12V 280Ah LiFePo4 battery Build and Test

Haugen

Tron God
I have a background as a Test Engineer and I am building my first battery from cells.
I have some pretty good equipment and I wanted to share with the group what kind of information I manage to acquire as I apply my trade to this new endeavor
With an eye towards the science of this emerging area of power storage, I hope to aid others in making some of the more difficult decisions associated with setting up LiFePo4 batteries.
I look forward to discussions with you to make the most of this topic
 

Dzl

Perpetual Newbie & Unofficial Forum Librarian
Staff member
Moderator
Sounds like this will be quite a valuable contribution to our shared and growing knowledge, looking forward to seeing how this develops (y)
 

mckennab

IV Watts
Wow 280Ah - is this even a thing? I was impressed with 150Ah, so for $1600ish I could get close to 7kW battery bank? That's crazy. Hope it works out.
 

Dzl

Perpetual Newbie & Unofficial Forum Librarian
Staff member
Moderator
Wow 280Ah - is this even a thing? I was impressed with 150Ah, so for $1600ish I could get close to 7kW battery bank? That's crazy. Hope it works out.

Most popular cells on the site right now are the 280Ah EVE cells sold by Dongguan Lightning and Xuba.
See here and here (xuba) and here (dongguan lightning)

But, if you want to see some really crazy big cells check out Winston's high capacity cells, most notably this big boy, 10,000Ah, weighing in at 335 kg / 738 lb:

2020-lyp10000aha1.jpg
 
Last edited:

Haugen

Tron God
I ordered the cells from Shenzen UNIS. The pandemic made the delivery time 52 days.
They arrived in good condition. The only physical damage was one label on top of a cell was peeled up on one end. It might have happened when sliding the cell into the box and the edge caught the foam.
They want me to test first before sending a replacement label.
Cell voltages as received:
1 - 3.2970
2 - 3.2992
3 - 3.2997
4 - 3.2995
20200612_172527.jpg20200612_164234.jpg
 

Dzl

Perpetual Newbie & Unofficial Forum Librarian
Staff member
Moderator
I wonder what the hell 10,000Ah cells are used for, that's 40,000 Ah for a 12V pack (sometimes 3000 lbs. Half a million Watt-hours, or half a megawatt-hour! Correction: I'm a dummy, you are correct. 10,000A, 120,000Wh, 3000lb
 
Last edited:

nebster

battery dude
I wonder what the hell 10,000Ah cells are used for, that's 40,000 Ah for a 12V pack (sometimes 3000 lbs. Half a million Watt-hours, or half a megawatt-hour! Correction: I'm a dummy, you are correct. 10,000A, 120,000Wh, 3000lb

They use them in submarines.
 
  • Like
Reactions: Dzl

Haugen

Tron God
They use them in submarines.
Who knows, as we move to this more distributed power network where small solar is powering more than the needs of the owner, there is probably a business plan for storing energy for keeping the grid supplied in the event of outages. Maybe an HOA putting their neighborhood on a giant UPS.
 
  • Like
Reactions: Dzl

Haugen

Tron God
Power Supply arrived today!
I took some time to check it out a little and it seems to be fairly good for the cheap price.(<$100). It will put 10A into a cell. That will be important. Unfortunately we won't get to hit substantial C rates unless I get creative.
I set up cell #1 to charge it to 3.62V, but the supply loads down to 3.43V. We will have to wait and see if it will recover as the current settles out. The voltage reading on the front is off by 100mV. You can see my Fluke shows 3.43 at the terminals and the supply is at 3.51. There is about 10 milliohms of resistance in the leads causing the other 100mV of difference that is being read at the battery. I'll build bigger cables for the real testing. I just happened to have some 14 AWG wire and crimps handy to try a first check of the supply's capabilities.
 

Attachments

  • 20200616_210648.jpg
    20200616_210648.jpg
    59.4 KB · Views: 106
  • Like
Reactions: Dzl

Haugen

Tron God
It took a few days with only 10A charge capacity to get the cells to full charge for a top balance.
I'm now in a holding pattern waiting for the BMS to arrive.
In the meantime, I have ordered some copper and aluminum bar stock to make some improved bus bars. I bought both because I'm still debating in my head and researching which is the lesser of the two evils. Lower conductivity of the aluminum, or the galvanic reaction between copper and aluminum.

The interesting thing is that the bolts that came with the cells are brass to throw in another galvanic element. I'm leaning towards heavier aluminum bus bars as long as I can find 6mm aluminum screws to hold it all together.
 

Ampster

Renewable Energy Hobbyist
I'm leaning towards heavier aluminum bus bars as long as I can find 6mm aluminum screws to hold it all together.
I am using stainless steel studs because everything I read said the threads tended to strip out with multiple uses.
 

Colonel.lp

Solar Enthusiast
Just to chip in, generally aluminium/stainless is a really bad combo for galvanic corrosion, as it seems also with brass or copper. How that equates to humidity around battery terminals I have no idea, I'd be tempted to use silicone grease on contact areas, but when I take the plunge with the Eve cells I'm going to be looking here to see what you decide. 😁
 

Haugen

Tron God
Whatever I use, I will definitely put connector lubricant on it to reduce the available oxygen to cause corrosion.
I read the contents of Noalox and I'm not a fan because it has zinc suspended in it.
I have a can of SuperCorrA that does an amazing job of protecting connectors.
 
Top