TRYING TO MAKE A DECISION ON TO BUILD MY OWN BATTERY BANK, OR JUST BUY THE EG4-LL SERVER RACK STYLE.

[JJJALLOFFGRID]

First off new to this form. My question is I currently have 1200 watt solar array "Renogy", a sigineer all in one M3024NC 24 Volt System. I have 4 Renogy AGM 12v 100ah amp wired 2 in series, and other 2 in series and parallel those together. I have this in a small cabin on my 65 acres in KY. In cabin I have a Refrigerator that pulls max of 350 watts for 8 hours out of 24 hour day and some low watt led lights maybe 11watts, a box fan on low @ 40 watts. The Renogy AGM batteries do good, but this summer added a window unit A/C 650 watts. Noticed that the solar could pull all loads but didn't have enough to recharge battery bank from the previous night use to a full state, and discharge was borderline damaging spec. So with all this known, I want to move on to LifePo4 but unsure if I should go with 2 EG4-LL server racks 24v 200ah tied parallel to make 400 ah, or should I build a 16c 24v battery using EVE 304ah cells? Any help would be greatly appreciated.

 

[hwy17]

Noticed that the solar could pull all loads but didn't have enough to recharge battery bank from the previous night use to a full state

You know that more battery won't solve this right? But Lifepo4 won't mind being left not fully charged like AGM, maybe that's what you're after.

Otherwise, I don't think anyone can answer this for you. It has to do with your preferences, do you want a hobby to tinker with or do you want something that you connect and it works?

 

[Robbert]

Building yourself is fun. If you want to do it right, with the right fuses, terminals etc, the costs could be very much comparable with the eg4 server rack batteries.

Maybe there is a solution in the middle, building the battery yourself in a pre-made kit (like Seplos).

Still the fun of assembling yourself, and the advantages of a clean looking battery. Also you might save some money here. You can also tweak a bit, by adding a balancer etc.

 

[RV10flyer]

I have over 3,750 pounds of LFP or 210 kWh of DIY and 1 ea nice Trophy 220aH. I don’t tinker with any of them. I built them out of Grade A cells or the best I could find and they just work…Like my two Sol Ark 12 K‘s. I use JK 200A BMS’s…they just work too. I’ve scrapped a lot of Chinese junk in the process of getting educated on this wonderful hobby, because I sure as heck wasn’t going to sell it to another solar guy.

Of course I recommend DIY. Grade A cells and JK BMS from 18650 battery near Atlanta, Georgia. If they are in stock as I have bought a bunch in the past year.?

 

[JJJALLOFFGRID]

You know that more battery won't solve this right? But Lifepo4 won't mind being left not fully charged like AGM, maybe that's what you're after.

Otherwise, I don't think anyone can answer this for you. It has to do with your preferences, do you want a hobby to tinker with or do you want something that you connect and it works?

Alrighty then. So more battery wont solve this, I'm guessing more solar panels then?
I was going to add another 1200 watt array to my system along with either a DIY lifepo4 or the EG4-LL 24v 200ah X2.

 

[JJJALLOFFGRID]

I have over 3,750 pounds of LFP or 210 kWh of DIY and 1 ea nice Trophy 220aH. I don’t tinker with any of them. I built them out of Grade A cells or the best I could find and they just work…Like my two Sol Ark 12 K‘s. I use JK 200A BMS’s…they just work too. I’ve scrapped a lot of Chinese junk in the process of getting educated on this wonderful hobby, because I sure as heck wasn’t going to sell it to another solar guy.

Of course I recommend DIY. Grade A cells and JK BMS from 18650 battery near Atlanta, Georgia. If they are in stock as I have bought a bunch in the past year.?

Can you provide a link to the website for the JK BMS. Also if I build 2 8c 24volt batteries and parallel them together. I would need to run 2 8c BMS's? or 1 16c BMS?

 

[RV10flyer]

These are the ones that I use. Look on their website, you will also find the JK BMS’s for either 8S or 16S or one does both. James is the gentleman I always speak with.

EVE LF304 Grade A Cells - 3.2V LiFePO4 304Ah Battery

Buy high-quality EVE LF304 Grade A Cells, a 3.2V LiFePO4 304Ah Battery with flexible bus-bar, nuts and bolts included. Designed for longevity with 10+ years design life, 4,000 cycles, and a rechargeable feature. Get the full excel report by request.

www.18650batterystore.com

 

[RV10flyer]

Can you provide a link to the website for the JK BMS. Also if I build 2 8c 24volt batteries and parallel them together. I would need to run 2 8c BMS's? or 1 16c BMS?

You are bettter off having two separate batteries with their own BMS. Remember redundancy. If one fails, you can run on the other one as long as you don’t overload it.

Two 8S using those 304aH cells will give you 15.56 kWh of capacity.

There are tons of YouTube videos out there and on the forum here on building these batteries and what you’ll need to order. Ask questions if you want before you order items that you choose. Have fun. You’ll save about 30%.

 

[Rednecktek]

And don't forget to build a box for them! ?

+1 for building your own. Outside of the issues I have with JK, it's plenty easy enough. Go for a JBD BMS (or clone) if you can find one, it's less hassle than the JK's.

 

[RV10flyer]

And don't forget to build a box for them! ?

+1 for building your own. Outside of the issues I have with JK, it's plenty easy enough. Go for a JBD BMS (or clone) if you can find one, it's less hassle than the JK's.

The only batteries that I built with a box around them went in my work van 10kWh of 105aH 8S X 4ea. He’s got a cabin, so having easily accessible is fine. I protect mine with polyamide tape, 1” cargo straps keep a little compression on oak end boards. Works great and gives me something to mount breaker/BMS to.

 

[JJJALLOFFGRID]

These are the ones that I use. Look on their website, you will also find the JK BMS’s for either 8S or 16S or one does both. James is the gentleman I always speak with.

EVE LF304 Grade A Cells - 3.2V LiFePO4 304Ah Battery

Buy high-quality EVE LF304 Grade A Cells, a 3.2V LiFePO4 304Ah Battery with flexible bus-bar, nuts and bolts included. Designed for longevity with 10+ years design life, 4,000 cycles, and a rechargeable feature. Get the full excel report by request.

www.18650batterystore.com

Thank You kindly Sir.

 

[JJJALLOFFGRID]

You are bettter off having two separate batteries with their own BMS. Remember redundancy. If one fails, you can run on the other one as long as you don’t overload it.

Two 8S using those 304aH cells will give you 15.56 kWh of capacity.

There are tons of YouTube videos out there and on the forum here on building these batteries and what you’ll need to order. Ask questions if you want before you order items that you choose. Have fun. You’ll save about 30%.

Thank you. One more question actually 2 what size bms? Jk lists several different amps and different balance amps. I've understand you are supposed to go over your actual amps. I've got the batteries in my cart you recommended, but unsure if I should by 2 of what size bms's. I also just purchased 1200 watts worth of panels they will be here next week. So I will have a total of 2400 watts PV once set up.

 

[DIYrich]

If you are getting 300ah cells, then you need the 2a active balance bms.

 

[JJJALLOFFGRID]

The only batteries that I built with a box around them went in my work van 10kWh of 105aH 8S X 4ea. He’s got a cabin, so having easily accessible is fine. I protect mine with polyamide tape, 1” cargo straps keep a little compression on oak end boards. Works great and gives me something to mount breaker/BMS to.

Great idea. I actually going to build a metal box with some thermo cooling fans I saved from an old project, and use all thread rod protected by a pipe bushing sleeve cover for compression . My trade is Gm Master Technician. I am a certified welder. So fabrication is gravy for me.

 

[JJJALLOFFGRID]

If you are getting 300ah cells, then you need the 2a active balance bms.

Thank you yes they are EVE 304 ah cells. 2 8c 24 volt paralleled together. What about the amps 150 continuous 300 peak, or the 200 continuous 350 ?

 

[JJJALLOFFGRID]

If you are getting 300ah cells, then you need the 2a active balance bms.

Thank you yes they are EVE 304 ah cells. 2 8c 24 volt paralleled together. What about the amps 150 continuous 300 peak, or the 200 continuous 350 ?

 

[DIYrich]

I would get the 200/350. Your cells can easily handle it. You never want to run at 100% anyway.

 

[cs1234]

I would get the 200/350. Your cells can easily handle it. You never want to run at 100% anyway.

I see bigger numbers, and want to get them. Unless the price number is too much bigger.. then I get sad, and get nothing, because I know there was something with bigger numbers I could have bought but couldn't afford.

 

[DIYrich]

You will have 2400 watts of panels. At 24v, that is 100 amps. The 150/300 bms can handle that.

 

[JJJALLOFFGRID]

You will have 2400 watts of panels. At 24v, that is 100 amps. The 150/300 bms can handle th

Thank You Again Sir. I will add that to my battery order and checkout. Wait I will be needing 2 of these for each bank in the case one bank goes down correct?