BigBattery Reputation?

[aaron_c]

@aaron_c I'd guess under 2% to start with on a single cell. These cells all just have higher vs spec IR so out of the gate Id think of it as an aged cell. The way this DIY powerwall groups uses them taking them to 100% is gonna age them faster vs the higher IR i bet.

Makes sense. So assuming I decide to only ever charge my nominal 24V battery bank to 28.2V (which is what Prowse recommends for a LiFePO4 pack with varying internal resistances)....any idea what kind of capacity I'd be losing over a battery pack with well-matched internal resistances?

PS @Ampster As much as I love some of the prices on Alibaba, I may not be able to wait 1-3 months for them to arrive. I can wait a month, but two or three is getting too long, and there would be a significant cost associated with a late arrival. I need this battery to power the fan on my trailer's heater. Winter is coming!

 

[aaron_c]

Sorry, I should try to answer my own question first. So here's my attempt to answer it with a graph from electric car parts company:



It looks to me like Prowse is suggesting that folks charge the battery up to about 98% capacity or some such...it's only the last 2-3% where the voltage hops up from 3.2 something volts to 3.5V. Does that really mean that I'd only lose about 2% of the pack's capacity if I did it this way?

 

[Solarwanabe]

I see Will Prowse linked some BigBattery battery banks from his website...and damn if the price doesn't beat the ebay mysterymeat price for LiFePO4 batteries, even were I to DIY the whole thing myself.

What do people think? Worth taking a chance on?

Specifically, I'm looking at their 24 V 123 AH LiFePO4 batteries with some kind of BMS. They're selling for $900 including shipping.

The battery you are looking at uses brand new cells from A123. I have purchased one of these and will get back to you once it is installed.

 

[aaron_c]

Small update: I talked to BigBattery and here is what they said on the topic of their products with new cells:

Typically if we have new batteries they aren't factory rejects on the battery cell side, it is just connected to a system that they would otherwise throw out. We re-test all cells and only use good cells at current capacity. So the capacity is what we list on the page, and should be good for the new cells.

I then asked if that meant that the products with new cells should have cells with similar internal resistance and capacity and he said

all NEW products will have similar internal resistance and capacity. The recertified cells could have slight differences there though

 

[MrGreen]

Be aware that the word on the block is that those LFP power banks were used heavily in a past life, so expect them to be noticeably less dense storage wise compared to new cells. That said, they seem to be originally 5kWh and cycled down to 3kWh usable capacity.


If the drawback of it taking up more space and being heavier than a new battery is
not a problem, perhaps continue.

Hello CuriousCarbon,

To clarify, these PowerWalls are all Brand New Cells. I Guarantee this.
You will be very happy with our LFP Cells by Lishen in our 4SLA and 8SLA (12V/24V) Power Blocks. We Guarantee It. : )

If you have any questions, feel free to let us know at Sales@BigBattery.com

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

The battery you are looking at uses brand new cells from A123. I have purchased one of these and will get back to you once it is installed.

Hello Solarwanabe,

Yes, These A123 Cells are all Brand New. Here is a picture of the crates in which they came from. : )

We Guarantee you will be happy with them. If you have any questions, feel free to let us know at Sales@BigBattery.com

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

At that price 3kWh is $300 per kWh vs. $125 for Alibaba batteries that many here have had success with. Why would anyone take a chance on used when you can get new for less?

Hello @Ampster,

These LFP batteries & cells are new. Hope this helps. Thank you.


Sincerely,
Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

Model 3 2170 cells sold by Big Battery are rejects that are not up to the correct capacity. Never formed into packs. He will run out soon.

@Picasso,

You are somewhat correct, these units are all NEW Model 3 Cells which were never put into use in packs. We extracted these cells and they are measuring 98-99% of original capacity. We have parts for another 700+ Packs, then we will be sold-out of this product. If you have any further questions, feel free to inquire at Sales@BigBattery.com (or) feel free to email me direct at Eric@BigBattery.com

I have included a video here of the Tesla Re-Purposing Process:

It's a LOT of work but we are happy to do it if it means keeping these new cells out of landfills.

Our goal is to make sure that Non-Used Tesla Packs do not become premature eWaste. We could argue that this pack has the lowest carbon footprint of any battery on the market. The mass majority of our batteries are in fact NEW but we do like to re-purpose Overstock & Non-Used Cells whenever possible, even when it is more time-consuming, Its best for the environment that we all share. You as the customer will always know which is re-purposed as we state it on our website and all batteries are sold at or below true capacity.

Thank you for your comment, If there is anything else that we can answer for you feel free to eMail me at: Eric@BigBattery.com

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

Oh man, there is always a catch with bigbattery, isn't there?

What's the downside to using these cells? Will it not charge properly (or waste power doing so)? I've read about problems buying cells that aren't sized quite right, but I'm not clear on exactly what the problem with it is, other than the need for some kind of balancing prior to setting up a battery bank.

@aaron_c ,

I built this company to be straight-forward and honest. These cells are in fact never used in any application. My Model 3 Cells have 1-2% Degradation as they were literally pulled from Model 3 Packs that were never used. The mass majority of the battery packs that we sell are in fact "Brand New Cells" but sometimes we like to do our part for the environment and use surplus cells that were never utilized. When we do this, we market the packs as such. Our goal is always to do right by our customers and we stand behind every product that we sell. If you have a bad experience with any of our packs, please contact us so that we can fix it right away. Thank you for your feedback. : )

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

On the other hand this offering from Big Battery says it's using NEW cells. Makes a big deal about that. Do we know anything about Model 3 2170 cells?

Hello @aaron_c ,

Here is a link to an independent tester whom reviewed our batteries in our Model-3 Packs:

Here is another link of the extraction process for the Model-3 Cells:

Please note, NONE of these cells were actually used - they sat in new packs until we extracted and repurposed them. There will be minor degradation over time but no cycles were applied on the cells other than our testing. Again, These were extracted from packs that were never placed in vehicles, re-tested, installed in our packs and re-tested again for capacity. We do this to attempt to re-purpose working cells as it is the best solution for our planet, in most cases we are working with brand new cells but in the case of #Tesla - we thought it would be great to help them re-purpose their non-used packs to serve 2nd-Life applications.

This is a limited run and when these are out, we will go back to using brand-new cells. We hope that #Tesla in the future will repurpose their own new technology into 2nd-Life applications as it is the right thing to do for their customers and this planet we all share.

Thank you for your feedback, I hope the video's above help to answer your questions. If you have any further questions - you can always reach me directly at Eric@BigBattery.com. Have a wonderful day! : )

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[MrGreen]

The battery you are looking at uses brand new cells from A123. I have purchased one of these and will get back to you once it is installed.

Hello Solarwanabe,

Yes, These A123 Cells are all Brand New. Here is a picture of the crates in which they came from. : )

We Guarantee you will be happy with them. If you have any questions, feel free to let us know at Sales@BigBattery.com

Sincerely,

Eric Lundgren : CEO
Eric@BigBattery.com

 

[curiouscarbon]

Hello CuriousCarbon,

To clarify, these PowerWalls are all Brand New Cells.

Dear Eric,

Thank you for addressing this topic. I will cease with the conjecture. BigBattery offers many interesting options for energy storage, and I will continue to consider your business as a source in the future.

Building DIY packs is a non trivial endeavor, and seeing the good quality of hardware inside BigBattery packs encourages me to consider them as an alternative that involves less labor.

Kind regards

 

[Rocket99]

Be aware that the word on the block is that those LFP power banks were used heavily in a past life, so expect them to be noticeably less dense storage wise compared to new cells. That said, they seem to be originally 5kWh and cycled down to 3kWh usable capacity.


If the drawback of it taking up more space and being heavier than a new battery is
not a problem, perhaps continue.

Big Battery says "New A123 LiFePO4 Modules" (on the page for

24V - A123 8S6P LiFePO4)​

.... can it be they are used?

Yes well online forums are a source of all kinds of BS. Problem is how does one decide who to listen to. You really cannit easily decide without learning the information your self.

So much Bullshit

 

[curiouscarbon]

Cool. Previous listings had KWh and weight figures that suggested the packs were less dense than expected for the chemistry. That was a long time ago. Being aggressive isn't an effective rhetorical strategy. have nice day

 

[lllaible]

Here is my experince with big battery I ordered 4 24v power blocks and cable to make 48v. I was missing 1 serial cable I paid for and no one calls back to make it right. I messed up and destoried 2 BMS my fault but I need to pay and replace but no one calls me back after 4 phone calls. I have batterys I can't use. I will not buy from them again. No product support and they could care less about your buiness after get your money.

 

[HaldorEE]

Oh, that's really interesting. If they are cycled down to 3kWh usable capacity, should I expect them to have as many cycles as a "new" 3kWh LiFePO4 battery?

I wouldn't make that assumption. Battery life is typically defined as the point where the battery has 80% of the rated remaining charge capacity.

3kWh for a 5kWh rated battery is only 60% of original capacity. If batteries were still reliable when this heavily used, then why would industry standard be to replace batteries that have dropped to 80%? Its not like people like throwing away money.

Using these could be a real crap shoot. They might be good for a long while yet, or they could die tomorrow.

-Edit-

I see the owner of the company jumped in and explained these are built using NOS cells. That can be good, depends on how the batteries were stored. What SOC and temperature where they stored at? BB probably knows, question is where they all treated the same or are they kinda random. Some stored at 100% SOC outside in Phoenix? Some stored at 30% SOC in Minnesota. Storage conditions makes a huge difference (give me the Minnesota cells over the Phoenix cells).

If BB is sorting and binning cells by capacity and IR, then these could be an excellent value. If they are just grabbed at random from a crate, then it could be random luck what quality of pack you get.

Also are these batteries packs built using individual cell fuses? Telsa cells have an individual fusible link for each cell so if any single cell goes bad you just lose a bit of capacity. Without this, a dead cell could result in a dead battery pack or worse a fire.

Here is a D.I.Y. friendly example of cell fusible links.

NICKEL FUSE 2P-6P WIDE CONTINUOUS ROLL BY THE FOOT! 18650 CELL LEVEL FUSING

Each foot equals 15 cell connections long by 2, 3, 4, 5, or 6 wide. For example 2p wide would be 30 cell connections per foot (2 wide x 15 long) and 6p would be 90 cell connections per foot (6 wide x 15 long) Introducing custom cell level fused nickel design that can be spot welded with ease...

batteryhookup.com

-Double edit-

Now I am really confused, the BB owner claims these are from Tesla battery packs, but then I see claims they are LiFePO4 cells. To my understanding Tesla uses Lion cells, not LiFePO4. What voltage are these cells? 3.2V or 3.65V?

 

[HaldorEE]

Sorry about the repeated editing of my post. I just didn't want to leave erroneous statements in my post. And the word "Fire" should only be used if these are Lion cells. LiFePO4 cells should be safer.

 

[Crowebar]

I see Will Prowse linked some BigBattery battery banks from his website...and damn if the price doesn't beat the ebay mysterymeat price for LiFePO4 batteries, even were I to DIY the whole thing myself.

What do people think? Worth taking a chance on?

Specifically, I'm looking at their 24 V 123 AH LiFePO4 batteries with some kind of BMS. They're selling for $900 including shipping.

I purchased two 24v A123’s they arrived with no paperwork whatsoever, as is the story with multiple others. Also they are not what is shown on the site they show a breaker and came with a push button on/off. They have been very responsive... after I posted a nasty review on their YouTube channel.

 

[solarbot]

What risks would I face ordering from Alibaba?

You have to worry about shipping details like F.O.B. and may need to wire transfer instead of waving your plastic. It is really set up for b2b and bulk purchases, though some vendors seem to be shifting towards a more retail friendly stance. You are unlikely to get free shipping for returns.

 

[Ampster]

I view the risks as global risks but as easily found here in the USA as 15,000 miles away. The previous few posts illustrate that more than any words I can type. There many stories about Big Battery disputes and Ebay scams. Caveat Emptor is a Latin term that may be thousands of years old.
I was an Alibaba sceptic until I joined this forum and applied risk management strategies like using credit cards and Paypal.