Chapter 17 - Engine Charging -

The Right Way

Our previous month's installment gave us an overview of some of the more common methods of charging house batteries from a vehicle's generating system, and touched upon the advantages and disadvantages of each system. This issue, I'll expound on my opinion about the only correct method of using an internal combustion engine to replenish energy removed from batteries, using a separate alternator/generator which is dedicated only to the house batteries.

Installing a second alternator in your house truck or bus for the purpose of keeping your house batteries charged might seem like a lot of extra expense and work, but the results will be more than worth the effort. As we have learned, deep-discharge batteries should be charged at very specific currents, and the terminal voltage should be regulated carefully at each stage of the charging cycle. Attempting to control the current and voltage from an alternator that is also trying to charge your engine starting battery and run the loads and accessories in your vehicle is asking too much of a system that was designed by the manufacturer for a single purpose.

The nuts-and-bolts of such a modification to your engine is beyond the scope of this series of articles. In some vehicles, extra pulleys are available to run the second alternator, and convenient tapped bolt holes will allow the physical mounting to be accomplished. In other cases, there may not be enough room under the bonnet for the added equipment, or specialized brackets and mountings may need to be constructed to securely mount the new alternator. Each installation will present its own features and problems.

In any event, if a second alternator is installed, a purpose-built regulator must be installed to take advantage of the separate circuit to charge the house batteries. The stock factory regulator will not be sufficient to do the job, as it is engineered (again) to charge engine batteries and run vehicular accessories such as lights, heater, wipers, etc. Crafty truckers with electronic assembly skills will be able to construct their own regulators. Those who cannot cobble components will need to purchase ready made regulators, built for the task

An interesting aside is that if you aren't finding yourself moving your house truck or bus very often, and need to charge your batteries from an engine, a 5 - 8 horsepower horizontal-shaft, one-cylinder engine can be rigged to an alternator of this type to provide the needed charge without the necessity of running your vehicle engine for hours on end.

Not to leave you hanging without providing some support documentation, the following few paragraphs will allow the reader to access more information on proper alternator regulators, and provides some fairly descriptive instructions for building your own engine-generator:

Home Power Magazine is by far the most prolific source for information about charging deep-cycle batteries, and Renewable Energy in all forms:
     Home Power Magazine
     P.O. Box 520
     Ashland, Oregon, 97520, USA
     On the Internet: www.homepower.com
An article written by Richard Perez, editor and publisher of Home Power Magazine, describes an engine-generator construction project, and includes schematic diagrams and parts lists for the "Mark 8" regulator. Contact Home Power by mail and request a copy of back issue #42, which contains the article.

Another interesting and information-filled article is available on the Internet at: www.theepicenter.com/tow02077.html This is a very detailed description of constructing an engine-generator system, with several possibilities of engine types and alternator configurations, and gives important details on choosing pulley sizes, belt types, etc. I would caution the reader to ignore this sites' repeated insistence that only a self-regulated alternator be used, as this is exactly the wrong type of power plant for our purposes.
Readers may also be able to procure copies of this article by contacting:
     Epicenter Supplies, LLC
     384 Wallis St. #2
     Eugene, OR 97402, USA
     (541) 684-0717

Hopefully, I haven't given away too many of my carefully-guarded information resources in this episode.