My Screwy 31
First off let me say I am not stressing over this. It's just a battery, it is only money, it is meeting my overnight needs, but it is displaying strange behavior, and I am curious as to why. So th...
Forum Discussion
The Screwy 31 is over a year and over 300 cycles at this point.
I've been working it hard since my return from the month long road trip. I've not been doing any Hydrometer dipping as curosity is not very high and performance is as expected, nothing unusual.
But my Meanwell RSP-500-15 has been used a bunch of times to bring it back to 100% with time at 15.3v and lesser times at 16v, and the amps required to hold these voltages have returned to levels noted 6 months previously, whereas just before road trip, they had been higher than 6 months previous.
It has obviously lost capacity. I don't really know how much and won't be doing a steady 6.5 amp load for 20 hours to make an estimation.
Last time I took 70 amp hours from it it had touched the 11.6v level, likely under a 3.2 amp load just before sunrise.
So, it still is easily meeting my needs, and being worked pretty hard, but perhaps one night a week I am floating it via the meanwell overnight after bringing the battery to 15v and holding it there until amps required to hold 15v drop below 2.
Sometimes I drop MW voltage to 14.7v and bring in AGM battery for the topping charge, but this battery rarely gets discharged much at all and eventually both 31 and AGM together at 14.7c drop to 1 amp levels, with the AGM taking only 0.2a of that.
I've found after a 15 volt until 2 amp charge is performed, and I reduce the MW to the unloaded 13.12 minimum voltage, and wait for the loads to bring the 31battery to under 13.1v, then plug MW back in, there is still amps flowing out of battery until I crank MW back upto 13.43 volts to get a 0.0amp flow into/out of battery.
8 hours later this will have crept up to 0.1amp and dialing it to 13.3 returns monitor to 0.0a. I reduce solar voltage to 13.6 max after a nightly MW float, and raise it again when cycling.
But I have to question the accuracy of the monitor at these very low amp levels.
Anyway, I am thinking 400 cycles is not out of reach at this point. But will update when voltage under load really tanks and replacement becomes imminent. Or perhaps before another longer roadtrip where battery aqcuisition would be impaired.
I've been working it hard since my return from the month long road trip. I've not been doing any Hydrometer dipping as curosity is not very high and performance is as expected, nothing unusual.
But my Meanwell RSP-500-15 has been used a bunch of times to bring it back to 100% with time at 15.3v and lesser times at 16v, and the amps required to hold these voltages have returned to levels noted 6 months previously, whereas just before road trip, they had been higher than 6 months previous.
It has obviously lost capacity. I don't really know how much and won't be doing a steady 6.5 amp load for 20 hours to make an estimation.
Last time I took 70 amp hours from it it had touched the 11.6v level, likely under a 3.2 amp load just before sunrise.
So, it still is easily meeting my needs, and being worked pretty hard, but perhaps one night a week I am floating it via the meanwell overnight after bringing the battery to 15v and holding it there until amps required to hold 15v drop below 2.
Sometimes I drop MW voltage to 14.7v and bring in AGM battery for the topping charge, but this battery rarely gets discharged much at all and eventually both 31 and AGM together at 14.7c drop to 1 amp levels, with the AGM taking only 0.2a of that.
I've found after a 15 volt until 2 amp charge is performed, and I reduce the MW to the unloaded 13.12 minimum voltage, and wait for the loads to bring the 31battery to under 13.1v, then plug MW back in, there is still amps flowing out of battery until I crank MW back upto 13.43 volts to get a 0.0amp flow into/out of battery.
8 hours later this will have crept up to 0.1amp and dialing it to 13.3 returns monitor to 0.0a. I reduce solar voltage to 13.6 max after a nightly MW float, and raise it again when cycling.
But I have to question the accuracy of the monitor at these very low amp levels.
Anyway, I am thinking 400 cycles is not out of reach at this point. But will update when voltage under load really tanks and replacement becomes imminent. Or perhaps before another longer roadtrip where battery aqcuisition would be impaired.
