LiFePo4 legit offer?

[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.

[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]

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.

[mstasko]

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

[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).

[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.

[mstasko]

@hammick Hi - in short I purchased 66 280ah EVE cells for $6500, $98 per cell. The price included shipping, buss bars and fasteners. This breaks down to a cell price of $80 a piece and $18 to ship via sea to US. I ordered during the height of the coved lockdowns so everything was delayed and it took almost 60 days to get here. I ordered two extra cells as insurance but ended up needing 7 more since they were damaged in shipping. Ironically the damage was done here in the states by FedX, they manhandled my ordered. Receiving the replacements was straightforward and the vendor shipped them by air for me, although I had to kick in some money to offset the extra shipping charge. Vendor was Deligreen and I would order from them again. If you are in no rush and can wait the extra time then it’s a no brainer from my view to go this route. Btw - the cells I received met my expectations.

Good luck

Looks like the cells are the same unit cost: https://deligreen.en.alibaba.com/pro...ery_280AH.html

[openplanet]

Stekiar--Your high current bistable relays look to be Littlefuse HD series:
https://www.littelfuse.com/products/...hd-series.aspx
From what I can see though, 24 volts D.C. appears to be the highest they offer. How are you using these with your (nominal) 48 volt system? Thank you.

[hammick]

T

@hammick Hi - in short I purchased 66 280ah EVE cells for $6500, $98 per cell. The price included shipping, buss bars and fasteners. This breaks down to a cell price of $80 a piece and $18 to ship via sea to US. I ordered during the height of the coved lockdowns so everything was delayed and it took almost 60 days to get here. I ordered two extra cells as insurance but ended up needing 7 more since they were damaged in shipping. Ironically the damage was done here in the states by FedX, they manhandled my ordered. Receiving the replacements was straightforward and the vendor shipped them by air for me, although I had to kick in some money to offset the extra shipping charge. Vendor was Deligreen and I would order from them again. If you are in no rush and can wait the extra time then it’s a no brainer from my view to go this route. Btw - the cells I received met my expectations.

Good luck

Looks like the cells are the same unit cost: https://deligreen.en.alibaba.com/pro...ery_280AH.html

Thanks for the great info! I assume I have to call them to confirm the details? Their site is silent on shipping, buss bars and connectors.

BTW what are you guys doing with all these cells. I can't imagine needing 1,120ah of LifeP04 power.

[mstasko]

@hammick No problem! So with Alibaba they have a built-in text feature that I believe most vendors leverage when communicating with customers. In may case the whole deal from negotiating price, what addons to include (buss bars), customs and shipping was done through this feature. I liked the idea of having a 'written' transaction of what was agreed upon before receiving the invoice. So you would want to outline those up front when requesting a quote.

I learned a lot in terms of purchasing from Alibaba and knowledge on "how to" from this site and others (secondlifestorage.com & diysolarforum.com) through folks that already went through this experience.

As for what I am doing with the cells... powering my house. Always had an interest in solar and finally pulled the trigger a couple years ago and started building my system. In short, I learned a ton about our family usage (5 of us) and the original intent was to just offset our loads but once I went through a whole year and compared the performance of the system the gap between supporting 60-80% of our needs to more like 95-100% was small. The biggest gap was in our battery storage, I was losing power most days since our battery bank was topped out and the power had no place to go. Note - net metering is out of the question in my area due to a few reasons, crappy credits, monthly 'convenience fee' being imposed and the threat of future increases with the fee. As a result we self consume everything we produce, no grid tie. The 1120ah bank provides a buffer for those multiple cloudy days.

[PNW_Steve]

Alibaba - unless you know the import & duty fees system well, it's a gamble. Overseas shipments of expensive electronics, unless either store promises how to walk you thru customs.

Ask the seller to ship "DDP" not "DAP".

When shipped DDP the seller handles shipping and duty and the package comes to your front door.

[Ampster]

When shipped DDP the seller handles shipping and duty and the package comes to your front door.

I agree, DDP, is the way to eliminate any risk of import or duty fees. I used credit cards so I would have that extra protection. My first two orders were six months ago. I just received another 8 cells and they have tested well. They took about 50 days from the time they were shipped until they cleared customs. Fedex delivered them in two business days after that. Over the past six months I have purchased a total of 44 cells from three different supplier with good results.

[PNW_Steve]

I have 16 x 280A/H on the way. It's like waiting for Santa....... Are they here yet??

[stekicar]

Stekiar--Your high current bistable relays look to be Littlefuse HD series:
https://www.littelfuse.com/products/...hd-series.aspx
From what I can see though, 24 volts D.C. appears to be the highest they offer. How are you using these with your (nominal) 48 volt system? Thank you.

I appologize for late reply but I do not recevice any notification although I am subscribed to this post ...
I hope you found out answer already. But in case, God forbid, you did not:
Relay voltage is not for relay itself but for coil that opens/closes relay. I use 300 amp model "Cole HerseeTerra 880086" and it can withstand 300amp no matter voltage. I hope this answer your question.
Oh, and it is LittELfuse, not littLEfuse ...
This was my order:
Waytek order.png

[stekicar]

Here is the breakdown for 1st year (2020) of 720Ah LiFePo4 battery use:
Grid power used per month in kWh: 881, 636, 313, 252, 64, 14, 0, 0, 51, 157, 543, 1157
Total: 4068kWh or $770.39
I have an EV that used 2435kWh for approx 16k miles.
Solar power produced 9417kWh. Unfortunately, hard drive went bad and all my solar data was lost so I cannot show solar production per month.
Calculated PV capacity for my location (SE Michigan) and panel setup is 11513kWh (from https://pvwatts.nrel.gov/). This tells me that my solar setup used 81.8% of its capacity. During June, July and August solar panels produce more than I need and Decembar and January are the worst months and I barely use solar and batteries.
I just installed DIY BMS from Stuart Pittaway to monitor each cell voltage and temperature. Verrrry nicely made system so kudos to Stuart.