MPPT Charge Controllers

There are a few common types of charge controllers: single or two-stage (shunt or relay type); pulse-width modulated (PWM); and maximum power-point tracking (MPPT). While non-MPPT charge controllers are less expensive and still have their place in the battery-based PV market—especially for lighting and small developing-world systems—just about all modern home- and cabin-scale PV systems include an MPPT charge controller, as they offer several advantages.

MPPT Advantages
More watts. Recall the power equation—volts × amps = watts. The more voltage captured from an array, the more power (watts) can be sent to the battery bank. An MPPT charge controller (for example: RENOGY 40 AMP MPPT CHARGE CONTROLLER keeps the array operating at the peak of the current-voltage curve, and converts array voltage above battery voltage into extra amperage, thus absorbing more watts from the array. A non-MPPT charge controller chains the array’s voltage to the battery’s voltage, effectively limiting the array’s power output.

Array voltage varies with cell temperature. For example, when the cells are cold during winter, yet receiving full sun, the array voltage is higher. Higher array voltage translates into greater wattage. Here’s an example: Considering average winter and summer temperatures in Boulder, Colorado, there would be about a 12% difference between average winter versus summer array power output, and up to a 25% difference on a cold winter day versus a hot summer day. For off-grid systems that have higher loads in the winter, the extra energy input offered by MPPT-based systems can be a big benefit. At higher temperatures, which usually occur in the summertime or year-round in mild climates, array voltage drops, and an MPPT controller may be less advantageous.

Step-down. Voltage conversion is another benefit that is built into MPPT charge controllers. An MPPT charge controller is a DC-DC converter—with computerized controls. It can take a higher voltage and lower amperage, and convert those to a lower output voltage at higher amperage. For example, instead of an array producing a nominal 24 V and charging a 24 V battery, an MPPT controller can step-down an array producing 60 V to charge that battery. This frees the array from having to be matched to the battery voltage, and mitigates some wire-sizing (and cost) issues.

In that example, pushing 30 A at 24 V a distance of 40 feet would require large-gauge (expensive) cable—2 AWG—to keep voltage drop under 2%. For the same amount of power, pushing 12 A at 60 V that same 40 feet with 10 AWG will keep voltage drop under 2%, with the MPPT charge controller stepping the output voltage down to 24 V for the batteries. THHN #2 wire retails for about $1.24 per foot, and #10 sells for about $0.19 per foot, saving $84.00 on that two-way wire run, even without considering conduit size and the physical difficulties of pulling large wire.

Higher Input Voltages

Until recently, most charge controllers could accept a maximum input voltage of only 150 V. Today, one manufacturer has models that accept 200 or 250 V input, and two have models that accept up to 600 V input. Having these options provides more flexibility in designing module strings for battery-based systems. For example, instead of designing strings of three modules in series, strings of six modules in series are possible. This reduces the number of strings needed by half. At half the amperage and twice the voltage, the same size wire can be used, but at four times the distance—without losing power. A 600 V charge controller may be able to accommodate a single series string of 12 modules, negating combiner boxes completely. This translates into less equipment, wire expense, and labor.

Two local veterans receive Quilts of Valor quilts

Alan "Lindy" Linda of New York Mills and Dr. Bill Rose of Perham, both Vietnam veterans, were presented quilts through the local Quilts of Valor group during its annual fundraiser held each year on March 17, at the American Legion Hall in Underwood.

Linda and Rose, a Purple Heart recipient, were among the 11 quilt recipients. Jenny Caughey, state Quilts of Valor coordinator, also spoke at the event last Friday.

Quilters Embrace, the local quilting group that presented the quilts, is comprised of quilters from Amor, Dent and Fergus Falls, according to Nett Kupferschmid of Perham.

The fundraiser has helped pay for a bus to take the quilters to various Army bases around the country to present the handmade quilts and fabric to continue to make the quilts.

Thousands of quilts have been given at locations around the country, Kupferschmid said, but recently the focus has been on presenting quilts to local veterans.

Business Exits: Selling to Private Equity v. Selling to a Strategic Buyer

Selling your business to private equity (“PE“) is very different to selling to a strategic buyer. They each approach deals in different ways, so you need to understand these differences and respond accordingly so as to secure the best deal.

As a general proposition, there are usually two types of buyers for a mid-market business:
A financial buyer — one who seeks to get a return on the investment made in the company and looks for businesses with growth opportunities and defensible competitive advantages. The return sought is an attractive return on investment and a profit on the sale of the company in a trade sale or IPO. PE companies are often financial buyers.

A strategic buyer — one who seeks out companies that have products or services that are complementary to their own, customer bases that they would like to own or IP they would like to own. They intend to integrate those businesses into their own business to create long term shareholder value. Growth oriented companies in the same or similar industry segment are often strategic buyers.

Inflation: Blowing Up the Dollar

Nearly 20 years ago, in my reporting days, I remember interviewing a couple of guys who started a business selling prescription medicines for pets over the Internet.

Today, we’d say “ho-hum.”

But in 1998, this company was edgy. As you probably know, animal prescription drugs are as tightly regulated by the FDA, DEA and state authorities as human drugs are. I was intrigued, but I remember the doubtful looks of my newsroom bosses: “Sounds risky,” one said. “They’ll never make it,” said another.

The story died on the vine. But the company did not. It grew and grew. Today, it’s a $400 million company.

What’s my point? Sometimes the biggest chance you can take with your wealth … is taking no chances at all.

Without taking judicious, well-researched “chances” such as:

• Buying stock in rapidly growing companies
• Buying gold
• Buying international real estate

Small Businesses Thriving on Amazon

Amazon is featuring Clip-n-Seals again this week on their homepage because the story has been updated with a video, and it’s part of their Success Stories series. The video was shot in Seattle and in Yakima, Washington at our factory. It’s about how we made an idea into reality and shipped it eventually to tens of thousands of Amazon’s customers.

Who knew extrusion could look so good.

JD runs our factory in Yakima.

This brought a big boost to our sales. More importantly and what’s key in the video is that there are people right here in America, like JD, who partner with entrepreneurs like me.

JD and I have worked together for a decade. He took our smallest, possible minimum order when other factories didn’t return our call. As the story goes, I have

… vivid memories of tweaking that 25th not-quite-right prototype and waking up in the middle of the night, filled with stress that his “entirely self-funded” venture might fail and drag his family down.