LiFePO4 Load test
warrenh
Registered Users, Users Awaiting Email Confirmation Posts: 2 ✭
I have a 200ah LiFePO4 battery that cost $1750 (local brand) and only 12mts old. Been suspect about it's capacity, so as soon as I got back from our 12mth caravan holiday I got it load tested. First at Battery World who failed it because after numerous trials it always shut down before a print out could be obtained. Then the manufacturer SPB asked to send it to their representative, who could not get the EOD past 11.8v. I got a print out of 174.9ah. Then I bought a load tester and it cut out at 173.75ah. My question is should I get warranty or are these results acceptable? I don't have the IEEE standard to refer to. The manufacturer has refused warranty so far, but advises to now set the battery capacity in the TREK to 170ah. Here is a link to my load test. 
https://youtu.be/kk40FQgMRLQ
https://youtu.be/kk40FQgMRLQ
Comments
I don't see you doing anything wrong. The only question I would have regards the calibration of the current meter(s)... It looks like you have at least two instruments that are reporting current draw--And they seem to be in agreement (?)--Which is probably good enough for your test results.
Your battery does appear to only have 85% of advertised capacity before the internal BMS shuts down (?) of 10.0 volts?
https://teambmpro.com/products/12v-200ah-lithium-battery/ (your battery?)
It seems there is a 3/5 year warranty (different websites). No details on what is a "failed" battery.
Do you see the battery shutting down because of low voltage (10.0 volts)? Or does it shutdown before hitting that output voltage (could be because of "programmed" capacity in BMS, or possibly a single per cell low voltage protection (internal cell shuts down at 2.5 volts).
I don't see why you should be accepting a battery that does not meet the specifications. And if a single cell (or paralleled pair of cells) is failing voltage and the other cells are OK--That could be an indication that the battery could have an early life failure in its future.
A bit of information comparing Zeal and a "high end" battery.
https://www.mygenerator.com.au/zeal-12v-200ah-lifepo4-lithium-battery
It is recommended that you use the following inverter sizes with the relevant Lithium battery:
Invicta are a premium level offering and they come with a 7-year warranty. They are built to higher specifications, including an engineered BMS to ensure extra protection against overcharge, and higher level of independent certifications (IEC 62619 and IEC 62133 certified) meaning they are suitable for commercial and industrial level use if required. In short; Invicta can handle more rigorous use / conditions and are designed to do so. We find RV customers with larger premium caravans that travel frequently and for prolonged periods like the Invicta product. Invicta also has a much larger range, including some slimline options.
Zeal are an entry level lithium product, with a 3-year warranty. The BMS is more basic and is not designed to handle commercial grade application. Zeal is quality budget friendly recreational option, meant for the everyday caravan/RV owner. Currently Zeal have only two sizes: 100Ah and 200Ah.
The Invicta batteries do come equipped with in built blue tooth monitoring, whereas the basic BMS in the Zeal battery is not blue tooth enabled. We often see customers use the extra savings to purchase an external Bluetooth enabled battery monitor like the Victron BMV-712.
The Zeal lithium range comes with a built in Battery Management System but it does not feature Bluetooth connectivity. We recommended purchasing a good quality external battery monitor that has it's own Bluetooth connectivity inbuilt. (BMV-712)
Just as an FYI--Here is one review that tested capacity (199.3 AH for 200 AH spec'ed battery) and did a tear down on a different battery brand. Pretty interesting:
-Bill