I have had so many requests to open this article I have decided to remove the password protection.
Please understand this article is still not entirely complete or done, but there is still a lot of information in it now. An article like this takes lots of time to write photograph and proof read and I still have a very busy marine electrical business to run.
Please be patient. If you see typos feel free to point them out so I can edit and proofread faster.
Ever since I began my foray into LiFePO4 batteries readers of this site have been asking for more information. I thought now was as good a time as any to share my experience.
Unless you want a big fat dent, where your wallet used to be, I do not believe LiFePO4 is ready for mass DIY prime time builds. Read with CAUTION!!! If you think you want LiFePO4 PLEASE READ VERY CAREFULLY! Once you are done reading this, and it makes sense to you, then please spend another 6-8 months reading everything you can including every single LiFePO4 white paper you can get your hands on.
Since opening this article to the public I have now had what I consider and insane number of folks contact me who have ruined LiFePo4 batteries. In almost all of these cases of destroyed LiFePO4 batteries the resounding tone I hear come through is; "People on the internet made it sound easy." The internet has a name for these kind of cheerleaders "fan boys". Do yourself a favor and don't jump to conclusions where large sums of money are involved over "fan boy" postings. DO YOUR RESEARCH! Trust me, it does NOT end with this article. This article is BARELY scratching the surface.
Sadly, only a few of the cases of destroyed LFP batteries I have been contacted about are reported in on-line in forums, on blogs etc.. The folks destroying these LFP batteries are not all boaters. Some are electric vehicle guys, some are RVer's, one or two of them were off-grid and the rest are boaters.
The one thing they all had in common was a grossly incomplete understanding of a what a BMS is, what a BMS should do, how to wire a BMS and how to properly & safely use, charge and discharge LFP banks.
So here are the stats (n=68):
#1 Cause of LFP Death = Over Charging - Almost always incorrect absorption duration and too high an absorption voltage. Voltages were above 14.2V in every case.
#2 Cause of LFP Death = Float Charging - In almost every case these owners insisted on floating LFP. Solar was #1 with shore power charging close behind. If you think a bank can't be overcharged at a 13.8V pack voltage think again and please do more research.
#3 Cause of LFP Death = Over Charging Due to Cell Imbalance - In about half the cases the owners were monitoring only "pack level" voltage and in the other half it was incorrect pack balancing.
#4 Cause of LFP Death = Incorrectly set up BMS - I really hesitate to even call some of these "systems" a BMS but in each case the "protections" the owner had put in placed failed to protect the battery. About 4 of these cases were a simple "low voltage disconnect".
#5 Cause of LFP Death = Over Discharging - In many of these cases incorrect battery monitor SOC programming and lack or BMS protection lead to over discharged batteries. Some were cell imbalances and one or two not accounting for parasitic loads.
*Please note that in all 68 of these RUINED LFP banks, that I have to date, there was not one incident of fire, explosion or dangerous off-gassing. Lots of bloated cells but no fire, just thousands and thousands of dollars in hard earned money GONE.
I apologize but I have stopped all long distance consulting on LFP. If the boat is not readily accessible here in Maine, Casco Bay to be specific, I simply can no longer do LFP consults. Why? Far too many owners insisting on cutting corners and multiple situations where things were not done to design or design criteria. Bottom line is this; if I can't lay my hands on it, I am no longer designing or consulting on it. If you happen to glean something from this article, that is fine, but please don't email me with further questions on LFP. This article is for INFORMATIONAL & EDUCATIONAL PURPOSES ONLY.
***What this article will discuss, and what it won't discuss***
#1 This is meant as a general overview of LiFePO4 batteries (no other Li chemistry) for use as house banks on boats only. This is not about electric propulsion or electric vehicle use, just house bank use on cruising boats with both factory made systems and custom builds. I will sometimes refer to this type of use as "fractional C" use.
#2 It is the sharing of my learning, experimentation & Installation/implementation of LiFePO4 batteries on boats. I DO NOT consider myself an expert on the subject of LiFePO4. If even the Chinese manufacturers don't fully understand this technology, inside and out, how can I? If there is no solid data on fractional C use then how am I to be an expert on it? Again this article is the sharing of some of what I have learned about LFP...
#3 This article will not show you every little "Betty Crocker" detail to build your own bank or give you every last ounce of detail & specific wiring diagrams. It is my belief that those final details need to be ironed out by whomever decides to DIY with the specific equipment chosen. If you do not have the ability or inclination to figure out the last few, connections of the dots, then perhaps you & LiFePO4 a poor fit, at least right now....
#4 This article is not a suggestion or an endorsement for widespread DIY builds of LiFePO4 batteries. It is intended as educational in nature only. I am a firm believer that this is a level 11 on a scale of 1-10 for the average DIY to grasp. Unless you are an EE or have a very high, high, high electrical aptitude, and penchant for electrical systems, this is simply not prime time ready for the average DIY.
#5 LiFePO4 can put a HUGE dent in your wallet if not done correctly. In my experience there is lots of misguided advice on the net about doing this. One must read it all to decide which way will work best for them. I have a folder on my computer full of white papers and yet there are still massive holes in the data, when applied to fractional "C" use for house banks on boats. Many cells have been destroyed by folks trying to cut corners, take shortcuts or not doing enough research. I can only share what I have learned through research, physical testing & actual real world use.. This article is not to suggest there is only one way to use Li on boats. I do however believe, for house bank use on boats, there is a right way and a wrong way. I will not tell you how you should do it, but I will share the why's and how's and why's and how's of how I came to decide on this or that methodology or practice.
The Shipment: These cells came from Balqon Corp in California and this is how they arrived, very well packed. I got a good deal on these cells but I can't, with a good conscience, recommend dealing with Balqon. In my experience they are scatter brained, disorganized and shipping is EXTREMELY expensive. Some owners have waited many MONTHS to get their cells. If things change at Balqon, and they get better, I will be sure to let you know. Until then try to find USA stock of LFP cells, such as CALB, elsewhere.
EDIT: Balqon is apparently out of business. Winston cells are available in the US branded as Voltronix. Contact Voltronix if you want more information on their cells. Other options are Sinopoly or CALB cells.