LiFePo4 legit offer?

[stekicar]

And price includes shipping, any custom fees, doo to door.

[vincent1984]

How about shipping them to Costa Rica? Is this free of duty for Solar Panel as the article below is saying?

https://usgshipping.com/shipping-to-central-and-south-america/shipping-to-central-america/shipping-to-costa-rica-from-us

I know Costa Rica is after the renovable energy but not sure if there is local manufacture or we must have to export it from the US or China?

[stekicar]

Well, I do not know for Costa Rica. You will have to check with their customs. You can also check with sellers on Alibaba. They can check through their shippers.

[Paul Land]

"Legit" was more related to battery specification, not if company is legit or not. Transaction is secured by Alibaba and in case that delivered goods are not per agreement they get involved in dispute. I talked to Alibaba representative and he explained the process of dispute pretty well. As for the warranty, it is same in US per my experience, it is just a sales pitch. I asked them about warranty and they say that they will guide me on how to test the battery and if bad they will ship new one(s) for free.
Offers I got were pretty similar, within $100, shipping included.
As for the discharge rate it can peak at 2C but they state 1C continuous. Capacity was rated for 0.2C as per battery specification. My concern was mostly about internal resistance which is stated at 0.1 to 0.2 miliOhms. Doesn't this sound too low for LiFePo4 batteries? I was expecting something like 0.4-0.5 miliOhms.
Here is the quote detail:
Battery Quote.png
Second offer states that batteries are grade B from CATL and they have 0.8miliOhms internal resistance for this batch. Previous batch had 0.4miliOhms.
As long as all batteries in pack are within certain range for IR I think it will be ok for my application. My theoretical max amperage is 350Amp.

Oh my GOD! that $30.00 is Trumps tariff deff, a deal killed. Its not the Chinese crap its the tariff!!

[stekicar]

Errrr, bank "handle" fee is actually a racket you have to pay to the banksters, so they can stay rich ...

[Jordan]

Wonder, did you get those batteries finally ????

[stekicar]

Yes, I did. I got 48 of 320Ah for 720Ah total (3p16s). I am running them since mid November 2019. SInce March this year I did not use grid power except for couple of rainy days. I charge them up to 3.475V and drain them not below 3.15V (3.18-3.2 actual). So, far they are really good. Three of them came damaged so they sent replacement. And replacement came damaged... So, third time I got good ones. Actually, I ordered three more to be shippped with replacement and half came damaged and other half was in good condition.

[mstasko]

Yes, I did. I got 48 of 320Ah for 720Ah total (3p16s). I am running them since mid November 2019. SInce March this year I did not use grid power except for couple of rainy days. I charge them up to 3.475V and drain them not below 3.15V (3.18-3.2 actual). So, far they are really good. Three of them came damaged so they sent replacement. And replacement came damaged... So, third time I got good ones. Actually, I ordered three more to be shippped with replacement and half came damaged and other half was in good condition.

stekicar

What brand/company did you end up going with? What is the BMS that you are using?

I am interested in this cell chemistry (LifePO4) and trying to decided between the different case types (calb, aluminum, etc) going with a smaller ah or larger ah cells, 100 vs. 180 or 200ah, etc..
Any insight welcome.

Thanks

[stekicar]

These are B grade (as per seller) CATL batteries with Aluminium case. I went with Guangzhou QiHua Technology Co., Ltd. Contact name was Sylvia. As for BMS I am "using" Chargery BMS16T. I bought it because it has serial port and I can communicate with it using Raspberry Pi. Communication is only one way but it is enough for me because I am just using it to monitor voltages of each cell. As for balancing, I do not think it is doing any work because it has only 1.2A capacity which I do not think it is enough for my 720Ah system. But, batteries are even with voltages. Unfortunately, serial port on BMS unit stopped working 4 months after and I cannot even update firmware for some reason. I started looking into something like this: https://shop.gwl.eu/GWL-Modular/GWL-...e-Monitor.html. This unit does not have communication port but version 1.8 will but it is still in prototype stage. This GWL unit does not have balancing capabilities.
If you have any other question, feel free to ask.

[mstasko]

Thanks for the info.

Any noticible performance hit being grade B cells, loss in ah?
what voltage range do you run the pack?
also how did you construct the battery bank, any compression or fasteners to keep the cells from moving?

I currently have a Nissan leaf pack that I’m trying to decide on expanding or selling off and going this route instead. With the leaf cells they require compression so I have them essentially fastened together so they wouldn’t be able to move I’m sure if that type of set up is required for these types of cells.

Thanks again..

[stekicar]

Batteries work without any problem. I use them since November last year. I charge them up to 3.475V (upper 90%) and discharge them down to 3.15V (lower 20%) which is 70% capacity. My system is set based on charge/discharge data given by seller. Batteries have more capacity than it is stated, I never go below 3.2V even after I used 70% of available power. Batteries are grade B because nominal voltage is 3.3V instead of 3.2V. I made wooden frame out of 2x4 and place all batteries in 3p16s setup. I connected battery pack to inverters (3kW and 12 kW) and Victron solar charges through bi-stable relays which are controlled with Raspberry Pi and also with manual switches. I did not compress these batteries.

[mstasko]

Thanks. I did inquiring on Alibaba and some of the quotes I am seeing are crazy competitive to used cells..!

Shenzhen Youngpower Technology Li

EVE A- grade 3.2v 280ah Aluminum case, priced at $82 for 48. Works out to $102/kw !
or $120 including shipping (by sea).


Looks like I'll pursue this cell type, now I need to decided on cell ah size and number in parallel that I want.

For your cells did you do any sort of top or bottom balancing before setting them up?

[stekicar]

Batteries I bought are not the used ones. They are brand new, grade "B" due to 3.3V nominal voltage instead of 3.2V. They came exactly at 3.30V+0/0.02. I measured voltages, internal resistance and weight on all of them upon arrival.
I did not want to buy used ones because there is no way knowing how much they were used. I did not do any bottom nor top balancing because they came with exact same voltage.

[Ampster]

Thanks. I did inquiring on Alibaba and some of the quotes I am seeing are crazy competitive to used cells..!
............
For your cells did you do any sort of top or bottom balancing before setting them up?

I know those prices are tempting.

I always parallel the cells for a few days before assembling them. There are advocates for both top and bottom balancing but I don't think doing that on an individual cell basis provides any marginal benefit. Maybe in an EV conversion that is going to be pushed hard but with a stationary pack there is an opportunity to extend the pack life by using less of the capacity. Doing that avoids any risk of a weak cell hitting the top or bottom before charging or discharging is cutoff.

[stekicar]

I also did parallel all batteries for a week (because I did not have rack built). I also set BMS balancing to start around 3.4V during charging.