LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[JmanC]

I read conflicting info on the charge speed to full with say pack voltage of 14.6V vs just 13.8V with 4S batteries. Some say at 13.8V is way longer to full(99%+), but my testing on my dropin shows only about 20-30mins extra at the most at 0.3C charge rate. Unless I'm doing something wrong.

Again some say there is extra capacity to be gained by charging to 14.6V until current tapers down to 0 vs 13.8V. But again my testing shows virtually no difference.

In both cases I put a hefty load on the battery until terminal voltage was under 12V and I withdraw almost the same exact AH in both cases, actually a few AH more with 13.8V.

[andyalford]

Originally Posted by s/v Jedi

Can you post an URL where you ordered them and other details like price, cost of shipping etc? Tnx!

I need to write a full report, as I spent a long time researching this.... I will post that on the thread for price and model info, once the batteries arrive and I can report on the whole experience.

I am based in Philippines, so wanted to source direct from China. I scoured the Aliexpress, Alibaba and Made in China. I contacted everybody listing cells there. A massive task! I also searched facebook and many manufacturer web sites.

Winston Cells - Direct

Hannah Yap, Sales
winston999@thundersky-winston.com
$1.20/Ah but gave me a discount less than Deligreen
Hannah has been helpful through my purchase
The battery test data looks perfect. See attachment.
Thunder Sky Winston Battery (Chang Tai)Limited thundersky-battery.com 深圳市醒狮动力电æ±*有é™�å…¬å�¸

Winston Distributor - Deligreen

Wendy <sales8@deligreenpower.com>
$1.07/Ah
Also sells some Chinese BMS and offers new CALB & GBS at cheaper prices to Winston
I think I would trust them to supply new stock reliably, but lots of add-ons to her prices

Winston Distributor - EVLithium

Tony Wang
EVL <evlithium@163.com>
Winston Battery, CALB, LiFePO4 Battery - Evlithium - nice website for information, but be careful!
Winston Battery facebook pages also links to this guy
They quoted me for batteries and I later concluded that they were B grade, meaning old / liquidation sale / mismatched / badly stored / who knows. Good price, so maybe that is ok, but I would have liked to be told before getting them delivered! Basically I don't trust this guy.

CALB Direct

konky@calb-tech.com - Sales, responsive and honest responses
$0.9/Ah
Lecrae <lukuiru@calb-tech.com> - Technical guy, with some English
www.calb.cn

There are a lot of other distributors, selling B Grade / liquidation stock / mismatched batteries. They buy these for about $0.4/Ah, and sell them around $0.59/Ah. At this price, you can buy a few spares and pick the best!! Very tempting.

I can vouch for Alibaba's Trade Assurance programme, because my first order was through another distributor. Simon of Dongguan Huanhuan - very nice guy and easy to deal with, but rather backward with coming forward with information. They had quoted me for CA400 cells, which after the money was transferred, I discovered must have been > 4 years old. They gave me my money back very promptly, and then offered me SE200FI cells instead (the newer version.) Eventually I got a straight answer that they were 2 years old and B grade, potentially rejected for some QA reason. Just not worth it.

Shenzhen Wanhong Technology Co., Ltd

wanily@whepower.com
Very nice girl and incredibly responsive on email. She will email you every day!
$0.44/Ah for Aluminium cased cells, incredibly light for capacity. Ideal for EV.
There is one manufacturer I came across selling their own sells direct, which are incredibly cheap.
I think this might have been the only actual bargain that I found. But I like the plastic case type.
If I was building another project though, I would definitely give them a try.


3 Test Reports as attachments
1. Winston's perfect score - less than 1% deviation
2. SE200FI - not bad for 16 of these cells, I planned to use 4 as a portable bank. I decided against this 'hodge podge.'

3. CA400 - at least one cell of this pack looks broken - very strange charge curve. I rejected these

[Delfin]

Originally Posted by JmanC

I read conflicting info on the charge speed to full with say pack voltage of 14.6V vs just 13.8V with 4S batteries. Some say at 13.8V is way longer to full(99%+), but my testing on my dropin shows only about 20-30mins extra at the most at 0.3C charge rate. Unless I'm doing something wrong.

Again some say there is extra capacity to be gained by charging to 14.6V until current tapers down to 0 vs 13.8V. But again my testing shows virtually no difference.

In both cases I put a hefty load on the battery until terminal voltage was under 12V and I withdraw almost the same exact AH in both cases, actually a few AH more with 13.8V.

The thread on memory effects of long term under charging of LFP batteries is worth a read. The consensus seems to be that periodic charging to 3.65 vpc helps avoid a longer term reduction in usable capacity that may, or may not be permanent depending on how long the condition has existed.

[ReneJK]

As I am preparing to switch to lithium I read most of the thread, thanks everyone for a wealth of info !

Originally I planned to make a DYI 3P4S 600Ah bank with 200Ah cells with all bells and whistles (BMS , Latching relays , separate load, charge and engine busses etc)

But digging a bit deeper I stumbled across this 'green' LifePo4 12 volt battery with built in 'Lith power' BMS with Canbus

https://www.alibaba.com/product-deta...22b95bdbTxK02v

that got me thinking and wanted to get more info before exploring the feasability

Could this battery with Canbus be connected to the Victron 12/200 BMS and the Victron Venus GX (or VCGX) and our Victron MPPT ?

And then let the Victron Venus do the load / charge bus controls / relays ?

it seems that if I would order 6x 100Ah , 3x 200Ah or even 2x 300Ah lifepo4 batteries from this company with Canbus instead of going the Victron Lithium w/ canbus (ve.bus) route could safe me a ton of money ?

the internal Lith BMS uses Canbus 2.0B , which seems to be compatible with Victron as well

[john61ct]

Do you have reliable information that the actual cells inside these assemblies are of good quality and will deliver the sort of longevity the known makers deliver?

Or would you be happy to just get a couple thousands cycles before needing to replace them?

That issue is more critical to me than the packaging and features like an included BMS.

[newhaul]

Originally Posted by ReneJK

As I am preparing to switch to lithium I read most of the thread, thanks everyone for a wealth of info !

Originally I planned to make a DYI 3P4S 600Ah bank with 200Ah cells with all bells and whistles (BMS , Latching relays , separate load, charge and engine busses etc)

But digging a bit deeper I stumbled across this 'green' LifePo4 12 volt battery with built in 'Lith power' BMS with Canbus

https://www.alibaba.com/product-deta...22b95bdbTxK02v

that got me thinking and wanted to get more info before exploring the feasability

Could this battery with Canbus be connected to the Victron 12/200 BMS and the Victron Venus GX (or VCGX) and our Victron MPPT ?

And then let the Victron Venus do the load / charge bus controls / relays ?

it seems that if I would order 6x 100Ah , 3x 200Ah or even 2x 300Ah lifepo4 batteries from this company with Canbus instead of going the Victron Lithium w/ canbus (ve.bus) route could safe me a ton of money ?

the internal Lith BMS uses Canbus 2.0B , which seems to be compatible with Victron as well

that company is no longer listed on Alibaba .

[ReneJK]

Originally Posted by newhaul

that company is no longer listed on Alibaba .

maybe wrong link , but they still are ?

SHENZHEN SUNBANG TECHNOLOGY CO.,LTD

https://www.alibaba.com/product-deta...856304025.html

[ReneJK]

Originally Posted by john61ct

Do you have reliable information that the actual cells inside these assemblies are of good quality and will deliver the sort of longevity the known makers deliver?

Or would you be happy to just get a couple thousands cycles before needing to replace them?

That issue is more critical to me than the packaging and features like an included BMS.

to me its not as I was not asking about the cells , assembly or quality but I was specifically asking about the BMS and the Canbus interoperability

[newhaul]

Originally Posted by ReneJK

maybe wrong link , but they still are ?

SHENZHEN SUNBANG TECHNOLOGY CO.,LTD

https://www.alibaba.com/product-deta...856304025.html

the link looks different yes
must have been my connection because it told me they were no longer on b2b then I got a message from Lisa Huang their sales rep . Is there anything specific you would like to know from them?
I would be happy to get the info for you .

[ReneJK]

Originally Posted by newhaul

must have been my connection because it told me they were no longer on b2b then I got a message from Lisa Huang their sales rep . Is there anything specific you would like to know from them?
I would be happy to get the info for you .

I am more interested in if they work with the Victron VE.bus / Canbus

So I doubt this is something Lisa can answer but I am hoping someone with more Victron indepth knowledge can confirm (or deny) that the Lith BMS (Canbus 2.0B) will work with the Victron VE.bus / Canbus or if Victron uses another protocol

[newhaul]

Originally Posted by ReneJK

I am more interested in if they work with the Victron VE.bus / Canbus

So I doubt this is something Lisa can answer but I am hoping someone with more Victron indepth knowledge can confirm (or deny) that the Lith BMS (Canbus 2.0B) will work with the Victron VE.bus / Canbus or if Victron uses another protocol

I just got the reply and yes their batteries are fully compatible .

[CatNewBee]

What is inside of this batteries, what type of cells, what bms, are there any disconnecting electronics built in or just cell voltage sensors reporting to CAN and balancers?

You know, CAN BUS is just a digital protocol, it does not change physiscs. When you parallel batteries, each battery is a load and a energy source. Assuming one bad cell with shortcut, the bms may report it via CAN and the Victron may drop loads and charge bus, but still the other paralleled batteries will discharge tons of energy on that dead cell and eventually start a fire. Massive parallel banks need thread protection per unit, you have to monitor each battery separately and disconnect it in case there is a problem with one cell, leaving the other batteries connected. In parallel installations separating charge and load bus is tricky, because the batteries themselves can deliver energy to each other.

Most of the time the system will work, but you are not on the safe side if you do not take additiona protection measures, simplest way is to add a fuse per battery, more sophisticated solutions may involve a solenoid per battery to disconnect them individually and some electronic to process the signals independently per battery, instead of daisy chain them.

[ReneJK]

Originally Posted by newhaul

I just got the reply and yes their batteries are fully compatible .

thank you !

[ReneJK]

Originally Posted by CatNewBee

What is inside of this batteries, what type of cells, what bms, are there any disconnecting electronics built in or just cell voltage sensors reporting to CAN and balancers?

the BMS inside is this one (it will download the user manual)

https://www.google.com/search?rlz=1C...dUDCAY&uact=5#

all disconnect electronics are build into the battery but I would much rather have outside disconnects and was wondering if these CANbus batteries will talk to a Victron BMS 12/200 and Venus GX , who will then operate the outside protections , display SOC /DOD , currents and voltages

Originally Posted by CatNewBee

You know, CAN BUS is just a digital protocol, it does not change physiscs. When you parallel batteries, each battery is a load and a energy source. Assuming one bad cell with shortcut, the bms may report it via CAN and the Victron may drop loads and charge bus, but still the other paralleled batteries will discharge tons of energy on that dead cell and eventually start a fire. Massive parallel banks need thread protection per unit, you have to monitor each battery separately and disconnect it in case there is a problem with one cell, leaving the other batteries connected. In parallel installations separating charge and load bus is tricky, because the batteries themselves can deliver energy to each other.

Most of the time the system will work, but you are not on the safe side if you do not take additiona protection measures, simplest way is to add a fuse per battery, more sophisticated solutions may involve a solenoid per battery to disconnect them individually and some electronic to process the signals independently per battery, instead of daisy chain them.

Fuses is a good idea
I was thinking Blue Sea ML-7700's that are operated by the Victron or internal BMS (ie bring the connect / disconnect for the charge and load to the outside)

[ReneJK]

https://www.google.com/url?sa=i&sour...65105874454924

I hope this link works better to download the BMS manual