BobCollins
New Member
I am finally putting my van power system together and have some observations on charging from the AIMS mains charger.
The system:
2) The transition from absorption to float involved cycling between the two several times with a period of several minutes. The cycling was observable due to the voltage changing from about 14.4 V and 13.6 V and back again (see note 3). Eventually, the system settled into "float" mode which seemed persistent. Having a "float" mode at all for a LiFePO4 battery is, of course, not ideal, but it was expected from this charger.
3) The "float" voltage is about 13.6 V, in spite of the manual on page 7 indicating the float is 14.4 V. This is a good thing, though I don't understand the discrepancy with the manual.
4) The AIMS charger consumes about 2 W with the AC mains disconnected and the power switch in either position. This may be part of the voltage detection (12 V vs 24 V) function. As battery power is applied to or disconnected from the charger, the click of a relay is heard from the unit.
Note: the AIMS charger appears to be mostly (or completely) and analog system. Monitoring the voltage and current using the digital sampling of the SmartShunt provided a confusing display as the values jumped between the quantization levels of the meter. The result is what looks like a significant oscillation on the "Trends" display, but is likely a minor ripple in the analog electronics of the AIMS charger.
I am interested in other user's thoughts on my observations and conclusions. I am not happy with 2 W of wasted power, but I am not particularly interested in another switch either.
Cheers!
Edit (2022-06-27): I fixed the errors in my description here where I left off the tens digit several voltage values. Thanks sunshine_eggo!
The system:
100 A-h LiFePO4 12.8 V battery
battery switch
AIMS 12V/24V charger (switches set to 00, LiFePO4 mode)
Victron Energy SmartShunt
multimeter to confirm voltages
1) The absorption stage (constant voltage) was indistinct and quick. After taking hours to reach about 14.1 V (in the bulk stage, constant current), the voltage quickly climbed to 14.4 V in a couple of minutes, at which point the current dropped (sorry, I didn't record the bottom current value at this point).2) The transition from absorption to float involved cycling between the two several times with a period of several minutes. The cycling was observable due to the voltage changing from about 14.4 V and 13.6 V and back again (see note 3). Eventually, the system settled into "float" mode which seemed persistent. Having a "float" mode at all for a LiFePO4 battery is, of course, not ideal, but it was expected from this charger.
3) The "float" voltage is about 13.6 V, in spite of the manual on page 7 indicating the float is 14.4 V. This is a good thing, though I don't understand the discrepancy with the manual.
4) The AIMS charger consumes about 2 W with the AC mains disconnected and the power switch in either position. This may be part of the voltage detection (12 V vs 24 V) function. As battery power is applied to or disconnected from the charger, the click of a relay is heard from the unit.
Note: the AIMS charger appears to be mostly (or completely) and analog system. Monitoring the voltage and current using the digital sampling of the SmartShunt provided a confusing display as the values jumped between the quantization levels of the meter. The result is what looks like a significant oscillation on the "Trends" display, but is likely a minor ripple in the analog electronics of the AIMS charger.
I am interested in other user's thoughts on my observations and conclusions. I am not happy with 2 W of wasted power, but I am not particularly interested in another switch either.
Cheers!
Edit (2022-06-27): I fixed the errors in my description here where I left off the tens digit several voltage values. Thanks sunshine_eggo!
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