malcolm

At the moment, I believe the ESS works with groups of four Li-ion cells for the purposes of charge monitoring and balancing. In this paper published in September, Texas Instruments seem to be suggesting that larger group sizes are possible.

"Battery fuel gauging applications requiring five- to eight-series cells may not have an obvious solution. While fully functional solutions are anticipated in the future, currently available chipsets tend to address end-products where four-series cells are the maximum. This report presents an inexpensive solution, using the bq20z80 fuel gauge."

http://focus.ti.com/analog/docs/tech...ctName=slua435

Cobos

Why do you want to use bigger series? Less weight overhead for the ESS or? Don't you loose flexibility at the same time so the effect isn't as usefull?

Cobos

malcolm

Until a manufacturer produces a single chip to monitor eight cells, it seems as though any attempt to reduce the hardware cost/complexity in the ESS would have to be matched by an increase in firmware complexity/development cost. TI suggest that this is not a viable business option (are they preparing to roll out new hardware?)

But we've been here before. Some well-established business says "This can't be done" and Tesla promptly tears up the rule book.