Off Grid Cabin - Will this work as intended?

[TorC]

Depending on the design of the inverter it may be able to do some power factor correction, but the safe assumption is to calculate the fridge as consuming the VoltAmp product.

 

[Roc off-grid in Quebec]

Long time lurker, first time poster. I have been planning a solar system for my parents off grid cabin near Ottawa Ontario for a long time now. The cabin is boat/ATV access only and has no option to connect to the grid. The cabin is fully wired for AC and they currently use a Honda 2200w generator for power when required (lights at night, charging cellphones, basic power tools when working on the place). The cabin is currently used 3 seasons and closed for the winter but they do have a woodstove and insulation so it could feasibly be used in the winter. The cabin is usually used 3 or 4 days at a time and maybe a few week long stays throughout the spring/summer/fall.

The main objective of the solar system is to run a refrigerator full time whether they are there or not (May 1st -September 30th roughly). The next objective is to power a few lights at night, charge cellphones, run a vacuum occasionally, and a few hours of tv a day while they are there. With this system being unattended for periods of time throughout the season it needs to be as dependable and redundant as possible. Please have a look over the planned system and give any feedback you may have before we pull the trigger and start buying stuff!

Planned 48V System:

-16 Eve 230AH Cells with 200A JK BMS (~9.4KWH Storage using 80%)
-4 x 235w panels in series on pole mount 100ft away (119.2Vmp/148Voc)
-10AWG RPVU90 from pole mount to controller (100ft)
-Victron 250/60 MPPT
-Victron Multiplus 2 3kva (2400w Cont/5500w Surge Inverter Charger)
-Midnite Solar 125A Disconnect/Breaker Box (Battery to Inverter Breaker/Battery On/Off Switch)
-63a/150VDC Midnite Breaker Controller/Battery Connection
-30a/150VDC Midnite Breaker (array wire breaker/mostly a switch to shut off PV to controller)

I realize the array is quite undersized compared to the rest of the system, already have the panels and can expand this part of the system if the need arises. As the system currently sits will this power a fridge worry free for 3 seasons and still have power left for lights and cellphone charging etc when visiting. The system looks overbuilt for this on paper, will it have limitations in the realworld? Any comments, feedback, criticisms are very welcome! Only want to do this once!

Thank you!

Will

Hi Will - my situation is very similar, though on a mountain vs lakeside. Are you planning to build the battery yourself?

 

[Checkthisout]

Depending on the design of the inverter it may be able to do some power factor correction, but the safe assumption is to calculate the fridge as consuming the VoltAmp product.

So I guess my last question. Is my $9.00 wifi outlet with current measuring doing pfc??

Neat!

 

[willh]

Hi Will - my situation is very similar, though on a mountain vs lakeside. Are you planning to build the battery yourself?

Yes, batteries are on their way from China as I write this. Excited to see how it all comes together.

 

[willh]

Long overdue update on this project. Life happened and the timeline has went off the rails. Battery has been assembled and am finally running some tests on the pack via the Multiplus 2 3000va. So far could not be happier. Don't have the equipment for super accurate capacity testing but I'm confident they are close to if not better than advertised.

Currently setup in garage for testing/temporary use. Plan to complete install at cabin in the spring.

 

[Daddy Tanuki]

you go girl!... did I just self cancel due to improper use of pronouns? OMG!

 

[Roc off-grid in Quebec]

Long overdue update on this project. Life happened and the timeline has went off the rails. Battery has been assembled and am finally running some tests on the pack via the Multiplus 2 3000va. So far could not be happier. Don't have the equipment for super accurate capacity testing but I'm confident they are close to if not better than advertised.

Currently setup in garage for testing/temporary use. Plan to complete install at cabin in the spring.

Awesome! Thanks for sharing. Did you install at your cabin?

 

[willh]

Awesome! Thanks for sharing. Did you install at your cabin?

Installed, finally! Have been so busy with new baby at home, work, life etc not a lot of time for this stuff lately. My parents actually finalized the install with me helping a bit over the phone. Everything seems to be working great! Only got it operational a few weeks ago but in that time everything is as good or better than expected.

They bought a 10.1cuft fridge made by frigidaire, advertised at 297kwh/yr. It is running full time while they are there and away. While at the cabin they use lights, tea kettle, toaster, TV, tools and charge phones.

So far their biggest solar day was when they hooked the system up. The panels generated +3kw and the battery went to float. It seems they use about 1.5kws a day on average (less when they aren't there), so far the panels are replacing that even when fairly cloudy.

 

[willh]

Panels are used and didn't know what to expect, they are performing great. Victron app shows that they peaked at 940 watts today, which is incredible given its mixed/used panels in series (2x230w and 2x235w). The pole mount is a scrap steel build. The material the panels are mounted on are actually industrial shelving channel like you'd see at home depot. Pipe was what we were able to find used for cheap, think its 4 inch. Rented a home depot rotary hammer drill and epoxies 3/4 inch bolts into the bedrock about 18 inches down, seems to be sturdy.

 

[willh]

 

[willh]

Picture of new fridge and ancient servel propane fridge removed. And other pic is how the pre-wired solar components fit in next to ac panel in the back of the camp, had just been mounted at that point. Also have multiplus wired to a Honda eu2200i, haven't needed it but tested function, worked exactly as expected and will be an excellent backup.

 

[Craig]

Long overdue update on this project. Life happened and the timeline has went off the rails. Battery has been assembled and am finally running some tests on the pack via the Multiplus 2 3000va. So far could not be happier. Don't have the equipment for super accurate capacity testing but I'm confident they are close to if not better than advertised.

Currently setup in garage for testing/temporary use. Plan to complete install at cabin in the spring.

Are you still housing your batteries in a wood case? If so I would advise against it. I had something similar and at some point the balance leads arked somehow nearly starting my box on fire. When i got to it the box was well chared I think my only saving grace was the box was somewhat airtight. Since then I now put batteries in a steel box lined with HDPE. Just my two cents based on experience of screwing things up.

 

[willh]

Another interesting note, the battery sat in an unheated garage in Belleville ON, no charge/discharge from October to nearly July, so all winter and then some. Bms was turned off and nothing connected. Voltage appeared the same as when shut off and judging by how much solar went into it to get to float remained around the same soc (approx 60-70%). Have no concerns for future winters after that, will be doing the same procedure when cabins not in use.

 

[willh]

Are you still housing your batteries in a wood case? If so I would advise against it. I had something similar and at some point the balance leads arked somehow nearly starting my box on fire. When i got to it the box was well chared I think my only saving grace was the box was somewhat airtight. Since then I now put batteries in a steel box lined with HDPE. Just my two cents based on experience of screwing things up.

Yes still in wood, something to consider for sure thank you.

 

[Horsefly]

Hey @willh - What fridge did you buy? I see the goofy "EnergyStar" tag, but I'm not sure that means anything.

Yes still in wood, something to consider for sure thank you.

 

[willh]

Hey @willh - What fridge did you buy? I see the goofy "EnergyStar" tag, but I'm not sure that means anything.

https://www.frigidaire.ca/Kitchen/Refrigerators/Top-Freezer-Refrigerators/FFET1022UW/

My mom picked this one, said it didn't seem a cheap as some of the others in the size range (danby/magic chef to name a few). System seems like it could definitely handle more fridge but this is good for their use, larger freezer was a plus on this one as well.

Doesn't seem to use a lot of power so far although I have no hard numbers on it. Will update once the system has been in use for longer.

 

[willh]

So far nothing but great things to report, system is functioning above and beyond what I had hoped for. System was left on for a couple weeks running the new fridge and the charge controller made it to float every day except one. The only reference I have to power used/generated per day is the victron logs on the charge controller. Judging by the logs the fridge and inverter consume between 700-1000w per day. I'd say it averages 850w, not sure what accounts for the variance, likely outside temperature alone and potentially the timing of the defrost cycle on the fridge.

When family is at the cabin consumption is near double with the use of lights, TV, kettle, toaster and charging of various things. System still reaches float with the approximately 1kw array. Battery hasn't been below 80% so far.

Current charge settings are bulk 55.2 (3.45v per cell), absorb 15mins, then float at 53.2 (3.32v per cell). Batteries set to balance above 3.45 and they occasionally do during the absorb phase. I considered more aggressive settings initially to maximize solar but it appears my assumptions were on point and there is no need to charge higher.

Anyways, hoping for many trouble free years of use. Victron equipment seems solid and was very easy to use/configure. I couldn't be happier with the victron charge controller especially, it displays and logs so much useful info for seeing how the system is performing. Docan 230ah cells seem to be as advertised in my case, no complaints. While I don't have experience with any other bms's the jk suits my needs perfect and offers a lot of system monitoring info as well I find.