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BQ24650: Power from mains/wall adapter

Part Number: BQ24650

Hi

Our company have already designed equipment with solar charger for a 12V SLA battery using the BQ24650 and 18V solar panel.

We have set the MPPT to 17.2V, and set the charge current to 1A using a 0.04ohm resistor between SRP and SRN.

One of our customer didn't want to use the solar panel, because he's got mains/wall power next to the equipment.

So my question is if we supply a 2A 18V or 24V DC power supply, the MPPT shouldn't be able to pull the voltage down to 17.2V right? 

And also when battery is full, MPPT wouldn't try to get more current than the battery needs correct?

Cheers

Harry

  • Hello Harry,

    The BQ24650 operates from either a solar panel or wall adapter. The MPP circuit only clamps the input voltage 17.2V if the charger's input voltage droops down due , for example, to too much series resistance. If the power source is a solar panel, that resistance is the panel's internal impedance. If the power source is an adapter, that resistance could be the cable or a damaged adapter, assuming the input source is sized correctly for the desired charge current setting. A 2-A rated 18-V or 24-V adapter should easily be able to provide 12V and 1A to a lead acid battery.