Off Grid PV Systems

 The heart and soul of any off grid PV system is the battery bank.  Typically, batteries used for this type of application are referred to in the industry as "vented" or "wet-cell" batteries, where excess charging of the batteries is allowed to off-gas.  Wet-cell batteries offer the most affordable and durable choice for applications requiring frequent battery discharge, such as off grid PV systems. For remote homes, weekend cabins or RVs, wet cell batteries are often the best choice and offer the longest life possible for a battery.

 Hydro Electric offers two choices in off grid batteries; Deka 8L16 Solar Batteries and Trojan RE Series batteries.  Both batteries offer superior performance/value and are manufactured specifically for renewable energy applications.

Please review the manufacturer specifications on these batteries at the following links.

Deka Solar Batteries:  http://www.eastpenn-deka.com/assets/base/0919.pdf

Trojan RE series:  http://www.trojanbattery.com/Products/documents/RE_ProductSheet_000.pdf

 

 

Grid Tied PV Systems

 The incorporation of batteries in a grid tied PV application is strictly optional.  The typical grid tied PV system does not use batteries, as any excess power not consumed on site is routed back up onto the grid transmission lines, where you can gloat how you are now providing excess power to your neighbors!

 However, there is an option for grid tied PV systems to incorporate batteries strictly for emergency use.  That is, folks who simply cannot afford to be totally without power at any time may consider the use of batteries within their PV system.  These batteries are used to provide necessary power to "critical" electrical circuits when the grid goes down.  In this application, "sealed" or "maintenance-free" batteries are incorporated into your PV design and are used by your inverter only when the grid fails.

 Because of their intermittent use, these batteries do no require periodic full cycle charging as would an off grid system.  Though more expensive, sealed batteries require no maintenance, produce no off-gassing and are more durable over the long-term when spending most of the time in a full state of charge.

 When designing a grid-tied battery back-up PV system, we will discuss which electrical circuits in your home/business are the "critical" circuits (i.e., those circuits you must have working in the event of a grid shut down).  After identifying these circuits, we will move these circuits into a new and separate breaker panel referred to as the "critical load panel".  Your grid tied inverter will then route normal grid power to this critical load panel during normal operations.  However, when the grid power supply goes down for whatever reason, the inverter automatically switches to draw DC power from both your PV array and the batteries.  This transfer of power supply will keep the identified electrical circuits now in your critical load panel up and running.  When the grid power returns, the inverter switches back to normal operation, and keeps the batteries fully charged for the next emergency.

 Please visit the same web links listed above for the grid tied battery back-up PV system batteries.  Look for the maintenance free, or sealed batteries that are recommended for this application.