I apparently may be over simplifying, which might not turn out to be useful logic.
That is what you are doing..
I figured if the 100w panel via MPPT is delivering 7 amps mid day, I'm getting 7 amp hours in an hour at that time, then in the late afternoon if the controller (Genesun) is delivering 2 amps, I'm getting 2 amp hours etc. I'd like to know total amp hours delivered at the end of the day, regardless of amp hours drawn for use during the day. I can't accurately say how many amps delivered in a day based on only momentary ammeter readings.
Delivered vs.
actually stored is the real key. Delivered tells you next to nothing and can actually be very misleading and this is why Ah counters are not inexpensive and need a shunt at the battery...
While cruising, at anchor, the solar setup I have has been able to recharge to a controller-indicated full state by about 2pm during the summer in So Cal.
Absorption or Float and
full are not one in the same. Just because the light is constant green this only means you're either in absorption or float mode. Absorption or dropped to float does in no way mean your bank is full. With the Genasun controllers it means you've;
#1 Increased bank voltage to the CV (constant voltage) limit (absorption)
#2 At the CV transition a 2.5 hour time-clock starts for absorption
#3 2.5 Hours at absorption voltage has expired and now the controller has dropped to float.
A single solid green light indicates either absorption or float.
Even the most efficient AGM batteries require more than 2.5 hours of absorption before attaining the 100% SOC mark. Genasun is better than most but most controller makers err on the side of caution when using "
voltage regulation". Your batteries are really not
full until you have attained absorption voltage and less than 1% of Ah capacity in accepted current flowing into the battery. The Genasun gets you close to full before dropping to float but not all the way. Some folks use 2% @ absorption voltage as an indicator of 100% SOC for cruising but this leads to PSOC capacity walk down.
I've made a calculation on 24-hour amp hour usage based on the estimated time, volts and device/bulb rated watts used. Therefore, based on the time of day when the controller says full, I can estimate/confirm amp hours used and charged over 24 hours, especially if a meter indicates how many amp hours were delivered to cause the controller to indicate full.
--the meter would be on the solar side only, and unaware of amp hours consumed by the boat.--
I know the previous article is complex but take a good read of it....
Full is easy - ABSORPTION VOLTAGE and LESS THAN 1% in TAIL CURRENT flowing into the battery with a source fully capable of well exceeding the minimum. (for
actual full 0.5% in acceptance is much better to use)
A long winded way to say, "oh look the meter says the solar delivered 25 amp hours since 2:00pm yesterday. Now the controller says full. I must have used 25 amp hours since 2:00pm yesterday. And my solar system is working well".
Or:
"The solar delivered 25 amps hours, but still not full. I need to cut down on power usage."
Etc.
Again your controller does not tell you "full" it tells you when it attained the absorption voltage or when has dropped to float or from the CC to CV transition + 2.5 Hours. One solid green light for both absorption & float. Most makers of CC/CV charge equipment finish charging the batteries during float because predicting time to full by voltage only is very difficult.. The problem is once we drop to float, the accepted current into the battery also drops, and this means well in excess of 24+ hours to really get your batteries back to 100% SOC...
Also, while you may deliver 25 Ah's to your bank but at high SOC this energy is not actually
stored in the battery due to Coulombic efficiency..
This is why Ah counters cost so much. Even then they are very difficult for the average user to keep accurately programmed because a battery is an ever moving target and charge efficiency, Peukert, battery temp, and actual Ah capacity are every changing...
