Skibane
San Antonio, TX
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Microlite Mike wrote:I have the Easy Start installed on my 13,500 btu A/C and power it with a Champion 2500 w Inverter generator. Does fine and will even start A/C when on 'Eco". Don't know what size engine in my 2500W Champion Inverter but I do know it's enough to run my A/C. Perhaps not for a 15,000 btu model though.
The amount of current demanded by an A/C varies quite a bit with ambient temperature - For example, Coleman lists their Mach 3+ as drawing 12.8 amps when in cooling mode, but also lists a 15.4 amp draw for "desert" conditions.
That's a 20% difference.
And, you also have to take into account the generator's reduced power output with altitude (approx. 3% per 1000 feet), less-than-perfect state of engine tune, fuel quality variability (i.e., amount of ethanol in the local gasoline)...
So, you have situations where a marginal generator starts and runs the A/C in moderate conditions, but not in extremes.
* This post was
edited 07/20/22 10:11pm by Skibane *
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fj12ryder
Platte City, MO
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theoldwizard1 wrote:fj12ryder wrote:theoldwizard1 wrote:The Micro-Air EasyStart works differently than most "hard start" add-on, which is why it actually works ! Just curious what the difference is between the Micro-Air EasyStart and the SoftStart by SoftStartRV.
I am NOT intimately familiar with EITHER design, but the most common "hard start" add-on are basically just a large(er) start capacitor.
The short (lots of hand waving) electrical engineering explanation is as follows. Electric motors make their most torque (mechanical power) are zero RPM, so it makes sense that this is where they draw the most current (electrical power). A start capacitor gives them an extra "shot" to get them started (they likely would not start at all without the start capacitor)
The problem is, a fully discharged capacitor "looks like" a dead short until it charges up (less than a second). That split second is enough to trip the breaker. The solution is to limit how fast the capacitor charges up (limit the amount of current it can draw). Once the capacitor is "full" it discharges starting the motor. This all happens within 1-2 seconds so you don't even notice it.
DIY soft starter Thanks.
Howard and Peggy
"Don't Panic"
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Itinerant1
Itinerant
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1L243 wrote:bob_nestor wrote:From other postings I've seen where people have tested running their A/C off batteries and they are reporting that you can get about 1 hr of run time for each 200aH of battery.
I wonder how long it will be before RV manufacturers start offering an option of placing Lithium-Ion (or sodium) batteries in the generator bay, installing an inverter at least 2800W, wiring all the 110v outlets and appliances in the RV thru the inverter, and putting Soft Starts in the A/C. And with Lithium or sodium batteries, installing the second high-output alternator in the chassis in addition to as much solar as then can fit on the roof.
While recently researching for my next RV I found one that I liked which I thought could be built this way quite easily to match my camping style. (I'm not looking to run the A/C on batteries other then when I'm traveling, hence the second alternator. Plus future battery technology may improve well beyond where it is now.) I figured I could replace the generator with about 1200aH of Lithium batteries (pricey, but doable). When I contacted the manufacturer with my requested changes, they flatly refused - said the generator couldn't be eliminated and they'd never wire the A/C and microwave thru the inverter. Reluctantly crossed them off my list and moved to other manufacturers.
If you want to be able to boondock all year round and run at least one AC you will need that large battery bank 1200ah in lithium would cost you a bundle. Throw in 1500 watts of solar on the roof and some nice Victron electronics and you into a 25k+ solar system not counting labor. Now if I had a little piece of land somewhere where I could park when not traveling maybe the price would be worth it.
I'll respectfully disagree. 500ah & 1,280w solar, I boondock fulltime with over 1,000 days in a consecutive stretch. I don't scimp on power, live like I'm pluged into the grid. ![[emoticon]](https://forums.goodsamclub.com/sharedcontent/cfb/images/wink.gif "wink")
12v 500ah, 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 2,500+ partial cycles.
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ReneeG
Meridian, Idaho
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What about a 15k btu ac, Easy Start and Honda eu2000i? Or do we need the 2200?
2011 Bighorn 3055RL
2011 F350 DRW 6.7L 4x4 Diesel Lariat and Hensley TrailerSaver BD3
1992 Jeep ZJ and 1978 Coleman Concord Pop-Up for remote camping
Dave & Renee plus (Champ, Molly, Paris, Missy, and Maggie in spirit), Mica and Mabel, both Rat Terriers!
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3 tons
NV.
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ReneeG wrote:What about a 15k btu ac, Easy Start and Honda eu2000i? Or do we need the 2200?
Honda 2200 is rated at 18.3a (short term), and 15a continuous, so you’d need to check out your air conditioner amp spec’s to be sure, and have your onboard converter-charger disabled (at the breaker)… ‘Eco mode’ might be somewhat questionable, though maybe possible with a soft-start…Concurrent solar can take care of charging duties while the converter is disabled…
As previously mentioned, elevation and higher ambient temps will derate any generator’s output, so maybe a few actual users will chime in! JMO
3 tons
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ReneeG
Meridian, Idaho
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3 tons wrote:ReneeG wrote:What about a 15k btu ac, Easy Start and Honda eu2000i? Or do we need the 2200?
Honda 2200 is rated at 18.3a (short term), and 15a continuous, so you’d need to check out your air conditioner amp spec’s to be sure, and have your onboard converter-charger disabled (at the breaker)… ‘Eco mode’ might be somewhat questionable, though maybe possible with a soft-start…Concurrent solar can take care of charging duties while the converter is disabled…
As previously mentioned, elevation and higher ambient temps will derate any generator’s output, so maybe a few actual users will chime in! JMO
3 tons
Thank you. We have an inverter and solar system, but we don't intend to use it for AC, yet this adds another thought.
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MNRon
Tennessee
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Running AC off of 12v means LOTS of amps (100+ —>200 depending on other minimal loads). It *can* be done, but LA voltage droop will be significant, Lithiums less so. Regardless, 100s of amps isn’t great for lots of things, not the least of which is inverter circuitry. Few minutes for microwave, or hair dryer, etc isn’t a concern IMHO but I wouldn’t recommend it constantly for AC in high heat. Some do successfully; but my recommendation would be to set up a 24v system, or better yet 48v, if you want to run AC off of batteries a lot.
I have 540AHr lithium and a 3kW whole-house boost inverter, not saying I’ve never run AC off of my batteries but I have a 4500 Westinghouse generator that I use if I want to run AC. Even that only put out ~20A+ when we were camping at 9300ft a few weeks ago.
Back to OP original issue, I also have MicroAire’s on both 15kW ACs. Doesn’t change current draw while running, but eliminates the inrush current and loud bang when they start up, significantly reduces the voltage droop from batteries OR generator which are not as close to ideal sources as shore 120v.
Ron & Pat
2022 F350 Lariat CCSB SRW Diesel
2019 VanLeigh Vilano 320 GK
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3 tons
NV.
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While at Donner Lake today…
I decided to do some raw meter testing, AFTER an initial camper cooldown from 84d/f to 77d/f…Start of 1300 test, outside temp was at 90d/f, and end of test 1500 outside temp was at 88d/f…(FWIW, I took a nap in between these hours…).
Equipment:
Two 200a/hrs LFP (actual load tested at 215a/hr per).
2000w ProSine PSW, pass-thru inverter-charger.
Victron SOC meter with bluetooth.
660w solar (serial add-ons…).
System is 12v, 0004 cables 6’ roundtrip…
Coleman Mach 1 P.S. 11kbtu air conditioner (w/Easy-Start)
Single full wall slide-out, 10’ Eagle Cap Truck Camper.
Duty cycle (after initial cooldown period) was approx 5 min ON, 5 min OFF (fan continuous run on low). Readings were via Victron BMV-12 SOC meter:
1300 (compressor ON, fan low)….Note, upon edit, to clarify (say upon test start) the -57amp figure (below) represents the difference between the amount being harvested vs air conditioner consumption, which is why the negative value referred to as the deficit…
*************
Starting SOC: 85.5% (approx 340a/hr of remaining capacity at start).
Amps (e.g. deficit after harvest amount): -57amps (dc)
LFP Voltage: 13.05v
**********
1500 (compressor ON, fan low)
Duty cycle had now increased to approx 8.5 min ON, 6.5 min OFF (fan continuous).
SOC: 72% (approx. 288a/hrs remaining capacity).
Amps (e.g. deficit after harvest amount): -54.5amps (dc)
LFP Voltage: 12.97
***********
Using a separate hall effect meter at the inverter’s 120v output (compressor ON, fan low):
Amps (ac): 8.5
Pf: 0.97
Hz: 60
Watts: 972
Voltage: 116
************
BTW, between compressor ON-OFF cycling, I used the Keurig one time at about 125 amps (dc), for an additional 2 a/hrs of battery consumption - Brewing completed before next compressor run call!!
************
FWIW (since writing the above summary - compressor ON, fan low), here’s two more unplanned readings at 1600, and 1700…Temps are now starting to drop off a bit….I’m expecting temps to be pleasant again starting at around 1800-1830 as sun angle drops off…(Cools off rather nicely here in the evenings ![[emoticon]](https://forums.goodsamclub.com/sharedcontent/cfb/images/smile.gif "smile")
1600:
SOC: 64% (approx. 256a/hrs remaining capacity).
Amps: -63 (dc)…Some dang tree shading now over a couple of PV panels…
LFP Voltage: 12.94
1700:
SOC: 55% (approx. 220a/hrs remaining capacity).
Amps: -73 (dc)…Heavier shading
LFP Voltage: 12.90
Compressor duty cycle (at 1700 was 5 min ON, 6.5 min OFF…).
*****************
We maintained a comfortable 77d/f t-stat setting the whole time (still ongoing…). The main variable was the eventual tree shading of the panels, but still lots of battery reserve and will likely be at 90’ish % charge (this, my ‘normal full’ by say noonish - except for periodic cell-balancing…
Most importantly (non-intuitively so!), note that in this example, harvesting at a rate of 1 to 1 ratio with power consumption is not necessary…Having a deep enough reserve is what’s needed, aided by Lithium’s relatively flat discharge plateau…
Quite naturally, various equipment, camper size and user experience will vary…Though understandably not for everyone, yet at least this provides an example of what might be achievable - haven’t started the Honda 2200 in nearly a year…
***************
Oops, and this one final 1800 result for an even more comprehensive trend-line:
Compressor duty cycle (at 1800) was 3.5min ON, 9 min OFF…
Now starting to cool off nicely!
SOC: 45% (180a/hrs remaining capacity)
Amps: -76.4 (dc) still heavy shading….
LFP Voltage: 12.90
Total run time (including initial 100% duty cycle cooldown), 5hrs 25min…
Hope some find this example interesting …
3 tons
* This post was
edited 07/24/22 12:10am by 3 tons *
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BobsYourUncle
Calgary Alberta Canada
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3 tons:
Yes, interesting! I enjoy mind bending technical geek stuff..
Trying to wrap my little brain around it all is another thing - Haha! ![[emoticon]](https://forums.goodsamclub.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
That was a lot of work for you to do all that, record and post the results. Thanks for taking the time to do it.
2007 GMC 3500 dually ext. cab 4X4 LBZ
Dmax/Allison
2007 Pacific Coachworks Tango 306RLSS - 32'
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3 tons
NV.
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Yep, one’s own instincts often tend to default to a required 1 to 1 harvest to demand scenario, but in a broader real world context this is not necessarily the case…
What also needs to be considered is compressor duty cycle, concurrent harvesting, and the restoration of full amperage to battery charging that occurs in between each compressor ON-OFF cycle, and the ‘available’ battery Depth of Discharge (DOD) till start of the next day’s harvest cycle…Where battery storage is tight (as in a truck camper - resolved by under dinette mounting), Lithium is what makes this become viable possibility,,,
FWIW, total air conditioner run time (cycling - ending at 1915) was about 6.75 hrs…
Hope this adds some enlightenment
3 tons
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