2K offgrid solar cabin layout check please

plaidcabin

Solar Enthusiast
Joined
May 3, 2021
Messages
28
Please forgive the sloppy paint work. Graphic design is not my strong suit!

6 335w Canadian Solar PVs will be roof mounted, I may add a 3rd mppt for vertical wall mounted winter panels at a later time. Cabin is intended for full time use, and should have thermostat controlled propane heat, with supplementary woodstove - so low temp is not as much of a concern.

Some are wondering why so many 100AH cells, it was what I could get a good deal on! And 5 Parallel is quite redundant if there are any issues...

Not pictured here are the 5 Daly 8S 24V 100A BMS, 2 Epever Tracer MT 50's, and the 300A Shunt display.


All input is welcome, I am faking it til I make it here. Thanks for looking!
 

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Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,590
Location
Rural NE Ontario Canada
You could cut your expenses by 1/3 if you wanted to.
Use ONE MPP Solar AIO. 24V/4000W can be had as 120VAC or 240VAC. Stackable so they can grow out.
2x 24V/280AH will give you 560AH / 14.336 kWh. 2 Packs in a Bank is easily managable. Anything greater than 4 packs in a bank requires additional considerations which usually mean a centralised BMS and more. It CAN be done with basic SmartBMS' but it can quickly become problematic, there are many gotcha's lurking in those weeds.

BTW: I'm in the North near Algonquin Park, Ontario Canada. Full Time off grid residence.
100% Offgrid, 2kw of panel, 4kw Samlex Inverter/Charger and 910AH / 23kWh of LFP. Been at this for a few years now.
 

plaidcabin

Solar Enthusiast
Joined
May 3, 2021
Messages
28
You could cut your expenses by 1/3 if you wanted to.
Use ONE MPP Solar AIO. 24V/4000W can be had as 120VAC or 240VAC. Stackable so they can grow out.
2x 24V/280AH will give you 560AH / 14.336 kWh. 2 Packs in a Bank is easily managable. Anything greater than 4 packs in a bank requires additional considerations which usually mean a centralised BMS and more. It CAN be done with basic SmartBMS' but it can quickly become problematic, there are many gotcha's lurking in those weeds.

BTW: I'm in the North near Algonquin Park, Ontario Canada. Full Time off grid residence.
100% Offgrid, 2kw of panel, 4kw Samlex Inverter/Charger and 910AH / 23kWh of LFP. Been at this for a few years now.

The system was modelled after Will's 4K offgrid system. Panels were selected to utilize the Tracer's 150V PV input, Inverter comes highly recommended and is also favored by Will.

I did not see an All In One unit suggested for this level of system, have you got one in mind you would have recommended? If going that route, I'd want to have the capacity for at least 9 to 12 modern higher wattage panels. As I'm sure you're aware, we can have some pretty short days up here.

Most of the components have already been purchased unfortunately, so I'll likely stick with this, at least for the time being. The Epever Tracers should last for a long time, if I reconfigure this system later on I'm sure that I'll find another use for them.

I have already secured the 100AH cells, but if you have sources for the larger 280AH cells in Canada, please share. I agree that it would have been better, but I didn't find any in Canada. Most retail LiFePo4 batteries advise against wiring in series as the bms are limited, and the ones that are able to handle it seem expensive or unavailable, unfortunately. This is the reason for the very large busbars and diagonal connections from MPPT and Inverter. It balances the load equally against all batteries, at least that's what I was led to believe.

Since I am working with time constraints and supply chain issues, the choice was made to grab these 100AH cells while I could. Hopefully I don't regret it, the BMS selection was confusing at first but I believe it to be correct now. It also allows for batteries to be removed for any reason, or the entire bank replaced and these ones could be used for other purposes.

I have not ordered my Solar Panels yet, found one supplier with the Canadian Solar CS1H-335 for $220 each. Seemed like a good deal, just waiting on a shipping quote before finalizing the order, have you got a better suggestion?


Thanks for the thoughtful input Steve, I'm doing my best!
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,590
Location
Rural NE Ontario Canada
Unfortunately, when Will made the original webpages for his site he was still Van Lifing and the RV'ing before he got a fixed address. So everything reflects that. The newer pages like this have this info: https://www.mobile-solarpower.com/all-in-one-122448v-packages.html

I deal with Amy Wan @ Luyuan tech in Shenzen. She supplies my battery requirements and it's never an issue.
There are no cell sellers in Canada as such. We don't even make the darn batteries here yet BUT we have all the ingredients & tech to do so, way more than what the public is aware about. The MNR Database has it all located and just sitting waiting for NIMBY's to STFU.

There are indeed Solar Deals to be had in Canada but it depends on where you are as to where to go. That's the problem with having such a big country. (6,521 km (4,025 miles) from coast to coast. )

This vendor has pretty good deals (also email from stuff not listed) in both New & Used as well as New Old Stock panels.

NB: Some panels are Bi-Facial while others are not. Each have their own requirements for installation. There are 60 & 72 Cell Monofacial Panels as well. CSP has released 675W panels already. It is expected that by Q1 2022 1000W Panels will be available, these will be large scale though.

Paralleling Battery Packs is not rocket science BUT it does need to be properly setup to work optimally. It is quite easy to mess up. The real key is Balance. Battery Cables MUST be the same length from battery to DC Bus Bars. All Wire Guages MUST be the same at that point. IE: All 2/0 or all 3/0 etc. BMS settings need to be the same and have their protections enabled. Each Pack should be able to handle your Inverter Discharge & Solar Charge rates as a single battery operating in Standalone Mode.

Battery Pack shunt monitoring can be "Inserted" into the NEG line between Batt Pack & DC Bus Bar, for individual battery pack monitoring.
A Shunt can be placed between the Battery DC Bus & the Inverter/SCC to monitor overall energy flow from going IN/OUT from the equipment to Battery Bank.

BTW, I know your new here. Just so you know, I wrote the manuals for Chargery BMS' and the Luyuan LifePo Assembly docs and more. Some of us have been at this a wee while, hehehe. Check out the links in my Signature, some may be helpful to you and your ongoing project.

Hope it helps, Good Luck
Steve
 
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