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BQ24650 for 24V battery

Other Parts Discussed in Thread: BQ24650

Hi,


I have to charge a 24V lead acid battery stack but for that, the output voltage has to reach 29V (which is above the limit for the BQ24650) .

The input voltage is also high. Two solar panel in series with Vmmpt = 17.2V (25C) each. The reason of combining these in series is that I have to use the same battery stack (24V) as for a wind turbine, which has better power output capabilities at that voltage. Furthermore, the BQ24650 is a buck converter so I need an input voltage higher than those 29V.

Is there a way to achieve higher voltages? (Both at the input and output by adding an external circuit, ICs, etc).

Also, I don't understand the "Solar Cell Half Panel" label on VIN.  http://www.ti.com/general/docs/datasheetdiagram.tsp?genericPartNumber=BQ24650&diagramId=SLUSA75


Thank you!

  • It sounds like your system is too high of voltage for what the IC is designed for.  It is possible for a very experienced power suppy engineer to design a circuit that takes the higher voltages and translates them down to the common mode range of the IC, but this is a complicated task to get it to work in normal operation.  It is even more complicated to get it to work through all sorts of transients.  Sorry we can't support this design effort.

    Please check with the solar manufacturer to understand their specification