Albert,
Not sure, but I think the Zamp works connected to a single 12V battery bank (even if made up of several 12v batteries in parallel) - a BMS (or EMS as sometimes referred to) is necessary to balance the individual cells. The Zamp does not balance the LiFEPO4 cells, it just provides a chargin profile suitable for LiFEPO4 batteries. On some other forums, people have been connecting it to banks made up of 12V LiFePO4 units, each with integral BMS. Other than Technomadia, who made their 12v units up from individual 3.2 v cells, most have been buying 12V units from places like Stark.
I took a look at Stark Power and Smart Battery, and I'm not sure if they have a real system to balance cells either... Based on the pictures available on their websites it looks more like overvoltage/undervoltage/termal protection? Looks like they are building their batteries using many small cells, so if their battery comprises a few dozen of small cells (some connected in series, other connected in parallel), how much would the cost of complicated system to individually balance and maintain them?
I'm curious if these Chinese cells from EVTV are also build from many small cells connected in parallel?
On a side note, cheap Chinese LifePO4 18500 can be found for a couple of bucks a piece, if anyone can design and manufacture a controller which can monitor/balance/maintain/charge a few dozen of 18500 cells, it might be an interesting DYI project to build a LifePO4 battery out of them. Additional benefit would be very low cost of maintenance and repair. If controller has ability to automatically identify a bad/degraded cell, just swap it out with a brand new spare 18500! Can easily be done in the field.
-albertr
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