I'm looking into getting four malectric, open source car battery powered spot welders.
More info on them here: https://malectrics.eu/product-category/arduino-spot-welder/
They have an "auto pulse" mode where they automatically fire a set time after an electrical connection is sensed. I need...
I have it from Okashira that they weigh 60 to 52 pounds, with the newer ones being lighter, this means only 14% of the mass of a new module is non-battery, pretty good.
Thank you Okashira!
The mass of a whole pack was obtained by Car and Driver in 2013 but the pack includes a shield on the bottom and plays double duty as a structural element in the car. A better measure of the energy density Tesla has achieved would be module level mass.
I know at least a couple users here have...
That sounds like a giant pain :evil:
If you didn't catch it from the first post (don't want to be an a@@ but most people haven't heard of this stuff) silver epoxy is itself very conductive, easily conductive enough for a123 cells at 25C discharge (and don't get the cheaper stuff! It has ~10x...
You could try high end silver epoxy too: http://www.amazon.com/MG-Chemicals-Conductive-Extreme-Conductivity/dp/B018AAT4VC/ref=sr_1_7?s=industrial&ie=UTF8&qid=1453580131&sr=1-7&keywords=silver+epoxy
Just make sure you keep the bond line thickness low, keep it under pressure for half a minute...
That GBS system will work fine I think, but I'm not sufficiently familiar with the cycle life and safety specs on it to give a good comparison with the LFP options.
Gravimetric energy density almost identical to a123 26650s, price higher in quantity, less safe...
But that cycle life and fast charge capability sure look interesting, and perhaps these cells are not less safe, one can hope...
There are a number of LFP automotive battery replacement packs that are essentially 12V LFP packs.
These guys have a solid BMS though the 100ah is $1300... I doubt you'll get cheaper: http://www.lithiumion-batteries.com
I second A123, you can get them here: http://www.a123batteries.com
As to whether they can be balanced, yes of course they can; but you're either going to have to pay for a module with built in BMS, add the BMS yourself, or do manual balancing.