Converting Mini Split AC to DC Power w/ 48V Motor: Expert Advice Needed

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Discussion Overview

The discussion revolves around converting a mini split air conditioner from AC to DC power to be compatible with a 48-volt battery bank, which would be recharged by a hybrid solar panel and wind turbine system. Participants explore the feasibility of replacing the AC compressor motor with a 48-volt brushless permanent magnet motor and the implications for the internal circuit board.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant, Magnetic_mike, questions whether the existing circuit board can handle 48 volts or if modifications are necessary, and seeks advice before proceeding with the conversion.
  • Another participant suggests that the feasibility of the conversion depends on the specific air conditioner model and proposes considering the opposite approach of converting 48V DC to 220V AC instead.
  • There is a repeated inquiry about how many batteries would be needed to achieve 220 volts from a battery bank, emphasizing the desire for an off-grid solution.
  • A participant mentions the possibility of using a DC to AC inverter, noting that while 48V input inverters may be rare, there are options for 12V and 24V input inverters that can output 220V AC, and highlights the efficiency of modern inverters.
  • Concerns are raised regarding the wattage requirements of the air conditioner and the sustainability of the battery bank's power supply, suggesting that a significant solar panel array would be necessary for adequate charging.

Areas of Agreement / Disagreement

Participants express differing views on the approach to powering the air conditioner, with some advocating for the conversion to DC and others suggesting the use of an inverter. The discussion remains unresolved regarding the best method to achieve the desired outcome.

Contextual Notes

Participants have not reached consensus on the technical requirements for the circuit board or the optimal configuration for the power system. There are also unresolved questions about the specific wattage needs of the air conditioner and the capacity of the battery bank.

magnetic_mike
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I want to convert a mini split air conditioner from ac to dc so it can be powered by a 48 volt battery bank and rercharged by a solar panel and wind turbine hybrid system.(hybrid charge controller) I want to replace the ac compressor motor to a 48 volt brushless perminent magnet motor of similar rpm torque size etc. My questions are what about the the circuit board inside? Do I have change anything in there or will it work with the 48 volts from the battery bank? Is the 220 or 120 volt normnal current stepped down for the circuit board and it will step down any voltage input or do I need to make alterations there as well? I haven't tried it yet I am waiting for your expert advice. Thanks in advance. Magnetic_mike
 
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Welcome to PF...

...It depends on the air conditioner... But why aren't you trying the opposite: converting the 48VDC to 220V AC?
 
I want to run the air conditioner from a battery bank. Do know how many batteries it takes to get 220 volts? I want a system that is recharged from wind and solar panels. I want the air conditioner to be free from the grid.
 
magnetic_mike said:
I want to run the air conditioner from a battery bank. Do know how many batteries it takes to get 220 volts? I want a system that is recharged from wind and solar panels. I want the air conditioner to be free from the grid.

what Russ is saying to you, is for you to use a DC to AC inverter, now I don't know of any that have 48V input (there my be?), but there are plenty of 12V and 24V DC input ones with 220V AC output and have wattage ratings of up to 2 - 3kW.
Inverters are pretty efficient these days, 95 - 98%, it would definitely be worth investigating

regardless, you are going to have to consider the wattage required by the aircon and how long any sort of batter bank is going to be able to sustain that power drain before it goes flat. Its is going to require a serious solar panel array to handle the charging required

Dave
 

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