20W solar...need controller?
I have acquired a 20W solar panel that shows 20vdc when not connected to anything (in full sun). When hooked up to a 12v battery, I have seen it as high as 17vdc. I'm wondering if I can get away wit...
Forum Discussion
Two indicators are omitted in he discussion IMHO
The first is with AGM the determining charge rate once the charge acceptance rate reaches 1/2 percent @ 14.40 volts should be reduced to the appropriate float potential. The greater the wattage potential Delta T @ (OCV) at 14.40 volts the greater the positive plate shedding. This is also called overcharge. Yes voltage will rise above 14,40 but at 14.5 it is destroying the battery. Curiously enough a flooded calcium battery demands higher voltage but does not exhibit the "brick wall" voltage/amperage effect as does an AGM battery.
At 50c I've seen the .5%@14,4 volts effect as low as 13.1 volts. The higher the voltage differential the more self destruction takes place.
Refer to the Lifeline manual for temperature compensation.
When sustained floating a flooded battery electrolysis indicates a battery is being overcharged. Hydrogen and O2 bubbling must be avoided.
A sum total of the number of hours the battery is being mistreated to (i.e. solar versus shore power) is very useful as the total number of hours the battery is accumulating damage.
An amp hour meter is useful here. Any totalization exceeding 120% is cause to for additional surveillance.
I use decay characteristics as a handy indicator of finding a proper float point. Hear me out...
Let's say your controller says "All is well"
Using a watch, impress 14.4 volts while using a digital ammeter. If amperage starts out at greater than .5% and takes longer than 5 minutes to recover to .5% the battery is being floated at too low of voltage. Don't forget to allow for a possible error in temperature compensation.
Trends and tendencies. This is beyond the scope of 'usual' battery charge float control. But for the ultimate (added 20% lifespan) in float parameters it's worth tinkering with.
The first is with AGM the determining charge rate once the charge acceptance rate reaches 1/2 percent @ 14.40 volts should be reduced to the appropriate float potential. The greater the wattage potential Delta T @ (OCV) at 14.40 volts the greater the positive plate shedding. This is also called overcharge. Yes voltage will rise above 14,40 but at 14.5 it is destroying the battery. Curiously enough a flooded calcium battery demands higher voltage but does not exhibit the "brick wall" voltage/amperage effect as does an AGM battery.
At 50c I've seen the .5%@14,4 volts effect as low as 13.1 volts. The higher the voltage differential the more self destruction takes place.
Refer to the Lifeline manual for temperature compensation.
When sustained floating a flooded battery electrolysis indicates a battery is being overcharged. Hydrogen and O2 bubbling must be avoided.
A sum total of the number of hours the battery is being mistreated to (i.e. solar versus shore power) is very useful as the total number of hours the battery is accumulating damage.
An amp hour meter is useful here. Any totalization exceeding 120% is cause to for additional surveillance.
I use decay characteristics as a handy indicator of finding a proper float point. Hear me out...
Let's say your controller says "All is well"
Using a watch, impress 14.4 volts while using a digital ammeter. If amperage starts out at greater than .5% and takes longer than 5 minutes to recover to .5% the battery is being floated at too low of voltage. Don't forget to allow for a possible error in temperature compensation.
Trends and tendencies. This is beyond the scope of 'usual' battery charge float control. But for the ultimate (added 20% lifespan) in float parameters it's worth tinkering with.
