Skip to main content ↑ ↓
Topic: Battery Capacity Remaining (Read 1302 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Battery Capacity Remaining

Yahoo Message Number: 5509
Hi Fred, where did you get the numbers for the battery capacity? Are these numbers the same for all types of batteries? Thanks, Dale

Re: Battery Capacity Remaining

Reply #1 –
Yahoo Message Number: 5513
Hi Dale,

Some battery grids are doped today with antimony, arsenic or calcium.
Lead/lead oxide plates (grids)with sulfuric acid makeup batteries that have a certain discharge rate dropping from 13.5 voltages steeply to 13.0, flattening out until 12.0 and then dropping rapidly off. The operating range is 13-12 vdc. Below 12.0 vdc, the battery is considered discharged and has received one discharge cycle. (Actually, 0 vdc per cell is fully discharged but that only applys if each cell's terminals are accessible.)

The actual service life of a grid plate battery in cycle service will vary with the average depth of discharge. The deeper the average discharge on each cycle the shorter the battery life. As an example 50% average discharge will give around 500 cycles; 30% average discharge will give in excess of 1000 cycles.
As more cycles take place, some cells get weaker and some stronger which means at the end of the recharge, some cells have slightly lower voltage and some higher. Many times on a discharge and recharge, the higher cell voltages charge quicker and drive the weaker cells into reverse polarity. Now you got a dead battery. If you read my recent emails on this subject, it will help make the 8Ds last longer.
The voltages I listed come from discharge rates published in the early 1900s and are verified in current day charts easily obtainable using Google.
Fred Kovol