LiFePo4 legit offer?

[hammick]

You guys have built some impressive battery banks. I want to go LifeP04 but not willing to pay 5 - 8k for a 150 to 200ah battery just because it's in a fancy case with a digital display. I'd like to hear your guy's opinions on this 280ah bank I'm looking to buy. Seems to be using cells that look the same as the cells you guys are ordering from China. The owner of the company spent 40 minutes on the phone answering all my questions. Company is in Colorado and I can pay by American Express. They are new grade A cells.

$3,274 shipped with 200a continuous BMS upgrade. Batteries come with special adhesive tape applied to put them together in either a single stack or double stack. Ring terminals already crimped and bus bars included.

The photo shown on the website is a 24v bank. Scroll down to see the description, features and specifications.

https://www.treelinepowersystems.com...-BMS_p_37.html

I'd really appreciate your guys feedback. I willing to spend more to get a complete package shipped from Colorado but there's a limit to how much more. I'd be interested in what this battery bank would cost if coming from China after fees and shipping.

Thanks.

[stekicar]

@stekicar Thanks for the pictures. Question on the picture that is a side shot of the battery bank, underneath the Blue Sea switch are those two relays the black boxes that have 4/0 cable attached..? if so how are you controlling them?

Appologize for verrrry late reply. I am using RaspberryPi with DFRobot's MOSFET Power Controller (https://www.dfrobot.com/product-1567.html).

[mstasko]

@ampster great. I'll see you there. I am 'solardad' on that site.

[Ampster]

Thanks. I registered on that site with the same handle. It has a lot of topics that interest me and a marketplace for some of the extras that I have accumulated over time. I am looking forward to an additional neighborhood.

[Ampster]

With nothing else to do, stuck in the home with shelter in place orders, I started messing around with the capabilities of my hybrid inverter. When bored with that I distracted myself with Alibaba searched and started exploring options. It may be necessary to expand the size of my pack sooner than later if I want to move to more self consumption based on some simulations I have performed.

@mtasko, thanks for your insight. I am requesting more information on EVE cells. Deligreen does seem to have the best prices and has been responsive. I may purchase a small quantity to evaluate. I like the form factor, especially the height and the energy per sq, inch. I got some good ideas for cabinets from those videos you posted. I may try some of those ideas to see if I can get it past the AHJ before I spend big bucks on a NEMA enclosure.

[Ampster]

I think we used the same napkin for our calculations...

Part of my reason for doing that is I am tired of hearing the usual banter that batteries are more expensive than the grid. That may be true in many cases. It all depends on where you are standing. Of course that implies understanding the total cost of ownership of batteries and the rate structure. .......

btw - here is another YT that leverages this cell form factor in a Craftsman cabinet. https://www.youtube.com/watch?v=xlxM-BcIxWE

I got a lot of good ideas from that video. I would have done some things differently but most of those are style or process issues. I will articulate them below in an effort to add to the knowledge base about pack assembly.
I agree sanding the battery terminals and connecting buss bars is important. I do that with 3M non conductive material that tends to leave less grit. I blow off the terminal threads anyway to make sure there is nothing on the inside threads. I also use NoAlox to prevent any oxidation or other reactions between the aluminum and copper. I only use it on the conducting surfaces and not on the threads. I have traditionally used copper buss bars that are a lot of work. I read on another forum that someone used Aluminum buss bars and they would have to be sized accordingly because Aluminum has less current carrying capacity than copper. I am going to research resistance before I make a decision. I also notice that he used studs and nuts. That may be because of the different thickness of his connection pieces and so he could make sure the studs had as much thread connection as possible. In my past pack assemblies I have just used two different length bolts depending on the thickness of the pieces being joined.
The orientation of the prismatics is an issue that the Nissan Leaf modules don't seem to care about since they are in the car horizontally. I have always mounted my prismatics with the terminals up since the ones I have used in the past always had a bleed valve. I will do more research before I decide but there are a lot of advantages to having them horizontal especially in a cabinet. The first one is that one could use different length buss bars for all the series connections. That is what Nissan does with the pack in the Leaf. I know it was a pain making buss bars but my hydraulic crimper is also a pain and time consuming and doing all those interties seems uneccessary when you could use one buss bar across the middle because the distances are all small. Another advantage of that horizontal mounting of the batteries is that the terminals are accessible. That make it easy to check the nuts and measure voltage if you are getting erratic readings from your BMS. Depending on the layout it could also mean you would not need longer interconnects between rows of vertically mounted cells. There are challenges about strapping the cells whether they are horizontall or vertical but I will deal with that if it comes up at inspection. I still might need to wait a year to make the correct assessment of my capacity needs so I have some time to think about those details.

As I mentioned earlier, I have only used prismatics in plastic cases. I did notice that he used plastic separators and insulated his cabinet. i will be interested what the manufacturer recommend or if there is any detectable voltage between the case and either of the terminals.

[mstasko]

I think we used the same napkin for our calculations...

I also have a Leaf Gen1 pack that I have used for the past year and have similar performance. They maybe rock solid, I never needed to balance them, but they also have crummy $/kWH when compared to these latest LifePO4 prices. I actually passed on another quote that would've been under $100 per kWH (I decided to go with a vendor that others have reported decent experience.). If my order was not so large, I might of gone with them instead.

Will do, my expectation is that these will not be arriving for at my door until 30-45 days from now.

btw - here is another YT that leverages this cell form factor in a Craftsman cabinet. https://www.youtube.com/watch?v=xlxM-BcIxWE

[Ampster]

@ampster Yes. Straps were included ............... wrt your AHJ you maybe able to buy a used Flammable Cabinet, most if not all are UL listed and they are just as rugged or more so than a NEMA cabinet given their intended use and possibly more cost effective. Here is a guy that leveraged one for his setup: https://www.youtube.com/watch?v=lfnscM1St5Q&t=2s

Oh and the cells are ordered are manufactured by EVE.............

That was a good video and I will be on the lookout for a cabinet like that. The other advantage those prismatics have is they are easier to configure into a cabinet. Based on the earlier post and some preliminary calculations that could be over 12 lineal feet of cells but they could be in several cells to a row and stacked several rows high to fit in a cabinet like that. I make up my own buss bars to connect the cells so I will probable continue with that strategy to reduce the risk of differences in resistance in the cell interconnections. The straps and bolts will be handy to parallel the cells before assembling them into a pack.

I will have to do some research on EVE. They resemble similar priced CATL (Contemporary Amperex Techjnology Ltd.) cells also sold by Deligreen. I have used CALBs, Winstons and Thunderskys on earlier projects, but these cells appear to have smaller form factor per kWh. Perhaps it is the aluminum case. I recently saw an interview of an American guy that served as the CTO for CATL for ten years during the time that they became the largest battery manufacturer in China. He got his start with GM and was involved with the EV-1. He also chairs some SAE committees on battery standards. He says the most important criteria is safety and that is a good reason to prefer LFP over other chemistries.

Keep us informed as you assemble your pack

[Ampster]

I did a little back of the envelope math and came up with a cost of $0.06 per kWh of usable storage over a 10 year life.
My assumptions were:
Ten year life using not more than 50% of the capacity.
Over that assumed life, one kWh of cell capacity could store and deliver 1800 kWhrs over that 10 years. If the cost of that kWh of capacity was $111 then the cost of a kilo Watt hour of usable stored energy would be $0.06 . That does not take into account the cost of solar panels and an inverter to generate that power in the first place. But if you add those costs together It still may be less expensive than energy from the grid in some high priced markets. That is the case in my energy market where the average cost is $0.20 per kWhr.

Based on the manufacturers life of 2500 full cycles, 5000 cycles at 50.% would be over 10 years giving some margin of safety. My Nissan Leaf modules are probably at 60% of original capacity and they are at least 8 years old. My point is that at a price of $111 per kWhr I will probably also sell my Nissan Leaf modules and invest in some new LFP batteries. I had considered Tesla modules but they are coming in at just under $200 per kWh. They are a more volatile chemistry and can not be consolidated into a pack as easily as these prismatic cells.

[mstasko]

@ampster Yes. Straps were included with fasteners. Correct. I like the idea if needed to bring one down for any maintenance. For 1+ year that has been my setup with a bank of Chevy Volt and Leaf batteries (to be sold). wrt your AHJ you maybe able to buy a used Flammable Cabinet, most if not all are UL listed and they are just as rugged or more so than a NEMA cabinet given their intended use and possibly more cost effective. Here is a guy that leveraged one for his setup: https://www.youtube.com/watch?v=lfnscM1St5Q&t=2s

Oh and the cells are ordered are manufactured by EVE: https://deligreen.en.alibaba.com/pro...37856c12HR2Y0C

[Ampster]

@stekicar @ampster - Thanks for your feedback. Just wanted to let you know that I ended up ordering 64 280ah cells Deligreen on Alibaba. Was able to talk them down to $80 per cell with shipping via sea at $1200. Plan on setting up two battery banks for flexibility as 2p16.

That is a good deal ($111per kWh). Did that include straps? I see Deligreen carries some brands that I have had experience with in the past. Which brand did you go with?

I am interested in what you mean by flexibility in terms of two banks? Is it the physical flexibility in layout or the ability to disconnect one bank to work on it while running your loads on the other? Some people will tell you that a strategy like that will shorten their life but I think that is less likely with Lithium. It does mean two BMSs and contactors. I am curious about your thinking to inform my strategy in the future because my AHJ requires a NEMA enclosure(s).

[mstasko]

@stekicar @ampster - Thanks for your feedback. Just wanted to let you know that I ended up ordering 64 280ah cells Deligreen on Alibaba. Was able to talk them down to $80 per cell with shipping via sea at $1200. Plan on setting up two battery banks for flexibility as 2p16.

[mstasko]

@stekicar Thanks for the pictures. Question on the picture that is a side shot of the battery bank, underneath the Blue Sea switch are those two relays the black boxes that have 4/0 cable attached..? if so how are you controlling them?

[NewBostonConst]

Very nice....

[stekicar]

Here it is:
20200412_153230.jpg