Remember, this chart is really just an educated guess. I’ve based these numbers on several different A/C units and batteries I’ve tested in my lab and GeoPro trailer. Most of it is extrapolations based on limited empirical data. But the ideas and trends should be correct. Powering an A/C overnight from batteries and solar panels is not cheap, but it is possible. However, powering it all day from batteries under high ambient temperatures will be challenging.
That’s correct. Most rooftop A/Cs are real power hogs. However, the Truma Aventa Comfort units I’ve been testing draw around 30% less current than my Dometic Penguin 2 test unit. And a Mini-Split DC Inverter A/C can be even more efficient.
Just for curiosity sake. How many amps is your 13.5 AC unit drawing while the compressor is on?
On another note. I have 630A/H@12V of LiPo4. I ran my 15K (super efficient GREE Rooftop) for 9 hours overnight (so no solar recharge) and still had 53% battery left in the AM. My unit draws 100Amps@12v but because it is a 15K unit it runs less than a 13.5
Good question! If I am interpreting Mike’s numbers correctly, he is saying his 13.5k BTU AC unit will discharge a 100Ahr LFP battery in 1.5 hours. This implies the system is consuming 800W from the battery. To back calculate the AC unit’s power consumption or current draw at 120V, we would need to know the inverter efficiency and duty cycle of the AC unit. Mike might want to comment here.
Remember, this chart is really just an educated guess. I’ve based these numbers on several different A/C units and batteries I’ve tested in my lab and GeoPro trailer. Most of it is extrapolations based on limited empirical data. But the ideas and trends should be correct. Powering an A/C overnight from batteries and solar panels is not cheap, but it is possible. However, powering it all day from batteries under high ambient temperatures will be challenging.
So, if I interpret this correctly, 9-hrs at 50% ALSO MEANS that 4.5hrs at 100% in heat of day will leave batteries dead.
That’s correct. Most rooftop A/Cs are real power hogs. However, the Truma Aventa Comfort units I’ve been testing draw around 30% less current than my Dometic Penguin 2 test unit. And a Mini-Split DC Inverter A/C can be even more efficient.
Thank you, this is very helpful.
Just for curiosity sake. How many amps is your 13.5 AC unit drawing while the compressor is on?
On another note. I have 630A/H@12V of LiPo4. I ran my 15K (super efficient GREE Rooftop) for 9 hours overnight (so no solar recharge) and still had 53% battery left in the AM. My unit draws 100Amps@12v but because it is a 15K unit it runs less than a 13.5
Good question! If I am interpreting Mike’s numbers correctly, he is saying his 13.5k BTU AC unit will discharge a 100Ahr LFP battery in 1.5 hours. This implies the system is consuming 800W from the battery. To back calculate the AC unit’s power consumption or current draw at 120V, we would need to know the inverter efficiency and duty cycle of the AC unit. Mike might want to comment here.