Purchased an Off-Grid Cottage/Cabin in Ontario - Critique my set up please

[bd0t]

Greetings everyone!

Last year I purchased a small 800sq ft cabin near Georgian Bay, Ontario. The cabin is off-grid and all of the components were already installed and up and running. Over the course of the summer we were up just about every weekend loving the cottage and getting the hang of all the solar stuff. Even though the cottage was only being used on weekends we were still running into the problem where the batteries would lose enough juice and the system would shut off and we'd have to fire up the generator to get them charged again. So naturally I'm thinking "I'll just add some more panels and we'll be good to go" but the more I read the more I think I'm beginning to realize it may not be that simple.

Our goal is to be able to use the cottage without worry of the system going dead with just basic weekend use. Our typical load at the cottage is fairly minimal already (charging phones and batteries for cordless tools, fridge, water pump, bosch propane tankless water heater, led potlights). In the future we'd like to have an LED TV and a dishwasher. We have pretty good sun exposure in the summer (panels are on the south side of the roof), in the winter the sun doesn't clear the trees for very long.

Current system components are as follows:

(2) 140w Kyocera panels

Morningstar TS-45 charge controller
- 45 amp PWM
- remote included

Magnum Energy MS4024 Inverter Charger
- 4000w
- 24v
- Remote included

(8) 6v 200ah Flooded batteries wired in series and parallel for a 24v setup
- Batteries are stored underneath the cottage and susceptible to the outdoor temperature fluctuations all year. As far as I know they are a couple years old. I check the water levels periodically and add more as needed. If the batteries are toast already I need to make sure it doesn't happen again!

3500w Champion generator for charging batteries etc.


So my questions are:

Do these components play well with each other or is there a weak link?

Can I add more panels without needing to upgrade something else? How many? I can purchase used 260w panels locally for about $100ea

Anyone that is familiar with the Magnum Energy remote, how do I limit the depth of discharge on the batteries so I'm not destroying the batteries prematurely? Any recommendations for my battery storage?


Looking forward to learning more about my gear and this place looks to be the best source of information that I've found so far!
If there is any more information you guys may need in order to give accurate advice just let me know!

-Brandon

[littleharbor]

First thing, You are WAY under paneled for a battery bank that large. At best you may be getting a bit over 7 amps A 24 volts from the two panels. That size battery needs from 20 to 42 amps to maintain a proper state of charge. They could be sulphated and irrecoverable..
Without knowing your loads it's impossible to say if your battery bank is oversized, undersized or right for your needs. If it appears to charge up rapidly from a low state of charge it's probably toast.
How much sun are your panels getting throughout the day and are there any shadows on the panels?

[SunEagle]

I agree with littleharbor. A 400Ah battery system should get somewhere around 40amp of charging. With that PWM type charger and only 280 watts of panels you won't reach the 40amps so your battery system will never get back to being 100% charged

For that matter with an existing solar / battery system that is not balanced I would figure a guess to say your batteries have been undercharged a number of times which lends them toward failing and will need to be replaced.

[bd0t]

First thing, You are WAY under paneled for a battery bank that large. At best you may be getting a bit over 7 amps A 24 volts from the two panels. That size battery needs from 20 to 42 amps to maintain a proper state of charge. They could be sulphated and irrecoverable..
Without knowing your loads it's impossible to say if your battery bank is oversized, undersized or right for your needs. If it appears to charge up rapidly from a low state of charge it's probably toast.
How much sun are your panels getting throughout the day and are there any shadows on the panels?

Yea I always assumed the panels were a little on the useless side but because they essentially had all week to charge without much of a load on the system until the weekend then maybe it was okay. Thats probably what the previous owner (guy who installed it all) thought too and just went and bought more batteries.

During the summer the panels get a pretty good dosage of sun, maybe from 10am - 6pm.
Winter is a writeoff, panels get buried in snow, its cloudy, sun doesn't get above the trees for very long.

We hardly use the place in winter right now. The water is turned off (water is pumped from the lake), plumbing is all antifreezed, no tv. Going forward, would it be wise to fully charge the batteries (or at least try) and then disconnect them for the winter?

These are the used panels I can buy:

Used Jinko 260W Solar Panel Made in Canada

In good and working condition, about 3% to 5% below the maximum power, 5 years old.

Model : JKM-260P
Vm: 31.1V
Im: 8.37A
Voc: 38.1V
Isc: 8.98A
65" x 39" x 2"

[bd0t]

I agree with littleharbor. A 400Ah battery system should get somewhere around 40amp of charging. With that PWM type charger and only 280 watts of panels you won't reach the 40amps so your battery system will never get back to being 100% charged

For that matter with an existing solar / battery system that is not balanced I would figure a guess to say your batteries have been undercharged a number of times which lends them toward failing and will need to be replaced.

Yep I wouldn't be surprised if that were the case. Do you think it would help in the short term if I just ran 4 of the batteries in a series?

When the time comes to replace these batteries (probably sooner than I hope) I want to make sure the rest of the system is good to go and not a battery destroying machine.

[littleharbor]

You can try to equalize them, 4, in series at a time. Meanwhile, leave the other half disconnected and sitting as full as you can get them, just as long as you have to, no more. Maybe you can get some more life out of them. Buy a good hydrometer and learn how to use it. There's lots of good info to be found in the stickies here on the forum.
The fact that you get no sun in the winter is very bad for your batteries, likely they're toast.
You might want to consider a new set of batteries , charge controller and those panels you mentioned. But first you need to figure out your loads which will determine your proper size battery, which will determine how much charging power you need. Also if you are using an inverter there are other questions. What inverter do you now have? Some are energy hogs and need to be used sparingly. Are you running refrigeration? Propane? Old AC powered refer?

[Sunking]

Yea I always assumed the panels were a little on the useless side but because they essentially had all week to charge without much of a load on the system until the weekend then maybe it was okay.

You have made a very common mistake.Batteries need a minimum charge current of C/10 and on a 400 AH battery would be 40 amps minimum.

None of that means your system will work because one major detail you left off is How Much Power Do You Require in a Day?. That determines minimum Battery Size, Panel Wattage, Controller Size, and Inverter size. With a 24 volt 400 AH battery means you minimum panel wattage requirement with a 40 Amp MPPT Controller is 1000 watts, and with an inexpensive PWM gets real expensive using 1500 watts of panels.

But like I said just based on battery size, requires 1000 to 1500 watts. No one can tell if it will work or not because you have not determined daily requirement. Three things can happen without knowing daily requirement, 2 of the 3 are bad news.

1. As you experienced, grossly;y undersized means it will fail, destroy the batteries, and will require a lot more money to fix.
2. You might over kill it and spend a lot of many needlessly.
3. You lucked out, guessed correctly which is extremely rare.

[bd0t]

You can try to equalize them, 4, in series at a time. Meanwhile, leave the other half disconnected and sitting as full as you can get them, just as long as you have to, no more. Maybe you can get some more life out of them. Buy a good hydrometer and learn how to use it. There's lots of good info to be found in the stickies here on the forum.
The fact that you get no sun in the winter is very bad for your batteries, likely they're toast.
You might want to consider a new set of batteries , charge controller and those panels you mentioned. But first you need to figure out your loads which will determine your proper size battery, which will determine how much charging power you need. Also if you are using an inverter there are other questions. What inverter do you now have? Some are energy hogs and need to be used sparingly. Are you running refrigeration? Propane? Old AC powered refer?

Ya I'm thinking I'll put 4 of the batteries in a series and run the system like that for now. Next time I'm up at the cottage I'll bring the other 4 back to the city and get them on a charger.

Current inverter is a Magnum Energy MS4024 Inverter Charger

[littleharbor]

Whatever battery bank you settle on you will at least be able to use a generator to supplement charging when needed. Equalizing takes time, not necessarily lots of power. Plan to bulk charge with the generator early in the AM and allow the charge controller to do the equalization once the bank is done charging to full.

[bd0t]

You have made a very common mistake.Batteries need a minimum charge current of C/10 and on a 400 AH battery would be 40 amps minimum.

None of that means your system will work because one major detail you left off is How Much Power Do You Require in a Day?. That determines minimum Battery Size, Panel Wattage, Controller Size, and Inverter size. With a 24 volt 400 AH battery means you minimum panel wattage requirement with a 40 Amp MPPT Controller is 1000 watts, and with an inexpensive PWM gets real expensive using 1500 watts of panels.

But like I said just based on battery size, requires 1000 to 1500 watts. No one can tell if it will work or not because you have not determined daily requirement. Three things can happen without knowing daily requirement, 2 of the 3 are bad news.

1. As you experienced, grossly;y undersized means it will fail, destroy the batteries, and will require a lot more money to fix.
2. You might over kill it and spend a lot of many needlessly.
3. You lucked out, guessed correctly which is extremely rare.

I apologize in advance for not knowing the exact consumption rates on these things.

My current power requirements are as follows:
-Charging phones
-charging dewalt cordless tool batteries
-maybe (12) 5w led bulbs in the whole place
-refrigerator
-water pump
-two oscillating fans on hot evenings
-Bosch gas tankless water heater (hooked to propane)

Eventually we will add:
- LED Tv
- Satellite for Tv
- Dishwasher
- Two Ceiling Fans

We don't use:
- Toasters
- Coffee makers (we boil water on the gas range and use a french press)
- Hair Dryers
- Laundry machines (no room)
- plug in power tools


The cottage is only 800 sq ft so there is only so much crap you can jam in there. Usage is only on weekends.

When you refer to expensive what kind of dollars are you thinking here? Lets assume I have a budget of $3000 CAD and don't really want to feel restricted too much with my usage and have a little room for heavier use in the future. What I'm preparing for are a few used 260w panels @ $90CAD each, Decent mppt charge controller, new batteries when mine are real rough shape.

[Sunking]

I apologize in advance for not knowing the exact consumption rates on these things.

No apology needed for us. Whether it works or not, or cost you a fortune is not our problem. I am just trying to help you understand the consequences of getting things wrong.

My current power requirements are as follows:
-Charging phones
-charging dewalt cordless tool batteries
-maybe (12) 5w led bulbs in the whole place
-refrigerator
-water pump
-two oscillating fans on hot evenings
-Bosch gas tankless water heater (hooked to propane)

Eventually we will add:
- LED Tv
- Satellite for Tv
- Dishwasher
- Two Ceiling Fans

The cottage is only 800 sq ft so there is only so much crap you can jam in there. Usage is only on weekends.

When you refer to expensive what kind of dollars are you thinking here? Lets assume I have a budget of $3000 CAD and don't really want to feel restricted too much with my usage and have a little room for heavier use in the future. What I'm preparing for are a few used 260w panels @ $90CAD each, Decent mppt charge controller, new batteries when mine are real rough shape.

You can drink a lot of beer on a weekend. I think we can make this work within your budget.

How many of those 260 watt panels?

That is important because it determines the size of the controller and batteries. Me thinks 3 panels is more than enough giving you roughly 750 watts. Now most will tel you to go with 12 volts, NOT ME, I am not stuck inside a DIY Toy Box. So here is what I would advise you to do.

Make a 24 volt system. It will save you a lot of money. Example if you went with 12 volts @ 750 watts would require 60-Amp MPPT Controller costing you $400 to $500. With 24 volts all you need is a 30-Amp Controller so I would use a 40-amp model and that will allow you to grow to a full 1000 watts down the road. DO NOT BUY a cheap MPPT Controller. You want a good quality unit with at least a 150 Voc input like a Morningstar MPPT Controller. Trust me here don't go cheap on controllers. This will allow you to wire all your panels in series using small 12 AWG wire and No Fuses of any kind needed between panels and controllers savin gyou more money and making the system more efficient.

For batteries use 6-volt Golf Cart Batteries. You will need 4 of them. Agai ndo not go cheap on batteries. Buy a good quality Flooded Lead Acid Golf Cart battery like Trojan or US Battery. With 500 watts use 200 to 225 AH which is a very common Golf Cart battery size. With 3 panels you will need 300 AH. Connect the dots, for each 250 watts of panels into a 24 volt battery requires 100 AH of battery. Makes the math stupid simple even a Millennial's can figure out with a calculator if they can afford to pay someone to operate the calculator for them. Again use a good quality battery. A good Trojan 225 AH GC battery cost $130 to $150 each and you need for of them.

As for an Inverter, don't go crazy on size. 1000 to 1500 watts is all the batteries can handle. Again don't use a cheap Inverter as they just waste a lot of precious energy burning off as waste heat.

So you can do this for less than $3K, just stick to a few simple rules for sizing. Feel free to ask more questions. I am happy to help, and I am a professional, not DIY. .

[bd0t]

No apology needed for us. Whether it works or not, or cost you a fortune is not our problem. I am just trying to help you understand the consequences of getting things wrong.

My current power requirements are as follows:
-Charging phones
-charging dewalt cordless tool batteries
-maybe (12) 5w led bulbs in the whole place
-refrigerator
-water pump
-two oscillating fans on hot evenings
-Bosch gas tankless water heater (hooked to propane)

Eventually we will add:
- LED Tv
- Satellite for Tv
- Dishwasher
- Two Ceiling Fans

You can drink a lot of beer on a weekend. I think we can make this work within your budget.

How many of those 260 watt panels?

That is important because it determines the size of the controller and batteries. Me thinks 3 panels is more than enough giving you roughly 750 watts. Now most will tel you to go with 12 volts, NOT ME, I am not stuck inside a DIY Toy Box. So here is what I would advise you to do.

Make a 24 volt system. It will save you a lot of money. Example if you went with 12 volts @ 750 watts would require 60-Amp MPPT Controller costing you $400 to $500. With 24 volts all you need is a 30-Amp Controller so I would use a 40-amp model and that will allow you to grow to a full 1000 watts down the road. DO NOT BUY a cheap MPPT Controller. You want a good quality unit with at least a 150 Voc input like a Morningstar MPPT Controller. Trust me here don't go cheap on controllers. This will allow you to wire all your panels in series using small 12 AWG wire and No Fuses of any kind needed between panels and controllers savin gyou more money and making the system more efficient.

For batteries use 6-volt Golf Cart Batteries. You will need 4 of them. Agai ndo not go cheap on batteries. Buy a good quality Flooded Lead Acid Golf Cart battery like Trojan or US Battery. With 500 watts use 200 to 225 AH which is a very common Golf Cart battery size. With 3 panels you will need 300 AH. Connect the dots, for each 250 watts of panels into a 24 volt battery requires 100 AH of battery. Makes the math stupid simple even a Millennial's can figure out with a calculator if they can afford to pay someone to operate the calculator for them. Again use a good quality battery. A good Trojan 225 AH GC battery cost $130 to $150 each and you need for of them.

As for an Inverter, don't go crazy on size. 1000 to 1500 watts is all the batteries can handle. Again don't use a cheap Inverter as they just waste a lot of precious energy burning off as waste heat.

So you can do this for less than $3K, just stick to a few simple rules for sizing. Feel free to ask more questions. I am happy to help, and I am a professional, not DIY. .

Beer stands no chance when you're on cottage time.

The panels I can buy are pretty cheap and the guy has a couple hundred I think. At 90$ each I'd rather have too many than 'just right' or not enough. Before I found this place and started talking with you fine folks I was thinking I was going to slap 12 of them up on the roof but now it seems I'll be getting off easy.

I already have the inverter. All hooked up and ready to go. Magnum Energy 4024 4000w 24v. Ideally this piece of the puzzle won't need to be moved/replaced/changed

I'll probably go with the Morningstar TS-MPPT-45 unless the 60amp model is the better move in order to not have to worry about upgrading later. Its about $200 difference, not crazy. I already have the 45amp pwm version, hopefully its a simple unwire and switcheroo!


Pics of the inverter and charge controller
20180217_151927.jpg20180211_151221.jpg20180211_151210.jpg20180211_151218.jpg

[NorthRick]

Your batteries may not be as bad off as everyone here is saying. You have a few things going for you to offset the poorly matched solar setup. 1) It's weekend use only, meaning the batteries get a chance to be fully recharged while you aren't there. 2) You have a generator and charger and use them. That helps with the fact that you currently don't have enough panels to charge properly off solar only. 3) You are in Ontario - it's cold much of the time. Abused batteries degrade much more slowly at 0F than at 100F.

If it were me, I'd first figure out what your current and planned loads are over a typical weekend stay. Then figure out what your ideal system should be. Next, I'd go buy the number of panels that you need for that system and then install them and use them with your existing system (or as many as your existing system can handle). Run that system until the batteries are really toast and then upgrade the rest to what you should have had all along. The worst that happens with this scenario is that you run the generator more and more as the batteries give up the ghost. And, it gives you time to shop for better prices on the items you need.

[Sunking]

The panels I can buy are pretty cheap and the guy has a couple hundred I think. At 90$ each I'd rather have too many than 'just right' or not enough. Before I found this place and started talking with you fine folks I was thinking I was going to slap 12 of them up on the roof but now it seems I'll be getting off easy.

Be careful here because not only do batteries have a minimum charge rate, they have a max charge rate. Not only do batteries limit what you can do, but so do controllers and inverters. All components must be sized to work with each other. To use an parody, you could end up with a bycycle trying to pull a train, or end up having a 18-wheel Tractor Trailer rig to run to the convenience store for a 6-pack. One will work, and one fails but both suck.

For a cottage stick to a charge rate of C/12 to C/10 where C = the battery AH capacity, and the number is Hours. Example a 200 AH battery charged at C/10 or 10 Hour rate is 200 AH / 10H = 20 amps. One you have the charge current solves the minimum Charge Controller Current and used to determine panel wattage. Panel Wattage required using a MPPT Controller you can get in the ball park by Wattage = Charge Current x Battery Voltage. For battery voltage add 1 volt for every 12 volts of battery. So say you have a 24 volt 200 AH battery and you want a C/10 charge current. 20 amps x 26 volts = 520 watts.

No wou can go higher up to say C/6 with golf cart batteries and C/6 on a 200 AH battery is 34 amps x 26 volts 884 watts. So 520 watt sis about perfect, and you could go up to 900 watts. Stay in the window with the example I used for you.

I already have the inverter. All hooked up and ready to go. Magnum Energy 4024 4000w 24v. Ideally this piece of the puzzle won't need to be moved/replaced/changed

Not a show stopper, but far from practicality. You can make it work, but there are limits and you will not be able to utilize all 4000 watts. Batteries not only have a maximum charge rate, they also have a maximum discharge rate. For a golf cart battery is around C/4 before voltage sag becomes significant. C/4 on a 200 AH battery is 50 amps x 24 volts = 1200 watts. Compound that with wiring and connector losses and your Inverter can have problems with any load over 1200 watts. In other words your Inverter can and will trip off-line from under voltage despite the battery being nearly fully charged up.

Th eother trap you have built for yourself is a 24 volt 4000 watt Inverter will require a 200-Amp circuit. That brings safety and workmanship baggage you are going to have to deal with. 200-camp 24 vdc circuit will require a minimum 2/0 AWG copper. Not many can terminate that size wire properly as it takes some expensive tooling and training to do correctly. If not done correctly you run high risk of fire and failure.

I'll probably go with the Morningstar TS-MPPT-45 unless the 60amp model is the better move in order to not have to worry about upgrading later. Its about $200 difference, not crazy. I already have the 45amp pwm version, hopefully its a simple unwire and switcheroo!

Good choice, no issues. Just wire the panels in series assuming you only use 2 or 3 panels. One thing to think about with panel numbers. You will need a minimum of 2 panels in series, and no more than 3 or 4 in series. That eliminates PRIME NUMBERS except 1 and 3. So you will need to group panels in 2 or 3's which means only whole numbers like 2, 4, 6, 8, 9.... will work. OK to have a spare, but no Prime Numbers operating except 1 and 3. 5 and 7 are queers.

[Mike90250]

> I'll probably go with the Morningstar TS-MPPT-45 unless the 60amp model is the better move in order to not have to worry about upgrading later.


The 60A has a nice web interface in it. the 45 does not