A from second alternator, plus 50A from solar, equals 90A per battery. If plugged-in to shore power, the MultiPlus will produce 120A for charging (an additional 40A per battery), for a total of 130A per battery -- still within the allowed charging rate spec. Of course, we don't ever expect to be charging from all 3 sources (solar, shore, and alternator) at once.

Power Sources

Everything in the van will be powered from the batteries; we will not have a transfer switch. To keep the 810 Ah of batteries charged, we will rely on solar and a second alternator. We hope/plan to rarely plug into shore power.
Solar consists of 3 x 175 watt Renogy rigid solar panels with Victron 100/50 MPPT controller.

Just an FYI on safety: to completely disable the entire board, you must turn OFF 4 sources:

Load Connections to the Lynx Distributor

Note that each of the four connection points has its own MEGA fuse, with rating shown in square brackets []

  1. Dometic RTX-2000 rooftop AC [80A]
  2. Victron MultiPlus 12/3000/120-50 [400A]
  3. Second alternator [300A]
  4. DC panel for refrigerator, misc LED lighting, USB ports, etc. [100A]
  5. Victron 100/50 MPPT solar controller [fused outside of the Lynx]

Note that the Lynx Distributor has only 4 connection points. Instead of adding a second Lynx, the solar controller is connected to the Lynx using the connection points on the right end of the Lynx busbar, which are normally used to add another Victron component. More on this below.

The Multi-Plus is connected to the Lynx using approx 3 feet of 4/0 cable.

The Blue Sea 5026 (ST Blade Fuse Block - 12 circuits with Negative Bus and Cover) is used for all DC loads except for the RTX-2000 AC unit. The fuse block is switched with a Blue Sea m-Series 6006 switch.
A Blue Sea m-Series 6006 switch is also provided for the feed from the second alternator.

The SmartSolar controller is connected to the Lynx using the connection points on the right side of the Lynx. The SmartSolar has breakers at both the inputs and outputs.
Starting from the Lynx, and proceeding to the right, the positive elements are:
Lynx unfused connection point
63A breaker
SmartSolar
16A breaker
wires (#10AWG) continue up to solar panels on roof

The breakers used are DC Miniature Circuit Breaker, 2 pole, with DIN rail mount, by Chtaixi. Compact, comes with mount, and breaks both pos and neg.

AC Uses of Power

The Blue Sea 8027 (Traditional Metal Panel - AC Main + 6 positions) panel serves two purposes: first, to protect the inverter from shore power, and second, to feed the various 120 VAC branches.
Shore power (hot & neutral) connect to the 30A double-pole, and then go on to feed the inverter. The bottom-most breaker (sized at 30A) is split from the bus; the hot from the inverter attaches here and goes on to the hot bus. This will leave 5 positions total available for 15A and/or 20A branches, which is enough. Note that we need a bus bar for the inverter neutral to land on.

Need to verify that the shore power and inverter power are handled as described above. I recall that the inverter output goes through the top breaker pair, and that the bottom breaker pair is unused. I am inclined to run the shore power through a surge protector, and let that device protect the Sprinter from external power issues.

Comments

The larger connections were made-to-order 4/0 cable from www.batterycablesusa.com    This is all-copper flexible welding-type cable to facilitate routing of cables.

 
Photo is out-of-date as of June 12th, 2022. Biggest change is that I decided to not use the Lynx Power-In, and instead used busbars to connect the batteries. Another visual change: the left-most port on the Lynx is lined up with the gap between the battery box and the Multi-Plus, so the two 4/0 cables from the Multi-Plus can feed straight up into the Lynx.
 
This photo is pretty wide, so be sure to scroll Left to Right as needed!