On Going Deals on Batteries.

[The Blind Wolf]

Well, Fixing to come in with some mo money, and looking for the best deal on batteries.    I wanting to keep with the Liphium LIF4 cells, I keep seeing these 280Ah cells, and I'm afraid to even buy them, cause I keep seeing folks getting ripped for grade B or worse.  I know currently I can make a 12v 100Ah battery for $282 bucks without the BMS.  Roghly $320 finished.  However, I'm dealing with 24v system so that would be roughly $640, and thats not including the time for me to spot weld everything lol.

 

I have one headway battery I made, love it, but hate the cost for one cell. for a new 8Ah cell is $15, and a used one is $10.

 

Any Suggestions?

[Cali Carlos]

The two main places I read about people buying Lifepo4 batteries from with good results are aliexpress.com and alibaba.com

Looks like roughly $1800 for a 16s 280ah with bussbars and shipping

[The Blind Wolf]

Here is where you can get 170Ah cells with box and everything else, and these are lab tested and are true spec.

 

https://store.currentconnected.com/?product=ea170

 

$120 Per cell.

[The Blind Wolf]

280Ah Batteries at $86 each.

 

https://offer.alibaba.com/cps/bednd4pd?bm=cps&src=saf&url=https%3A%2F%2Fwww.alibaba.com%2Fproduct-detail%2F4pcs-Lifepo4-3-2V-280Ah-Battery_62517113167.html

[Sid Genetry Solar]

7 hours ago, The Blind Wolf said:

Here is where you can get 170Ah cells with box and everything else, and these are lab tested and are true spec.

 

https://store.currentconnected.com/?product=ea170

 

$120 Per cell.

Always good to work up the price per kilowatt-hour of storage.  These cells work out to $222/kwh: 3.2v * 170Ah = 540Wh, so ($120 per cell / 0.54kwh stored per cell) = $222/kwh.  In my cheap opinion...that's about double the price/kwh I paid for the LFP bank I have (~$100/kwh--rechecked my math: $1200 for the bank / 12kwh = $100/kwh.)

 

7 hours ago, The Blind Wolf said:

280Ah Batteries at $86 each.

 

https://offer.alibaba.com/cps/bednd4pd?bm=cps&src=saf&url=https%3A%2F%2Fwww.alibaba.com%2Fproduct-detail%2F4pcs-Lifepo4-3-2V-280Ah-Battery_62517113167.html

Alibaba rule #1: don't take the given price on the listing.  It's usually a decoy price (or perhaps the price for 15,000 units)...when you contact them, the price usually is a good bit higher.  Also, you have to factor in tariffs and shipping rates--not cheap, either.

I know: I've done about a dozen transactions on Alibaba.  (Not for batteries, per se.)

My 2 cents on Alibaba/Aliexpress batteries: only buy from listings that someone else has already bought from and tested them.  (Yeah, someone's gotta take a gamble!)  While I haven't had any sleazy sellers on Alibaba (yet!), they are most certainly out there.

For a quick example, I'll figure $160/cell for these batteries (figure in the "real price" plus tariffs and shipping)...assuming that they're actually 280Ah cells, that's $178/kwh.

[The Blind Wolf]

Well these two listings are from a you tube lab tester that testing these batts and post the link of where they bought them.  So where did you get your $100 kw deal at?  I need to know before Tuesday, cause I'm fixing to order a ton of more batts.

[Sid Genetry Solar]

40 minutes ago, The Blind Wolf said:

So where did you get your $100 kw deal at?

It was a one-off deal of NOS (new old stock) LFP cells...they started out with a huge supply, but as word got out, they started to disappear faster and faster.  That was 4 years ago...so to be fair, it isn't a good benchmark comparison.

Will Prowse is one Youtuber whose videos I like, and especially his honest real-world tests of Chinese claims.  Here's a video he posted about some LiFePo4 batteries that measure up to the claimed specs; at the time of this post, they clock in at $130/kwh.  If I needed to make a battery bank, these are the cells I'd buy.

 

 

[The Blind Wolf]

*laughs* yes I been watching him for several years, he the one that got me into solar and building my own batts 😛

[The Blind Wolf]

alsy the first posting of the 280ah battery is the eve one as well. same one that will talked about.

[The Blind Wolf]

I am still searching, those eve batteries look nice, but seemed to be a big chance if I get them and the ones that are good.

 

I'm eyeing the battery hook up K2 2650 case of 120 cells at 3.8ah its almost $176 per KW.  Of course that not includeing the bms and the nickle strips, but, either way thats pocket change.

 

It seems a better deal then the battery hook up 6ah cells that I've been useing. cause that $217 KW

[kazetsukai]

This guy (Off Grid Garage) has done extensive testing of Alibaba 280Ah "EVE" batteries. Basen is the supplier, I just ordered a 14S3P 16S3P bank through them.

 

Big debate on the DIY solar forums around "compressing" these EVE cells (sandwiching them so they can't expand as easily). He doesn't seem to think its all that important.

[The Blind Wolf]

Well, I went with the K26650 route, its a lot cheapier then those eve batts and less likely to not be ripped off, plus these are new cells.

 

Ordered 3 cases of 120 cells with three BMS.  Will make three 114ah 12v bats two of them makeing a 24v and the other to go with the headway 128 ah pack I already got, so after that, I'll have 550 Ah at 24v ready for the GS Master inverter, and thats not including the other  two 110 ah packs of 18650 that I got sitting besides me, waiting for Sids Balancers before I add to the bank.

 

This is pretty much my last round of battery buying for the moment, solar panels and another wind turbin is next on my list.

[Sid Genetry Solar]

I'm not too familiar with using batteries in "compressed" state...though at least to my knowledge that usually applies to Li-Ion / Li-Po (and very high-C capable cells).  Not heard of it in LFP--I guess if they bulge, that's a clue 😉

[TheButcher]

I've been following the Off Grid Garage YT channel since day one.  I think the cell compression got him a bit arse backwards.  You have to be really careful with the wording when communicating with the Chinese sellers as it's all too easy for a misunderstanding in terms to happen.

From what I understand, which isn't necessarily reality, if you are wanting to get maximum cycle count from the lifepo4 prismatic cells you must stop them from expanding, just being constrained is fine no need to put a clamp on them.  If you don't care about maximising cycle counts you can leave them free to move but you'll probably only get the nominal cycle count (2000 or so) even if you 80/20 charge cycle.  If you do let them 'breathe', you also need to ensure there is enough space between the cells to accommodate it or have a non-rigid system for connecting the terminals on the cells otherwise you'll put stress on the terminals and internal attachments that they aren't designed to cope with.

Edited March 18, 2021 by TheButcher
left some words out :)

[Cali Carlos]

22 hours ago, kazetsukai said:

I just ordered a 14S3P 16S3P bank through them.

If you don't mind me asking, what was your OTD price? Looking to buy a 16s system myself 

[kazetsukai]

6 hours ago, Cali Carlos said:

If you don't mind me asking, what was your OTD price? Looking to buy a 16s system myself 

$5639 shipped. $0.13/Wh.

Have yet to order a BMS. I do have some Electrodacus BMSes laying around, but I may get a 250A Daly 16S LFP BMS.

[Sid Genetry Solar]

That'd be about $130/kwh, which is a really good price.

I would seriously recommend checking the balance current on any BMS system.  While we want to offer a high-current BMS solution at Genetry Solar (5A balance current) ideal for large off-grid battery banks, things keep getting on my plate that are a bit more pressing than launching a new product.

The 250A Daly BMS has a rated balance current of 0.2A.  More than the 0.03A typically offered...but even so, Sean tested a BMS with a 1A rating (Chargery) and it wasn't sufficient to keep his Li-Ion powerwalls in balance (>400Ah).  YMMV.

Electrodacus SBMS0 balance current is 0.14A.

[kazetsukai]

4 minutes ago, Sid Genetry Solar said:

That'd be about $130/kwh, which is a really good price.

I think so.

 

4 minutes ago, Sid Genetry Solar said:

I would seriously recommend checking the balance current on any BMS system.  While we want to offer a high-current BMS solution at Genetry Solar (5A balance current) ideal for large off-grid battery banks, things keep getting on my plate that are a bit more pressing than launching a new product.

The 250A Daly BMS has a rated balance current of 0.2A.  More than the 0.03A typically offered...but even so, Sean tested a BMS with a 1A rating (Chargery) and it wasn't sufficient to keep his Li-Ion powerwalls in balance (>400Ah).  YMMV.

Electrodacus SBMS0 balance current is 0.14A.

I found a balancer that did 2A at one point. Honestly I'm not sure more is going to be better in this case. LFP has a very flat voltage curve especially in contrast to LiCoO2, and current BMSes can only balance based on voltage even though we know its a horrible indicator of SoC.

I think every few years if one wants their LFP pack to last, its going to need to be disassembled and top balanced manually. 

I've seen no data on expected cell drift in LFP banks either...

[Sid Genetry Solar]

13 minutes ago, kazetsukai said:

I think every few years if one wants their LFP pack to last, its going to need to be disassembled and top balanced manually. 

I've seen no data on expected cell drift in LFP banks either...

So as someone who personally has a 12kwh 16S LFP bank, I do have a few comments 😉

I've had it for roughly 4 years with absolutely no issues whatsoever.  I do have 3A home-made (hand-soldered) balancers on it, and I also do not regularly cycle the battery to a very low SOC (been twice in 4 years that I'm aware it's gotten down to the "falloff knee" on the discharge curve).

One serious risk with LFP and balancers, is that when they reach a full SOC, the voltage immediately begins to rise--meaning that the balancers have next to zero warning before they get slammed with full load work.  If they can't keep up, then cell voltages will go out of range, hurting longevity.

With that in mind, it may be wise to charge the batteries the first time with a bench supply, watching the cell voltages to make sure the balancer can keep up.  If an imbalanced Li-Ion bank is connected to full solar on day 1, the cells very well could sustain damage due to overvoltage...and if the BMS is set up to disconnect the batteries in event of a cell voltage issue, you likely will end up with a smoked MPPT, as it seems that most of them will blow up if the battery is disconnected while solar is present.  (I digress!)

In my case, it took 3-4 days (with a time-limited "absorption" cycle, which is why it took so long) before the batteries were fully balanced.  Ever since then, I've checked the battery voltages about once per year just to make sure the hand-assembled balancers are functioning...and have never had reason to manually balance the cells.  The balancers each have a little "active" LED on them--and every day during the "absorption" cycle, some cell LEDs will barely light (indicating a very low balance current.  How much, I have no idea.)

With that in mind, I would conclude that LFP batteries should do better with a (comparatively) low-current balancer, than, say, Li-Ion batteries.  That is, providing you aren't deep-cycling the batteries every day--if that's the case, you're going to need one huge balancer.  I know someone who burned through several sets of LFP batteries in about a year's time--but they were running 80-100% DOD cycles on a daily basis, and only had a cheap 0.03A eBay balancer to try to hold them together.  Which it...didn't.

[kazetsukai]

Yeah, I'll be sticking between 20% and 80%, using a very very conservative charging profile. Even doing so I'll have between 4x and 5x the capacity I have now.

I actually have another problem I'm trying to solve... 3000W of solar was enough to charge my bank to full from zero in half a day of good sun, it wont be after this upgrade. So I'm working on trying to double up on panels (~6200W). Without any remaining roof space, that means designing a stacked panel slide out system. 

[dochubert]

Well, much as I admire you guys buying new battery cells,  I just can't spend that much.  Last fall, when my lead acid batteries started faltering, I bought used Byd modules from battery hookup.  It was the only way I could afford a sizeable bank in Lifepo4.  My 48v bank is (8) 24v byd modules arranged in (4) 48v sets.  Because they are not new, battery hookup suggests only using a 24v-27v range (in my case 48v-54v). 

I wanted more batteries but that was all I could afford at the time.  So, do they stay balanced?  Pretty much, that is until they get above 54v.  Then they drift a bit.  Not intolerably much, but I'm still trying different active balancers.  The daly bms' can't keep up, obviously at .2a.  Trying an active 1.2a balancer currently.  Without changing wire size can't go much higher in amp ratings.  Don't really want to take down the batteries to increase wire size.  Those things weigh 125lbs each!

I just ordered 8 more byd modules, this time from Battery Clearing house.  (Battery hookup hasn't had these for some time, except for a few 'bad-cell' modules - why would you want those?).  That will double my 48v bank size, which, for my needs should be a lot of overkill most of the time.  Short Idaho winter days and many of those with little to no sun motivates the increase in bank size.  The rest of the year is full off-grid time with the current bank being plenty!

So before I mount the new additional modules, I will add larger balance wires, parallel all the cells and use a 5a active balancer for the whole set.  Hoping to do much better going that route.  If the results are good enough, I'll eventually take the original 8 down and do the same for them.

The link to what I just ordered;

https://www.batteryclearinghouse.com/products/copy-of-byd-lifepo4-24-volt-battery-pack-freight-shipping-bulk-rate2?pr_prod_strat=collection_fallback&pr_rec_pid=4597369241678&pr_ref_pid=4437612265550&pr_seq=uniform

They are $295 each and flat $297 shipping for 1 to 12 modules.

So if anyone else is cheap like me,  its the best deal I found for lots of capacity at a good price.  Just not new....

[The Blind Wolf]

Yep, same here on my battery bank, 20 to 80%.  That is one thing I'm worried about is if these batts decide to cut off all at once, dang the poor mmpr ain't going to like it.  So far, its not done that with the three batt bank I got hooked up on it right now, but I've not been able to pull the batts down since I don't have anything 24v. . . .

[Sid Genetry Solar]

7 minutes ago, dochubert said:

The link to what I just ordered;

https://www.batteryclearinghouse.com/products/copy-of-byd-lifepo4-24-volt-battery-pack-freight-shipping-bulk-rate2?pr_prod_strat=collection_fallback&pr_rec_pid=4597369241678&pr_ref_pid=4437612265550&pr_seq=uniform

They are $295 each and flat $297 shipping for 1 to 12 modules.

So if anyone else is cheap like me,  its the best deal I found for lots of capacity at a good price.  Just not new....

Really not bad at all...$112/kwh considering worst-case of 3kwh/pack.  If they're 4kwh/pack, that's $85/pack.

You did really good 😉.

 

8 minutes ago, dochubert said:

Not intolerably much, but I'm still trying different active balancers.  The daly bms' can't keep up, obviously at .2a.  Trying an active 1.2a balancer currently.

Have to say that while I like the "active balancer" concept, I have yet to see a favorable in-depth review of them anywhere.  I've seen videos of them blowing up if not connected in the right sequence...or others where they further increase the cell imbalance (very hard to detect on LFP due to the sharp SOC curve).  Not saying they don't work, though.

Gotta love the charge-pump style with electrolytic caps...now THAT might last a brief minute 😉.

[The Blind Wolf]

Uhm,   I'm kind of stump, well, probley could find it on google if I loook, but what would be the voltage level of 24V at 20% to 80%?

[dochubert]

56 minutes ago, Sid Genetry Solar said:

Gotta love the charge-pump style with electrolytic caps...now THAT might last a brief minute

Sid, since I'm learning as I go with the balancer thing, could you expand on what's not good about these?  Thanks!