SolarfortheOuachitas
New Member
- Joined
- Aug 1, 2020
- Messages
- 43
Hello, Members. I’m looking for some advice on an idea that I have - specifically asking you how practical it is or for other suggestions on how to accomplish this project.
I have two solar installations. One is an off-grid cabin with a 3700 watt array and a older Trace SW4024 inverter, 220 volt transformer and 18, 12 volt 105 ah AGM batteries for storage.
The other is a grid-tied array of 7600 watts with no storage.
At my off-grid installation, I’m running a well pump, heat pump water heater, MrCool minisplit, frig, as well as lights, etc., off of the Trace inverter. The two 15 amp breakers on the 220 volt transformer from the inverter trip occasionally when I overload the system.
My electrician brother and I have balanced the loads, but I believe that my inverter has reached its limit - especially when I’m running the well pump, heat pump water heater and mini split and frig at the same time.
I’ve gotten spoiled with the great AC and heat that my Mr Cool minisplit puts out and am tired of using propane in the winter. I want to use the minisplit more often to heat the cabin when I’m there in the winter but it uses a lot of power and my array and battery bank can’t keep up during cold, cloudy days.
In the summer, I can pretty much run almost everything when I want, as long as I turn the minisplit off before I take a shower.
At my other installation, I have a grid-tied array of approximately 7600 watts and a net metering agreement with my utility. I’m currently carrying a net metering balance of over 4,400 kWh and have had the installation for over 3 years.
So, I was thinking about figuring out a way to take advantage of my net metering balance at my grid-tied installation by charging some lithium batteries at my grid-tied location and bringing the charged battery bank to my off-grid cabin and using the energy stored in the batteries to run my minisplit heat pump when I visit my off-grid cabin in the winter.
My tentative plan is to install a transfer switch at the minisplit service disconnect (it’s a 120 volt unit) and connect it to the fully charged battery bank (via an additional inverter) that I will have brought with me from my grid-tied residence and use that power for heat while I’m there, with the option to switch the power source back and forth between the cabin’s off-grid system and my lithium batteries from my grid-tied system.
In the winter, I generally stay at my off-grid cabin for 3 or 4 days at a time. The power house building holding my off-grid batteries is packed full and there is no room for any more batteries.
My tentative plan would be to leave the lithium batteries near the transfer switch and new inverter (outdoors) in a small weather tight storage box next to the cabin.
Does any of this make sense? Would I be better off by simply adding another separate solar array and battery bank with a transfer switch?
I don’t want to give up using my Trace SW4024 inverter as it’s reliable. The newer inverters seem to all have firmware issues, but I’m willing to learn and adapt - slowly by adding one to my system as an auxiliary unit through the transfer switch.
Does any of this make sense? Is it practical? Am I missing something very fundamental?
I’d sure appreciate your input and ideas!
I have two solar installations. One is an off-grid cabin with a 3700 watt array and a older Trace SW4024 inverter, 220 volt transformer and 18, 12 volt 105 ah AGM batteries for storage.
The other is a grid-tied array of 7600 watts with no storage.
At my off-grid installation, I’m running a well pump, heat pump water heater, MrCool minisplit, frig, as well as lights, etc., off of the Trace inverter. The two 15 amp breakers on the 220 volt transformer from the inverter trip occasionally when I overload the system.
My electrician brother and I have balanced the loads, but I believe that my inverter has reached its limit - especially when I’m running the well pump, heat pump water heater and mini split and frig at the same time.
I’ve gotten spoiled with the great AC and heat that my Mr Cool minisplit puts out and am tired of using propane in the winter. I want to use the minisplit more often to heat the cabin when I’m there in the winter but it uses a lot of power and my array and battery bank can’t keep up during cold, cloudy days.
In the summer, I can pretty much run almost everything when I want, as long as I turn the minisplit off before I take a shower.
At my other installation, I have a grid-tied array of approximately 7600 watts and a net metering agreement with my utility. I’m currently carrying a net metering balance of over 4,400 kWh and have had the installation for over 3 years.
So, I was thinking about figuring out a way to take advantage of my net metering balance at my grid-tied installation by charging some lithium batteries at my grid-tied location and bringing the charged battery bank to my off-grid cabin and using the energy stored in the batteries to run my minisplit heat pump when I visit my off-grid cabin in the winter.
My tentative plan is to install a transfer switch at the minisplit service disconnect (it’s a 120 volt unit) and connect it to the fully charged battery bank (via an additional inverter) that I will have brought with me from my grid-tied residence and use that power for heat while I’m there, with the option to switch the power source back and forth between the cabin’s off-grid system and my lithium batteries from my grid-tied system.
In the winter, I generally stay at my off-grid cabin for 3 or 4 days at a time. The power house building holding my off-grid batteries is packed full and there is no room for any more batteries.
My tentative plan would be to leave the lithium batteries near the transfer switch and new inverter (outdoors) in a small weather tight storage box next to the cabin.
Does any of this make sense? Would I be better off by simply adding another separate solar array and battery bank with a transfer switch?
I don’t want to give up using my Trace SW4024 inverter as it’s reliable. The newer inverters seem to all have firmware issues, but I’m willing to learn and adapt - slowly by adding one to my system as an auxiliary unit through the transfer switch.
Does any of this make sense? Is it practical? Am I missing something very fundamental?
I’d sure appreciate your input and ideas!
