I'm trying to understand if the performance I'm getting from my batteries is normal, or if something is wrong.
I turned my system on live about 18 months ago, the end of June 2021 and it has been running continuously since then. Fully off grid - no public power tie in. My house is a power miser. Propane cooking, hot water, clothes dryer and propane/wood heat. All lights LED. Refer and Freezer on timers so they only run during the day. Freezer in the garage where it's never above 40 in the winter.
Here's my setup:
6 Q panels outputting 2500 watts at 48 v DC
4 Kilovault AGM batteries - 2 pairs providing 360 amp hours at 24 v DC (max charge rate 14.1 or 14.2 - depending on which guide I consult - set to 14.1)
Conext inverter providing 220 v to service panel
5500 watt propane generator backup
Primus Air 30 wind turbine
Location: Central Montana West of the Rockies - prairie. Good sun and good wind (when they're available).
All wires and cables sized and torqued to manufacturer's specs.
What happened:
Going into my first fall as the days started getting shorter, I realized that I was going to need to start supplementing the solar with generator power I carefully configured the Conext per the Kilovault and Conext instructions as far as they took me, but the Conext was putting 29 volts into the batteries. This because I did not have the Conext-Kilovault integration guide and had the temperature correction variable set to factory, which was wrong. Until I got that corrected, I had several hours of overcharging over several days. (About two weeks and four tech support people later (altEstore and Schnieder Electric), someone finally sent me the integration guide.)
What's happening now:
Even on days when the batteries get a minimum of 8 hours of good solar charging with full sun, if I have no nighttime wind the batteries are unable to hold up to over 50% by morning. Typically, I'll go to bed with the batteries at around 60% to 65%. The overnight load is less than 3 amps - this consists of a few LED night lights whose amperage are almost immeasurable and a CPAP machine which is about 2 amps at 120 v AC. This doesn't seem right. I'm not expecting good performance during these short winter overcast days with only 1 to 2 hours of generator time in the evening, but with a full day of unobstructed sunshine on the panels, I feel like the batteries should be holding out overnight. 2 or 3 amps shouldn't put them in the red.
After a generator charging cycle of 2 hours, the batteries will immediately drop from 28.2 to around 26 in the time it takes me to get from the generator to the inverter. Then the voltage drops more slowly to around 25.2 (65%).
Yes, I know that the integration guide specifies 8 hour charge cycle with the generator, but that's not the only charging the batteries are receiving and running the generator for 8 hours a day is simply not feasible with fuel costs. Might as well hook up to public power.
Did the initial overcharging of the batteries by the conext damage them in some way?
I'm weighing the pros-cons of spending $2000 on a propane refrigerator vs. $2000 on four more batteries, but I'm not sure if doubling my battery bank will provide $2000 worth of improved performance in these adverse conditions, nor am I convinced now that taking off the refrigerator load altogether is going to make any difference in performance since nearly 100% of the refrigerator run time is direct through-put from the panels, even with moderate overcast.
The only times I feel pleased with the performance of my system are on bright sunny days and during periods of night time gale force winds (15 to 35 mph).
Experimenting with these batteries is a pretty expensive proposition, so any knowledge of reasonable performance expectations is greatly appreciated.
Thanks
I turned my system on live about 18 months ago, the end of June 2021 and it has been running continuously since then. Fully off grid - no public power tie in. My house is a power miser. Propane cooking, hot water, clothes dryer and propane/wood heat. All lights LED. Refer and Freezer on timers so they only run during the day. Freezer in the garage where it's never above 40 in the winter.
Here's my setup:
6 Q panels outputting 2500 watts at 48 v DC
4 Kilovault AGM batteries - 2 pairs providing 360 amp hours at 24 v DC (max charge rate 14.1 or 14.2 - depending on which guide I consult - set to 14.1)
Conext inverter providing 220 v to service panel
5500 watt propane generator backup
Primus Air 30 wind turbine
Location: Central Montana West of the Rockies - prairie. Good sun and good wind (when they're available).
All wires and cables sized and torqued to manufacturer's specs.
What happened:
Going into my first fall as the days started getting shorter, I realized that I was going to need to start supplementing the solar with generator power I carefully configured the Conext per the Kilovault and Conext instructions as far as they took me, but the Conext was putting 29 volts into the batteries. This because I did not have the Conext-Kilovault integration guide and had the temperature correction variable set to factory, which was wrong. Until I got that corrected, I had several hours of overcharging over several days. (About two weeks and four tech support people later (altEstore and Schnieder Electric), someone finally sent me the integration guide.)
What's happening now:
Even on days when the batteries get a minimum of 8 hours of good solar charging with full sun, if I have no nighttime wind the batteries are unable to hold up to over 50% by morning. Typically, I'll go to bed with the batteries at around 60% to 65%. The overnight load is less than 3 amps - this consists of a few LED night lights whose amperage are almost immeasurable and a CPAP machine which is about 2 amps at 120 v AC. This doesn't seem right. I'm not expecting good performance during these short winter overcast days with only 1 to 2 hours of generator time in the evening, but with a full day of unobstructed sunshine on the panels, I feel like the batteries should be holding out overnight. 2 or 3 amps shouldn't put them in the red.
After a generator charging cycle of 2 hours, the batteries will immediately drop from 28.2 to around 26 in the time it takes me to get from the generator to the inverter. Then the voltage drops more slowly to around 25.2 (65%).
Yes, I know that the integration guide specifies 8 hour charge cycle with the generator, but that's not the only charging the batteries are receiving and running the generator for 8 hours a day is simply not feasible with fuel costs. Might as well hook up to public power.
Did the initial overcharging of the batteries by the conext damage them in some way?
I'm weighing the pros-cons of spending $2000 on a propane refrigerator vs. $2000 on four more batteries, but I'm not sure if doubling my battery bank will provide $2000 worth of improved performance in these adverse conditions, nor am I convinced now that taking off the refrigerator load altogether is going to make any difference in performance since nearly 100% of the refrigerator run time is direct through-put from the panels, even with moderate overcast.
The only times I feel pleased with the performance of my system are on bright sunny days and during periods of night time gale force winds (15 to 35 mph).
Experimenting with these batteries is a pretty expensive proposition, so any knowledge of reasonable performance expectations is greatly appreciated.
Thanks