diy solar

diy solar

Is there any reason not to do this in a car: DC-AC-DC over DC-DC?

Joined
Dec 10, 2020
Messages
95
I just wanted to confirm I'm not missing anything.
Assuming you have a LiFePO4 battery and an AC charger, is there any reason not to hook up an inverter and connect the AC charger to it, rather than having a dedicated DC-DC charger?
The only two things I can see are the following:
  1. Convenience. Having a DC-DC means that you don't need to chop and change and can just keep it in place at all times.
  2. Efficiency. Obviously, DC-AC-DC is not the most efficient way of doing things.
Am I missing something? I just want to make sure I don't have a blindspot somewhere.
 
I just wanted to confirm I'm not missing anything.
Assuming you have a LiFePO4 battery and an AC charger, is there any reason not to hook up an inverter and connect the AC charger to it, rather than having a dedicated DC-DC charger?
The only two things I can see are the following:
  1. Convenience. Having a DC-DC means that you don't need to chop and change and can just keep it in place at all times.

Yep.

  1. Efficiency. Obviously, DC-AC-DC is not the most efficient way of doing things.

Yep... only about 75% efficient.

Am I missing something? I just want to make sure I don't have a blindspot somewhere.

Just making sure you're not powering the inverter with the battery you're trying to charge... :p
 
Yes, it will work, but as you suspect, it is less efficient.

And there is a slight positive. You now have the AC power available if you need it. Depending on how you set it up, it should work just fine, but really look at the wattage and the losses. This is one odd case where a cheap modified sine inverter could do the job just fine. Most battery chargers will just have a rectifier to a storage capacitor. And then a switching power supply from there to charge the battery. Don't try that with an old transformer battery charger though. Transformers get hot on modified sine inverters. You could do better than 75% efficient, but don't expect to hit 85%. I get almost 88% round trip efficiency with my charger, then inverter storage system, but that is a really efficient inverter.
 
Back
Top