Project Lithium NiMH to LiFePO4 conversion for Toyotas

[S Keith]

Originally Posted by Isaac Zachary

Ya, some of those points I already knew. I also learned some too, so thanks!

From what I can tell the guy is quite the amateur who exaggerates a lot in an attempt to convince everyone. It does seem like he might be hiding something and trying to cover it over with exaggerations. Or he's just exaggerating to try to convince everyone.

But in the end, I don't see any real advantage of his product unless it had more capacity. If the lithium battery has less of an internal resistance it may soak up and let out more of it's capacity than the NiMH. But he doesn't explain how he knows that for sure.

I don't have hard data, but I've done extensive testing on both LFP and NiMH. The LFP voltage curve is flatter for a very large portion of its capacity. From a pure performance standpoint:

EV range will be farther.
Peak power can be sustained for longer periods.
Likely mpg improvement in driving scenarios where hybrids offer advantage.

However, ALL of the above will come at the cost of reduced battery life. Until I see cycle life vs. DoD curves, they're just blowing smoke.

I am NOT anti-LFP. I have about 10kWh of it in loose CALB cells. Pretty amazing chemistry, but I'm aware of some hurdles that need to be overcome by managing kW input and output limits based at least on voltage, and they've stated they don't modify the ECU. They're counting on a "feature" of LFP that will be exploited routinely and likely result in premature loss of cycle life.

I'm anti marketing-bull****-passed-off-as-training-or-technical data and DIY hacks trying to come off as experts.

If they spoofed the HB computer with block voltages that allowed accurate representation of the needed SoC to kW management scheme appropriate for LFP, they could compromise the performance benefits and settle on a design that performs a bit better and likely lasts longer.

I'm tempted to buy a C pack to test the **** out of the modules.

[rmay635703]

Originally Posted by Isaac Zachary

Ya, some of those points I already knew. I also learned some too, so thanks!

From what I can tell the guy is quite the amateur who exaggerates a lot in an attempt to convince everyone. It does seem like he might be hiding something and trying to cover it over with exaggerations. Or he's just exaggerating to try to convince everyone.

But in the end, I don't see any real advantage of his product unless it had more capacity. If the lithium battery has less of an internal resistance it may soak up and let out more of it's capacity than the NiMH. But he doesn't explain how he knows that for sure.

His product could be sold for 1/3 his current retail

If he would use that advantage...

But he likely wants to make the most out of limited demand

[S Keith]

Originally Posted by rmay635703

His product could be sold for 1/3 his current retail

If he would use that advantage...

But he likely wants to make the most out of limited demand

Commodity LFP is about $120/kWh.

His pack is 1.5kWh.

He's priced at about $1300/kWh for the Prius pack.

Granted, there's some engineering in there, and evidence of a rudimentary BMS, but mark-up seems a little high.

In addition to limited demand, once this is subjected to the abuse of the unwashed masses, it will likely emerge as no better than the garbage "D" cell kits you can get from China.

[Isaac Zachary]

Originally Posted by S Keith

Commodity LFP is about $120/kWh.

Wow! Where could I find some at that price! Is this the price for cells with such a high C rate. 120amps at 6ah is 20C.
Of course if I could get some 40ah cells at 3C rate, that would be even better.

Originally Posted by S Keith

His pack is 1.5kWh.

He's priced at about $1300/kWh for the Prius pack.

Granted, there's some engineering in there, and evidence of a rudimentary BMS, but mark-up seems a little high.

In addition to limited demand, once this is subjected to the abuse of the unwashed masses, it will likely emerge as no better than the garbage "D" cell kits you can get from China.

Ya, it's hard to beat tried and true OEM batteries, which can cost similar if not cheaper than this.

[S Keith]

Originally Posted by Isaac Zachary

Wow! Where could I find some at that price! Is this the price for cells with such a high C rate. 120amps at 6ah is 20C.
Of course if I could get some 40ah cells at 3C rate, that would be even better.

Ya, it's hard to beat tried and true OEM batteries, which can cost similar if not cheaper than this.

"commodity" is more commonly used for power storage, not EV or high drain - typically 1C with capacity in the 280Ah/cell range.

Late last year I bought 9 Eve cells from a supplier in China delivered for about $122/kWh.