I have used Gill batteries in various aircraft for a number of years with good success. I typically have replaced the G35 in My Cessna 182 every three years at annual time. However the one I installed last year was not holding residual charge so I contacted Gill. I learned a lot about aircraft batteries from that call and a number of follow-up calls. In particular, I learned of the many differences between aircraft batteries and car/motorcycle batteries. Aircraft batteries are designed to operate at a higher voltage and must be charged accordingly. Gill ended up replacing my 182 battery under warranty, but I expect the problem was more related to improper charging than it was to the battery having a factory defect. If anyone is having problems with a Gill battery, I suggest they contact Hector Vara at Gill Customer Service 800-456-0070
Here is some of what I learned from my conversations with the Gill representative: I had replaced the voltage regulator in the 182 last Spring. According to my engine monitor, the new regulator was holding the charge to a maximum of 13.3 volts. That may work for automobiles and motorcycles, but aircraft installations need to be in the area of 14.2 or 14.3 volts. I also learned that aircraft batteries use electrolyte with a higher specific gravity than car batteries. That was news to my mechanic as well. I will no longer will try to save money by buying electrolyte from Autozone. The initial charge on a brand new battery is extremely critical. It takes 24 hours. And be careful not to overfill. Follow the battery manufacturer's instructions closely. It is much more common for aircraft batteries to fail because of under-charging than over-charging. This is especially true for aircraft that are flown infrequently and/or on flights of two hours or less. A voltmeter (or VOM) and hydrometer are "must tools" for maintaining batteries. There are a number of good chargers on the market, with the Battery Maintainer possible being a very good choice. The Maintainer has a number of different models, depending upon the type battery being maintained. Given the proper care, a standard flooded cell Gill battery should last well beyond 3 years. Possibly as much as 10 years. After an aircraft has had no charging activity for 24 hours, the residual voltage needs to read at least 12.5 to 12.6 volts. If it is lower than this, something is wrong with the battery itself or the charging system. And it just so happens that I recently installed the B and C alternator (from Classic Aero) in my 415C Ercoupe. It required a lot more labor than I had anticipated. The instructions are very detailed, and every part required for the installation is included with the kit. The unit has performed perfectly since installed. The majority of the labor is involved with building and mounting the regulator. The paperwork, in particular the STC, is somewhat confusing. My Ercoupe now has both the lightweight starter and alternator. In my opinion, B and C make superior products. Milton
