Another new guy, building a home battery backup system.

[Q-Dog]

The Raspberry Pi now resides mostly hidden on top of the breaker panel. This morning I had data on the VRM portal, accessible from anywhere in the world!

 

[Starlyte]

The system had been working without any issues for about 3 months, so time to make some changes.

I pickup up a few watts of solar panels and a small charge controller to eventually install on my RV. But, until then I put together a small temporary ground mount and started experimenting. I have been charging the battery backup from solar for about a month now.

I started with 400 watts and that was almost enough to keep the system topped up on sunny days running the refrigerator and some internet stuff. But with 3 or 4 cloudy days the system needed a little charge from the grid to keep going. I added another 200 watts, so 600 total, and the solar charger will now finish absorption and hit float before the end of the day on a decent sunny day. The ground mount is light enough that I can move it around to track the sun ... good for trying to figure out best angle for a future permanent solar installation.

Today is my first cloudy day since adding more solar, so I don't yet know how that will affect things. By then end of a sunny day I have 99% of battery capacity and when the sun comes up I am sitting at 70 or 75% of capacity, and that is running the refrigerator, phone base/charger and a lamp on the system full time. I plug in the computer and network stuff when the weather gets bad.

We are doing some work on our house and I have some reflective insulation board, so tried to do a little experiment. As you can see, cats don't care about your little solar experiments. This photo also likely explains why the panel output would sometimes drop out for no apparent reason. I have no idea why they sit down in front of the panels.

View attachment 44040

Cats love sitting on warm places, like reflective insulated boards, photocopy machines, polystyrene cases, telly decoders, etc. but tend to block the ventilation on electrical stuff. Also if you read books or newspapers your cat sits itself right in the middle. I don't know if they're big enough to effect the output from solar PV panels though. It could be the sun's angle.
I'd like it to stop raining long enough here, in the "sunny" S of France, to get on the roof and finish the installation of ours. It's been raining almost non-stop since last August. It's not normal here, and a real pain, but I guess for the weather changing, we can only blame ourselves!

 

[Q-Dog]

Crawled under the house yesterday and ran some conduit for this handy dandy generator inlet installed on the back of the house. Conduit is big enough that I can pull in some heavier wire if I ever decide to get a bigger generator.

And on the other end is this ... grid on the left, generator input on the right. My generator has circuit breakers so I didn't install any on this circuit. This isn't much more than a built in extension cord. These are under the battery backup and next to the dryer in the laundry room. I use gray for all of the outlets associated with the battery backup system.

I need to dig out the label maker.

 

[wattmatters]

Crawled under the house yesterday and ran some conduit for this handy dandy generator inlet installed on the back of the house.

Nice. Are planning to provide other outlets around the house?

 

[Q-Dog]

Nice. Are planning to provide other outlets around the house?

The critical loads panel from the backup system is tied to new circuits behind the refrigerator, next to the network/computer gear, and in the living room near the TV/stereo.

 

[wattmatters]

and in the living room near the TV/stereo

so all the critical stuff then

 

[Q-Dog]

so all the critical stuff then

? But seriously, when a hurricane is blowing in it is somewhat helpful to know what is going on.

 

[Q-Dog]

Oh boy, this is fun!!

I have doubled the battery capacity, so now 400ah at 24 volts ... or 10kWh of storage. I made new 2AWG cables for the batteries to the bus bars and still have a little more tidying up to do, but the system is back up and running. Still debating if I need to install the 300 amp main fuse and where will it go.

Future plans: I need to lengthen and reroute the charge controller negative. I had to remove my 12 volt and 120 volt outlets because I ran out of room, so need to find a spot for those. I also need to secure the batteries to the shelf and make a cover for them. Right now they are just sitting there. We don't get earthquakes, but I still don't like the idea of the batteries being able to get pulled off the shelf. I am working on getting a match for the 150 amp BMS on the left, to replace the 100 amp on the right bank.

 

[Supervstech]

I dont like your choice in fuses.
Those are automotive class, not suited for the punishment 400Ah of lithium can dish out.
Please invest in some t-fuses with t-holders.
Also, consider a steel enclosure for the batteries.
Too many entries in the smoke forum for my taste.

 

[Q-Dog]

I dont like your choice in fuses.
Those are automotive class, not suited for the punishment 400Ah of lithium can dish out.
Please invest in some t-fuses with t-holders.
Also, consider a steel enclosure for the batteries.
Too many entries in the smoke forum for my taste.

Thanks for the heads up. Can I ask what is wrong with these? Bought them with the battery.

I was runnning this 300 amp in the main inverter positive. I need to make up another cable and find a place for it. And I have been thinking about welding up a metal cabinet for the batteries.

 

[Supervstech]

Automotive fuses do not deal with the DC arc potential of a multi thousand amp short circuit…
T-type fuses do.
If something bad happened to any of the equipment, that bank of batteries can turn your wall, and all plastic around it into a flame fueled by a bank of electrolyte.
A t-type dc fuse has a sand arc extinguish feature that properly trips when overload occurs.

 

[aulii_419]

Today was a very dark, overcast and slightly drizzly day and the solar panels aren't making any power, so I did a stress test. Plugged a 12,000 btu window air conditioner into the system and set it to High. Also, refrigerator and phone stuff are always running off of the system. Then I plugged the little 2200 watt inverter generator into the Multi and started it up.

The system ran for 2 hours and even managed to put some charge into the batteries. I shut down the generator to top off the gas tank, then restarted and the air conditioner and refrigerator didn't even hiccup. Fantastic! I did a few things like open the fridge doors and turn on an electric kettle. Switching from grid to inverter to assist was seamless.

The only issue I could find today was one plug on the extension cord I used for the generator got a little warm so I limited 120 AC input into the Multiplus at 10 amps. I already have some 10 AWG cable to build a bigger generator cord and my next project is to build a permanent generator input into the house. Then I should be able to run the 120 AC input at 15 amps to charge the battery faster.

Future project: My wife has figured out how to configure a Raspberry Pi to run the Victron Venus monitoring software, now I need to order a few things to make that happen.

At what latitude is your property? What you're doing is very close to what I would like to do, but I live at 38 degrees north and don't have good solar exposure due to a large tree on the property, so would have to adjust accordingly.

 

[Q-Dog]

At what latitude is your property? What you're doing is very close to what I would like to do, but I live at 38 degrees north and don't have good solar exposure due to a large tree on the property, so would have to adjust accordingly.

Around 30º. South Louisiana.

 

[aulii_419]

Around 30º. South Louisiana.

Good to know, thanks!

 

[wattmatters]

Around 30º. South Louisiana.

Same as us, except we are South.

 

[Q-Dog]

There is a storm brewing in the gulf and we have a couple of days before it might get here BUT I hadn't really pushed the backup system since I doubled the battery, so, yesterday I plugged in the window air conditioner plus all the regular stuff I would want to run during a power outage. I ran the system for 5 hours during the middle of the day and with the solar panels adding in some watts between the clouds I got down to 50% of battery capacity while using approximately 1.2kW per hour. No issues to report. Just for fun I also boiled water in an electric kettle and ran a hair dryer for a few minutes, pulling almost 3000 total watts. That finally managed to get one connection a little bit warm.

Then as the sun went away I plugged in the gas generator and in a couple of hours added 30% charge back into the batteries, all while everything kept running. I estimate I can run the air conditioner about 7 hours over night if I have to. I didn't really design the system to do that but pleased it can. The house didn't get over 80ºf yesterday with the outside tamps in the 90s. I think I am good to go. Today I need to pick up any loose things from the yard.

Also, I got a call last evening to go out and troubleshoot my Dad's whole house generator that had a "check battery" yellow light. Turns out it was just corroding battery cables on the starter battery. It sure is nice to have the whole house running automagically during a power outage, but damn that thing is loud.

 

[aulii_419]

There is a storm brewing in the gulf and we have a couple of days before it might get here BUT I hadn't really pushed the backup system since I doubled the battery, so, yesterday I plugged in the window air conditioner plus all the regular stuff I would want to run during a power outage. I ran the system for 5 hours during the middle of the day and with the solar panels adding in some watts between the clouds I got down to 50% of battery capacity while using approximately 1.2kW per hour. No issues to report. Just for fun I also boiled water in an electric kettle and ran a hair dryer for a few minutes, pulling almost 3000 total watts. That finally managed to get one connection a little bit warm.

Then as the sun went away I plugged in the gas generator and in a couple of hours added 30% charge back into the batteries, all while everything kept running. I estimate I can run the air conditioner about 7 hours over night if I have to. I didn't really design the system to do that but pleased it can. The house didn't get over 80ºf yesterday with the outside tamps in the 90s. I think I am good to go. Today I need to pick up any loose things from the yard.

Also, I got a call last evening to go out and troubleshoot my Dad's whole house generator that had a "check battery" yellow light. Turns out it was just corroding battery cables on the starter battery. It sure is nice to have the whole house running automagically during a power outage, but damn that thing is loud.

Loud is exactly the reason I'm hoping to get a solar backup system in place. We live in a fairly dense suburban area, and even if I had enough fuel on hand to run my generator I really don't want to either annoy our neighbors or attract any undue attention.

 

[aulii_419]

There is a storm brewing in the gulf and we have a couple of days before it might get here BUT I hadn't really pushed the backup system since I doubled the battery, so, yesterday I plugged in the window air conditioner plus all the regular stuff I would want to run during a power outage. I ran the system for 5 hours during the middle of the day and with the solar panels adding in some watts between the clouds I got down to 50% of battery capacity while using approximately 1.2kW per hour. No issues to report. Just for fun I also boiled water in an electric kettle and ran a hair dryer for a few minutes, pulling almost 3000 total watts. That finally managed to get one connection a little bit warm.

Then as the sun went away I plugged in the gas generator and in a couple of hours added 30% charge back into the batteries, all while everything kept running. I estimate I can run the air conditioner about 7 hours over night if I have to. I didn't really design the system to do that but pleased it can. The house didn't get over 80ºf yesterday with the outside tamps in the 90s. I think I am good to go. Today I need to pick up any loose things from the yard.

Also, I got a call last evening to go out and troubleshoot my Dad's whole house generator that had a "check battery" yellow light. Turns out it was just corroding battery cables on the starter battery. It sure is nice to have the whole house running automagically during a power outage, but damn that thing is loud.

Damn, Ida forecast to make landfall in Louisiana as a Cat 4 hurricane - hunker down and best of luck!

 

[Q-Dog]

Loud is exactly the reason I'm hoping to get a solar backup system in place. We live in a fairly dense suburban area, and even if I had enough fuel on hand to run my generator I really don't want to either annoy our neighbors or attract any undue attention.

I don't care aout annoying my neighbors ... they all have loud generators. I mostly care about my own sanity.

 

[Q-Dog]

Damn, Ida forecast to make landfall in Louisiana as a Cat 4 hurricane - hunker down and best of luck!

I'm on the western edge of all this mess. Very little wind for me and the power only flickered once. We get worse during the typical afternoon thunderstorm.