Capacity Testing and 20 HR Rating
I'm thinking about doing a capacity test on my four GC2's. They have a 20hr rating of 215Ah. One thing I'm curious about is how the 20hr rating would have been determined. Being 6v, would they h...
Forum Discussion
Welcome to the wonderful world of "corrected" Plug N Play monitoring. A kWh meter and intermittent hydrometer verification -zeroing- or dialing in, is even more accurate than the three hundred dollar meter. I tried to explain this several times on this forum to no avail. Measuring chemistry is not possible without contact with the chemicals. Voltage and amperage trends & tendencies are a derivative manner of measurement but interpolation-type state of charge analysis is anything but accurate. The error grows with time expended in process.
Of the trends & tendencies experienced with ampere hours, the percentage of positive ampere hours needed to reach 100% SOC is a direct statement whether or not the measurement process is reasonable accurate. Example: 63 ampere hours charging needed to negate 51 amp hours extracted is excessive for a known good 5% antimony battery. By utilizing a kWh meter, which has no Peukert correction, a return to zero then cumulative excess kWh can be interpreted on a simple calculator. Render the difference into percentage and you end up with a CEF charge efficiency factor, which is of value only in near-future analysis.
Hydrometer confirmation/calibration is only necessary every three to six weeks.
However keep in mind the entire protocol, every last datum has be to temperature compensated, just like hydrometer readings. This can be performed on a correction chart.
But, boiling this all down to heavy syrup, a kWh meter, and a hydrometer would serve nicely. A single rundown to 50% SOC on a new battery after 20-cycles would render a base reference point. Follow this will a normal recharge routine and several values will make themselves available. The most important of course is the differential kWh needed the "Delta T" between kWh consumed and kWh hours needed to recover.
This sounds infinitely more confusing than it really is. Everything is based on relationships. Delta T percentages. A C20 protocol is gentle enough to provide reliable data.
Of the trends & tendencies experienced with ampere hours, the percentage of positive ampere hours needed to reach 100% SOC is a direct statement whether or not the measurement process is reasonable accurate. Example: 63 ampere hours charging needed to negate 51 amp hours extracted is excessive for a known good 5% antimony battery. By utilizing a kWh meter, which has no Peukert correction, a return to zero then cumulative excess kWh can be interpreted on a simple calculator. Render the difference into percentage and you end up with a CEF charge efficiency factor, which is of value only in near-future analysis.
Hydrometer confirmation/calibration is only necessary every three to six weeks.
However keep in mind the entire protocol, every last datum has be to temperature compensated, just like hydrometer readings. This can be performed on a correction chart.
But, boiling this all down to heavy syrup, a kWh meter, and a hydrometer would serve nicely. A single rundown to 50% SOC on a new battery after 20-cycles would render a base reference point. Follow this will a normal recharge routine and several values will make themselves available. The most important of course is the differential kWh needed the "Delta T" between kWh consumed and kWh hours needed to recover.
This sounds infinitely more confusing than it really is. Everything is based on relationships. Delta T percentages. A C20 protocol is gentle enough to provide reliable data.
