LiFePO4 reseller in Canada

[Sunking]

Sunking Any issues with 5P8S instead of 4P8S? I find it easier to find 180Ah cells to meet my estimated power requirements.

Other than more hardware count, NO. FWIW with Lithium batteries S is expressed before P. Threw me for a second. Example 8S5P

I suggest you buy two tools you are going to want in the long run.

1. Torque Wrench. Regardless if you do 8S4P or 8S5P a torque wrench is going to come in handy once a month doing PM while checking torque. You are going to have a lot of money tied up in batteries, $50 is money well spent on a T wrench

2. I do not know how you intend to protect your batteries, but if you Bottom Balance, a Cellpro Powerlab 8 should be high on your list. It makes quick work performing the initial Balance either at the Top or Bottom. It is 8 cannels which is a perfect match for any 8S system. It also makes it a snap to rebalance if it ever becomes necessary, can diagnose problems, and a monitor/alarm if you want to use it as such. Just wire you a port at an accessible point with a JST connector.

[Sunking]

Something I ignored earlier, but might be of great interest to you. I assume you are looking to run 24 volt battery. That is raising a Red Flag because of the amount of capacity you talking about. With a LFP system the batteries are sized for 3-Day capacity @ 80%. Example if you are talking about 24 volts @ 900 AH indicates a daily usage of about 6 Kwh. The problem is 80 amp Charge Controllers are limited to 2000 watts of panels. With you being in Canada it is highly unlikely you can generate 6 Kwh/day with a 2000 watt system. Most likely will require 3000 to 4000 watts.

The solution is simple, run 48 volt of 16S. That same 80 amp controller can handle 4000 watts, and if it is something like a Midnite Solar Classic 150 can go as high as 5200 watts @ 48 volt battery. Instead of say a 8S4P battery, with the exact same batteries arranged 16S2P.

Something to think about.

[extrafu]

You are totally right - I totally forgot about 8S vs. 16S on the voltage. I really want to run 48 volts.

I initially wanted to 16 x 400 Ah CALB batteries, but I realize with information you guys gave me that is is better to run 16S2P for reliability reasons. CALB doesn't have 200Ah batteries - only 180Ah, so I would loose in capacity for reliability. Synopoly and Winston have 200Ah ones. I could also spend a bit more and go with 16S3P with 180Ah cells, or 16S4P with 100Ah ones.

When having in mind the 16 x 400 Ah CALB batteries, I originally thought about having 24 x 265W solar panels, with 3 MPPT charge controllers. During the December (worst month), I should be able to generate about 12 Kwh/day with that (1.56 Kwh/m^2/day of solar radiation in December, 1.6m^2 per panel, 24 of them for 38.4m^2 so 60 Kwh/m^2 of radiation, 20% efficiency: 12 Kwh/day).

That might need to be reviewed if I end up getting 48 or 64 batteries.

[Sunking]

Extrafu tap the brakes before you do something you might regret later. Very first thing you need to do is determine how many watt hours you need in a given day. Do you have that number? It determines everything else. You might get a pleasant surprise taking a lot less batteries and panel wattage. A 16S 400 AH battery has a total capacity of 19.2 Kwh. For a Lithium system you only 3 day reserve capacity, so a 19.2 Kwh / 3-days = 6.4 Kwh/day. That is a lot of energy for an off-grid battery system. So how much power do you need in a day?

When you get that number, multiply it by 3, and then divide by nominal battery voltage to find the Amp Hours. If you really need a 6400 watt solar panel is going to demand you divide the panels up into two panel arrays of 3200 watts each, and 2 65 Amp MPPT controllers.

One thing you have not mentioned is a Generator and a AC Battery charger powered by the generator. With an Off-Grid system requires a genny. Especially one as large as your appears to be. You do not want to risk loosing your batteries, and a generator will prevent that from happening. Just one careless over discharge on Lithium batteries will destroy cells. Of course there are ways to prevent that, but WTF are you going to do after 2 or 3 cloudy days. You wil have to set their powerless for a couple of days charging the batteries before you can power up again.

Second thing a genny can do for you is allow you to make the panel wattage smaller. On those short winter days when you use more power than the panels can generate, you run the generator on those days for a little while in winter. So instead of 6400 watts of panel and 2 controllers run say 5000 watts with a single Midnite Solar Classic 150.

Since you are planning on using Lithium batteries, you have to be very careful with Controller selection. Most controllers on the market are made with Lead Acid batteries. There are a few for lithium but they are made for 12/24 volt system and 10 amps. That is not going to work. You are going to need a controller you can set the voltages and force the Controller to work as CC/CV. Not many can do that. Midnite Solar will work, and also allows you to interface to some monitor and control circuits.

So tap the breaks, step back and take a break until you are certain what you want to do. Last thing you want to do is screw up $10,000 worth of batteries.

[extrafu]

Hi Sunking

No worry, I indeed estimated the power requirements to my best knowledge So far, I'm nearby 6.2Kwh per day. We still have some items to add in the list and note that would be for a garage with a living unit on top of it, and a 3,000 ft solar passive house. The heating system will be taken care by a pellet boiler.

I also thought about the generator, but I would certainly be looking at a small model, like a Honda EU2000i (2000 watts). With 8h hours for 1 gal of gas, I think it would be good enough to charge my batteries during winter time if needed.

The Conext XW+ 6848 would handle a generator. As for the MPPT controller - I'm considering the Conext MPPT 60/150 - mostly because all the Conext gears can be connected though a Xanbus and be "centrally" managed - which is rather cool. The 24 solar panels would be split in 3 arrays, 4S2P.

Thanks!

[Sunking]

I also thought about the generator, but I would certainly be looking at a small model, like a Honda EU2000i (2000 watts). With 8h hours for 1 gal of gas, I think it would be good enough to charge my batteries during winter time if needed.

That may sound like a good idea to you, but not likely works like you think and can waste fuel. If you are using a Inverter with built-in support for a generator and Built-In charger you want the generator sized to be able to max the charger current out as that will minimize run time and fuel burn, plus enough to carry some load so you do not set there in the dark waiting 12 hours for the batteries to charge. Your LFP batteries can easily handle C/2 charge current.

2000 watt generator on a 48 volt 400 AH battery will only generate 40 amps of charge current. You might want to reconsider. Also gasoline is not a good choice of fuel for off-grid. For one you are likely paying road tax on gasoline unless you have a license/permit to buy and a source for dyed gasoline without Road Taxes. Gasoline does not store very long, and gas generators like lawn mowers do NOT LIKE gasoline with Ethanol added.

[extrafu]

Sunking Got it, thanks for your feedback!

I know about Ethanol added fuel issues - especially when dealing (like I do, for fun) with 2 strokes snowmobile engines

[Sunking]

Sunking Got it, thanks for your feedback!

I know about Ethanol added fuel issues - especially when dealing (like I do, for fun) with 2 strokes snowmobile engines

Don't see many snowmobiles, ice skates, and bobsleds in Panama.

[extrafu]

You don't know what you're missing my friend!

[extrafu]

5 years is from experience of hundreds of DIY EV users. My first set was GBS, and in 6 months had significant capacity loss. Today I use quality LEAF cells from a salvaged Nissan Leaf. Chi-Coms are not known for quality lithium batteries. Warranty of 1-2 year tells you what to expect. Quality Prismatic cells from companies like Boston Power, A123, LG Chem, ect.. will cost you 3 to 8 times more than Chi-Coms.

Any opinion on Victron Energy batteries? Like this one: https://www.victronenergy.com/batter...-battery-12-8v

[Sunking]

Any opinion on Victron Energy batteries? Like this one: https://www.victronenergy.com/batter...-battery-12-8v

Do not have experience with the battery, but I see a bunch of red flags of incompatibility. Stick with single cells.

[extrafu]

Sunking Great, thanks!

[Sunking]

You are welcome. You need access to cell voltages. That battery would be OK as a drop in replacement for a 12 volt 125 AH battery. It appears to require a proprietary BMS. You want no part of that.

[extrafu]

Other than more hardware count, NO. FWIW with Lithium batteries S is expressed before P. Threw me for a second. Example 8S5P

2. I do not know how you intend to protect your batteries, but if you Bottom Balance, a Cellpro Powerlab 8 should be high on your list. It makes quick work performing the initial Balance either at the Top or Bottom. It is 8 cannels which is a perfect match for any 8S system. It also makes it a snap to rebalance if it ever becomes necessary, can diagnose problems, and a monitor/alarm if you want to use it as such. Just wire you a port at an accessible point with a JST connector.

I've found this nice video showing the Powerlab in action: https://www.youtube.com/watch?v=20CRXvLrUZE

When having cells in parallel, do you have to remove the bus bars for those cells before balancing them?

[dax]

Ncs55, Don't know where you are, but I'm in Australia and been installing off grid for a very long time. Know from what I've read and conversations with those in the USA and Canada, they seem way behind us in understanding lithium and especially lifepo4 off grid and grid connect. The biggest drawback is the supposed qualified electrical people who claim they know everything, because they've been programmed into 19th century technology and that gives them the right to push their primitive minded barrow, into realms they have little on hands experience or actual real working knowledge in.

We have qualified electricians, but they went through a 6 weeks retraining program to rid them of their opposite understanding of lifepo4 systems. We only use them because they are required for grid connect and 240v wiring, which now consists of just about every install. Low voltage is just too expensive to install and set up for, when you can run your home on 240v inverted lifepo4 with ease and all from a 12v pack. As soon as you go up in voltage, you lose many controls, especially when wiring in series.

My post describes our systems and if you understand how lifepo4 works, you'd understand why we use those parameters. Trying to comprehend 21st century technology using 19th century logic, means you don't have clue. As a builder, started installing off grid solar back in the late 1970's after going off grid myself, then panels was horrendously expensive and we made up our own 300w inverters, using 2v x 500-1000amp cells. Back then, we used 240v for colour TV and other electrical appliances and 12v stuff was cheap for lighting. Most of these big cells lasted well over 10 year, but capacity dropped and they require lots of maintenance and control. The biggest problem with lead acid is you only get to use about 1/3 of the energy before voltages become almost useless.

We set our controllers to re-start charging at 13.6v so they aren't really cycling, but topping up. Of course this all depends on the size of your system and energy requirements, but on average all our systems rarely get below 3.1v per cell line and customer logs on average show this fact. We always factor in all scenarios for storage, to 5 days without sun. This will include varying size wind generator or small 12v diesel generator, which depends on the size, capacity and usage.

What I've always laughed at when talking to electricians is, they claim to know what they are talking about, but don't even know how to control a decent lead acid system, let alone a lithium ones. And you never read anything of real use, but claims of their superior knowledge and qualifications.

Start asking these fools about how to control temps in lead acid and lithium energy packs, or temp controls in electronic systems modules, they don't know. All our systems are environmentally controlled, they don't sit outside, or in a shed where temp range from 0-35deg, but in insulated modules. That's how you shorten the life of your energy pack whether it is lead acid or lifepo4, uncontrolled environments. So our modules are separate from each other in the one housing and each section has it's own controls, which keep pack temps at X deg, electronics at a different X deg. So there is never any problems, as the system always sits within an environment which we've found is best suited for performance, longevity and reliability.

One last thing, if you are going to use a lifepo4 pack in off grid, never bottom balance, or you will stuff at least one cell line. We've found over many years of experimentation, the best balancing system is your load and if you install the system at 3.2v balanced, it never needs balancing again. Have a customer who went the bottom balance way for a 1500amp x 50amp cells and wouldn't listen to us as the suppliers. He was an electrician and read about bottom balancing somewhere from another electrician, who claimed to know what the facts are and this was last year. If we had a choice we wouldn't have supplied him, but he paid upfront and the office accepted it. Only to be inundated with never ending crap about how we should change our system to suit him and he wanted his cells delivered as we got them so he could implement his parameters and controls. So when he collected the system, we made him sign a warranty clause which stated if he opened the system, or altered the parameters, his warranty would be void and sealed the system. We balanced the system at 3.2v before delivery and didn't take any notice of his rants.

Typical expert, didn't listen, drained his pack to bottom balance and couldn't understand why it only rated at 900-amps when charged. So opened it up and found the middle cell lines were hot and sat at 2.4v. His bottom balancing had drained the cell lines first and buggered the cells as at the level of charge, you can't pack bulk into them, but a very slow charge to 2.8v. Ended up costing him a heap as we refused to do anything for him and lost his court case against us, the judge pointing out he didn't listen and failed to adhere to the warranty obligations in any way.

You do your own experimentation and research, then listen to and buy systems or components from those who have real experience with them and not hobbyists, Ev or some electricians last century crap. Most of these people claim li-ion is lifepo4, which is hilarious and very dangerous for any who listen to their lies. Li-ion are very unstable just like li-poly and nothing like lifepo4.

[ncs55]

Thanks for the detailed reply. I am in the USA and you are right that most do not understand lead acid and are relegated to 5-7 year lifespan. We build custom boxes with thermal blocking to keep our batteries at a constant temperature range and maintain them according to the battery manufacturer, IE daily depth of discharge, recommended bulk, absorb float and equalize parameters according to daily load cycle. It is a lot to get your head wrapped around. So most installers are selling gel batteries and the lower line of the lead acid line. We work with Crown and set our charge controllers up according to the parameters above. If the customer follows the procedure or hires us to do it, we are seeing around 10 year life span give or take with 6V batteries which are the most common out here. I live with 2V batteries and we have been able to push them to 14 years and are still around 90%. However I want to replace them with something different that requires less maintenance when they fail. Is that retraining program available over here? I would be interested in learning everything I can about the lifepo4 from the book and most importantly from the guys in the field. I realize from my experiences that there is a difference in those two training scenarios and both are required IMO for a full understanding of the design and how the operation and the system reacts to real world usage. If you can send me any links or PM me with them I would appreciate it. Thanks for sharing the information so far.

[Mike90250]

Any balancing scheme can be defeated by abuse, either driving low capacity cells too deep into discharge, or overcharging the low capacity cells to get the extra capacity cells full. The user must be educated and made aware of these requirements, or the installer has not done the job.
But if your middle cells are hot, and low V, then both the entire pack was poorly matched to begin with AND your fancy environmental controls failed.
But you will never sell me with mumble-jumble about environmentally controlled off grid battery packs, because it's totally not needed at sub C rates, low iR never heats the cells. (which is why in the cold environments LFP must be heated). Getting too fancy and you forget the K.I.S.S. (Keep it simple stupid) principle. https://en.wikipedia.org/wiki/KISS_principle