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

[nebster]

I've been unable to*observe a reduction in charge capacity after 200 "short" cycles that is different than the normal, well-documented losses of 1-2% at that battery age.

I do see changes in the shape of the charge curve, though.

Specifying a charging voltage by itself is not enough to describe how a battery will be charged. Rate prior to and holding time at that voltage also influence what SOC will be achieved.

[Waveguide]

My cell over temp detection:

I am using these sensors for detecting over temps on cells: https://www.digikey.com/products/en?...s=399-12215-ND

The sensors open at 50 degrees C, and reset at 40C. They are sealed and the screw mounting tab is electrically isolated. I have one sensor attached mechanically to each cell directly to a cell terminal, with the sensors wired in a series-interlock configuration. If one sensor opens, a relay is de-energized, isolating the pack from both charge and discharge.

If an over temp ever exits, I don't want the protective circuit to ever reset automatically, since it could cycle states unattended. Something is terribly wrong that needs to be corrected. In my implementation, I use a wired-latching (not mechanical-latching) relay so the circuit has to be manually re-energized by closing a momentary-action push button switch. It includes a gawd-awful loud alarm. The circuit cannot be reset if any of the sensors are still open (the cells haven't cooled).

My cabin ambient temps are never over 30C, so the sensors can reset.

[SV THIRD DAY]

I think it's been close to 5years since I installed my 400AH Prismatic cells
(4-3.2v 400AH cells). I can report back now that not only is LEAD DEAD...but once you make the change to LiFePO4 batteries it's a complete game changer for full time live aboard cruising. I think that's almost a universal feeling I get when I talk to other early adapters of the technology. My original install was dead bones simple. Cell monitoring with a cell log and then I simply set all of my charging devices to 13.4 initially then over the years bumped it up to 13.6v. Being a full time liveaboard I never risked long periods of 100% SOC or overcharging due to the lower voltage charge set-point. For safety I had a low voltage buzzer...no cut off (full timer aboard remember). Original cost installed for the system: $2400.

The original set-up is still going great, but it's time for an upgrade and HOLY Smokes has the technology matured and come down in Cost. At today's cost the only thing keeping every cruiser from switching to LiFePO4 batteries is the initial upfront cost, because in the long run, LiFePO4 is now simply cheaper than Lead. Folks on this thread probably don’t need to hear that, but I remember all the slings and arrows from the naysayers back in the early days.

I'm about to pull the trigger on the following:
16qty 3.2v 280AH aluminum cased prismatic cells at $82.67ea
So total battery bank capacity will be 1120AH. (usable 10% to 90%, or 80% of capacity = 896AH)
Total Cell cost will be $1322.72
Shipping China to San Diego will cost $512
So my batteries with terminal buss bars included cost will be $1834.72.
I will add a BMS to each of the 4-280AH 12v battery banks at $80ea (with Blue Tooth)
So for the battery with BMS I will be paying landed in San Diego, $2154.72
The cost per Usable Amp Hours is $2154.72/896 = $2.40

Now some easy math, my first 400AH LiFePO4 bank 5yrs ago with NO controls/BMS cost me $7.5/Amp Hour for the usable AH. ($2400/320AH). Fast forward 5yrs and now my NEW Bank today will cost me $2.40/Amp Hour. ($2154.72/896AH).

Now let’s do some easy math of a Lead Acid Comparison. Just because it’s fun for the new folks who still think LiFePO4 batteries are too expansive. Being Generous, to buy usable amp hours of 896, you would need to double that to 1792AH of lead. (yes we all know you really have less than that…but lets do a lead best case). You can buy a 225AH Lifeline AGM GPL-8DL off Amazon for $770. https://www.amazon.com/Marine-Lifeli.../dp/B0029XJ1UQ
So you will need 8 of the lifeline AGM GLP-8DL batteries at $770ea so a total cost of $6,160. Your Cost per usable Amp Hour turns into $6.87!!! That’s just economics, not counting the space, weight, and other benefits of LiFePO4 Batteries.

Ok ok…ok….you are cheap and say you can buy Costco wet lead acids for less and my numbers are skewed for Lifeline AGMs. Ok, lets play that game next. You go to Costco and get your free lunch samples and still using the generous 50% usable rating from your Costco batteries you would need 14 of the $89 batteries to give you the same usable 896AH, maybe you can put them in your Keel for ballast? So that would cost you $1246…plus tax and battery core charges…�� https://www.costco.com/Interstate-27...100476408.html

So looking at the Costco Batteries you are paying $1.39 per usable Amp Hour ($1246/896AH) vs the LiFePO4 of $2.40, but you did get a free lunch and some new ballast for your boat. But that fee lunch doesn’t sound so hot when you will have to replace those 14 costco batteries 4-5 times during the lifespan of the same LiFePO4 battery bank….how much did you save again?

[AndyEss]

Excellent analysis Rich - gracias.

Just stay away from those street fish tacos

[Wood]

Are those 280AH cells manufactured by EVE? I have eight on the way. Including bolts and bus bars $1,018 to my door on the east coast.

What BMS are you using?

[SV THIRD DAY]

Originally Posted by Wood

Are those 280AH cells manufactured by EVE? I have eight on the way. Including bolts and bus bars $1,018 to my door on the east coast.

What BMS are you using?

Bingo....exactly.

After seeing a few friends go this route, the only thing holding this approach back from mass market take over appeal is the shipping cost and nervousness of ordering and sending money to China. But all the LiFePO4 battery cells are made in China, so that's the current Game. If they had a US Distributer they would be selling these like Tacos on Cinco de Mayo! Heck...I even thought of doing that myself but my wife said NO...you already have too much SH!# going on for fun.
For the BMS, I'm going with the 120A version of this:
https://batteryhookup.com/collection...31523195289732

Like many things, I believe in the Sailing/Cruising World, people LOVE to make it sound more difficult than it really is and the techy nerds LOVE to argue the details and finer points and overthink and design it. After all, if it was easy...they wouldn't be the "Smart Guys"...ja ja ja.

[Wood]

EVE has a US presence. I spoke with them. Too cautious to sell direct. I was not able to glean info on the recent quantity of 280AH cells now available through Chinese traders. Tight lipped.

But considering the cost and testing data provided for the individual cells I believed it worth the riisk.

[Oceanride007]

I pulled the trigger on a system called EVG Power Pak, consisting of 3 of 160AH LFP batteries and a Loop type BMS called a BCU-PPAK+4C that provides me with cell failure, Cell LV & Cell HV protection and top active balancing. This selection was based on getting max power density in available space, personally would prefer single 1P4S rather than 3P4S, but no choice.

Really this whole process was rather confusing, rather than delay any longer, went for these LFP Batteries. Purchase locked in before our currency fluctuations and future supply went into doubt. Installed yesterday, I only have 2 MPPT controllers on the charge side, this may be enough.

Today watched the BMV 712 as MPPT bring the voltage up to 13.8 before the Current started tapering, Terminal voltage topped out at 14.1 Volt, cell difference nothing more than .001 Volt (Supplier did say they were balanced) and no active cell balancing occurred.

Supplier did say, connect up and all will be good. Well SFSG. At this time this set up will do. I have no need yet for intended DC2DC charger (but would choose a Enerdrive DC2DC charger, https://enerdrive.com.au/product/epo...rger-40a-plus/ when required and connect existing Alternator to existing LA start Battery.
Yet to decide on inverter and/or charger, maybe Electrodacus SBMS0 Battery Monitor, but no hurry.

[newhaul]

Originally Posted by Oceanride007

I pulled the trigger on a system called EVG Power Pak, consisting of 3 of 160AH LFP batteries and a Loop type BMS called a BCU-PPAK+4C that provides me with cell failure, Cell LV & Cell HV protection and top active balancing. This selection was based on getting max power density in available space, personally would prefer single 1P4S rather than 3P4S, but no choice.

Really this whole process was rather confusing, rather than delay any longer, went for these LFP Batteries. Purchase locked in before our currency fluctuations and future supply went into doubt. Installed yesterday, I only have 2 MPPT controllers on the charge side, this may be enough.

Today watched the BMV 712 as MPPT bring the voltage up to 13.8 before the Current started tapering, Terminal voltage topped out at 14.1 Volt, cell difference nothing more than .001 Volt (Supplier did say they were balanced) and no active cell balancing occurred.

Supplier did say, connect up and all will be good. Well SFSG. At this time this set up will do. I have no need yet for intended DC2DC charger (but would choose a Enerdrive DC2DC charger, https://enerdrive.com.au/product/epo...rger-40a-plus/ when required and connect existing Alternator to existing LA start Battery.
Yet to decide on inverter and/or charger, maybe Electrodacus SBMS0 Battery Monitor, but no hurry.

sounds like a decent setup . Just a couple of questions . What size is your alternator?
Is there a specific reason you are only using a 40 amp b2b ? That only gives you a .083 charge rate .

[ssmoot]

I don't know if this helps anyone, but I was able to pick up 14.4kWh (24V 600Ah) for under $3,500 from BLS Battery.


I've ordered stuff from China before, but I wanted to make sure to find a vendor that took VISA for this purchase in case anything went wrong.


It came very well packed, with plastic corner reinforcement taped onto the outside of the boxes, and a good 2" of foam inside protecting the individually boxed batteries (four per shipped box). Inside the individual boxes was another half inch or so of foam.


The cells are 150Ah and 2.95kg, so about 163Wh/kg and 95kg for the whole setup (bare batteries).


That all seemed like a decent deal for Grade A, aluminum prismatic LiFePO4 cells, in-quantity, with buyer protection, to me.


I don't want this to come off like an advertisement. I'm not affiliated other than being a customer. But the internet isn't exactly crawling with vendor reviews for bare cells so I thought it might be helpful. I'm balancing and capacity testing now, so it could still all go south. I can update if there's interest.


I'm probably just going to connect these to a 200A Daly BMS I have, but if I could do it over I think I'd just add the cheap 8S Active Balancer Amazon is selling (about $40 I think), an appropriate fuse, both of which I'm doing anyway, and an Electrodacus SBMS0 instead. That would be cheaper, and offer more flexibility and features. Lessons learned.


The biggest surprise of this adventure for me was trying to figure out how to make a weatherproof battery box. This is for a travel trailer and the dimensions and installation location I have to work with mean I haven't found a good drop-in solution. Not a deal breaker, but definitely the biggest challenge and poorly planned expense so far. Maybe not an issue for most here.

[carlosproa]

Originally Posted by ssmoot

I don't know if this helps anyone, but I was able to pick up 14.4kWh (24V 600Ah) for under $3,500 from BLS Battery.


I've ordered stuff from China before, but I wanted to make sure to find a vendor that took VISA for this purchase in case anything went wrong.


It came very well packed, with plastic corner reinforcement taped onto the outside of the boxes, and a good 2" of foam inside protecting the individually boxed batteries (four per shipped box). Inside the individual boxes was another half inch or so of foam.


The cells are 150Ah and 2.95kg, so about 163Wh/kg and 95kg for the whole setup (bare batteries).


That all seemed like a decent deal for Grade A, aluminum prismatic LiFePO4 cells, in-quantity, with buyer protection, to me.


I don't want this to come off like an advertisement. I'm not affiliated other than being a customer. But the internet isn't exactly crawling with vendor reviews for bare cells so I thought it might be helpful. I'm balancing and capacity testing now, so it could still all go south. I can update if there's interest.


I'm probably just going to connect these to a 200A Daly BMS I have, but if I could do it over I think I'd just add the cheap 8S Active Balancer Amazon is selling (about $40 I think), an appropriate fuse, both of which I'm doing anyway, and an Electrodacus SBMS0 instead. That would be cheaper, and offer more flexibility and features. Lessons learned.


The biggest surprise of this adventure for me was trying to figure out how to make a weatherproof battery box. This is for a travel trailer and the dimensions and installation location I have to work with mean I haven't found a good drop-in solution. Not a deal breaker, but definitely the biggest challenge and poorly planned expense so far. Maybe not an issue for most here.

Can you share the vendor’s name

[ssmoot]

Originally Posted by carlosproa

Can you share the vendor’s name

I'm not sure the rules about linking, but if an admin doesn't like it I guess they can just remove the comment.


https://blslifepo4battery.com/


I guess the company name is just "BLS". I found it after many google combinations searching for LiFePO4 pricing. I think I also found them on Alibaba, but again, I wanted to use a credit card in case a chargeback became necessary. They seem legitimate in hindsight, but I don't see any reason to just wire a bunch of money when there's other options with better protection.



I forgot to mention, it took about two months to receive the cells. I'm not sure how much (or not) that wait was impacted by the virus.

[Convertible13]

I’m having a problem with my lithium battery system I can’t figure out. I bought a Morgan 321 with lithium batteries as the main battery source and an AGM battery as a back up a couple years ago.
To engage the lithium batteries, I turn the main battery switch to the lithium bank and push a contacter button to engage the contacter which then completes the circuit and powers everything. My problem is now when I hit the contractor button, it momentarily engages then disengages. If I switch to the AGM, the contacter engages and stays engaged. The AGM doesn’t have a contacter button. The contacter automatically engages when I switch the main battery switch to the AGM. Ive replaced the relay and ECPC 404 intelligent AH meter and checked all fuses I could find.
Any idea what else I could check? I appreciate any help with this and I’ll be the first to admit that I don’t know much about the lithium system I inherited when I bought the boat.

[Oceanride007]

To Newhaul. My alternator is a Motorola 55Amp, and burns up belts quickly. The Enerdrive B2B has some pretty nice features but is only available in 2 Models the 30 and 40+ models. The 40+ can do 50Amps if you follow there instructions regarding wiring.

[Oceanride007]

Convertible 13, If the energise button is related to a BMS then it may be locking you out for a reason, cell protection either low or high voltage check all cell voltages, also find some instructions do you have cell balancing, any small wires across top of LFP battery? is your energise button mounted on a black box, whats inside, look for a name, your on a learning curve.