Easy Start By Micro Air

3 tons wrote:
From my own perspective (of one who occasionally runs their air conditioner from the inverter), a few observations, but for background, my equipment:

400a/h LFP (formerly, 2 GC wet-cell), 2k watt PSW pass-thru Inverter, 660w solar, Coleman 11kbtu air conditioner w/soft-start, Honda 2200 (formerly, Honda 2000) - system incrementally ($$) upgraded over the years…

***************

Several Observations:

First off (retrospectively…), compared to wet-cells, voltage sag with LFP’s is uber brief and relatively insignificant in such that (in my view…) this sole characteristic ‘may’ even negate the need for a soft-start - However, this is not an ‘anti-soft-start’ argument, of which I believe is superior to a conventional start cap…FWIW these clever proprietary ‘black boxes’ have even replaced capacitors on modern 120v single-phase, home HVAC blower motors, which ‘electronically synthesize’ a far more efficient three phase current during motor start-ups accompanied with variable start-up frequency, negating the need for the old school capacitors previously used to help keep start-up current and voltage in phase…

So I’m somewhat impressed to know that your 2000w inverter (pass-thru or PSW type - I donno??) will run a 13.5kbtu air conditioner (i.e. via characteristically voltage sluggish wet-cells…) interesting - Kudos to the Easy-start!…

So for raw estimation purposes only:

Considering all loads, your fully charged 340a/h capacity wet-cells have an effective useable capacity of only about half that (170a/h), although supplemented with 500w of solar…

However, when using wet-cells, a lower limit of say 60% SOC (State of Charge) seems more practical due to the effects of voltage sag on the compressor motor (ugg!) and what’s now become a struggling inverter…Rising ambient temps will also play a roll increasing motor amperage as well…

A rough thumbnail sketch:

So assuming an air conditioner duty cycle of say 2/3rds, concurrent with say 2/3rds productive solar harvest, and a 40% battery DOD (Depth of Discharge) equaling say 136 usable battery a/hrs:

120a/hr (dc) air cond @ 2/3rds duty cycle = approx 80a/hrs (dc)

18a (dc) concurrent hourly harvest = 62a/hrs hourly run deficit = about 2hrs runtime (compressor cycling) to 124a/hrs consumed, with 12a/hrs in reserve before 60% SOC - 46a/hrs in reserve before 50% SOC…).

Here again, due to their much deeper depth of discharge and nearly stable voltage, LFP’s have a clear advantage via longer run times…

*************

Some Notes:

Initial camper cooldown period (depending on volume) may require a full duty cycle.

This example does not consider ‘other hour’ solar harvest.

Onboard Converter-charger (etc) disabled.

JMO Only,

3 tons