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10 Kilowatt Lithium Battery System in Mercedes Sprinter: Parts and Wiring Overview
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Continued from 10 Kilowatt Lithium Battery System in Mercedes Sprinter: Introduction.
This page gives an overview of the parts need to wire up a 10 kilowatt lithium iron phosphate dual-battery system in a 2017 Sprinter 4x4 van.
In late March 2018, I drove my Sprinter to ADF Sprinters of San Fernando, CA to install a 48 X 29 inch hickory table, a key working space in my van. The table serves both as a work desk and as the mounting platform for the dual Xantrex Freedom XC power inverters. No cheap Formica or particle board table for me; hickory is the hardest toughest American wood that exists, and still it can be dented without too much trouble.
Why mention the table? Because mounting two 17-pound inverters and heavy 4/0 and 1/0 cables demands a robust mounting platform. On very rough roads, the idea of counting on the particle board yuk installed in most vans definitely to hold screws in place is a risky idea—already sheet metal screws have worked their way out of metal on such roads, in my van. Nothing but very strong solid wood will do for hard-duty usage, in my view.
Parts summary for symmetric/balanced dual-battery 10 kilowatt system:
The following parts were needed, which the following pages detail:
- Sturdy mounting platform for the inverter(s). I used my hickory table as per the above. For longevity, the idea of using particle board or similar inferior materials seems unwise. I have already had sheet metal screws rattle themselves out on rough roads.
- Two (2) Lithionics 12V400A-5D-CTRL400 each with 5120 watt hours (usable around 4600 WH), dimensions 24.0 X 8.0 X 15.9, weighing 125 pounds each. Custom support/stands likely needed for most configurations.
- Shore power charging: external 30 amp socket using heavy duty 8 AWG wiring into van interior. External 50-foot heavy duty 30 amp cable (for 30 amp outlets) and heavy duty 15 amp cable (for 15 amp outlets), for either/or usage depending on what is available.
- Two (2) interior AC sockets for shore power, into which each inverter/charger can independently plugged or unplugged for controlling the shore power current draw, so as to allow use of either a 15 amp or 30 amp shore power supply.
- Two (2) Xantrex Freedom XC 2000W inverter/charger units, each capable of inverting 2000 watts and charging at 80 amps, for a total of 160 amps of shore power charging capability. Add the GFCI outlet option for two onboard AC outlets (I use these a lot).
- Two (2) Blue Sea marine-grade 8-post 600A bus bars (one for positive/hot and one for ground), the focal point for all connections. These are 2.3 pounds bus bars, basically a thick chunk of tin-plated copper, very beefy high-grade stuff.
- Two (2) Blue Sea Mega Amp 300A fuse blocks each with a 250-amp fuse between batteries and bus bar. Note: I now recommend 300 to 400 amp fuses, because if one battery goes off (drained), it would immediately blow the other fuse if 300 amp load were in progress.
- Two (2) 1/0 cables from the stock alternator to POS bus bar, for charging when shore power is unavailable (most of the time, in my travel).
- Two (2) 4/0 grounding cables from batteries to van chassis.
- Two (2) grounding cables from (one from each inverter) to van chassis.
- Heavy duty welding cables throughout, 4/0 for any run over 18 inches, with 1/0 for short runs.
- Crimping of lugs to cables with high-quality hexagonal or circular crimping, to ensure good contact and to minimize hot spots.
- Two (2) AC-out wall sockets, at least one socket from each inverter.
Discussion continues in 10 Kilowatt Lithium Battery System in Mercedes Sprinter: Challenges in Routing/Organizing/Placement.
Shown below is partial wiring prior to installation, inverters and bus bars attach to table bottom while leaving forward part of table/desk free for user knees/chair.
