Alibaba LiFePo4 batteries

[Steve_S]

Well the photo's are representations of the format of what they are selling. I highly doubt that anyone takes the time to photo every cell and change ads for each product. The key is how much faith you have in the seller and their reputation. Making assumptions based on incomplete information and jumping to conclusions based on that is almost always a mistake. Due Diligence as demanded by "The Wallet" says, do your research, read the feedback and if possible get personal statements from people who bought & use said product. 2nd & 3rd hand info is pointless.

 

[Jejochen]

Well the photo's are representations of the format of what they are selling. I highly doubt that anyone takes the time to photo every cell and change ads for each product. The key is how much faith you have in the seller and their reputation. Making assumptions based on incomplete information and jumping to conclusions based on that is almost always a mistake. Due Diligence as demanded by "The Wallet" says, do your research, read the feedback and if possible get personal statements from people who bought & use said product. 2nd & 3rd hand info is pointless.

That' s why i ask if someone here knows more about them

 

[Staffan]

Blue" Aluminum LiFePO4 batterie

I have studied many posts in different Forums regarding "blue" Aluminum LiFePO4 batteries, and came up with some comments.
When testing the power of a battery you should use the current specified as the optimal for batteries, in the example it was a 75Ah battery and then you would have discharge with 37.5A ie 480W and not with 150A corresponding to 2C, which battery but can with less capacity and higher heating. The probability is that Ri also rises when you discharge the battery and then the loss effect increases even more.
It became too much rattling over the enclosure and difficult to get stable battery pack, and it became hot 60 degrees (loss> 28W at 12V versus 7W at 12V and 0.5C). The accompanying interconnection was also poorly made, easy to change to the usual flat copper paths normally used.

If you take Wh / Kg as a comparison between aluminum and plastic-enclosed batteries, the flat-enclosed battery is probably also plastic around an aluminum enclosed battery. If you count on the weight of a 5mm thick plastic capsule and reinforced top and bottom, it will be approximately, (Winston 200Ah) 7.9-2.3-0.2 = 5.4Kg. A little closer to an aluminum enclosed battery that weighs about 4.1Kg for equivalent capacity. The difference after this calculation is that the plastic battery has a slightly larger volume, which may be because it has better structure for having better balanced Ri differences.
When building DIY with aluminum encased, you have to think a little more about how to assemble the individual cells into a package. The advantage of aluminum enclosed must be that the thermal connection to the environment is better. It would be interesting to discharge a plastic battery with 2C a full discharge and then measure the temperature of that battery.

When choosing a battery, one must take into account the purpose of the battery pack. If it is to be able to drive for example 10KW, then you have to count backwards and see how much current my converter needs, depends on the voltage. For example, in a 48V system need to be able to leave about 200A, if the normal discharge current of the used batteries is 0.5C then you must have 400Ah batteries or parallel connected batteries with lower Ah values which together give 400Ah.

My own design is to take out maximum of 2500W, which gives about 100A in a 24V system to my boat. I have expected to use 16 pieces of 202Ah cells from RJ-Energy, and I have had contact with a seller at www.rj-lithium.com. After some mail exchanges to sort out document differences on their website, I have received a price and shipping cost proposal, depending on the shipping method. The price including shipping was $ 140.125 and $ 120.125, respectively.
I had thought of incorporating the cells into a stainless steel box (0.5mm thickness) the size of the AGM batteries ie 510x232x225mm, where it can also fit BMS, fuse, switch, temperature sensor, DCDC for + 13.6V / 5A for various systems in my boat, see attach file.

Comparison LiFePO4 batteries

Prismatic plastic housing Calculated
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Without
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .plastic. . . . . . . . . . . . . . . . . . . . . . . . . . . Optimal. . . . . . .Max
Brand / Dist.. . . Color. . . . Ah .......Wh /Kg.. . . .Wh /Kg. . . .Ri mOhm. . . .Wh / l. . . discharge. . . . . discharge
Winston. . . . . . . Yellow. . .200 . . . .81 . . . . . . . .114. . . . . . . . .<0.4. . . . . . .36. . . . . . .0.5C. . . . . . . . . 3C. (Pulse 10C)
Sinopoly. . . . . . . Black . . . .200.. . . .110 . . . . . . .151. . . . . . . . .<0.4. . . . . . .58. . . . . . .0-3 C. . . . . . . . 3C


Prismatic aluminum with blue plastic
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optimal. . . . . . .Max
Brand / Dist.. . . . . . . . . . . . . . . Color. . . . .Ah. . . Wh / Kg. . . . Ri mOhm. . . Wh / l. . . .discharge. . . . . .discharge
RJ Energy/ rj-lithium.com . . . .Blue. . . . 202. . . . . .157. . . . . . . .<0.5. . . . . . 107. . . . . . . . . 1C. . . . . . . . . 2C
ETC /BLS. . . . . . . . . . . . . . . . . . . .Blue. . . . 206. . . . . .164. . . . . . . .<0.4. . . . . . 106. . . . . . . . .0.5C. . . . . . . . .1C (Pulse 3C)

 

[Staffan]

That's a very good deal I think. I tried to find info on "RJ Batteries" but couldn't. Have you come to a decision on a BMS ?
Another forum member gave me a link in another thread and there is great info on the site, batteries, bms', chargers etc...

Li-Ion BMS - Lithium-Ion Battery Management Systems and large battery packs

Hello
RJ batteries are available at www.rj-lithium.com. I have had email contact with them and it is from there I got the data sheet of the 202Ah battery.

As for BMS, I was thinking of using BMS123SM-SET which costs about $ 324, not so cheap but seems good. There are videos on YouTube where they show how it is connected.

/ Staffan

 

[erik.calco]

The battery w/shipping



If anyone buys one, they are required by Solar Law and Ohm's Law to share their review here, with video.

 

[erik.calco]

Hello
RJ batteries are available at www.rj-lithium.com. I have had email contact with them and it is from there I got the data sheet of the 202Ah battery.

As for BMS, I was thinking of using BMS123SM-SET which costs about $ 324, not so cheap but seems good. There are videos on YouTube where they show how it is connected.

/ Staffan

Now we're talking:

 

[Newenough]

I reached out last night. Gave me a good deal on 60ah at $36 each. Ordered 8 for a test. Have 360ah now, so hopefully they will play well with others. Shipping was $128.

 

[Aussiecroc]

Im not sure what is the reason but 4 times 190 ah blueys just jumped from $879 to $931 Australian overnight pus about $87 freight.
too many people on here buying them lol. I sent Jason (from BLS)a letter telling him that our forum are watching his price movements in comparison to other brands and makers. The closer the price gets to Sinopolys the more I might jump in that direction.

 

[gnubie]

It's good that RJ does actually admit the life cycle of their battery via this graph, but they still slather 6000 all over the place without upfront telling you that to get that you have to consider the usable lifespan to be down to 70% of original rating. As you can see, their 80% rating is around 2000 cycles which is what is expected from lifepo4 cells.

Don't get taken in by the 6000 cycle count and think that this is a superior product. It might be a perctly fine normal run of the mill battery.

 

[Aussiecroc]

I have trouble understanding that graph. Its says capacity retained. What does that mean? So if I discharge down to 15 percent I will get 2000 cycles? 75%(down to 25%) I will 4000 Thats double the cycle life for 10 percent less! So If I never go lower than 30 I might get 6000 cycles plus? Am I thinking about this right?

Maybe age and Aussie 30 c plus temp will kill them sooner

 

[gnubie]

It's the % of rated capacity left after X cycles charge discharge cycles. Normally a charge / discharge cycle is charge to 100%, discharge to 20%.

Assume a 100ah battery. After 6000 cycles the capacity is reduced to 70% of the original, ie 70ah. 80% is the industry standard so when you see high cycle life times you can bet they are doing the cheap way out and lowering the point at which they consider the battery to be end of life.

It's important to remember that the battery could still be a quality reliable battery, they've just embiggened the figures to make it look like something special.

 

[Aussiecroc]

Of course -now I understand thanks

 

[Newenough]

RJ reached out this morning. Said the 60ah is out of stock. Are giving me 75ah instead....nice.

 

[Aussiecroc]

Can I ask the price new?

 

[Newenough]

Can I ask the price new?

$36 each for 8, and $128 to ship.

 

[Newenough]

It's the % of rated capacity left after X cycles charge discharge cycles. Normally a charge / discharge cycle is charge to 100%, discharge to 20%.

Assume a 100ah battery. After 6000 cycles the capacity is reduced to 70% of the original, ie 70ah. 80% is the industry standard so when you see high cycle life times you can bet they are doing the cheap way out and lowering the point at which they consider the battery to be end of life.

It's important to remember that the battery could still be a quality reliable battery, they've just embiggened the figures to make it look like something special.

Not as bad as advertising 9600mah 18650's! That always makes me laugh.

 

[Staffan]

Hello
If I read the curve it will be about 3000 cycles at 80%. In the data sheet for the battery it says that Life Cycle is> 6000 times (100% DOD).
I guess 100% DOD is that you charge up and down to 100%.
I my datasheet I miss the curve.
/ Staffan

 

[offgriddle]

Guys be positive most lifepo4 are made In China. Over 85% of western companies get their products made there. Be positive. My iPhone parts are manufactured I n China and supposedly assembled in the US.

It is difficult to be 100% positively in favor of millions of jobs for the US masses lost over the past 50 years, accompanied by a general decline in the quality and durability of a wide range of Pacific rim sourced products, along with a significant increase in the the prices of the aforementioned poor quality products do to the lack of consumer choice. Sometimes it is acceptable for human beans to take notice of certain situations and say, "hey, hold on, that's not okay"! The realisation that it is not okay to vote for one's own enslavement to excessive debt and the shrinking federal reserve note will not happen in the USA as long as the mass proletariat continues to be common core raised in government's illegal, anti trust act violating, public school monolith. Untill the day of realisation should come, the word of the day is, "thank you Aunt SAMantha may I have another"?

 

[Bob B]

It is difficult to be 100% positively in favor of millions of jobs for the US masses lost over the past 50 years, accompanied by a general decline in the quality and durability of a wide range of Pacific rim sourced products, along with a significant increase in the the prices of the aforementioned poor quality products do to the lack of consumer choice. Sometimes it is acceptable for human beans to take notice of certain situations and say, "hey, hold on, that's not okay"! The realisation that it is not okay to vote for one's own enslavement to excessive debt and the shrinking federal reserve note will not happen in the USA as long as the mass proletariat continues to be common core raised in government's illegal, anti trust act violating, public school monolith. Untill the day of realisation should come, the word of the day is, "thank you Aunt SAMantha may I have another"?

I don't know if it is the cheap labor that makes the US uable to compete ...... or if they have cornered the resources necessary for making these modern lithium batteries .... but I do think it is a national security issue going forward to have China controlling this market. Maybe somebody will figure out a way for us to get competitive in this market.
As it is, I will buy direct from the manufacturer if I can in order to save as much money as I can.
We lost a LOT of jobs to Japan when they started selling cars over here that were better, more reliable and cheaper .... but that forced the US companies to get their act together to provide a competitive product.
If their governments subsidize a product in in order to kill our companies we have to fight that as well.

 

[erik.calco]

Maybe somebody will figure out a way for us to get competitive in this market.

I think our biggest problem is our bloated patent laws. We now have US/EU startups going to Shenzhen to build new products and sell them there. Only a tiny portion of the innovation there will reach the US.

Factories get built around these innovation centers. So, Shenzhen is the largest manufacturing hub in the world. It is also the fastest growing city in history.