MEOW: Difference between revisions

Purpose

This is the Operation and Maintenance (O&M) manual for CCAT MEOW (Mobile Energy Operations wagon). Please refer to it and keep it up to date with any O&M changes.The MEOW was constructed originally in 2003 to showcase solar electric power at concerts and other public gatherings. At these events the bikes are removed from the interior of the trailer and can generate electrical output when used. This power charges the same battery bank associated with the PV system and in turn the system together can power different loads at the event such as the sound system.

Operations

Maintenance

Solar Panels

It is important to clean solar panels on a regular basis to get optimal performance. Usually dust and bird droppings prevent solar radiation to fall on solar cells and thereby reduce the power output of the solar panel. As MEOW is mobile vehicle and used for various purposes in different locations within the community, it is a good practice to inspect and clean the solar panels before every use.

Cleaning of the surface of the solar panels with warm water and dishwashing soap to remove any accumulation of dust is one of the most cost effective methods. When cleaning also clean the frame and backing of the solar panel. If the surface of the panel is hot due to outside ambient, it is recommended to cool it down before applying soap. The hot panels could cause soap residue to form on the panel that would inhibit the passage of light (Meg harper, 2010).

It is also advised to check open circuit voltage (Voc) and short circuit current (Isc) of the solar panel before every use of MEOW. These parameters are used to find out the state of degradation of each solar panel and to determine if further testing or maintenance is required on the panels. A solar panel that produces noticeably less power than the others in the array can act as a resistor rather than a power source, reducing the productivity of the entire array ( Harper, 2010).

Junction Box

As humboldt county has relatively long rainy season, it is advisable to inspected junction box periodically to ensure that water is not collecting in the box. A maintenance person should look for degradation of the box itself or seal that could allow water into the junction box. If water is allowed to enter the junction box, the water could then enter the electronics located inside the trailer and cause electronic failure.

Battery and other electrical devices

For keeping a battery healthy and durable, the system should maintain a “state of charge” that is above 60% of the battery’s rated capacity. If the battery is discharged below this level, it should be recharged using an external source as soon as possible. The charge controller in MEOW is configured in a way to control the battery’s state of charge. The display of the battery meter provides information about the state of charge of the battery. Each cell's state of charge should be measured after the addition of electrolyte. The state of charge can be determined by many methods. Equalizing a battery is performed in order to bring every cell of the battery to an equal charge. This operation increases the life of the battery. The batteries should be equalized if the specific gravity of any of the cells varies from highest to lowest by 0.015.

The electrical devices of the trailer such as charge controller and inverter require little maintenance. A certified technician should be contacted in case of an operation problem of these devices.

Schedule

Daily or Every use

• Check state-of-charge reading on charge controller (~1.25 at full charge)
• Inspection of junction box during rainy season

Weekly

Monthly

• Check electrolyte levels of each cell of batteries
• Inspect battery terminals for corrosion, debris, or loose/exposed wires

Every 3 months

• Equalize batteries

Every 6 months

• Cleaning of MEOW solar panel during rainy season
• Inspection of junction box. Check junction box seal, box degradation and inspection of water inside

Every year

• a yearly task
• a yearly task

Every 5 years

• task
• task

Instructions

Step by step process for maintenance and inspection of various components of CCAT MEOW are given below. These are based on the MEOW maintenance manual developed by the 2010 Humboldt State University ENGR 535 class.

A multimeter, screwdriver, and ladder will be needed to measure Voc and Isc.

Troubleshooting

This is only how to troubleshoot basic operation. For complex issues, the solution might just say contact ________. It should be a table in this format:

Suggestions for future changes