Battery Sizing & Location

BATTERY SIZING

Your batteries need to be large enough to provide energy for extended overcast periods when there is little to no charging.

To determine your needed battery capacity:

1. Consider your average winter energy needs on a daily basis (in amp-hours at your system voltage). We use the winter months because they are usually the most overcast and the days are shorter. This figure should allow for future expansion of system and increased electrical demand.
2. Now, multiply daily amp-hour demand by the number of consecutive days without significant sunshine. (For the Ozark region, 5 days of cloudiness is not uncommon.) So, multiply this number times your winter energy demand (amp-hours). This figure will give you the amount of usable battery storage your system will require. Ideally, this figure should be 50% or less of the total capacity of your batteries. If your batteries are true deep cycle, then your usable storage could equal 70 to 80% of your total capacity. If you plan on using ni-cad batteries, then, you can figure on 100% usable storage.

This big battery bank is efficiently tucked away in a room with a three-tiered steel rack. The room is actually the entryway to the basement that houses the rest of the system's controls and the inverter. This battery room is vented and closed off from the rest of the basement. These are the ultimate conditions for safety and the health of the batteries.

This is an add-on type of battery shed in construction. This shed will be insulated and vented at the top. the top will be hinged and open up for battery inspection.

BATTERY LOCATION

Battery location is not a factor to be taken lightly. They need to be protected from excessive temperatures, precipitation, dust, and direct sunshine. Batteries prefer a cool, stable environment. Lead-acid batteries have greater capacity when they are warm (90 degrees F.), but, age faster. At extreme freezing temperatures (sub-zero), they can lose up to 50% of their capacity. If discharged low enough they can freeze, and possibly bust their jar.

Housing batteries in an adjacent shed to the house or in the crawl space under the house is good, if accessible and centrally located, so that wire runs into the house and from the array are at a minimum. It is good to locate an adjacent shed for batteries on the south side so that some degree of passive solar heating will help keep the cells from excessive low temperatures.

Batteries need some ventilation in their enclosure so flammable and corrosive gases can not build up to hazardous levels. Vents should be located at high points in the enclosure and on either side of the battery to allow for a cross-flow. It is good to insulate batteries from the ground, especially if the ground is subject to freezing temperatures and moisture. If the foundation for the batteries is on cement blocks or a concrete slab, use plywood and/or ¸" or 1" rigid insulation between.

WE DO NOT RECOMMEND putting batteries in your living space. There is too great a potential for Murphy's law to manifest when batteries, fire and humans (especially kids) occupy the same space. Batteries don't get lonely. They do well without human company so put them outside or build them their own room.

Back to top

Types of Batteries| Battery Maintenance

Home | About Us | Products |Site Map