Recently set up, ebay 16 cell LiFePO4 battery and Cycle Analyst 3. "State of Charge" indicator says the battery is full, when it actually should be down to about 40%.
Questions:
1. The way I read this, the computer would need to keep track of the battery's ongoing state for these calculations. Particularly, "... while tracking Ah at all other times." CA displays an Ah statistic on the first screen, but that isn't the one it needs for this - it's just Ah since last time the data was reset, and not tied to battery cycle or even which battery. Can it actually track Ah on the battery and display mid range state of charge? How - how can it reliably reconnect to a battery and know how many Ah it has on it since last full charge? (Extra credit if this hypothetical ability can also be relied on after incomplete charge-up.)
2. This all seems critically dependent on some base voltage. Seller says 16 cells, which CA reckons is 51V; actual reported voltage is 52.2V right now, so that seems fair enough. Sold as 48V. Does CA derive "top knee", "middle voltage zone" etc. from this 51V, or is this another stored state that would have to be tied to battery cycle in some way of which I can't conceive?
(My other "48V" battery is Lithium 2.4Ah cells, but the number of cells needed to get CA to consider it a 48V battery is 13, which would add up to quite a bit more than the advertized 23Ah. If CA needs to know the 52V or something that it actually puts out, I can probably ask the manufacturer what to tell CA.)
Bonus question 3. Just now while checking numbers, I got "Setup changed!", and now I see that it's reporting about one less Ah, and Regen has gone up to an impressive 31%. What's up with that? Before this, I was pleased to see regen at a modest 8% or something. I guess it might be time to reset the data.
The bottom line is of course just that it would be real nice to know where I am on battery charge.
user guide said:Note: Unlike other chemistries, LiFePo4 has a very flat discharge curve making it particularly difficult to ascertain SoC by voltage. The CA handles LiFePo4 uniquely, disregarding voltage as a SoC metric except at the knees of the curve. This allows it to accurately detect 'full' and 'empty' conditions by voltage while tracking Ah at all other times. This generally gives a reliable charge indication but anomalous LiFePo4 displays are possible if the voltage makes transient low excursions due to sag (more pronounced in cold weather), slow controller capacitor discharge when powering down, etc. In these situations the lower SoC indication due to low voltage can 'stick' as the CA ignores subsequent rise to higher voltages in the middle voltage zone. A fresh charge brings the voltage above the top knee and restores proper indications.
Questions:
1. The way I read this, the computer would need to keep track of the battery's ongoing state for these calculations. Particularly, "... while tracking Ah at all other times." CA displays an Ah statistic on the first screen, but that isn't the one it needs for this - it's just Ah since last time the data was reset, and not tied to battery cycle or even which battery. Can it actually track Ah on the battery and display mid range state of charge? How - how can it reliably reconnect to a battery and know how many Ah it has on it since last full charge? (Extra credit if this hypothetical ability can also be relied on after incomplete charge-up.)
2. This all seems critically dependent on some base voltage. Seller says 16 cells, which CA reckons is 51V; actual reported voltage is 52.2V right now, so that seems fair enough. Sold as 48V. Does CA derive "top knee", "middle voltage zone" etc. from this 51V, or is this another stored state that would have to be tied to battery cycle in some way of which I can't conceive?
(My other "48V" battery is Lithium 2.4Ah cells, but the number of cells needed to get CA to consider it a 48V battery is 13, which would add up to quite a bit more than the advertized 23Ah. If CA needs to know the 52V or something that it actually puts out, I can probably ask the manufacturer what to tell CA.)
Bonus question 3. Just now while checking numbers, I got "Setup changed!", and now I see that it's reporting about one less Ah, and Regen has gone up to an impressive 31%. What's up with that? Before this, I was pleased to see regen at a modest 8% or something. I guess it might be time to reset the data.
The bottom line is of course just that it would be real nice to know where I am on battery charge.