12v Charged from 24V

[Dustin Smith]

I need to do one of two things,either
1. Charge a 12V AMG battery set from my 24V LifePo4 set.
or
2. Use something like a buck converter to supply my 12V loads.

The benefit I see of #1, is that my battery bank is expanded.
The benefit I see of #2, is that it's easier to do.

Recommendations? If I do #1, can I set it up as follows, 24V battery to 3A buck converter (what I have on hand), to a 7A charge controller to my 12V battery set? Would the buck converter be a problem being a lower amperage? I don't see the need to match to the charge controller, because there is no actual "load", is that correct?

I await your recommendations and insights to my problem. Thanks

 

[Harald Kapp]

I don't see the need to match to the charge controller, because there is no actual "load", is that correct?

The battery is the load. The charge controller will try to charge the battery with 7A, thereby overloading the buck converter.
What is the input voltage to the charger? Surely more than 12 V to account for the increase in battery voltage during charging. You'll have to set up the buck converter accordingly ( a beefier one to deliver > 7 A).

Best option is to use a charger that works on 24 V input voltage and does all the necessary conversions internally.

 

[Dustin Smith]

The input voltage to the 12V charge controller can be as high as 28.5V, as set up on my charge controller to the 24V system. I believe the 7A charge controller can handle up to 20V, so I need to drop it down a bit. I think I may just buy a beefier buck converter in this case, because another charge controller would set me back more money. I will check, if the price is within a few dollars, I will buy a different charge controller. Thanks for your reply.