Secondary power system
A 200 Ah LiFePO4 house bank on a REDARC Manager30, running Starlink and everything else off a pure sine inverter.
Two charge sources at a time, never three
The Manager30 does simultaneous multi-source charging but only uses two sources at any one time. Priority is Solar, then AC Mains, then DC Vehicle. If solar and AC are both working, the DC input voltage will show on screen but the bar graph will display the "not available" symbol. Total output is capped at 30 A regardless of how many sources feed it, so a third source would add zero amps.
Build guide Part 0, Limitation 1
It cannot jump the start battery
The Manager30 is a one-way charger. It takes power from the start battery and gives it to the house battery, and it deliberately isolates so there is always power to start the truck. Nothing in it can push power back to a dead start battery. Jump capability is a separate circuit you build yourself.
Build guide Part 0, Limitation 3
It will not charge lithium below 32 degrees F
The lithium profile halts charging and throws an under-temperature fault below 32 degrees F, measured at the battery by the supplied Battery Sensor. It resumes automatically. Discharging below freezing is unaffected and loads keep working on the coldest night.
Build guide Part 0, Limitation 4, and Part 6
The battery sensor is the only thing on the house battery negative post
Every load, every accessory, every inverter negative lands on the common ground busbar, which is the ground side of the sensor, not the battery side. Hang an inverter negative straight on the battery post and the sensor never sees that current, and the Manager30 reports full charge on an empty battery.
Build guide Phase 5
Within 6.5 ft of the bank, 4 in above the heatsink, never inverted
The Manager30 must sit within 6.5 ft (2 m) of cable to the house battery, needs 4 in minimum clearance above its heatsink fins, must be horizontal or vertical but never upside down, and must not be in the engine bay or exposed to rain, snow or spray. Four M6 or quarter-inch bolts, all four holes, screws only, no adhesive.
Build guide Part 0 spec table and Part 3.1
Where does the system live?
The Manager30 and the batteries are a package: the unit must be within 6.5 ft of cable to the bank, so they go in the same place. That one decision changes phases 02 and 03 completely and leaves everything else shared. Pick one to see the checklist, parts and guidance for it. Switching later keeps every box you have already ticked on the shared phases.
What the build guide would build. Temperature, weatherproofing, security, short cable runs and real crash-rated structure all point the same way, and in Juneau the temperature argument is worth the seat by itself.
- Cab holds residual heat and never sees direct precipitation, so self-heating batteries draw a fraction of the heater power
- The Manager30 is not weatherproof and in the cab that problem disappears
- Roughly $2,500 of lithium and electronics locked behind glass and a door
- Display, batteries, brain and inverter all cluster in one place
- Rear seat mounting points are welded nuts in the floor pan and back wall, engineered to restrain a loaded seat in a crash
- You lose the back seat
- You give up dry interior storage
- Roughly 110 lb sits behind the driver
Switching keeps every box already ticked on the shared phases.
Read all of Part 4 before starting phase 01. Several phases want holes drilled or wire routed before other things get bolted in.
- Step 1Critical
Confirm your cab config. Double Cab (full rear doors, 60/40 bench) and Access Cab (rear-hinged half doors, jump seats) have different rear structures. Everything below assumes Double Cab; Access Cab is similar but roomier once the jump seats are out.
- Step 2
Measure the actual space behind the driver: floor to seat-back top, cab wall to seat back, wheel well to transmission tunnel. Write it down.
- Step 3Critical
Cardboard mockups. Cut a 17.5" × 7.3" rectangle for the Manager30 and blocks for the batteries and inverter. Place them in the truck.
- 4" of clear air above the Manager30's heatsink fins
- Unit is horizontal or vertical, never inverted
- Battery terminals aren't up against sheet metal
- Manager30 is within 6.5 ft of cable to the batteries
- Nothing blocks the driver's seat travel or your rearward visibility
- Nothing blocks the rear seat belt anchors if you're keeping them
- Step 4
Pick the display location. It has a 6'7" R-Bus cable (replaceable with any CAT5 patch cable up to 32 ft). Common spots: lower dash left of the wheel, center stack blank, A-pillar pod. There's a 1:1 drill template in the back of the manual.
- Step 5
Walk the cable route front to back and confirm it's clear.
- Step 6
Sketch the whole thing on paper with wire gauges and fuse values marked. You'll refer to it constantly and it becomes your troubleshooting document later.
Power budget
Move any input and watch the daily balance, runtime and recharge time follow. Defaults reproduce the build guide's own table exactly.
Consumption exceeds what driving and solar replace. The bank drains a little further every day. Cut Starlink hours first, then add driving time, then consider a second DC-DC charger.
Break even needs 5.7 h of driving a day with no solar. From empty, a full recharge takes 6.7 h.
Guide: roughly 20 W idle, 50-75 W active, snow-melt cycles spiking to 80-100 W. 60 W is the guide's daily average for Juneau.
The single highest-leverage setting in the system. Overnight sleep cuts the daily budget by roughly a third. Set it in the Starlink app.
Guide states 150 Wh/day for a VHF/UHF mobile at 11 A TX / 1 A RX, light use, and gives no watts or hours. Entered directly as Wh.
Guide states 60 Wh/day and gives no watts or hours. Entered directly as Wh. Counted as an AC load because the chargers run off the inverter.
Guide states 100 Wh/day and gives no watts or hours. Straight off the 12 V fuse block, so no inverter loss applies.
Manager30 supports 40-800 Ah. 200 Ah is two 100 Ah in parallel.
Guide says LiFePO4 usable capacity is ~90-100%.
Manager30 caps at 30 A and no setting makes it faster. Above 30 A means a second DC-DC charger in parallel, which needs the alternator checked first.
Manager30 solar input caps at 520 W. 12 V nominal panels, parallel only.
The guide gives two bands and no monthly table. May through August, a decent day, 300 W might return 400-900 Wh. November through February, almost nothing. The four shoulder months are a gap in the source and are shown as such.
| AC loads | 1,740 Wh |
| DC loads | 250 Wh |
| Device side | 1,990 Wh |
| Loss, AC × fraction | 209 Wh |
| From the battery | 2,199 Wh |
Loss is applied the way the guide applies it: loss = AC load × loss fraction. The stricter model divides AC load by an efficiency instead and lands about 30 Wh/day higher. Both are offered; the guide's method is the default. See the source discrepancies note.
Guide: 300 W might return 400-900 Wh on a decent day
2,199 watt hours a day from the battery, 172 amp hours. Net balance -1,431 watt hours. Net deficit.