I currently have 220 ah lead acid batteries in a 24 volt configuration, 15 years old. They need replacing and I'm considering Lithium Iron Phosphate. I see a lot of deals on aliexpress. How can I confirm they are grade A and not B. I want to get at least 15 years out of them and I'm nervous about the condition of batteries. Are there any out there who have used Ali batteries for a couple years?
Buying 280 ah Lithium Iron Phosphate Batteries
- Thread starter ddutton
- Start date
Purchase directly from the manufacturer (EVE). All of the cells sold by resellers/trading companies are factory rejects (out of spec on some way or old) and while most seem to hold close to full capacity, the only way to get true grade A cells with a full manufacturer’s warranty is to purchase directly from the manufacturer (at a significantly higher price).
You know the old adage: ‘if it’s too good to be true, it probably is’
Those budget-minded DIYers (looking into purchasing used Lion cells (Lithium-Ion, different chemistry from LiFePO4) from Nissan Leaf or other EVs, for example) have been pretty happy with the value for money of these aftermarket/grey market LiFePO4 cells (me included).
But if you want to be sure your going to get full cycle life from your cells, you should be paying up to purchase directly from EVE (as several on this board have done).
Search for EVE store on Alibaba, they are there...
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They've not been available for a couple of years. I bought mine about a year ago, and they'e been in operation for the last 6 months or so. I don't think you'll get data that goes back further than that.
Just to clarify Nissan Leaf batteries are not LiFePo4 batteries. I know you kinda said that but may ne confusing to newbies.
Good catch, thanks. Went back to edit the original post.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Clarifications:
ESS (Energy Storage System) cells are ALWAYS cheaper because they do not have High Discharge & Charge rates.
Typically they cannot exceed 1C Rate for discharge and should not be charged beyond 0.5C Rate.
A-Grade means no blemishes, no faults, pass factory Grade Classification and meet "A" grade qualification criteria.
B-Grade may have physical blemishes but still pass as qualified cells. They may also fall short of stated Capacity Range. Often these are derated so a 200AH cell that is Grade-B, may be relabelled as 175AH or 180AH depending on batch capacity averages.
C-Grade does not meet basic requirements, may be seriously derated. Can be blemished or have other physical faults.
Matched/Batched & Binned cells are tested from full charge (3.650V) to full discharge (2.500V) with logging and sampling at every 100mv difference through typically 3 full cycles. This is a costly process and takes time... Easily add 50% of cell cost on top. PROPERLY MATCHED & BATCHED cells will be in sets that have all cells that match throughout their full cycles. (Just like they have to be for EV's)
NOTE: Many vendors sell "Matched" cells but they are ONLY Voltage & IR matched at their storage voltage.
See link in my signature regarding ESS Cells.
EV Grade cells (higher quality materials all around) are typically capable of 3C to 5C Discharge & Charge rates. They can also usually handle up to 8C Surge discharges. These cost MUCH MORE. No One uses EV Grade cells for light ESS usage, there is no point really. The only instances such MAY be used is for industrial / commercial ESS but that is quite another game... Think of Machine Shop using batteries, not light stuff.
100AH Cell @ 1C=100A, 0.5C=50A
Lithium Based batteries do NOT use C/20 or other Leadisms.
They only require CC/CV Charging (Constant Current / Constant Voltage) no Equalizing or any other "stuff".
Nor do we talk about DOD, we use SOC which is different. People interchange the terms but they aren't the same.
I moved from 956AH of Heavy Rolls Surette Lead to 910AH LFP and now using the Lead as a secondary backup bank.
There are several links in my signature which would help you out.
We DO KNOW Good Vendors and even BAD Vendors and there is a great deal of experience here with these folks.
Myself, like MANY others have used Luyuan Tech for cells and very few issues have been raised by anyone.
We have a Member here who is bulk buying cells and doing really well, he is in the states, look for @Michael B Caro thread on 280AH cells.
Take your time, do your research, Learn about LifePo and remember that many things applicable to Lead Batteries do not apply and terminology is different, even if it seems similar. NEVER IMPULSE BUY A THING ! There are always Sales & Deals to be had...
Hope it helps, Good Luck.
ESS (Energy Storage System) cells are ALWAYS cheaper because they do not have High Discharge & Charge rates.
Typically they cannot exceed 1C Rate for discharge and should not be charged beyond 0.5C Rate.
A-Grade means no blemishes, no faults, pass factory Grade Classification and meet "A" grade qualification criteria.
B-Grade may have physical blemishes but still pass as qualified cells. They may also fall short of stated Capacity Range. Often these are derated so a 200AH cell that is Grade-B, may be relabelled as 175AH or 180AH depending on batch capacity averages.
C-Grade does not meet basic requirements, may be seriously derated. Can be blemished or have other physical faults.
Matched/Batched & Binned cells are tested from full charge (3.650V) to full discharge (2.500V) with logging and sampling at every 100mv difference through typically 3 full cycles. This is a costly process and takes time... Easily add 50% of cell cost on top. PROPERLY MATCHED & BATCHED cells will be in sets that have all cells that match throughout their full cycles. (Just like they have to be for EV's)
NOTE: Many vendors sell "Matched" cells but they are ONLY Voltage & IR matched at their storage voltage.
See link in my signature regarding ESS Cells.
EV Grade cells (higher quality materials all around) are typically capable of 3C to 5C Discharge & Charge rates. They can also usually handle up to 8C Surge discharges. These cost MUCH MORE. No One uses EV Grade cells for light ESS usage, there is no point really. The only instances such MAY be used is for industrial / commercial ESS but that is quite another game... Think of Machine Shop using batteries, not light stuff.
100AH Cell @ 1C=100A, 0.5C=50A
Lithium Based batteries do NOT use C/20 or other Leadisms.
They only require CC/CV Charging (Constant Current / Constant Voltage) no Equalizing or any other "stuff".
Nor do we talk about DOD, we use SOC which is different. People interchange the terms but they aren't the same.
I moved from 956AH of Heavy Rolls Surette Lead to 910AH LFP and now using the Lead as a secondary backup bank.
There are several links in my signature which would help you out.
We DO KNOW Good Vendors and even BAD Vendors and there is a great deal of experience here with these folks.
Myself, like MANY others have used Luyuan Tech for cells and very few issues have been raised by anyone.
We have a Member here who is bulk buying cells and doing really well, he is in the states, look for @Michael B Caro thread on 280AH cells.
Take your time, do your research, Learn about LifePo and remember that many things applicable to Lead Batteries do not apply and terminology is different, even if it seems similar. NEVER IMPULSE BUY A THING ! There are always Sales & Deals to be had...
Hope it helps, Good Luck.
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