|Special Tester designed for testing aircraft batteries. Requires only a small amount of fluid. ideal for close quarters. Float calibrated from 1.100-1.300 Sp. Gr. in 5° intervals.|
The instructions for using this hydrometer are contained in the GILL Battery Maintenance Manual. This document can be downloaded from the GILL battery website
Made by Freas, Conshokocken PA, in the USA. Manuf since 1926. I have used Freas hydrometers since 1974 and Freas is the best. Comes in an unmarked wholesale box. INSRUCTIONS ( from an old retail box in the hangar) TO ASSEMBLE: Put the hydrometer in the barrel, thin end first. Then wet the plug and push it in barrel up to ring, and the instrument is ready to use. HOW TO USE Hold the instrument in a vertical position, compress the bulb and insert the nozzle as far as possible in the electrolyte gradually lesson the pressure on the bulb until the electrolyte rises in the barrel enough to float the hydrometer about 1/2 inch. The reading on the instrument must be taken when there is no compression on the bulb at the surface of the electrolyte. ( NOTE: this means you will need to extract the tip from the battery to let any remaining air out of the bulb) The specific gravity of the electrolyte is an indication of the amount of charge in a battery. When the battery indicates 1300 on the hydrometer at full charge, and after the battery has been in use and the hydrometer indicates: 1250 70% of charge 1225 50% 1200 40 % 1175 20% When 1150 the battery is exhausted and must be recharged. NOTE BY COMMENTER: An auto battery starts out at 1300 specific gravity. The best I have ever seen a Gill wet battery is about 1285 when new and fully charged. Save some of the Gill electrolyte shipped with a new battery to use as a reference test of the hydrometer. Freas test point is set at 80 F to match the Gill specs for 1285 sg. Go to Gill website to download their battery manual for variations is specific gravity from 30 F to 120 F.
Useful in only the most rudimentary way. The marks are so close together that you really cant tell the difference between 100% charged and 75% charged.
Doesnt come with any directions...
Per the distributor: Made in the USA. The FR-1 has been made by a company that specializes in scientific glass works in Pennsylvania since 1905.