Thread: Lifepo4 Cell's

Just picked up these 4x lifepo4 cell's from the same guy i bought my solar panel from, he is saying they are Weld Tech brand nothing is coming up for the QR code scan, they have no studs or threads so was skeptical of buying them but $25 per cell i took the gamble

The cells are slightly off voltage from each other so i will need to charge them seperatly using my hobby charger before building the pack

Looking to install them into a waterproof electrical box the gray type

If they have metal cases, regardless of whether they are coated with plastic or paint make sure you insulate between the individual cells/cases as often the case is at the negative potential and a short to the next cell isn't pretty.
There have been plenty of problems with metal encased cells shorting.

You may be able to drill and tap them. Like many of them are. The cells with studs have them laser welded on. An option if you know someone with one....
Also, legally these cells are now meant to be housed in gasketed metal housings with a vent to the outside of the building or campervan/caravan they are kept in.
Take note of PJames' comment about the call cases!
Did you find and try the QR decoder and the fake warning/instructions from Gobel Power? https://www.gobelpower.com/lifepo4_decoder.html

Thank's fellas i have just seperated the cell's, i ran a search thank's for the link, they are coming up as 2012 build date 12 year's old yikes!! Should i keep them?

To order a daly bms, a spot welder (im not confident drilling lithium battery) a roll of nickle stipping, and a hard case from SCA will set me back another $120-$130, batteries cost $100

Did'nt realise it was going to be so expensive but all i can afford was a $250 battery from ebay and after watching video's last night on youtube i really could'nt afford to be stuck with a pouch cell battery which have no vents on a boat

Most of the under $300 100amp hour battery's are running pouch cells

Think i may be in a bit of crap,

cell 1: April 2013
cell 2: June 2012
cell 3: June 2012
cell 4, July 2018

Seller is saying it's not possible for the cells to be 2012 models, anyway i took a gamble and drilled the terminal's some are 3.5mm some are 4mm i don't feel comfortable drilling any further plan is to use a bottom tap and some type of conductive lock tight

I read on google the ideal max drill depth is 6.5mm and u need 5mm depth minimum to tighten M6 bolts

Got them all drilled to 5.5mm used my vernier caliper depth gauge to measure the holes, was a lot of stopping and measuring as not to over drill and destroy the whole 4 pack's so took my time, all 4 cells 8 terminal's have been taped using a M6 bottom tap hard to source!!! We must have a shortage my local nut and bolt shop had completely sold out of all metal types of M6 taps, went to Total Tools none on the shelf but the lady looked up stairs they had 1 in stock

The negative terminal is copper i found it really hard to tap the tap kept binding like a bolt galling but a little bit of pressure and the thread cleaned out, i ran the tap twice to clear each thread

The positive terminal is aluminium peice of cake to tap

Bargain price. Worth a shot for sure I reckon. So they haven't been used at all if they came with tapped holes?

100ah?

Originally Posted by disco stu

Bargain price. Worth a shot for sure I reckon. So they haven't been used at all if they came with tapped holes?

100ah?

It appeared to be a bargain at $25 a cell but the build cost add up, cheap knock off Daly BMS IS $50 or geunine $150, than a storage container, insulation for the cells, foam packing, copper tabs, bolts nuts, a needed tap and drill bits

Cost just keep's adding up, these are used cells they have previously been welded u can see in my pic's the left over bits of sand like on the terminals

The guy i bought them from work's in a small section of a huge factory the factory sells all new products but the guy is a one man business that tried to fix returned products if he can't fix them he parts them out and sells what's salvagable

Like these cells he would have had a few batteries in with a bad cell or bad BMS so he strips the battery and salvages the cells

I plan on doing something like these pictures they are from Super Cheap Autos reviews of a hard case with a amp meter and anderson connectors with lithium batteries inside, really neat design i like it

Originally Posted by gazza2009au

Got them all drilled to 5.5mm used my vernier calliper depth gauge to measure the holes, was a lot of stopping and measuring as not to over drill and destroy the whole 4 pack's so took my time, all 4 cells 8 terminal's have been taped using a M6 bottom tap hard to source!!! We must have a shortage my local nut and bolt shop had completely sold out of all metal types of M6 taps, went to Total Tools none on the shelf but the lady looked up stairs they had 1 in stock

The negative terminal is copper i found it really hard to tap the tap kept binding like a bolt galling but a little bit of pressure and the thread cleaned out, i ran the tap twice to clear each thread

The positive terminal is aluminium piece of cake to tap

Hi Gazza,
The technique that I use to ensure that I only drill to a specific depth, is to use a piece of tube over the drill ! This means that you cannot drill any deeper than the tube. This is particularly useful when using a pistol drill.

Are you looking at the parts in Australia? I thought decent BMS was much less than that on AliExpress

If you can buy (from Ali Express) or borrow a cell capacity meter, you could fully charge and discharge each cell to see what their actual remaining capacity is. Or you could do it the simple way - if you have a known good adjustable charger: Charge each cell to 3.645V, then set your charger to constant voltage and monitor the current draw of the cell until it fall off noticeably. Then discharge each cell with a resistor - measuring the current and the cell voltage - back down to 2.5V. That will give you the capacity too.
There's a good chance the cells will still have 80% or more of their original capacity. They age very well if not discharged to below 2.5V EVER and not fully cycled too often. Even fully cycled they should last for 3 or 4000 full cycles (some say double that for half or thereabouts cycles). If that was a full cycle EVERY single day, it would be around 10 years. 1/2 cycles 20 years. Fully cycled twice a week makes that 40 years.
That's unlikely to happen, because they also have a calendar lifespan of around 25 years - unused.
In any case, you are likely to have a bargain. Look after them.

Didnt mean to ask for pictures lol fat fingers, just bought a small hard case and 1 cell fits perfect im hopping with some thin insulation between the cells all 4 will fit plus the bms which i will be on a budget so ordering from online

I've made up about half a dozen lithium batteries using Winston cells, I just made plywood boxes to suit. The oldest pack of 400ah is now approaching 13 years old and back when I built it a suitable BMS was unobtanium so I just use a 4 cell RC car monitor to keep an eye on individual cell and pack voltages, combined with a programmable solar controller and constant use it has never been overdischarged or overcharged.
I would try to keep the cells upright with the terminals at the top as it will make it much easier to connect them and also maintain the terminals. You should use conductive grease between any connecting straps and cables to prevent any poor connections.

Originally Posted by PJames

I've made up about half a dozen lithium batteries using Winston cells, I just made plywood boxes to suit. The oldest pack of 400ah is now approaching 13 years old and back when I built it a suitable BMS was unobtanium so I just use a 4 cell RC car monitor to keep an eye on individual cell and pack voltages, combined with a programmable solar controller and constant use it has never been overdischarged or overcharged.
I would try to keep the cells upright with the terminals at the top as it will make it much easier to connect them and also maintain the terminals. You should use conductive grease between any connecting straps and cables to prevent any poor connections.

What material did you use for your plates? I am thinking 20x2mm copper but im seeing everything on ebay is coated nickasil? Or something like that