Hi and thanks for taking the time to read my post.
I'm trying to calculate my power and battery needs. If anyone can check my math and formulas or offer advice on where I go now to decide on batteries I would appreciate it.
I would like to power/charge the below items for up to 3 hours continuously and I would like to the system to run in 12V so that I can use a 12v to 110v inverter.
1. Laptop (from wall outlet charger)- AC input: 100-240V ~2.5A
DC Output: 19v 4.74A
2. Iphone (from wall outlet charger)- AC input: 100-240v ~0.15A
DC Output: 5v 1A
3. Ipad (from wall outlet charger)- AC input: 100-240v ~0.15A
DC Output: 5.2v 2.4A
I would like to power this item 24h a day
1. Arduino (from Arduino specifications) - the Arduino takes 9v DC @ 2.1A
I'm pretty sure i've calculated the power requirements correctly (below) but I wanted to be sure. Before I get to this I want to include that i'm thinking to plug these into an inverter that will draw off the batteries so that I have a 110v AC outlet and a USB port. I was looking at this one in the 15Amp version for my needs (i'm open to suggestions for a different one). here
I feel like there is a lot of power loss converting from DC (the batteries) to AC (through the inverter) and back to DC (through the respective components adapter) but i'm not sure of a better way to insure I can power as universal a set of components as possible.
I'm not certain how i'm going to wire the Arduino in at this point so lets put that aside I guess.
AC to DC calculations: I found the formulas on this site to be
1A AC = 10A DC. to find DC Amps necessary for the system.
A DC X 12V = DC Watts
So here are the numbers I got for DC Watts
Laptop - 2.5A AC X10 = 25A DC. 25A DC x12V = 300 DC W
Iphone - 0.15A AC X10 = 1.5A DC. 1.5A DC x12V = 18 DC W
Ipad - 0.15A AC X10 = 1.5A DC. 1.5A DC x12V = 18 DC W
I'm pretty sure these are the numbers I need to start with but correct me if I'm wrong.
Okay, so now I add the total DC Watts together to get the maximum load I would draw per hour.
300 DC W + 18 DC W + 18 DC W = 336 W / H
So if I want to run these for 3 hours maximum with all 3 devices plugged in that would be
336W/H * 3 = 1080 W total
lets add 10% for the loss from the inverter and that's 1188 W total
Here is where I get a bit stuck and I'm looking for advice.
How many amps should my inverter be to handle the devices I laid out.
How many and what type of batteries would I need? I was looking to go with a couple 6v Golf Cart batteries in series mostly because of the size of the area I need to put the batteries in. How many Amps out should I look for in batteries given the inverter I specified and the draws of the devices.
If i'm missing anything just let me know or if there are any considerations I should make when choosing power please feel free to advise.
Thank you one and all for taking the time to look at this.
I'm trying to calculate my power and battery needs. If anyone can check my math and formulas or offer advice on where I go now to decide on batteries I would appreciate it.
I would like to power/charge the below items for up to 3 hours continuously and I would like to the system to run in 12V so that I can use a 12v to 110v inverter.
1. Laptop (from wall outlet charger)- AC input: 100-240V ~2.5A
DC Output: 19v 4.74A
2. Iphone (from wall outlet charger)- AC input: 100-240v ~0.15A
DC Output: 5v 1A
3. Ipad (from wall outlet charger)- AC input: 100-240v ~0.15A
DC Output: 5.2v 2.4A
I would like to power this item 24h a day
1. Arduino (from Arduino specifications) - the Arduino takes 9v DC @ 2.1A
I'm pretty sure i've calculated the power requirements correctly (below) but I wanted to be sure. Before I get to this I want to include that i'm thinking to plug these into an inverter that will draw off the batteries so that I have a 110v AC outlet and a USB port. I was looking at this one in the 15Amp version for my needs (i'm open to suggestions for a different one). here
I feel like there is a lot of power loss converting from DC (the batteries) to AC (through the inverter) and back to DC (through the respective components adapter) but i'm not sure of a better way to insure I can power as universal a set of components as possible.
I'm not certain how i'm going to wire the Arduino in at this point so lets put that aside I guess.
AC to DC calculations: I found the formulas on this site to be
1A AC = 10A DC. to find DC Amps necessary for the system.
A DC X 12V = DC Watts
So here are the numbers I got for DC Watts
Laptop - 2.5A AC X10 = 25A DC. 25A DC x12V = 300 DC W
Iphone - 0.15A AC X10 = 1.5A DC. 1.5A DC x12V = 18 DC W
Ipad - 0.15A AC X10 = 1.5A DC. 1.5A DC x12V = 18 DC W
I'm pretty sure these are the numbers I need to start with but correct me if I'm wrong.
Okay, so now I add the total DC Watts together to get the maximum load I would draw per hour.
300 DC W + 18 DC W + 18 DC W = 336 W / H
So if I want to run these for 3 hours maximum with all 3 devices plugged in that would be
336W/H * 3 = 1080 W total
lets add 10% for the loss from the inverter and that's 1188 W total
Here is where I get a bit stuck and I'm looking for advice.
How many amps should my inverter be to handle the devices I laid out.
How many and what type of batteries would I need? I was looking to go with a couple 6v Golf Cart batteries in series mostly because of the size of the area I need to put the batteries in. How many Amps out should I look for in batteries given the inverter I specified and the draws of the devices.
If i'm missing anything just let me know or if there are any considerations I should make when choosing power please feel free to advise.
Thank you one and all for taking the time to look at this.
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