A123 LiFePO4 Cells - the iron man’s battery

Pulled it out to remind myself to find a torx bit set

T8 SECURITY BIT

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get yourself a good set. bad bits can ruin your day.

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get a Wera set :+1:

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Just arrived :hugs:

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How many amps do you think can be safely pushed through the already welded nickel plates? Can I just wire 3x of the 4s1p cell strips in series for a 12s1p pack?

I doubt so. Hard to tell from the pictures how thick they are. You can calculate their current capacity from here: Conductor Current Ratings [SRO]
Rough rule of thumb for continuous:

  • safe: 5A/mm2
  • Hot: 10A/mm2

When you open it up, please do us a favor and measure the thickness and width of the nickel, and overall dimensions of the 12s4p block in the cellholders (without case and bms).

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Got it, thanks. Happy to document more after I tear it down.

If I cut off the plating around the cell, can I spot weld a thicker strip of nickel on top of the remnant nickel strips?

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If you want to do it by the book: No.
If you trust your judgement: Test it.

Edit: Either way, make sure you use at least 25x0.2mm nickel (Nkon has) and make sure the spotwelder is strong enough to punch through that and the extra layer into the cell. or just solder copper braid on top.

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You should make a thread about this. I bet a lot of folks will want to make this.

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it’s the exact same as a DPS5005, just higher input/output voltage

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Which PSU are you using?

I dont have one currently that goes high enough and both my boosters are dead :yum:

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You should make a thread about it :slight_smile:

lol I don’t think it needs its own thread, there are several dps charger related ones already, there’s no significant difference and frankly I found an even better option since then

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fwiw my favorites so far are

buck boost 50v 5a. buck boost means you can power it with just about anything. Make an adapter and hook it up to your tool battery pack or whatever lipo or old meepo pack.

This one feels like a really nice piece of equipment! Can get a $25 70v 400w psu, throw it in the enclosure, awesome. Has numeric input, graphing, a wattmeter ammeter and a funky battery charger mode. Really like it.

I haven’t tried the high power stuff we’re talking about (Juntek). Yet.

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Anyone know if the A123 battery hookup deal was a once off?

I saw the deal was still on last week but haven’t looked since then

Looks like they’re sold out now :expressionless:

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They have the deal available almost constantly, unless out of stock. Give it a couple weeks and you should be good

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I got over 2000$ worth! If anyone is interested in trying this pcb with 36 of them welded on for a flexible battery I’ll sell it for 200$.
All cells show over 95% of capacity. 12s3p. 7.5 amp hours

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What’s the dimensions on that? Also have we confirmed if these are actually good for 50A discharge per cell?

I suspect that the form factor is not fit for my application but would be interested to know :slight_smile:

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