First Post, Hello All! And a question to get started.

[DonnyO]

I'm planning to go completely off grid and I am gathering as much info as possible before I make big moves or purchases. I am a retired Auto Diagnostic Technician so I have a ton of experience with DC electronics. I also have built PC's and have a general knowledge of communications, but not detailed experience. I understand all these will come in to play going forward.

I will be on a strict budget but I want to have true energy independence so I plan to over build. My question is since this requires a lot of battery capacity and I am hands on, DIY everything, can I build my own batteries? I'm looking for multiple 48v 280ah batteries and it looks like building them is a few thousand cheaper than retail with the battery box kits.

My concern is will any of the BMS's be compatible with the EG4 inverters? Are there work arounds? Are they safe? My power requirements will be minimum day to day, just the basics and for anything crazy (car lift, welder) I will have a generator on hand.

I have read a lot about non supported batteries being an issue, not just DIY batteries but retail off brands as well.

Any information or advise is greatly appreciated.

 

[42OhmsPA]

can I build my own batteries?

Absolutely. I'm currently ~54KWh of DIY and still expanding.

My concern is will any of the BMS's be compatible with the EG4 inverters?

Most likely, what led you to EG4?

Are there work arounds?

Absolutely, open loop.

Are they safe?

If your settings are safe and you use proper wiring, connections, over current protection etc.

Welcome to the forum.

 

[DonnyO]

Absolutely. I'm currently ~54KWh of DIY and still expanding.



Most likely, what led you to EG4?

Absolutely, open loop.

If your settings are safe and you use proper wiring, connections, over current protection etc.

Welcome to the forum.

Sounds like I have a lot more to learn.

As like many things the main stream YouTube channels seem to be directing me to these big brands and EG4 seems to cover all the bases. If there are more basic options that get the job done I'm interested in learning about that, especially if there is money to be saved.

Do you have a recommendation for the battery box w/bms or what to look for?

Thanks for the welcome!

 

[Wessss77]

Sounds like I have a lot more to learn.

As like many things the main stream YouTube channels seem to be directing me to these big brands and EG4 seems to cover all the bases. If there are more basic options that get the job done I'm interested in learning about that, especially if there is money to be saved.

Do you have a recommendation for the battery box w/bms or what to look for?

Thanks for the welcome!

Welcome @DonnyO as @42OhmsPA said there are alternatives. He runs the SRNE inverters and I run some SRNE clones. Same inverters different branding. Cost savings on the EG4s.

Batteries don't have to be in boxes... You can put them on shelves if you wanted to save money and then move them later if you want to.

I run JKBMS and he runs the JBDBMS. They are configurable to be able to communicate with almost everything. Using open loop (not communicating with the inverter) is better in many instances as you let the inverter configurations do the heavy lifting and the BMS is your failsafe if the inverter goes tango uniform.

What are your electric requirements so you can figure how much battery and how much solar you will need? How much power is the third piece. An electric bill will help in getting this info. Kwh used per month divided by 30 will give you an approximate daily requirement. This should get you started in data collection.

 

[42OhmsPA]

We are learning every day, that's why we are here.

I'll say I have nothing against EG4 and think its great they are offering US support and creating jobs in the US but at the end of the day they are a middle man selling a "box" made by someone else.
I avoid middle man when I can and go straight to the source to maximize savings at the risk of less support, but can normally save enough to buy spares....

I think you'll find my latest build thread very helpful.

Currently my 4 packs sit naked on a shelf I repurposed but if you search for the big blue box by Zwy on here you'll get some great inspiration for a top notch build.

I use contactor type JBDs and am happy, others like JK, Batrium, etc.

 

[DonnyO]

Damn guys, you got me starting over, lol.

I think you'll find my latest build thread very helpful.

Can you post a direct link to that?

What are your electric requirements so you can figure how much battery and how much solar you will need? How much power is the third piece. An electric bill will help in getting this info. Kwh used per month divided by 30 will give you an approximate daily requirement.

I've been doing the math.

Short story is, we are using about 18k a day, I live with two very wasteful women. Wife and I are separated, getting divorced and I will soon be on my own living a very minimal existence. My plan includes the equivalent to a 1 bedroom house and a workshop. My plan would be to have just what I need, a fridge and simple other basics like a tv, some type of cable and probably Starlink. Maybe a Hybrid minisplit for cooling and heat. But I also may use other energy (propane) for some of that like hot water, etc. An estimate would be 6-8k.

I also do want the capability for a simple two post car lift, welder, etc but those would be occasional uses and a generator on site for that and backup power.

 

[DonnyO]

I will also add I may not be comfortable with loose batteries and BMS to learn and figuring out how to configure all that. I like the contained setup of a pre made box kit style setup. It still looks like I would be saving about 1k per battery building them. Maybe not that much with cabling and other stuff but still not retail. On top of the solar, inverter I think it's a lot and easy to get overwhelmed as a newbie.

 

[42OhmsPA]

Can you post a direct link to that?

Here you go.



Pinging @agtcovert , he's been building out some boxes recently.

 

[JMACK61]

The EG4 6000XP will be $1610 shipped to California. Buy your panels from Auctions, Craigslist. Christopher Beene on the Facebook DIY Solar Page and get a 20 kWh battery from me for $3500. I’m in Hayward, Ca. And I am 100% off-grid with 35 kWh battery and 4 kW of solar panels on the roof. EG4 inverter/Charger. No grid hooked up.

 

[OffGridForGood]

Welcome to the forum @DonnyO - glad you joined.
A couple things in addition to all the great comments already posted:
1. you show CA location - California has their own rules it seems and a list of CA approved inverters. This may not apply to your set up if you end up completely off-grid, but something to know just the same.
2. Energy audit - there is a speadsheet available on the resources section to help you calculate the likely daily energy use, and peak demand from your planned set up.
3. PV Watts.nrel.gov - this is a solar calculator that you plug in your location and how big a solar array you are planning - it calculates the likely solar collection per month. I like to just plug in 1kW array - then all the monthly numbers are easily scaled ie 3kW array = 3x the numbers.
4. Going completely off-grid - this can be done, but running a generator is the most expensive kWh you can get. If you will be in a location where the grid is just not available then generators are a given. If the grid is available, you will find paying for some grid use occationaly will be less costly and less work, and will allow the system you design to be smaller (also less costly). Since you mention being on a budget, this may be important.
I find the cost of electricity is lowest from PV-Inverter, next battery-inverter, then grid, then generator. For me gen-set power is over $1/kWhr.
5. Car-lifts, welders, big air compressor - these can be run on Inverters but it takes a pretty big system to start those motors properly. I find an up-right 6Hp air compressor is the biggest start up load of anything I own. Again, if you have grid available it may be worth it for starting these types of big loads instead of starting a generator up.

Keep asking questions and working through your design, you did the right thing NOT buying anything, coming online and asking questions first.

 

[DonnyO]

1 you show CA location
2. Energy audit
3. PV Watts.nrel.gov
4. Going completely off-grid
5. Car-lifts, welders, big air compressor

Keep asking questions and working through your design, you did the right thing NOT buying anything, coming online and asking questions first.

1 Location will be Mohave County AZ

2 I am familiar with the calculators

3 Again, I have been doing this part of the research

4 I plan to oversize by quite a bit and the generator will only supplement if my system cannot sustain the loads. There is no grid where I will be. As far as the compressor it gets limited use because many of my tools have gone to battery powered electric and can be charged in off periods. The load of a lift will only be for vehicle maintenance and is in use for about 45 seconds while lifting a vehicle, I don't see why that can't be sustained. As far as cost per KW the generator "should" only be for very limited use and back up.

I plan on engineering everything for minimal usage and maximum capability from the start. Likely a 12v fridge, lighting and minimizing 120v ac as much as possible. I would like to double the recommended reserve from 3 days to 4-6 which hopefully will also keep me with enough reserve power for the things I've discussed. I don't have a huge budget but I would rather spend the money up front and not worry about it. I'm likely only going to be around another 20 years, who knows maybe 30

Thank you all for the great advise!

 

[agtcovert]

Here you go.



Pinging @agtcovert , he's been building out some boxes recently.

I haven't read the full thread but wanted to give you a view on batteries:



I've built 5 batteries for my bank, the last was finished on Friday. I've been happy with ordering from Docan and the person I've worked with. The Apexium cases are good and well built. You can see here with my addition of breakers. I wish these cases had that, and standard M8 terminals. You can ask for them.

This set is 4 EVE 280Ah and 1 REPT 280Ah pack. Had it running for 6 or so weeks now. Zero issues. Like you, I wanted batteries contained in a case and not open. There are other options out there, these are a good one.

Feel free to ping me with questions. ASP questions too, I've pushed a pair pretty hard and they have held up well so far, exceeding my expectations.

Welcome!

 

[MattMan119]

Lots of good information here… I have eg4 equipment and love it. But there are lots of good options … welcome to the forums ..

 

[jjww]

Just want to point out the safest battery is one that is out in its own building

 

[doox00]

For diy batteries check out this video (great youtube channel in general as well) I just built 2 of these and 2 in the gobel power diy box.. both were good but the Yixiang was easier and a bit more polished and I would go with those ones. I am completely new to this and it was a breeze to put together. I bought all Eve MB30 306 AH cells for these 4 boxes using JK 200 amp BMS's with 2a active balancers. My system has 3 EG4 6000XP inverters and is only days away from being complete (was mostly all diy) and can schedule a final inspection.

Part 1

Part 2

 

[OffGridForGood]

Likely a 12v fridge, lighting and minimizing 120v ac as much as possible.

I don't recommend any 12v appliances.
Since the build location is AZ - likely very high solar available, and correspondingly high A/C loads likely (unless at high altitude area).
If this is a brand new build, you will not have the benefit of past utiliity data to guide the sizing of the system, making the energy audit all the more important.
keep posting your thoughts and questions, everyone on the forum is super helpful - except @sunshine_eggo (joking) - he knows AZ well and can provide real world local experience to the discussion.

 

[DonnyO]

I don't recommend any 12v appliances.

Curious as to why. I was considering a 12v fridge because we have a trailer with only 200w of panels and 2,
64ah AGM batteries and it runs the fridge 24/7 without a blink, very efficient. It will run 3 days with no solar.

That's just the setup it came with but it's far better than a propane/electric as far as energy consumption. Propane fridge's suck, the newer 12v compressor one's are ready to go in less than an hour of being turned on.

 

[MattMan119]

Yeah would like to know why also, there are a lot of us RV users that push this kind of solution. I have 120v power but all that requires conversions and losses, why not use battery when you have it?

 

[teal95]

The issue with the car hoist isn't the amount of energy it uses, it's the large surge when the motor starts. So you don't need a large amount of PV for this but you do need a large inverter (15 kW?) and sufficient batteries to feed the surge the inverter will draw. And the same issue with a large air compressor. You'd probably be better running a couple/few smaller compressors feeding a common tank. Or maybe even 12v compressors (junkyard source from cars with air suspension) with some controls.

 

[alcook62]

Curious as to why.

I wrestled with this question myself when I went fully off-grid 6.5 years ago. It came down to my desire to avoid multiple different outlets and wiring while constructing my home, the availability and cost of special appliances that will run on 12 volts, the ability to service these appliances should they break, and the unfamiliarity of these appliances to my wife, who was already unsure of this journey.
If you size your system appropriately in advance, you can run a traditional-style home with traditional appliances. At least, to me, it would feel more like home, and not a long-term campout.
I believe @Steve_S wrote briefly about his decision to use a 120-volt traditional-style home vs. going the 12-volt route. It reaffirmed my decision, and I wish I could remember where it was posted.

 

[DonnyO]

The issue with the car hoist isn't the amount of energy it uses, it's the large surge when the motor starts.

Since this is a new thing to me and I do want to simplify and not experiment and just need it to work, what is the opinion of the new EG4 12k inverter. It's advertised to be able to handle large surge voltages and be able to start a 5 ton AC unit without issue. Also has a 10 year warranty. A little pricey up front but it does everything and would leave me to build some batteries and save money there.

Or just go smaller with something that has a generator input to handle the heavy loads when needed? Like I said these will be more occasional needs, not a daily thing.

 

[TechRider]

Keep in mind, some times the generator inputs don't help like you think they will. You'd have to have the generator on and running before the load was applied. Some welders can be nasty as well.

I recently did a "large" install. I've got 18k PV and just under 90kW Batteries. It's great having the battery power but nothing replaces having properly sized solar. I use 40-60kWH / day on average but have a 2400sq ft 95% electric house. I've dropped my power bill from $350-$600 a month to $36 - $88 / month.