Multi-Chemistry DC-DC Battery Charger

Buck Boost DC-DC battery charger. 4.5-55V input, up to 60V output. Support for Li-Ion, Lead Acid and CC/CV multi-stage algorithms.

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- Wide Voltage Range: 4.5V to 55V Input, Up to 55V Output (60V Absolute Maximums)
- Synchronous Buck-Boost DC/DC Controller
- Li-Ion and Lead-Acid Charge Algorithms
- ±0.5% Float Voltage Accuracy
- ±5% Charge Current Accuracy
- Instant-On for Heavily Discharged Batteries
- Ideal Diode Controller Provides Low Loss Power Path When Input Power is Limited
- Input Voltage Regulation for High Impedance Input Supplies and Solar Panel Peak Power Operation
- Onboard Timer for Protection and Termination
- Bad Battery Detection with Auto-Reset
- NTC Input for Temperature Qualified Charging

I've made the board fairly generic so a single layout can be used in multiple situations. By default it's setup for a 6 cell, 12V lead acid battery but can easily be modified for Li-Ion, 24V, 48V etc by varying component values. Check the datasheet for more information.

Intended use is for DC-DC battery charging of an auxiliary battery from a vehicle alternator. I would also like to see how it performs with a solar panel but there is no MPPT tracking at this stage.

The component footprints are a bit of a mixed bag because I am using what I already have in stock. I've used PLCC LEDs for example because I still have hundreds left over on a reel I originally purchased in the 1990s!


Bill of Materials

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Component Placement

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Schematic Diagram

Adobe Portable Document Format - 298.49 kB - 08/15/2020 at 03:45


  • System Integration

    Steven Merrifield09/28/2020 at 01:54 0 comments

    I'm pretty happy with the way the DC-DC board is working and also how the UVLO board functions. Now it's time to put it all together to form a complete battery management system. Waiting on some voltmeter/ammeter modules to arrive.

    Block diagram as follows:

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