I'm constructing a system to be used purely for emergency backup. Not grid tied, not used as a main source ran through a hybrid inverter ats. Just a bank of batteries hooked to an inverter, charged by sun for when/if shtf and there is no grid. The whole power audit thing really doesn't apply to me as I am making this for solely emergency use so in an actual emergency I could just reduce use if I had to, but for sake of argument lets say I want to comfortably run 10a of ac and have the system be ok with it. 10a ac or 55a dc on my idyllic 24v system. 10a ac in my home is every light I could want on, both recirculating pumps for heat, my fridge, my tankless water heater and whatever other small items I would want.
What i've got to work with as far as roof space is a 600sq ft 12x25 brand new roof at a 6/12 pitch. So plenty of space there. The sun passes over in an east to west fashion and both sides get a decent amount of sun throughout the day.
I've decided to go for the 3.2v cells, 300ah (or 271s or 310s if the 300s aren't available), 16 of them in parallel and then series. Giving me a 24v system @ 600ah. From Basen tech though alibaba. Several friends used them and had good results as well as good reviews online show them as one of the more reputable vendors.
I've chosen to use an all in one hybrid inverter. 24v- to 110v 3k. Specifically the LV2424, Growatt 24v-110v 3k, or one if its clones. I like them because from what I've read i can change the way it charges, making it use solar mainly but then if its plugged in to ac itself, switch to ac if the batteries are not charged enough when the solar input gets too low.
Where I would love some input is deciding on the arrangement and way to feed my bank with solar.
I understand if I am drawing a max of 10a ac or 55a dc I should have a system that allows for that much and more to be put bank into my bank. So I think that's around 1200-1400 watts of panels. If the LV2424 has a max input of 145vdc at 80a for example, what would be the best way/panels to use. I understand the difference, pros/cons of wiring panels in series vs parallel. But when wiring in series to increase voltage with the main benefit being using thinner wire, to me it doesn't seem that the loss of potential amperage is worth it unless there is more I don't understand yet. Should I find individual panels that can charge a 24v system on their own and put as many of them in parallel as I can while staying under the inverters dc input rating? I also know almost next to nothing about bms other than that they monitor the battery bank. So I will certainly need recommendations for a decent 24v bms that I will get two of for each string in my bank.
So thats basically it, a 24v system that is just for emergency, that'll have approx 600ah wired to a hybrid inverter. Looking for advice and suggestions on the array.
Greatly appreciate any and all advice.
Jim
What i've got to work with as far as roof space is a 600sq ft 12x25 brand new roof at a 6/12 pitch. So plenty of space there. The sun passes over in an east to west fashion and both sides get a decent amount of sun throughout the day.
I've decided to go for the 3.2v cells, 300ah (or 271s or 310s if the 300s aren't available), 16 of them in parallel and then series. Giving me a 24v system @ 600ah. From Basen tech though alibaba. Several friends used them and had good results as well as good reviews online show them as one of the more reputable vendors.
I've chosen to use an all in one hybrid inverter. 24v- to 110v 3k. Specifically the LV2424, Growatt 24v-110v 3k, or one if its clones. I like them because from what I've read i can change the way it charges, making it use solar mainly but then if its plugged in to ac itself, switch to ac if the batteries are not charged enough when the solar input gets too low.
Where I would love some input is deciding on the arrangement and way to feed my bank with solar.
I understand if I am drawing a max of 10a ac or 55a dc I should have a system that allows for that much and more to be put bank into my bank. So I think that's around 1200-1400 watts of panels. If the LV2424 has a max input of 145vdc at 80a for example, what would be the best way/panels to use. I understand the difference, pros/cons of wiring panels in series vs parallel. But when wiring in series to increase voltage with the main benefit being using thinner wire, to me it doesn't seem that the loss of potential amperage is worth it unless there is more I don't understand yet. Should I find individual panels that can charge a 24v system on their own and put as many of them in parallel as I can while staying under the inverters dc input rating? I also know almost next to nothing about bms other than that they monitor the battery bank. So I will certainly need recommendations for a decent 24v bms that I will get two of for each string in my bank.
So thats basically it, a 24v system that is just for emergency, that'll have approx 600ah wired to a hybrid inverter. Looking for advice and suggestions on the array.
Greatly appreciate any and all advice.
Jim
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