Build a LiFePO4 battery or buy one already made?

[BeerBrewer]

I know from a cost perspective that it's cheaper to put together your own LiFePO4 battery than buy one ready made, but I'm wonering which is more reliable? Assuming that I purchase Grade a cells and good quality BMS.

I've looked at Battle Born, SOK, LiTime, Lion Energy and others. All of which have some sort warranty, some have 10 year, some 5 year, some less. I haven't read all of the warranty documents, but I have read a few. So far everyone I've read says that they will fix or replace the battery at their descretion. Which means that they get to decide if they want to honor their warranty or not. I guess this makes sense because a perfectly good battery can be ruined if connected wrong or treated improperly. What surprised me however was that none of the warrantees covered shipping costs or any of thee damage done in shipping. So it is possible that you could spend more on shipping than the battery is worth, except possibly with a Battle Born. They are still crazy expensive and frankly not in consideration, even though they come with a 10 year warranty. For instance a 12V LiTime 100AH with low temp protection is now selling for $279.99. I can't imagine with it would cost to ship it back and forth to China for repair, but its got to more than $279.99. So in my opinion, the LiTime warranty is basically worthless.

So how reliable are these batteries? Is a DIY LiFePO4 (using grade A cells and good BMS) more reliable than store bought?

 

[Solarcabin Channel]

How cost effective a DIY battery is depends on your skills and what measure of safety you want.

UL certified batteries have passed safety testing.

The warranty for LFP is really irrelevant as only rarely would a battery not surpass the warranty and last 8-10 years of use at full cycles.

At prices today I don't see any savings in DIY batteries but I also don't build batteries.

 

[Solarcabin Channel]

none of the warrantees covered shipping costs or any of thee damage done in shipping

Most companies have a grace period for shipping damages and you just need to take pics and contact them within that grace period and they will replace it.

I have had many batteries shipped and all were well packed with no damage even with some of our stupid fed ex drivers here. UPS seems to be better at handling the packages.

You are more likely to get damaged cells and products ordering from overseas shippers like Ali Baba and I have gotten damaged products from them a few times. Those shipments are rough handled and may transfer between planes, ships and camels before it gets to you.

 

[SeaGal]

I'd say it depends on the amount of storage you are looking at. For 5kWh it would not be much more cost effective by the time you've added all the bits (BMS, housing, fuses etc). But if you are looking at 15kWh+, then yes, still cost-effective. I have a DIY 280Ah (14.3kWh) system, which worked out about 2/3 of the price of buying 3 x 5kWh racks. That's with buying everything locally, apart from the BMS that came direct from Florida.

And for me having better control over the system is more important, so I'd go DIY even if it cost a bit more ?‍?

As for reliability - time will tell... but apart from the cells themselves (which I have a spare) and the BMS (easily replaceable) then the rest is all my own work which I trust more than any commercial offering.

Solar-wise, I've only ever had to have a Victron component replaced, which was done without question, but it still took 2 weeks to send it back for testing before a new one was sent out - had that been a critical component, it would have been an unacceptable delay. So I prefer to 'self-warranty' and fix things myself wherever possible - but obviously everyone's mileage may vary, depending on skills, tools and how critical the system is.

 

[BeerBrewer]

Most companies have a grace period for shipping damages and you just need to take pics and contact them within that grace period and they will replace it.

I have had many batteries shipped and all were well packed with no damage even with some of our stupid fed ex drivers here. UPS seems to be better at handling the packages.

You are more likely to get damaged cells and products ordering from overseas shippers like Ali Baba and I have gotten damaged products from them a few times. Those shipments are rough handled and may transfer between planes, ships and camels before it gets to you.

I've yet to find any of the warantees mention any grace period about free shipping due to defects. The only grace period I've seen mentioned is for returns. Most give you up to 30 days to return unwanted items, but they almost always include a restocking fee. Typically the warranty includes statements that clearly state shipping there and back isn't free. The statement below is from the SOK warranty.

What does this limited warranty cover?​

This Limited Warranty covers any defects in material or workmanship under normal use during the Warranty Period.

During the Warranty Period, SOK Battery will repair or replace, at no charge(but NOT including the round shipping fee during warranty time), products or parts of a product that proves defective because of improper material or workmanship, under normal use and maintenance.

I'm only looking to build a 12V 400AH-500AH LiFePO4 battery bank for my travel trailer. I can do a DIY or I can buy assembled batteries. I'm wondering which way is more reliable.

 

[SeaGal]

I'm wondering which way is more reliable

Only you can answer that, knowing your skills and budget.

 

[shadowsteve]

I built 2x 280Ah @ 12v packs for my RV in 2021. We only use it heavily for 5 months in the winter (two so far) but it's been running fine since built. It sits beside the house and I can monitor the system from my local network. Currently it shows 50 cycles on the batteries. When I built the batteries I paid 1125$US for 8 cells & 2 BMSs shipped to Ontario Cda. I think BBorn 100's were ~1k$US at the time.

System has the two battery packs, 2x 150A BMS, 3000w inverter, Rover 40A, 840w solar, Pi4 main system, ESP32s on BMSs, Pi3 on touch display, ESP8266s for GPS/gyro & temp/humidity

 

[OTRwSolar]

Do you work on your own car? Do you enjoy maintaining most of the plumbing & electrical at home? If yes, you might be a good candidate for a DIY lifepo4 build.

In my opinion, purchasing from a reliable, proven source (typically US-based) is your best way to minimize major problems. That goes for pre-built or individual DIY purchases. Don't order until you're prepared to build and test thoroughly. On average, you may be good for 30 days of return/tech support, after that be prepared to be on your own. As for warrantees, if they deliver at all, consider that icing on the cake---placing upfront value on a warranty can easily disappoint.

When/if you DIY you may learn, whether you want to or not, everything you did or didn't want to learn about lifepo4 cells and BMS's. It's part of the territory. If this doesn't sound the least bit appealing---recommend a hard-pass on DIY.

Doing it DIY, you're in the best position to deal with issues---you built it, odds are high you can fix it. With pre-built you're at the mercy of the manufacturer or seller.

As for whether pre-built or DIY offers the best value, what's your time and knowledge gained worth to you?

Good luck!

 

[rhino]

Also see https://diysolarforum.com/threads/diy-lifepo4-cost-analysis-almost-february-2023-edition.53813/

 

[Crowz]

I was going to go diy but found a good deal on a 48v 100ah battery and went with it. One thing I plan on doing if a cell fails is taking it apart and diy battery from it using the remaining cells.

Not ideal sure but its how I talked myself into just pulling the trigger on the pre-made one

 

[Brucey]

I know from a cost perspective that it's cheaper to put together your own LiFePO4 battery than buy one ready made, but I'm wonering which is more reliable? Assuming that I purchase Grade a cells and good quality BMS.

I've looked at Battle Born, SOK, LiTime, Lion Energy and others. All of which have some sort warranty, some have 10 year, some 5 year, some less. I haven't read all of the warranty documents, but I have read a few. So far everyone I've read says that they will fix or replace the battery at their descretion. Which means that they get to decide if they want to honor their warranty or not. I guess this makes sense because a perfectly good battery can be ruined if connected wrong or treated improperly. What surprised me however was that none of the warrantees covered shipping costs or any of thee damage done in shipping. So it is possible that you could spend more on shipping than the battery is worth, except possibly with a Battle Born. They are still crazy expensive and frankly not in consideration, even though they come with a 10 year warranty. For instance a 12V LiTime 100AH with low temp protection is now selling for $279.99. I can't imagine with it would cost to ship it back and forth to China for repair, but its got to more than $279.99. So in my opinion, the LiTime warranty is basically worthless.

So how reliable are these batteries? Is a DIY LiFePO4 (using grade A cells and good BMS) more reliable than store bought?

I can't speak for the chins but my Redodo 12v 100Ah minis shipped from a US warehouse and were delivered in 2 days and would be returned to a US address if needed. I'm pretty sure if you have an issue they just ship you a replacement and don't worry about the return due to shipping requirements for lithium etc.

 

[Crowz]

So far I'm loving the 48v chins I bought off amazon. It puts out the claimed power when discharging. Cells seem to balance nicely too looking at the info on the bluetooth app.

The chins 12v I bought has low temp protection (according to the data sheet but who knows ) and has worked well too.

 

[Steve_S]

I build batteries and have been doing so for a while and I feel I better Chime In here.
- It is not that hard to do but it is not a simple slap-it-together deal, unless you want troubles.
There are tools required ! That costs money and a few things that can't be skimped on either such as a good quality Digital Multimeter (at least 2 decimal point accurate) with DC Clamp. Wire cutters, crimpers (Lugs & Terminals) and more... Of course a DC Charging Powersource to top balance etc... This stuff adds up FAST... some of us have the gear because we are into electronics etc but there is always something we don't have.

The Question, if you have the tools & equipment, then DIY is a great option, but if you do not have the tools etc, will that "investment" have more life beyond building the batteries or not ? That can only be answered by YOU !

Cells, Cases, BMS' etc are all easily obtained and there are Known Good Vendors that have been supplying the membership here for quite some time. You can build Larger Capacity batteries than those on offer by most vendors.
! Take 48V Rackmounts, they are mostly 100AH, a few get to 200AH but not beyond that.
A 48V/100AH Pack weighs 47kg (103.6lb) +/- Where a 48V/280AH weighs 135Kg (297lb) +/- a bit. and can't be mounted into a rack for obvious reasons.

 

[Robbert]

I build batteries and have been doing so for a while and I feel I better Chime In here.
- It is not that hard to do but it is not a simple slap-it-together deal, unless you want troubles.
There are tools required ! That costs money and a few things that can't be skimped on either such as a good quality Digital Multimeter (at least 2 decimal point accurate) with DC Clamp. Wire cutters, crimpers (Lugs & Terminals) and more... Of course a DC Charging Powersource to top balance etc... This stuff adds up FAST... some of us have the gear because we are into electronics etc but there is always something we don't have.

The Question, if you have the tools & equipment, then DIY is a great option, but if you do not have the tools etc, will that "investment" have more life beyond building the batteries or not ? That can only be answered by YOU !

Cells, Cases, BMS' etc are all easily obtained and there are Known Good Vendors that have been supplying the membership here for quite some time. You can build Larger Capacity batteries than those on offer by most vendors.
! Take 48V Rackmounts, they are mostly 100AH, a few get to 200AH but not beyond that.
A 48V/100AH Pack weighs 47kg (103.6lb) +/- Where a 48V/280AH weighs 135Kg (297lb) +/- a bit. and can't be mounted into a rack for obvious reasons.

That's 100% correct. If you add everything up, especially the tools, building yourself offers no large financial benefits.
The real benefit is that you know and understand the system and can decide what bms you want etc.

 

[Partimewages]

In my youth I did DIY for everything. If I could by parts and tools it was always DIY. Not so much now that I have all the tools and don't need to build up. But I'm here because I have to know what I'm buying is legit and still need to know how to fix it.

 

[RCinFLA]

Agree it depends on your knowledge level.

The balance you have to judge is your skill/knowledge level versus manufacturer of self-contained battery motivation to do it 'cheap' and how their quality control is.

If you have the knowledge, you can count on 'if you want it done right, do it yourself'.

If you do buy self-contained LFP, I would recommend you get ones with BT monitoring so you can read voltages on individual cells. Most common user issue with self-contained LFP batteries is allowing cells to become unbalanced due to lack of sufficient absorb charge time to allow BMS to balance cells.

 

[Partimewages]

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[BeerBrewer]

I am an engineer with a lot of experience with large 48V and 53V DC power plants. I am normally a DIY type of person. I do my own appliance repairs and I do the maintenance on my own vehicles. I've restored 5 "handy-man special" homes, inluding upgrading thier electrical panels. I also have an extensive collection of tools, meters, etc.. Having said that I would need to buy a variable DC power supply if I decide to put together my own LiFePO4 battery. So I'm sure that I have the skills and tools to build a battery. My quesquestion has more to do with reliability. Unfortunately I don't have any experience with LiFePO4 cells and I don't how reliable they are. So I'd like to hear your opinions on whether ready made 12V batteries more or less reliable than the DIY batteries. I am honestly leaning towards building my own battery, but I don't know how reliable those 3.2V cells are.

 

[Steve_S]

We have several Known Good Vendors who will deliver quality cells with factory test reports. A great deal of us have built our own batteries without issues mostly. One has to account for the people who should not touch tools, sad but those happen. LFP is very reliable and the safest of the Lithium battery family.

Important tips.
1) Build your batteries to the "Native Voltage" of your inverter system, do not bodge together 12V in series to make 48V, build a 48V battery directly.
2) A DIY battery pack can be disassembled & reconfigured if needed.
3) You CAN Add battery packs in parallel over time WITHOUT ISSUES ! FLA Battery rules do not apply.
4) LFP Cannot be charged below 0C/32F but can discharge safely to -20C/-4F *BMS' with warmer functions are avail, if required.

LFP is easy to work with and setup, there is no rocket science involved.
Links to help you to some of my resources... Will likely answer many questions.
General LiFePO4 (LFP) Voltage to SOC charts/tables 12/24/48V
Luyuan Tech Basic Lifepo4 Guide V1.0A

 

[SeaGal]

I am honestly leaning towards building my own battery, but I don't know how reliable those 3.2V cells are.

As @Steve_S said, LFP cells are very reliable. But with regard to your last question, you would be using the same type of 3.2V LFP cells whether you built your own or purchased ready-made.