Ananda's Power Center IV Tested by Richard Perez Power distribution, overcurrent protection, and instrumentation can become a nightmare in large, low voltage, RE systems. Our system had grown to the point where we needed a separate room just to house the fuses, circuit breakers, shunts, disconnects, and distribution terminals. Ananda Power Technologies Power Center IV packed our roomfull of equipment into a single two foot by two foot box. A Growing System We were designing a special room just to house the controls, inverters, fuses, circuit breakers, disconnects, instruments, 120 vac distribution panels, and 12 VDC distribution panels. The list of components that were supposed to go on the three foot wide by seven foot tall wall seemed endless. I broke out Claris CAD, a Computer Aided Design program, and tried to design the wall with all the necessary equipment in place. The wall was simply too small to house all the gear. Most of the space was occupied by fuses, disconnects, circuit breakers and instrumentation shunts. According to the NEC¨, these components must be housed in metallic boxes and must be interconnected with conduit. Our wall shuddered under a writhing mass of conduit snakes. I gave up and called the folks at Ananda. A Power Center A power center is just that, the center of a power system. It is where all the power inputs, DC outputs, and battery input/outputs come together. A power center not only elegantly and efficiently makes all the connections, but also houses safety devices like fuses, circuit breakers, and disconnects. In our case, Ananda's Power Center IV allowed us to dispense with seven wall boxes and eighteen conduit runs. The Power Center IV allowed us to have the gear we needed without having to knock out the wall and enlarge the power room. Without Ananda's Power Center there was no way that we could cram all that stuff on a three by seven foot wall. Packaging and Docs The unit arrived via UPS in two boxes because it was too heavy to travel in a single box. The unit was well packed with a bare minimum of ecological nasties. The documentation is superb and goes far beyond just installing the panel. It also covers wiring, battery care, and general RE topics. The Test System Home Power's RE system in Agate Flat, Oregon is far from typical. Ours is large (cycling about 7 kiloWatt-hours each day) and needs to be heavily instrumented. Power inputs include a variety of PV modules (28 in all) ganged into four major arrays. Total PV power is about 1,150 Watts peak (80 Amperes at 15 VDC). We also use a Survivor wind generator capable of delivering over 60 Amperes (via a Bobier LCB40) into the battery. The battery holds 1,500 Ampere-hours at 12 VDC and is composed of 150 NIFE, HIP-10, pocket plate nickel-cadmium cells. We use both 120 vac (from three different inverters) and 12 VDC (directly from the battery) for appliances. Our system is designed and constructed to meet all NEC¨ requirements. And the coup de grace is that we want to be able to instrument every component and function. The instrumentation alone requires eleven shunts for current measurement. The Power Center IV that Ananda made for us was designed specifically for our system. Although Ananda offers stock power centers, they will make virtually anything you require. In our case, we really put them to work. We not only wanted everything mentioned above, but we had other very specific requirements. We wanted the power center to directly connect to the 1.25 inch by 0.25 inch copper buss bar we used to connect the cells in parallel. We provided Ananda with a very specific system schematic, which specified everything. We also supplied Ananda with a scale drawing showing exactly where the buss bars and cable would enter and leave the power center. The power center they made met all specs and bolted right up. The Results The Power Center IV we have contains eleven shunts, four 50 Ampere circuit breakers for the PV subarrays, one 100 Ampere breaker for the wind generator, three 20 Ampere DC load breakers, and three 400 Ampere main fuses/disconnects protecting the battery and three inverters. All circuit breakers are DC rated Square-D QO types and all fuses are Class T current limiting types. We still have two open slots for input breakers and five open slots for DC output breakers. Everything in the power center is well connected using heavy wire, #00 copper welding cable, and more buss bar. Voltage losses within the center are virtually nonexistent: less than 0.2 VDC for 330 Amperes flowing through the center and into our big inverter. The net result of Ananda's Power Center is that we didn't have to build another power room. Instead, Ananda made us a two foot by two foot by six inch deep box that contained everything we needed. The power center is beautifully made and finished. For example, all the shunt leads are wired to a barrier strip with twisted pairs. All terminals within the center are plainly labeled. The center meets NEC¨ requirements. It is safe and very compact Ð which also makes it very efficient. The power center reduced our losses by reducing the heavy cable and buss bar that we would have used with separate boxes. The power center vastly simplified integrating all our various components into a system. It saved us mucho conduit, many boxes, and hours of rectal pain. Conclusions Folks who are designing and installing their own systems will find that the Ananda Power Centers provide simple, compact, secure interconnection for their RE components. In production versions, Ananda puts controls and the actual instruments (instead of just shunts) inside the power center. The power center will meet NEC¨ requirements and the system is well protected with overcurrent fusing and disconnects. The cost of regular production centers varies from about $1,150 to $1,395 and this includes 4/0 cables for the inverter and battery. Our power center was custom-made and is jam packed with goodies that are not normally used in most systems. Our center cost $3,000 and I figure that it was far cheaper than enlarging the power room, installing all the gear in individual boxes, and connecting everything with heavy cables inside conduit. According to Ananda, about half the power centers they build are custom-made at average cost of $1,600. If you are a dealer doing code systems, then you will find an Ananda power center will simplify your design and installation problems. It fits in a small space, will pass the inspector's evil eye with ease, and costs your customer less in labor, piles of boxes, and yards of conduit. Ananda has attractive dealer pricing; it figures since these guys started out as installing dealers. My compliments to Ananda Power Tech for building equipment of the highest quality. Further flowers for being able to take Home Power's demented requirements and actually make a center that works for us. Thumbs up, guys! Access Author: Richard Perez, c/o Home Power, POB 130, Hornbrook, CA 96044 ¥ 916-475-3179 Maker: Ananda Power Technologies, Inc., 14618 Tyler Foote Road #143, Nevada City, CA 95959 ¥ 916-292-3834