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kah68
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# Posted: 28 Nov 2022 08:38pm - Edited by: kah68
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Hey all, as the title says there's an old existing system consisting of the following.
2x 150W 2x 90 watt panels (facing North)
8 6V FLA golf cart batts (10+ years and pooched)
Pro Star PS 30 controller
Iota DLS 55/IQ4 charger
Iota ITS 30R Transfer switch
Pro Watt 1500 Inverter
Novax distribution box
The camp is wired for 120V AC and there's a Honda EU 3000is for back up.
I just bought 4 Sok 12V 206 Ah LFP and am now looking to put either the components together to make this bank work or replace everything with an AIO.
The Victron Multi Plus 2 48/3000/35 is interesting but I'm looking for help deciding the best route to go. My daily requirement is roughly 4.4 KW.
Any direction would be appreciated.
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kah68
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# Posted: 28 Nov 2022 08:40pm - Edited by: kah68
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This system will be used 8 months a year and removed for storage for the winter.
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curious
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# Posted: 29 Nov 2022 12:15am
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Quoting: kah68 panels (facing North)
Are you in the southern hemisphere?
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kah68
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# Posted: 29 Nov 2022 06:21am
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No, Central Ontario. Panels need to be relocated.
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Nobadays
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# Posted: 29 Nov 2022 09:42am - Edited by: Nobadays
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It appears your system is 24v? The reason this seems plausible is lota, to my knowledge doesn't make a 48v charger. Likewise I don't think Pro Watt makes a 48v inverter.
Know that you will not want to series the 150w and 90w panels or you will reduce the output from the 150w panels to that of the 90w's. Put them on separate input breakers.
The Pro Star 30 is built by Morningstar I believe, not a bad SCC but it is a PWM controller so you won't capture all you could.
From what I understand the lota equipment is good stuff.
The Pro Watt inverter is, I believe a Modified Sine Wave inverter. OK for a lot of uses but over time will damage any kind of motors that are hooked up to it, those that will run on it to begin with.
You can't go wrong with Victron equipment! Not sure you want to series 4 12v batteries to make 48v. Better to have 2 x 24v or if you can swing it a 48v battery. But if you stay with a 24v system 2s2p with your new batteries should serve well. (Can't help but plug LiFePo4 here.... when your new batteries fail, go LiFePo4! )
If you are trying to keep costs down but have a quality system, Growatt makes a nice AIO HERE. MPP has a pretty good track record as well, just be careful, if you need 240vac that the output is split phase 240v.
My one concern with your 4.4kw need is do you have enough panel to provide that. You have roughly 500w but will likely never see that as output. Probably more in the 60% or 300w range +/-. I'm doing quick math in my head but at 300w capture you would need ~14 hours of good daylight to produce that much power...? Someone check my math!
I question this as our usage is similar, slightly less and though we float most "bluebird" days by noon, on partly cloudy days it is often late afternoon before we float, if we do. We have 2,200w of South facing solar that most of the year receives 4-6 hours of sunlight.
Best advice I had designing my system was... ask yourself if you are going to the cabin to relax and enjoy or to fiddle with your solar system? Buy once, cry once!
My 2 cents...
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kah68
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# Posted: 29 Nov 2022 01:15pm
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Hey Nobadays,
Sorry the batts are LiFePo4.
The system voltage was explained to me by the former owner, I have not tested any of it. So it may in fact be 24V.
Sok shows series connection of the 12V206AH up to a 48 volt system. I am not set on anything right now but a bigger bank than my usage.
I think the array will definitely need to be increased and relocated and is part of the upgrade plan.
Definately only want to do this once with the potential to expand if need be.
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Nobadays
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# Posted: 29 Nov 2022 01:31pm
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Quoting: kah68 Sorry the batts are LiFePo4.
My bad...see that now!
Quoting: kah68 Definately only want to do this once with the potential to expand if need be.
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Brettny
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# Posted: 30 Nov 2022 06:53am
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I also dont think you have enough pannels and the PWM controller is going to limit you alot. I would look into full sized pannels and at least 3x your current wattage.
What are you running that you need 4.4kw?
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FishHog
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# Posted: 30 Nov 2022 08:03am
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agreed, thats a large battery bank and small solar panel system. Might be OK for weekenders as you will have time for your panels to recharge while your away.
But that is a lot of power for weekend usage. Well its a lot for full time usage to me.
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Steve_S
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# Posted: 30 Nov 2022 08:15am
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PLEASE STOP BUYING STUFF !
Get a Plan, work through it and make sure you know what you "Need", then "Want" and Would Like" and make sure your plan will answer those requirements, in that order. Impulse Buying or buying things without a plan will ALWAYS COST YOU MONEY and often that includes wasted money !
Quick guidelines:
12V System supports up to 2500W Inverter @208A draw. (120V/20A or 240V/10A)
24V System supports up to 4800W Inverter @ 200A draw. (120V/40A or 240V/20A)
48V System supports up to 9600W Inverter @ 200A draw. (120V/80A or 240V/40A)
* Not Corrected for Inverter inefficiencies & losses, depending on quality/grade that can range from 85% to 95% efficiency for the inverters.
Batteries in Series (not advised) increase voltage but not capacity.
Batteries in Parallel increase storage capacity (Amp-Hours).
With Lithium Based batteries it is always best to use "Native Voltage" instead of adding battery packs in series. If one battery in a series chain fails for any reason, the others can be damaged. Most BMS' (Battery Management Systems) within a battery pack will not handle series connections properly. Some do but there are many tradeoffs that are often deemed a risk.
LFP/Lithium Iron Phosphate/LiFePo4 batteries CANNOT be charged below 0C/32F temps !
LFP discharges at 1C Rate and can only be charged at 0.5C Rate Maximum. IE: 100AH Battery can discharge up to 100A (1C) for 1 hour and be charged at 50A (.5C) for 2 hours.
All in One (AIO) or Component-Based solar system ?
AIO's are attractive because they simplify installation & operations, as well they can be cost-effective depending on the application. They are NOT Suitable for all applications though. These have the Solar Charge Controller (SCC), Inverter & Charger all built into one unit, as such, it's all either ON or OFF and when on they have a higher power consumption rate than component-based systems. Generally you cannot turn off "just the Inverter" and leave the Solar On to maintain the batteries. This makes usage in a Part-Time location less attractive because keeping batteries charged is important so the SCC needs to be on and if you are not powering devices "while away" you don't want/need power drawn by an inverter. There are options for Paralleling more AIO's together to expand a system but they are unique to each vendor & model which can & do change over time. Sticking to Tier-1 products like Victron who will maintain compatibilities is a wise option versus lower tier products which change product lines frequently.
Component-Based systems can have various components turned off when not required, such as the Inverter. These are more complicated to setup and usually do cost a bit more to put together properly. If properly designed from the start, these can also expand and grow with needs.
HF (High Frequency) or LF (Low Frequency) inversion is also an important issue to be aware of. Most AIO's are "HF" because it is much cheaper to manufacture and keeps sale prices down BUT there are negative trade-offs. READ MORE HERE: https://www.magnum-dimensions.com/knowledge/high-vs-low-frequency-inverters/inversion -methods-explained-high-frequency-vs-low I personally would NEVER Recommend "HF" for any residential application, because every "home" has motors (Fridge, freezer, AC Compressor motors, well pumps and more) and HF is not good for these devices.
120V or 240V split phase ?
If you do not need 240V you can go with 120V wiring & circuit panels without issues and operate a cabin to small home with the usuals just fine. BUT, this limits any future expansion capabilities which we all know, this changes and quite often folks hit the Should'a, Could'a, Would'a WALL head-first and those regrets can cost you more money doing retrofits, so do consider this in your planning. I very strongly suggest you design for a 240VAC System which still provides you with 2 legs of 120V for everything. Do wire for a 240V Stove outlet even if you won't be using it.
Well Pumps etc do NOT have to be 240V, there are MANY 120V SoftStart pumps and devices that can do the job very well & efficiently.
I'm 100% Off-grid, Remote & Rural near Algonquin Park Ontario. 24VDC to 120VAC w/ 33kWh of LFP. My Solar Setup info is here: https://diysolarforum.com/threads/my-diy-off-grid-cabin-setup-in-ontario-canada-24vdc -120vac.1484/
Some quick power usage #'s from my system which is 24V to give you an example.
- Panasonic 1200W Inverter Microwave draws 72A @ Full Power.
- Oster Coffeemaker with insulated carafe (no warmer) uses 50A while brewing.
- 2 slice smart toaster uses 50A on full power.
- Well Pump ramps to 48A when it reaches 52PSI cutoff. (Well Pump is a Grundfos SQ-5 120V Softstart model, 260' deep)
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Suggestions:
- Do an energy audit / assessment and really figure out how much power you think you will use per day, I use < 3.5kWh per day and I am Full-Time.
- Work out how many AC Amps you may draw at most at one time because you will need to know what you have to be able to supply for the heaviest load potential.
- ASSES your appliances / devices ! It is FAR CHEAPER to conserve energy than to generate & store it ! Old appliances are notoriously bad for efficiency and AC systems are the worst ! Good Upgrades like Mini-Split AC/Heat units can payback fast, even Heat Pumps can be amazing. Many good models are available for Canadian Climate and not crazy expensive either, several can be DIY'ed as well.
Buying ONLINE or not.
Often times some online deals look great but are not necessarily so great. By the time you add shipping + duties/taxes & currency exchanges you end up paying more with little to no support from a vendor. Solar Panels for one are often more costly and quite often problematic when damaged etc. Look for more local suppliers that you can drive to if needed or those that are more local (in Ontario for example) so any shipping is minimized.
Lastly, there are many ways to put together a solar system and DIY it to save a pile of cash. But be aware that Insurance Companies are nastily picky and virtually all want some sort of electrical inspection & sign off prior to insuring a property. Attached to a grid really makes that worse (more costly) to boot IF you are sending anything to grid. Take your time and do your research and wrap your brain around working with DC Power, the terminology and equipment. A Reminder: Electrical Welding is DC not AC which is converted to DC. Big BooBoo's are really easy to do !!!
Attached is a simple logical diagram of a component system setup with batteries in parallel. NOTE that this is not a complete schema with all the required items. Required components are also different if using an AIO based system.
Hope it helps, Good Luck.
Steve_S (here & at DIYSolarForum)
component system w/batts in parallel
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Nobadays
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# Posted: 30 Nov 2022 09:41am
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Well written Steve! I wish there was a way to make a "sticky" so folks asking solar questions could be directed here first! Thanks.
Moderators.... any way to make this a sticky or at least easy to point people to?
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Brettny
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# Posted: 30 Nov 2022 01:31pm
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I would advise against an all in one system. There was a member here that found there all in one inverter/charge controller/charger had a fairly big parasitic draw.
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kah68
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# Posted: 30 Nov 2022 01:46pm - Edited by: kah68
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Ok thanks guys, lots of info to digest. I will stop buying equipment until I figure out my needs. My initial energy audit was approx 3.4 KW per day so I added 1 KW just for some margin.
My goal is to have a weeks worth of reserve to keep an AC fridge running incase of a rainy week, and also enough power for my weekend needs which would either be a jet pump or well pump and the various other daily household electrical requirements. Larger loads will be handled by Generator ( Skill saws ).
I do like Steve's suggestion of having a component system and turning the inverter off leaving the solar and charge controller to maintain the batteries.
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kah68
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# Posted: 30 Nov 2022 01:49pm
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Ok thanks guys, lots of info to digest. I will stop buying equipment until I figure out my needs. My initial energy audit was approx 3.4 KW per day so I added 1 KW just for some margin.
My goal is to have a weeks worth of reserve to keep an AC fridge running incase of a rainy week, and also enough power for my weekend needs which would either be a jet pump or well pump and the various other daily household electrical requirements. Larger loads will be handled by Generator ( Skill saws ).
I do like Steve's suggestion of having a component system and turning the inverter off leaving the solar and charge controller to maintain the batteries.
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Brettny
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# Posted: 1 Dec 2022 08:09am
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Where did you get the KW useage for a fridge?
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Steve_S
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# Posted: 1 Dec 2022 08:33am
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Something from the Lessons Learned Dept.
When I started on my adventure, Victron was not available in Canada yet, so I chose Midnite Solar Classic Solar Controller and a cheap 3000W Chinese Pure Sine LF Inverter and Rolls Surette Lead Acid Batteries. I ended up upgrading that Inverter to a Tier-1 grade Samlex 4024 EVO Inverter/Charger which is amazing and eventually shifted from Lead Acid (428AH gross / 214AH useable) to LFP (LiFePo4) batteries which I built myself which now gives me 10 days storage in "scrimp" mode. No complaints over the choices except for one, it is a real bitch for software monitoring & management for all of it.
IF I was doing it all again and today, I would go All Victron Equipment which is extremely manageable & well supported by their software & more. I could even attach all 6 of my DIY Battery Packs and be able to manage them with it as well.
BTW: The Samlex EVO Inverter is Pure Sine, Low Frequency capable of surges up to 12,000W, It can run my big compressor and even my 120V MIG Welder as well as the usuals like Table Saw, Chop Saw etc without a blink. An HF Inverter could never do it.
Because you're "Local", as in the same province I must underline the fact that you cannot charge LFP below 0C and only at 0.2C until 5C temp. LFP Batteries are by far the best way to go BUT for us, we have to either have heated batteries with their own warmers or like me have a heated Powerhouse to keep our solar gear in. My powerhouse is also my pumphouse which has the well-head and the 50 Gallon Pressure tank within, so I built it hyper-insulated, with thermally broken walls and a frost-protected slab foundation (R20 Foam under it and up the sides of the slab) which is the same setup as my house.
Solar Panel Angle for me (optimal year-round) is 45 degrees which works OK but still needs to get the snow brushed off at times. My new solar array (2370W) going up next spring will be at 50 Degrees to be more optimal in Winter as that is when I need more solar to keep up with my battery bank. A quick BTW: 45 Degrees = 12:12 Pitch roof.
Hope it helps, Good Luck.
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kah68
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# Posted: 1 Dec 2022 09:31am - Edited by: kah68
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Helps immensely, thank you. I was looking at the Multi plus 2 with all their supporting components.
This is a water access seasonal cottage, my plan is to pull the batts in November and bring them back in April.
When I go in the winter I can run the Genny in the evenings for my power. Woodstove provides heat, no need for a fridge as a cooler works fine. I even considered a small inverter and bring 1 of the 12V LFP back and forth as they are easy to handle.
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Nobadays
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# Posted: 1 Dec 2022 10:53am
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Quoting: Steve_S IF I was doing it all again and today, I would go All Victron Equipment which is extremely manageable & well supported by their software & more.
This! I went with Schneider Conext which is tier 1 equipment as well but nothing like Victron for manageability! I designed and installed an off-grid system for my neighbor using Victron for the main components. Wow! Setting it all up with a laptop interface was so simple we looked at each other and wondered if we missed something! Went back through the setup and rechecked, nope all done! Been running for 2 years now flawlessly.
If I were to do it again, Victron all the way!
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FishHog
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# Posted: 1 Dec 2022 01:18pm
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Quoting: kah68 This is a water access seasonal cottage, my plan is to pull the batts in November and bring them back in April.
They can handle the cold, just can't be charged in the cold. You can still use the power in them when cold, so you could arrive, use what power is in them while they warm up inside, then recharge if needed. But you need to keep them warm when charging.
Leave them around 60% charge and they will be fine for winter, if you use a bit for lights while there you probably won't even need to worry about recharging.
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