thanks for the words of warning. while we've purchased the components of the system, we have not yet hooked anything up. because of that the batteries are not yet used so we feel adding new panels to the system now would not in any way impair the health of the ones originally purchased. would you agree with that interpretation? how many new batteries do you suggest we purchase to round out our system? thank you
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Battery size really depends on the loads your system has, you want to only cycle the batteries about 20% daily
Solar size is obtained via your location, weather and panel site.Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-ListerComment
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Originally posted by panderson03 View Postthanks for the words of warning. while we've purchased the components of the system, we have not yet hooked anything up. because of that the batteries are not yet used so we feel adding new panels to the system now would not in any way impair the health of the ones originally purchased. would you agree with that interpretation? how many new batteries do you suggest we purchase to round out our system? thank you
If you do not know how many watt hours you plan on using then I would suggest reducing the panel wattage so you only get charging amps in the 18 to 25 range. That way you can safely charge your existing battery bank and use it before you find out what you really need.Comment
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Originally posted by Mike90250 View PostBattery size really depends on the loads your system has, you want to only cycle the batteries about 20% daily
Solar size is obtained via your location, weather and panel site.
sometimes we're away from the cabin for a week or three. the intent behind the oversized battery bank is to capture the suns energy while we're away for our use when we are there living in the structure. thanks very much for your helpComment
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Originally posted by SunEagle View Post
As Mike states you first need to know what your daily watt hour usage is going to be and size your battery system from that value. Those existing 207Ah 12V batteries really should only be charged with 18 to 25 amps which is way less then what those panels can put out.
If you do not know how many watt hours you plan on using then I would suggest reducing the panel wattage so you only get charging amps in the 18 to 25 range. That way you can safely charge your existing battery bank and use it before you find out what you really need.Comment
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Originally posted by panderson03 View Post
thank you. does the charge controller control how fast the panels charge the batteries? thanks againComment
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Originally posted by panderson03 View Post
good morning. average monthly usage is 300 KWH with a spike in July to 400 KWH. daily usage can sometimes spike to 17KWH.
sometimes we're away from the cabin for a week or three. the intent behind the oversized battery bank is to capture the suns energy while we're away for our use when we are there living in the structure. thanks very much for your help
Since you have a lot of panel wattage maybe reducing the amount of panels and charging amps to about 20 to 25 amps to keep your existing 48V battery system happy and find a way to use the rest of the panels to charge a second battery system when you need it for the higher usage months. There are a number of ways to get power for your needs.Comment
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Originally posted by panderson03 View Post
we've purchased 9 370 watt panels and 4 12V SOK LiFePO4 batteries. seriously considering purchasing another 4 SOKs
I have a single 12v 200ah lithium. Charge at 40amps and have about 70% usable capacity. I could use a little more capacity but it drops off really fast at the end so monitoring and cut outs are fitted.
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Originally posted by Bala View Post
If these are Sok lithium 200ah battery then you get to use a lot more capacity and and probably have a higher charge rate than lead acid.
I have a single 12v 200ah lithium. Charge at 40amps and have about 70% usable capacity. I could use a little more capacity but it drops off really fast at the end so monitoring and cut outs are fitted.
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Originally posted by panderson03 View PostComment
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Originally posted by panderson03 View Post
thank you, Bala. would very much like to hear more about your experiences!
You do not really want the internal battery system getting to the low voltage disconnect point so best to fit an adjustable external unit in combination with battery monitoring. Lots of options there.
I have my LVD set at 40% State of Charge SOC. If it does cut out I can turn it straight back on and have a bit of time to get it charging again before it cuts out on the internal cut out.
So I have about 60% of my capacity to use, you could go to about 80% but the internal cut out may come into play. So you can decide on what capacity % you do your energy budget on.
You do need to be aware that some solar charge controllers are damaged if the battery is not connected so that is a factor if the battery cuts out on LVD.
Have a look online at lithium discharge curves, you will see that the voltage drops very quickly at the end.
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Originally posted by panderson03 View Post
......we are using SOK LiFEPO4 12V batteries. we have an Outback Flexmax 80 charge controller.
the idea is that our battery bank would be oversized for what our panels can output.
that way, when we're away from the cabin for a week or 2, the batteries can install an abundance of energy
....
9 kW solar, 42kWh LFP storage. EV owner since 2012Comment
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