StirCrazy
Kamloops, BC, Canada
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otrfun wrote: 11k btu a/c unit. Get about 85-90 min of continuous runtime when we're powering the a/c
oh tell me more about this AC, as in brand and model number..
2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100
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StirCrazy
Kamloops, BC, Canada
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otrfun wrote:
Choosing a capable 2000w inverter is important. Not all 2000w inverters are created equal. Although most inverters can supply their continuous current rating, many fall short providing suitable amounts of inrush current. Inrush current is necessary to successfully start a/c units and microwaves. Unfortunately, very few manufacturers provide inrush current specs for their inverters.
Good luck!
inrush and starting current are the same, just different names depending on the type of equipment. in rush covers any time a electric componant temporatly draws more power when you turn it on, in a motor it is generaly called starting current. every inverter I have seen lists this as peak power. and its usaly a couple K watts above the rated output. for example the renogy is a 2000 watt inverter continious with a peak of 4000 watts that will handle anything on a rv but maby not two large power users at once.
Steve
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otrfun
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StirCrazy wrote:otrfun wrote: 11k btu a/c unit. Get about 85-90 min of continuous runtime when we're powering the a/c oh tell me more about this AC, as in brand and model number.. It's a Dometic Penguin II that came OEM with our truck camper. Model number is 640310Cxx1C0. Some literature says it's a 10k BTU, others say 11k BTU. Typically this info is stenciled on the compressor housing, but it's not specified on our unit.
Unfortunately, I can't recommend this unit. On the up side, the outside shroud has a nice streamlined, stylish look. On the down side, it's noisy as heck and relatively inefficient. It draws 11-12a (I believe the LRA is approx. 55-56a) . There's a number of more efficient 13.5k BTU a/c's that draw the same 11-12a with a lower LRA. If it fails at some point we'll probably replace it with a 9.5k BTU RecPro.
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3 tons
NV.
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“But how do I find out about the inrush current matter? That's a bit concerning to me. I want to do all of this once only and get it right the first time.”
Microwaves are highly capacitive loads. Capacitors are known for their ability to perform a lightening-fast discharge!…Conversely, capacitors also want to accept a charge as fast as they discharge (ugg!)…With a decent 2000w PSW inverter (based on my previous…) there’s no need to wrap your mind around this characteristic…
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otrfun
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StirCrazy wrote:otrfun wrote: . . . Choosing a capable 2000w inverter is important. Not all 2000w inverters are created equal. Although most inverters can supply their continuous current rating, many fall short providing suitable amounts of inrush current. Inrush current is necessary to successfully start a/c units and microwaves. Unfortunately, very few manufacturers provide inrush current specs for their inverters.
Good luck! inrush and starting current are the same, just different names depending on the type of equipment. in rush covers any time a electric componant temporatly draws more power when you turn it on, in a motor it is generaly called starting current. every inverter I have seen lists this as peak power. and its usaly a couple K watts above the rated output. for example the renogy is a 2000 watt inverter continious with a peak of 4000 watts that will handle anything on a rv but maby not two large power users at once.
Steve IMO starting current is just a colloquial term to sometimes describe inrush current and not related to any particular type of equipment. Also, peak current is very different from inrush current (see last paragraph).
IMO the most important takeaway when discussing inrush, starting, peak, or surge, current is the following: unless a specific time or duration (or testing standard/protocol) is specified for any given current rating, the current rating provides little insight into how the device will perform in the realworld.
For instance, I could claim a 12vdc/120vac inverter has 2000 watts (16.6a) of continuous output. Notice I specified current AND time/duration (continuous). This is 100% useable data that translates into realworld performance. I could also claim this same inverter produces 4000 watts (33a) of surge or peak output. However, if I don't specify a time or duration it's a meaningless claim in terms of realworld performance. If I claimed it could produce 33a for, say, a few milliseconds, then that 33a is completely useless. Not enough time/duration to help start an a/c compressor or motor. Now, if I claimed it could produce 33a for almost a second (or longer), that's a huge deal in terms of realworld performance---exactly what an a/c compressor or motor needs to sucessfully start. Time/duration is everything in this context.
I've found the following to be generally true for consumer grade inverters and inverter generators: There is no standardized time/duration for a surge rating. Depending on manufacturer, it can range from a fraction of a second to as long as 30 min. A surge rating can be useful *IF* a specific time/duration is specified. IMO peak current is more of a marketing ploy because the time/duration for peak current (1 or 2 cycles) is too short to be of much use in a realworld environment. Time/duration for inrush current is much, much longer (approaching a second). Assuming sufficient current, this is exactly the time/duration necessary to successfully start an a/c compressor or motor.
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StirCrazy
Kamloops, BC, Canada
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otrfun wrote:
IMO the most important takeaway when discussing inrush, starting, peak, or surge, current is the following: unless a specific time or duration (or testing standard/protocol) is specified for any given current rating, the current rating provides little insight into how the device will perform in the realworld.
I do agree the lack of companies putting this in there advertising makes things a little more difficult. personaly I have never been met with any issues when I email the company and ask for that information.
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otrfun
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StirCrazy wrote:otrfun wrote:
IMO the most important takeaway when discussing inrush, starting, peak, or surge, current is the following: unless a specific time or duration (or testing standard/protocol) is specified for any given current rating, the current rating provides little insight into how the device will perform in the realworld. I do agree the lack of companies putting this in there advertising makes things a little more difficult. personaly I have never been met with any issues when I email the company and ask for that information. You mentioned the Renogy 2000w PSW inverter. Very popular unit. Always wondered what time/duration they used for their peak rating. Did you happen to get this info?
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LaneW
Hayden, ID
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otrfun wrote:StirCrazy wrote:otrfun wrote:
IMO the most important takeaway when discussing inrush, starting, peak, or surge, current is the following: unless a specific time or duration (or testing standard/protocol) is specified for any given current rating, the current rating provides little insight into how the device will perform in the realworld. I do agree the lack of companies putting this in there advertising makes things a little more difficult. personaly I have never been met with any issues when I email the company and ask for that information. You mentioned the Renogy 2000w PSW inverter. Very popular unit. Always wondered what time/duration they used for their peak rating. Did you happen to get this info?
No, I have not been able find that information - and would like to.
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theoldwizard1
SE MI
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LaneW wrote:You folks are very helpful, thanks. I do get it about wiring and will plan to discard what comes with an inverter and oversize the cabling.
A DC-DC charger is a must !
If you have not purchased the inverter, look at inverter/charger/automatic transfer switch. Remove your old converter. Wire the DC fuse panel directly to the battery (large fuse at the battery). Shore power cord directly to the inverter/charger input. Out out goes directly to the A/C breaker panel.
LaneW wrote:But how do I find out about the inrush current matter? That's a bit concerning to me. I want to do all of this once only and get it right the first time.
No manufacturer specs their in rush current. On refrigeration equipment you might find "locked rotor amperage" (LRA) which would be worse than normal inrush current.
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pianotuna
Regina, SK, Canada
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I can tell you that inrush on a 1000 watt psw inverter is high enough to blow a 30 amp fuse. And that is with no load. DAMHIK
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
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