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I need to charge a 12V LiFePO4 battery and to get full benefit from my 50W solar panel I need a bit over 4A charge current capabilities.

I've looked through MPPT charge controller ICs and there's the LT3652 which has a reasonably simple circuit design that I think I can handle. It seems to be used a bunch in the maker space. But it only supports 2A charge current.

The next step up in class of charger IC has vastly more complicated looking circuit design that would be a stretch for my current abilities. I looked at some of the EVB designs and the high component count, 6 layer boards with complex routing and stringent layout requirements are a bit much.

It's not a practical option to run two LT3652's in parallel from a single panel to a single battery, right? They would fight both in terms of tracking maximal power point as well as mess up each other's charge control?

Are there any approaches (that still involve designing my own PCB) that can make this more accessible to an intermediate (beginner?) skill level?

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  • \$\begingroup\$ You can parallel devices as per Chester's answer. The devices don't "fight" because the MPP is the same for both (all) devices because the solar panel is common to both ICs. There is only one MPP for a given operating point. You would have a "fighting" scenario with 2 separate panels because the 2 panels likely won't have the same MPP at the same time. \$\endgroup\$
    – MOSFET
    Commented Mar 15 at 9:17

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The Analog Devices Battery Charger’s Unique Input Regulation Loop Simplifies Solar Panel Maximum Power Point Tracking article contains:

Need More Charge Current? Use More LT3652s

Multiple LT3652 chargers can be used in parallel to produce a charger that exceeds the charge current capability of a single LT3652. In the application shown in Figure 8, three 2A LT3652 charger networks are connected in parallel to yield a 6A 3-cell Li-ion charger with a float voltage of 12.3V that uses C/10 termination. This charger is solar power compatible, having an input regulation threshold of 20V. This charger also implements an input blocking FET to increase charging efficiencies.

enter image description here

Figure 8. A 6A 3-cell Li-ion battery charger using three LT3652 charger ICs.

Based upon the above article, it appears a practical option to run two LT3652's in parallel.

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