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PC PSU + boost converter = LifePO4 battery charger?

Mof

New Member
Joined
Jul 7, 2021
Messages
32
Hello,

Apologies if this is posted in the wrong forum.

I opened up an old unused PC PSU and connected the 12V output (measures 12.19V) to a boost converter. 12V specs on PSU is 15A max. I set the output voltage (before adding a load) to 14.4V and and max out current on the boost converter to 10A. I screwed the boost converter on the inside cover of the PSU with the aim of using the PSU fan to cool it. I use it to charge my homemade 4-cell 50AH battery.

Any issues with what I've done?

Link below to boost converter:
 
The only concern I have is you have no means of terminating the output. Leaving the battery charger connected holding the battery @ 14.4V for extended periods is not good for it requiring you to terminate it once current has dropped to < 2.5A.

Power supplies don't generally work well as battery chargers as they may not like the battery voltage "pushing" back at them if they don't have diode protection in the output circuit, so you'll need to check that.

IMHO, for safety considerations, I would drop output voltage to 13.8V. This might add 1-2 hours to your charge to get to 98%+ full, but you could essentially leave it at that voltage for several hours and not have any concern about cell damage.
 
Thx. I could also figure out a shutoff with a voltage or current sensing relay. If I go down that road, I feel like I am reinventing the wheel and clearly the project purpose has changed to sport. And that's okay!
 
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