A New Inverter for the Cabin

Yesterday, after playing hooky all week at the Southeast Alaska State Fair (more on that soon) I got back to the business of the homestead. In a hot, frustrating, day-long whirlwind of activity, I completed our electrical system revamp by successfully installing a new inverter.

It started with a new solar array (see Power Shift: Increasing Our Energy Independence). As part of that project, we invested in a new Nickel Iron (NiFe) battery. The array “healed” our old battery bank, which we used for several more years, but this summer I installed the new bank (see Racing to the Summer Solstice). The higher charging levels of the new battery defeated our venerable old inverter, a Trace Engineering Model 812, so I purchased and installed one that operates at higher charging levels.

The Trace cut off power at 15.5 volts (VDC) as a safety feature. The NiFe battery charges full at 16.5-17+ VDC. Since installing the new battery, we’ve had to cut power from the solar panels and let the battery charge drop to about 14.5 VDC before we could use the Trace. The new inverter cuts power at 16.5 VDC, the highest I could find.

The new inverter is a Samlex PST 1500-12 (paid link). The 1500 nearly doubles the output of the Trace. It’s a bit of overkill, but we’ll endure, surely.

The new inverter on the wall, the newly arranged “gap tooth” breaker box (left) and the empty cubby where the old inverter sat (above). (Photo: Mark A. Zeiger.)

I reluctantly made this change, but now I see the advantages. The Trace came with the cabin. We’ve used it since buying the property. It met all but our heaviest needs; I couldn’t run power tools on it, but we managed without that for 12 years.

However, it’s a “modified” sine wave inverter. I won’t go into the details, which you can find summarized here, but “true” or “pure” sine wave inverters provide “cleaner” power, closer to what most people get from public utilities.

The old inverter provided very close to pure sine wave. We’ve had few problems with its less-than-perfect power, and have long lived with any disadvantages. However, even after briefly using the new inverter, we already notice improvements!

The venerable old Trace, ready for its next assignment, where ever that may be… (Photo: Mark A. Zeiger).

Most significantly, we’ve lost a few hums.

The receiver that drives our home entertainment system, our heaviest regular power draw, used to hum fairly loudly on the old inverter. I turned the system on after installing last night. There may still be a slight hum, unless I’m imagining it. It’s definitely improved! After years of trying to ignore the hum, it’s all but gone.

The Trace itself hummed while operating; the new one makes no sound at all, other than a wimpy beep when you power it up or down. We will appreciate this, although the hum used to remind us to turn it off! We’ll likely not need to worry about that as the new battery allows for more liberal power usage than the old bank.

Our system’s still not quite complete. I ordered new heavy duty 12 volt outlets to replace our old set, which hasn’t held up well (see New 12 Volt Outlets for the Cabin). That should prove a quick fix when they arrive.

I worked from about 8:30 a.m. to 11:00 p.m. yesterday installing the inverter and making small improvements to the whole system. In addition to a lot of other stuff, I had to install a fireproof shield for the inverter, weld several ring terminals, rearrange the breaker box, and chase down a loose wire inside the charge controller. I slept well last night!

Now that I’m done bragging to you about the install, I need to get off line and clean up my mess.