Siemens Solar in RVs and boats: installations and kits

Siemens Solar sold packaged RV Power Kits in 36, 50, 75 and 100 W versions, plus expansion kits, which it announced in July 1999, and a line of marine kits shipped to West Marine in June 2000. The sources also keeps two installation notes that show what owners did with them.

The Startruck, Jackson Hole, Wyoming

System components as published:

• 2 × ProCharger 4 JF solar modules
• 1 × 12 A charge controller
• 2 × 290 Ah batteries plus a 130 Ah backup and trolling-motor battery
• 8 × 30 W DC fluorescent lights, 12 V refrigerator, water pump, 1,500 W furnace, 13-inch TV/VCR, 700 W microwave, sound system, cellular phone, computer and printer
• 1 × 12 V, 2,000 W inverter

Our arithmetic:

• The note records 5 A into the battery bank in late October on Michigan’s Upper Peninsula with the modules flat, and 7 A at midday in northern Wyoming in November. At about 14 V that is 70 W and 98 W of charging power.
• Two 290 Ah batteries hold about 580 Ah × 12 V = 7 kWh nominal. At the 98 W midday peak, and roughly two to three full-sun-equivalent hours on a short autumn day, the two modules add about 200 to 300 Wh: enough for a few hours of lighting and the refrigerator, but not the microwave or furnace, which must run from the batteries.

The Oa Oa: Golden Gate to Lahaina, Maui

System components as published:

• 1 × M65 module, 42 W
• 2 × 100 Ah marine batteries
• 1 × 8 A charge controller
• 1 × 350 W gasoline generator

Our arithmetic:

• The loads were navigation and communications gear, mast-head and compass lights, wind instruments, autopilot and a stereo. At 42 W × about 5 peak-sun-hours × 0.75 the module delivers about 160 Wh a day, or 13 Ah at 12 V.
• That is a small load by modern standards, and the note says it was enough: only three hours of generator running over the whole crossing, despite two severe weather fronts.

What the kits promised

The RV Power Kit was a complete package intended for quick installation, from trickle-charging batteries to powering appliances, and modular so that panels could be added. The kit table lists panel dimensions of 25 × 21 in for the 36 W kit, 31 × 23 in for the 50 W kit, 48 × 21 in for the 75 W kit and 59 × 24 in for the 100 W kit. Those match the outlines of the SP36, SR50, SP75 and SR100 datasheets, but the source does not name the modules inside the kits. Each kit included a 20 A charge controller, and the 100 W kit was rated at 5.6 A. The July 1999 release also announced more than 350 Authorized PowerPro dealers in North America.

The Yachting World ‘Great Atlantic Gear Test’ mentioned on the SP36 and SP75 pages was run over about 5,000 miles of ocean sailing and tested the modules themselves, not the kits.

If you are replacing a kit module today, the calculator shows the controller current and the charging headroom for a 12 V battery.

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