Managing air conditioning amp draws in hot climates is challenging.
I've invested in A/C average draws of 35 amps. (28 low - 58 high)
Many of the locations I will travel will be at 90 degrees. With a insulated box with 55mm of composite walls this helps.
After dark is the issue since the temperature does not drop to 65 degrees until 3 am.
From 6pm to 3am the A/C unit will run off the battery bank. It is expected that the batteries may not support that timespan.
The 12v refrigerator cannot be in a situation with a battery bank with no power. My habitat is equipped with a custom fuse box just for the refrigerator. I could wire a circuit with a two way switch than enables me to plug in a portable power source for hot nights only.
Another solution is to plug in a 4000w propane generator from 7pm to 10pm into the shore power plug. This would charge batteries during that short timespan.
I asked chatGPT
Answer
To calculate how much battery capacity you could increase using a 4000W propane generator for three hours, we need to consider several factors, including the generator's output, the charger efficiency, and the battery's capacity.
Steps:
- Generator Output: A 4000W generator running for 3 hours provides:
4000 W×3 hours=12,000 Wh(or12kWh)4000 \, \text{W} \times 3 \, \text{hours} = 12,000 \, \text{Wh} (or 12 kWh)4000W×3hours=12,000Wh(or12kWh)
This is the total energy output the generator could provide.
- Battery Charger Efficiency: Assuming you're using a battery charger with an efficiency of around 85% (typical for many chargers):
12,000 Wh×0.85=10,200 Wh12,000 \, \text{Wh} \times 0.85 = 10,200 \, \text{Wh}12,000Wh×0.85=10,200Wh
This is the usable energy that can be sent to your batteries.
- Battery Voltage: Your battery bank is 12V, and the energy stored in batteries can be calculated in amp-hours. To convert watt-hours to amp-hours:
10,200 Wh÷12 V=850 Ah10,200 \, \text{Wh} \div 12 \, \text{V} = 850 \, \text{Ah}10,200Wh÷12V=850Ah
This means in an ideal case, you could theoretically charge 850 amp-hours over 3 hours. However, this doesn't account for charging losses or diminishing charge rates as the battery fills up.
- Charging Curves: Batteries charge faster when they're more discharged, and slower as they near full capacity. If your 600 Ah battery bank was deeply discharged, you could realistically expect a significant portion of this 850 Ah, though not the full amount due to charging tapering off. A rough estimate might be about 60-70% of that number during the initial fast charging phase.
Estimate:
If your battery bank is significantly discharged, you could expect to increase the charge by approximately
510 to 595 Ah during this 3-hour period with the generator.
This assumes optimal conditions and that your charging system can handle the full output of the generator.