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Above: Phil Evans (L) and author Chris Laughton (R) in front of the donated PV array.

Having already commissioned the battery and inverter, it was time to test the PVs. With the sun gloriously beaming in the June sky, I slipped each array plug into the sockets. Watching the E-Meter, I saw a very pleasant 32 DC amps flowing into the batteries causing the green "Full" lamp to start flashing in no time.

Problems

The first reported problems came about 8 months after the owners started using the solar-powered system. The inverter was occasionally cutting out, requiring a manual restart of the Trace. Eventually, the problem became worse, and we had done all we could over the phone. We arranged to take the Reclamator out of service for a few days so I could give it a thorough inspection. The battery under no load was showing 24.6 volts, but this quickly dropped to 23.2 volts under load, and the inverter was then switching off as part of its protection circuitry. No restart was possible until ten minutes had passed.

A problem with the batteries or cables certainly seemed likely, and yet the E-Meter (with an historical recording function) indicated an 82% charging efficiency, much higher than one would expect considering the abysmal battery voltages. All was explained by the next readings of the E-Meter. The charge/discharge cycles totaled

Photovoltaics only thirteen in twelve months of use, and the deepest discharge was 71%. It turned out that the owners had never charged the batteries from the grid and had only used a third of the PV array at the best of times, even in the depth of winter. This guaranteed the destruction of the battery! The high efficiency figure was due to the fact that the E-Meter will only re-calculate when the batteries become fully charged.

Cracked Batteries

The voltage of each individual 6 volt battery was recorded under maximum load and charge, which revealed two particularly poor batteries. We were not surprised when their removal revealed split cases with gel peeking out of the cracks! With these replaced and an overnight charge from the grid mains, the battery under no load was starting at 25.2 volts and dropping to 24.3 volts under maximum load. The final charge setting for the Trace inverter was left at 27.0 volts. The C40 was set for 27.6 volts for the bulk charge and 26.4 volts for the float charge.

When the owners were further challenged over the battery abuse, they claimed that the E-Meter ampere-hour meter and time-to-run feature never indicated a problem. This is a good lesson: These indicators are misleading unless the battery is regularly brought to a full state of charge to allow the E-Meter to recalculate. The owners also reported that they rarely used the full 12 module array due to the inconvenience, which shows the practical limitations of removable arrays.

A secondary problem was then addressed regarding the auto-search facility of the Trace inverter. Originally this was left in a medium search mode, which became energized when the conveyor was switched on. For safety reasons, this switching was controlled by a contactor by the original builders of the Reclamator. However, the owners reported that they could feel the contactor points bounce when using the inverter power, and that the coil would then slowly "suck in" allowing full power to pass. Fortunately, the bouncing turned out to be the pulses from the auto-search circuitry. By defeating this and manually switching the inverter to full output, the bouncing disappeared.

The Reclamator continues to reduce the waste put into landfill sites and brings the idea of solar power to even more people. Technically, it was quite a challenge to design, and engaged the thoughts of several solar engineers. Given the severe environment, the equipment has fared well. The owners no longer hire a generator—this alone is reason to celebrate.

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Author: Chris Laughton, The Solar Design Company, 57 Wood Lane, Greasby, Wirral, L49 2PU, England

UK +44 (0)151 606 0207 Fax: UK +44 (0)7070 731 369 [email protected] Web: www.solar-design.demon.co.uk

Reclamator Owners: Network Recycling, 10-12 Picton Street, Bristol, BS6 5QA, England UK +44 (0)117 942 2271 Fax: UK +44 (0)117 942 0164

Photovoltaics: BP Solar, PO Box 191, Sunbury-on-Thames, TYW16 7XA, England UK +44 (0)1932 779543 • Fax: UK +44 (0)1932 762686 Web: www.bp.com/bpsolar

Battery and cable supplies and workshop: Solar Sense, The Environment Center, Pier St., Swansea, SA1 1RY, England • UK +44 (0)1792 371690 Fax: UK +44 (0)1792 371390

Trace supplies and workshop: Wind and Sun, Humber

Marsh, Leominster, HR6 0NE, England

UK +44 (0)1568 760671 • Fax: UK +44 (0)1668 760484

Technical advice: SunDog, Fell Cottage, Matterdale End, Penrith, Cumbria, CA11 0LF, England UK +44 (0)17684 82282 • Fax: UK +44 (0)17684 82600 Web: www.sundog-energy.co.uk

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