Lithium NMC batteries - the energy density holy grail ?

[css145hs]

Originally Posted by john61ct

Kill switch for alt just works with Field input not power input

Actually you're right. I had forgotten about that. The electrician opened up the alternator to rewire the internal regulator so that it couldn't take over if the external failed, and to control the field input. Or something...

[nebster]

Originally Posted by css145hs

The individual batteries can also take themselves out, and since there's 3 of them, can totally run on two.

Keep us updated on how you like them, over time.

[css145hs]

I'll have two months of full time experience with them for the atlantic crossing in june/july. I think the only variable is the voltage drop. Everything else you'd have to wait years to hear back on, unless they blow up right away.

[caveman22]

Originally Posted by nebster

Another important difference: these NMC packs have a fan, and so they have an air clearance requirement for ventilation. In some situations, then, their volumetric efficiency will be reduced compared to stuffing in more cells.

If you really are after high density, and you want to eat your cake, too, you can get close to those performance with the right LFP cells today. Of course, then you have a science project where you get to do a ton of stuff yourself. But somewhere in the neighborhood of 200Wh/L and 140Wh/kg appear to be achievable with the right cells.

Ok you have whet my apetite - DIY 200W/kg - can suggestions how this could be achieved !

[nebster]

Originally Posted by caveman22

Ok you have whet my apetite - DIY 200W/kg - can suggestions how this could be achieved !

200W/kg isn't a quantity of interest here, but you did spell "whet" correctly, so points for that.

200Wh/kg in LFP is not achievable, but I think 140Wh/kg is given that there are several LFP bare cells from different manufacturers spec'ed at over 150Wh/kg now. (Then we sandbag some for interconnects.) I haven't personally verified those cells, but now that I see several being made I'm more inclined to believe the data.

200Wh/L is readily achievable in LFP, given bare cells are available close to 325Wh/L. My own cells are about 235Wh/L, before sandbagging for airflow and interconnect.