The Great Inverter War

As I talked about in my last column on refrigeration, the marketing of renewable energy seems to favor some companies and products over others. This is a shame because the loser in that strategy is almost always the consumer. In planning for a renewable energy system you need to be able to make informed choices from as wide a variety of options as possible. This industry will grow and the technology will advance when many companies are encouraged to provide products that fit consumers’ needs.

Take inverters, for instance. To view the catalogs from Real Goods, Jade Mountain, or Alternative Energy Engineering (AEE), you’d think the only real choice you have when it comes to buying an inverter to power an off-grid home is one made by Trace Engineering.

The latest Jade Mountain catalog has 5 pages devoted to inverters. The first 3 of those pages are given over entirely to various products from Trace Engineering. One-half a page mentions Exeltech inverters (much higher priced than Trace with better quality power output) and the other page and a half list smaller single use inverters, not big enough to power a home.

In none of the catalogs is there even a mention of Heart Interface, which has been in the business for years or the newer, more advanced units sold by BP Solar. Both of these other companies are doing some really exciting things to advance the technology of home power systems but you’d never know it by perusing the catalogs or visiting the showrooms.

This wouldn’t bother me nearly as much if companies like BP or Heart had other avenues into the home power market. Right now the market isn’t large enough to allow them to create their own distribution channels.

Compounding my frustration with this situation is the fact that all three of these catalog companies espouse the "solar lifestyle" and profess to want to bring solar energy to the world. In Real Goods Summer 97 Renewables Catalog John Schaeffer, Real Goods President, proclaims that it "…provides all the hot-off-the-press information on the newest products and recent developments.", which it clearly doesn’t do. Their deeds (in the form of the products they push) contradict their words.

All of this devotion to the "solar path" suggests they are interested in serving the needs of consumers wanting to live with renewable energy. But it seems to me they are more interested in serving the needs of a few select manufacturers, which results in limiting the options of consumers.

Complicating this problem of focusing on a single manufacturer to the exclusion of others is the fact that the Trace products are often marketed in misleading ways. Consider sine wave inverters (a sine wave is the graphical representation of the power produced by the utility grid). Inverters that can produce a true sine wave that is identical to grid power are able to run any device designed to run on AC power, including sensitive electronics. Non-sine-wave inverters have trouble running such things as laser printers and some computers.

In all the literature and catalogs the Trace "sine wave" inverters are constantly referred to as "pure" or "true" sine wave output. Unfortunately those statements are not exactly accurate. The output of the Trace inverter is, as Trace themselves calls it when pressed, a "stepped approximation of a sine wave". Good enough to fool 98% of the equipment that might be run by the inverter but not a real sine wave.

Both BP Solar and Exeltech produce inverters that do produce a pure sine wave and Heart Interface is coming out with their own pure sine wave inverter in the next few months. But only Exeltech even rates a mention in the catalogs.

In fact, in addition to that little marketing sleight of hand regarding the sine wave, Trace says their inverters are "certified to UL standards", implying approval by Underwriter’s Laboratories when no such approval has been given. Heart Interface has just instituted a lawsuit against Trace for this bit of marketing misdirection and also claims in the suit the Trace inverters may actually be unsafe in certain applications. It will be interesting to see how that one plays itself out.

BP Solar also sells a power center, a complete charge control and pure sine wave inverter system that is UL listed and needs only a set of batteries and a charging source (PV, wind, etc.) to power a home. But you won’t see it in the catalogs.

This doesn’t mean that if you buy a Trace inverter you’ve made a bad choice. A Trace may be just what you need. However, your decision should be an informed one, made by comparing all the available alternatives and picking the one most suited to your application. The way the system is set up now, you don’t get that chance.

All Contents © 1998
Wagonmaker Press
Thomas W. Elliot


Return to Article List