Storage of Batteries

The electricity generated from the solar panels will need a secure and viable area for storage. It must be protected from weathering of any harsh conditions throughout the year. 

Location & Requirements

For our storage location, we looked at the east garage at the University of Houston. 

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Figure 1 - University of Houston's East Garage

The storage room of the batteries for the solar panels would be located on the first floor of the University of Houston’s east garage. The room would consist of the batteries to be charged using solar energy and breakers. Ideally, it would be near the existing electrical room so that any connections to the electric grid can be compiled in one area. 

Because temperature and humidity affect the batteries discharge, it would be necessary for these elements to be manipulated in the room according to the products specifications. The optimum temperature for lead-acid batteries is 77 ˚F (25 ˚C). Higher temperatures lead to more chemical activity, and lead-acid battery discharge will occur at a faster rate. When mostly discharged, the battery can freeze at 32 ˚F (0 ˚C). The ideal humidity of battery storage is 50%. Terminals of lead-acid batteries can rust in high humidity and could result in connection issues. 

For lithium-ion batteries, the optimum temperature is 59 ˚F (15 ˚C). The range for this type of batteries, -4 ˚ F to 113 ˚ F (-20 ˚C to 45 ˚C), is more varied than lead-acid batteries. 

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Table 1 - Temperature Requires for Lithium-ion 

Room For the Two Batteries Chosen

A) Trojan Battery Company 

The chosen batteries from the Trojan Battery Company can be stacked side-by-side in metal cases with several levels in it. The cases can be put against the walls or in rows with holes for the wires to go through. It is space-efficient and the connection of the batteries, series and/or parallel, affects the capacity and voltage

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Figure  2 - Side by Side Storage of the Batteries

There is a real functioning completed project of an electric vehicle charging station powered by solar panels. From this project, the batteries were hooked to the same electric grid that charges the electric vehicles. There is direct contact between the batteries and the charging station. The batteries gather energy so that the charging station functions even at night without the solar panels harvesting energy.

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Figure 3 - Metal Casing for Batteries

B) Discover Lithium Battery

The lithium-ion batteries can also be put in metal cases like the lead-acid batteries put there are less space-efficient because of their size. There are products available with smaller sizes but generally their batteries are bigger than the lead-acid batteries. Case studies found that lithium battery are more efficient than lead-acid batteries in terms of charging and discharging effiency. This development results in decrease of energy loss in the system which is vital when the solar energy harvested is scarce.