Convert an AC air conditioner to a 12v dc?

[DanielVictor]

Is this possible? Is there any type of machine that you can use to convert it? Like plug ? the air conditioner into a machine and then on the other end it now uses dc power? Haha it has to exist

 

[Supervstech]

Is this possible? Is there any type of machine that you can use to convert it? Like plug ? the air conditioner into a machine and then on the other end it now uses dc power? Haha it has to exist

You mean, like an inverter?

 

[Dzl]

Is this possible? Is there any type of machine that you can use to convert it? Like plug ? the air conditioner into a machine and then on the other end it now uses dc power? Haha it has to exist

Lets start by defining what you are trying to accomplish. What you are describing is an inverter but I have a feeling that's not what you are looking for.

 

[DanielVictor]

Lets start by defining what you are trying to accomplish. What you are describing is an inverter but I have a feeling that's not what you are looking for.

Im not looking for an inverter. I want to run an air conditioner off of DC power so it doesn’t use up all my battery power. So I was looking for a way to convert my air conditioner from ac power to 12vdc power and then connect it to my solar battery bank (bus bar). An inverter takes my solar power and turns it into use for my AC power appliances that’s not what I’m looking for. Turns out I’m just going to order a 12v dc air conditioner from china

 

[nosys70]

"off of DC power so it doesn’t use up all my battery power "
but where the DC power will comes from ?
if it comes from the battery ("So I was looking for a way to convert my air conditioner from ac power to 12vdc power and then connect it to my solar battery bank") it will use your battery power.
if your battery is connected/recharged by solar and the solar is powerfull enough to fullfill the AC, the battery should not discharge, at least when sun is shining.
i do not see the reasoning behind.
running form AC or from DC, you will use the same power...and it must come from somewhere.
what you can do , is to use a low power AC (inverter model) to minimize the footprint on your system.
Looks like your system is undersized for AC.

 

[DanielVictor]

"off of DC power so it doesn’t use up all my battery power "
but where the DC power will comes from ?
if it comes from the battery ("So I was looking for a way to convert my air conditioner from ac power to 12vdc power and then connect it to my solar battery bank") it will use your battery power.
if your battery is connected/recharged by solar and the solar is powerfull enough to fullfill the AC, the battery should not discharge, at least when sun is shining.
i do not see the reasoning behind.
running form AC or from DC, you will use the same power...and it must come from somewhere.
what you can do , is to use a low power AC (inverter model) to minimize the footprint on your system.
Looks like your system is undersized for AC.

In theory doesn’t converting an ac appliance to a dc greatly lower it’s power consumption? If we use the formula to find watts multiplying by 12v makes a huge difference than multiplying by 110v. I actually have a 300ah lithium (lifepo4) battery bank. However I am installing radiant heated floors, air conditioning, 12v fridge, water heater, the works. I’m in the planning phase and am just doing my homework. I might add another battery but I need to find out if having that many batteries in parallel affect system performance. Any thoughts on the system performance with so many batteries in parallel?

 

[DanielVictor]

You mean, like an inverter?

Would you mind reading this thread and giving me your thoughts on my battery bank?

 

[nosys70]

"In theory doesn’t converting an ac appliance to a dc greatly lower it’s power consumption? "
no , we still live in an universe where energy conservation is a rule.
converting will just make you loose some additional energy, conversion is never 100% efficient.
just make the caclulation in WATTS, so all is levelled to same units.
Watts=amps x voltage. so if you AC need 1000W, it could be 110V x 9A or 12V x 83A

do not forget that power is usually spreaded over time, so a 1000Wh battery is ok to run a 1000Wh device, but only for 1 hours.
if you need to run an 1000Wh AC for 10 hours, you need 10.000W battery that is under 12V, 830Ah.
usually device have 2 rates on the sticker.
The hourly consumption and the instant power.
an 1000w AC running only 20min per hour, will be rated 300Wh, but once it start, it needs 1000W for the 20 min it runs.
in reality , lots of devices are rated as if they are running continuously since nobody can tell how long you will use it. (that is the case for an AC)
for a fridge, it could be different, since a fridge in normal condition, will operate in a know cycle.
so the Watt hours is used to plan capacity of battery, while the instant Watt power is planned to plan inverter, wiring.

 

[Supervstech]

Would you mind reading this thread and giving me your thoughts on my battery bank?

I’m sorry, I do not see any battery bank information in his thread? Did you forget to put in a link?

 

[nosys70]

"I actually have a 300ah lithium (lifepo4) battery bank. However I am installing radiant heated floors, air conditioning, 12v fridge, water heater, the works "
a 12V 300Ah is about 3000Wh. so you got 3000watts for 1 hours or 300Watts for 10 hours.
but for solar sizing , you need first to consider this battery as a load (since you need to charge it)
Solar is usually available only 5 hours, so your calculation will be 3000W spreaded over 5 hours that is 600Wh.
That is the minimum solar power you need to capture to charge your battery.
since you will probably also use the solar power to fullfill load as much as possible, you need to calculate your load and add those 600Wh.
so let's continue with this AC at 300Wh. for five hours, you got solar panel to produce 300+600=900Wh, so you charge the battery and you run the AC.
when sun goes down, you will to rely only on battery , so the 300Wh for the AC.
with 300Wh for AC on a 3000Wh battery , you can run 3000/300 = 10 hours.
if you need to run it longer, you need more battery and then more solar panels.
if you need to run other loads at the same time, you need at least more solar panels and probably more battery.
in each case, you will need also to increase wire thickness, and inverter power.
since the list of what you want to run seems pretty heavy, i think you can multiply your installation at least by a factor 2.
going 24V would be the easy way.
Also , select devices that are running with "inverters" (now you can find AC and fridge advertised with inverter vs the good old compressor run directly on 110V)

 

[DanielVictor]

I’m sorry, I do not see any battery bank information in his thread? Did you forget to put in a link?

Sorry about not describing it in more detail:

"In theory doesn’t converting an ac appliance to a dc greatly lower it’s power consumption? "
no , we still live in an universe where energy conservation is a rule.
converting will just make you loose some additional energy, conversion is never 100% efficient.
just make the caclulation in WATTS, so all is levelled to same units.
Watts=amps x voltage. so if you AC need 1000W, it could be 110V x 9A or 12V x 83A

do not forget that power is usually spreaded over time, so a 1000Wh battery is ok to run a 1000Wh device, but only for 1 hours.
if you need to run an 1000Wh AC for 10 hours, you need 10.000W battery that is under 12V, 830Ah.
usually device have 2 rates on the sticker.
The hourly consumption and the instant power.
an 1000w AC running only 20min per hour, will be rated 300Wh, but once it start, it needs 1000W for the 20 min it runs.
in reality , lots of devices are rated as if they are running continuously since nobody can tell how long you will use it. (that is the case for an AC)
for a fridge, it could be different, since a fridge in normal condition, will operate in a know cycle.
so the Watt hours is used to plan capacity of battery, while the instant Watt power is planned to plan inverter, wiring.

Thank you!

 

[Supervstech]

In theory doesn’t converting an ac appliance to a dc greatly lower it’s power consumption? If we use the formula to find watts multiplying by 12v makes a huge difference than multiplying by 110v. I actually have a 300ah lithium (lifepo4) battery bank. However I am installing radiant heated floors, air conditioning, 12v fridge, water heater, the works. I’m in the planning phase and am just doing my homework. I might add another battery but I need to find out if having that many batteries in parallel affect system performance. Any thoughts on the system performance with so many batteries in parallel?

Electric radiant heating will consume HUGE amounts of power in very little time.
Water heat electrical will as well...
If this is in a mobile RV, you cannot build enough solar panels on your vehicle to supply the watts needed to operate these two devices.
Get the total wattage of the flooring, and figure 8h operation time... so, multiply x8, and you have JUST the Wh needed for the floor...

 

[Nidhal]

There's a process I have seen here (with a radio) but I myself didn't try it with an air conditioner.
In principle any appliance that consumes AC current does 2 things with it: Transform it to 12V AC(usually), then redress it to DC using a diode bridge (or a Graetz bridge)
You can verify this using a multimeter and measuring the output of the diode bridge. You can then remove the transformer and the redresser and hook your DC input directly.

 

[DanielVictor]

"I actually have a 300ah lithium (lifepo4) battery bank. However I am installing radiant heated floors, air conditioning, 12v fridge, water heater, the works "
a 12V 300Ah is about 3000Wh. so you got 3000watts for 1 hours or 300Watts for 10 hours.
but for solar sizing , you need first to consider this battery as a load (since you need to charge it)
Solar is usually available only 5 hours, so your calculation will be 3000W spreaded over 5 hours that is 600Wh.
That is the minimum solar power you need to capture to charge your battery.
since you will probably also use the solar power to fullfill load as much as possible, you need to calculate your load and add those 600Wh.
so let's continue with this AC at 300Wh. for five hours, you got solar panel to produce 300+600=900Wh, so you charge the battery and you run the AC.
when sun goes down, you will to rely only on battery , so the 300Wh for the AC.
with 300Wh for AC on a 3000Wh battery , you can run 3000/300 = 10 hours.
if you need to run it longer, you need more battery and then more solar panels.
if you need to run other loads at the same time, you need at least more solar panels and probably more battery.
in each case, you will need also to increase wire thickness, and inverter power.
since the list of what you want to run seems pretty heavy, i think you can multiply your installation at least by a factor 2.
going 24V would be the easy way.
Also , select devices that are running with "inverters" (now you can find AC and fridge advertised with inverter vs the good old compressor run directly on 110V)

I hear you, thanks for sharing your insight! I live in Los Angeles so sunlight is amazing, prob have 1000 watts of solar, alternator charging, shore power capability and a back up gas generator if I ever need it. Adding up all the watt usage I should be ok. Radiant floors in such a small space is only 338 watts. So if ran for a few hours. I should be alright. I think ?

 

[John Frum]

There's a process I have seen here (with a radio) but I myself didn't try it with an air conditioner.
In principle any appliance that consumes AC current does 2 things with it: Transform it to 12V AC(usually), then redress it to DC using a diode bridge (or a Graetz bridge)
You can verify this using a multimeter and measuring the output of the diode bridge. You can then remove the transformer and the redresser and hook your DC input directly.

This is not the case for any air conditioner I have seen.

Slightly tangentially...
My 9000btu casement AC uses a pretty about 750 watts when the compressor is running and I would wild a** guess ~3x750 to get the compressor moving probably more if the compressor is hot.
Hmm now I am thinking about this tweak for the upcoming season.
BTW the guy in the video is a font of knowledge, especially on wind power.

 

[Supervstech]

Most electric floor heating systems use 12 watts per hour per square foot, meaning a 100-square-foot room would use 1200 watts in total every hour, or 300 watts LESS than the average space heater.
So, figure that x 8 and you have 9600Wh JUST for the radiant... /5 sun hours, you will need

 

[Supervstech]

There's a process I have seen here (with a radio) but I myself didn't try it with an air conditioner.
In principle any appliance that consumes AC current does 2 things with it: Transform it to 12V AC(usually), then redress it to DC using a diode bridge (or a Graetz bridge)
You can verify this using a multimeter and measuring the output of the diode bridge. You can then remove the transformer and the redresser and hook your DC input directly.

Unfortunately, no... an average AC unit uses a permanent split capacitor wound AC electric motor to compress the refrigerant gas, and another PSC AC electric motor to push air through the condenser and evaporator for heat transfer.

no conversion to dc is occurring unless you have an inverter driven variable system like a mini split would have... then, yes, dc is created from the AC, but it does this at approximately 300V...

 

[nosys70]

old school Ac or fridge are just running binary on or off when the temp is reached.
So usually the motor is sized to be able to provide the necessary kick at start.
this makes the compressor a bit oversized.
with inverter, you can modulate the power continuously and use smaller motor and variable speed.
the benefit is a lower power requirement

 

[DanielVictor]

Most electric floor heating systems use 12 watts per hour per square foot, meaning a 100-square-foot room would use 1200 watts in total every hour, or 300 watts LESS than the average space heater.
So, figure that x 8 and you have 9600Wh JUST for the radiant... /5 sun hours, you will need

Im only looking to heat a space of 20 - 30 square feet. Since I wouldn’t put the radiant heat under the cabinetry this is totally possible using limited power

 

[John Frum]

Perhaps this is what OP needs .