Life En Route

Solar/ HVAC

We have a fairly large and complex solar/ HVAC solution for off-grid use.

Our solar consists of 2925W of residential panels, 22.8kWh of 48V LiFePO4 batteries, two 48V 3kVA inverters configured for split phase 240V, an autotransformer for balancing 120V loads across the inverters, another autotransformer for stepping up single phase input sources to split phase, and several other components. The end result is that we have constant 120V/240V power supplied to the entire rig, that is only turned off if a fault or maintenance occurs. We have a built-in Onan 5500W generator for backup use.

The HVAC consists of a LG 30K condenser and two 15K indoor units. Since they are roughly three times as efficient as the original AC units, and provide more usable cooling power, these were a huge improvement for us. We’re able to run air conditioning throughout most hot days, and the electric heat pump on cool days, without having to plug in or run the generator. The condenser unit is mounted in a custom enclosure that is welded to the frame of the trailer.

We originally started with just 1950W of panels and 11.4kWh battery, but in order to accommodate running the mini-splits around the clock, we had to remove the rooftop AC units and add panels in their place. Additionally, we had to upgrade our battery bank because our observational math suggested that we would need twice the capacity. So far in practice, we’re waking up to around 45% SoC each morning when we’re run the air conditioning 24/7 on 95F days in Arizona and Utah, so it appears that we made the right choice on doubling the batteries.

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