Post Go back to editing

Active Cell balancing using LTC3300

Hi All,

We are designing a battery pack with balancing and monitoring circuits for off-grid storage. We decided to go with balancing IC LTC3300. We have few questions

Is there a limitation for no.of parallel cells in a 6s configuration for active balancing IC LTC3300. (our end product will require around 30 parallel cell stacks)

What are the external components that change with number of parallel cells

What is the difference between part numbers LTC3300-1 / LTC3300-2 ?

We used LT SPICE to simulate using the available model for LTC3300-1 however there's no model for companion monitoring IC LTC6803, so we couldn't do a simulation on that. is there anyone who did a simulation on these ic's if so please share your experiance

Thank you in advance

  • We regularly evaluate our battery-balancer evaluation circuits using a 12S25P LiPO4 battery, so you will have no problem with parallel cells.  Balancing current is determined by the selection of external components, in particular the primary and secondary sense resistors as well as the coupled inductor (transformer).  Can you give me an idea of your application and typical charging and discharging rates?  Feel free to contact me directly at william(dot)taylor(at)analog(dot)com if you prefer.

    The difference in the LTC3300-1 and -2 lies in the SPI communication with the device, especially if more than 6 cells are being balanced with more than 1 LTC3300.  The -1 is designed for a daisy-chained architecture in which communication with multiple LTC3300-1 is effected through a SPI bus to the device controlling the balancing converters for the 6 cells at the bottom of the stack.  This bottom LTC3300-1 then passes commands to the next LTC3300-1 (supporting cells 7-12), and so on.  See LTC3300-1 datasheet, p. 42.  Communication with multiple LTC3300-2 is effected over a SPI bus.  In this configuration, each LTC3300-2 is tied to the bus through a digital isolator.  Individual LTC3300-2 devices are assigned addresses using 5 pins on each device.  See LTC3300-2 datasheet, p. 38.

    There are serious problems with the LTC3300 LTSpice model which I am trying to have fixed.  I recommend you do not use it.

    Feel free to direct all your specific questions to me by email if you wish.

  • Thank you for the detailed explanation. I'll contact you if required

  • Hi, we have decided to go with Ltc3300. Since we can not simulate we decide to start with a prototype using LTC3300-1 and LTC6803-1

    Is typical application in datasheet good for a prototype (we hope to use 12s2p for prototype. Can I use those component values in datasheet for 2A peak balancing current.

    We think LTC3300-1 is better for this prototype (12s2p) but still unsure which Ic to use LTC3300-1 or LTC3300-2

    Thanks in advance, 

  • I'm pleased to have read your comment that the Spice model is defective as I was just about to model its use in a 4S3P system.  I chose the LTC3300 since it has a lower component count than the 8584 and also, most importantly since it has proven Demo boards and schematics.  Had there been a good demo board for the 8584 and, say LTC 8611, I would have chosen that pairing.

    Are there any limitations, other than those implied in the Demo board user manual, to implementing a 4S3P solution using a single LTC 3300-2?

    Thank you.

  • Here are some notes on the use of the LTC3300/LTC6811 in a 4S3P system.


    •   Cells in parallel should be connected before charging or balancing the cells.  After these connections are made, the battery stack becomes 4 cells in series from the balancer perspective.


    •   See Figure 47 of the DC2100B demo manual for an illustration of how to use the DC2100B (and LTC3300) with 4 cells.


    •   The DC2100B uses the LTC3300-1.  The difference in the -1 and -2 is the way the devices communicate on the SPI bus.  From a power-processing perspective, the devices behave the same.


    •   Note that the LTC6811 minimum supply voltage for guaranteed total measurement error is 11V (datasheet p. 6).  This may be an issue at the lowest cell voltages, but the part is sufficiently functional below 11V to indicate that a cell is severely discharged.