Wiring A/C to outlet load center

[Mjschwart]

I have a 2021 NE that has the full lithium package with ATS and Inverter. I was thinking about replacing the 2 gang outlet load center under the bench with a 4 gang and moving the A/C circuit to it from the WFCO. That way, I’d be able to get a little over an hour of A/C on batt (useful for that road side stop with the kids and dogs). Has anyone done this? Seems like a simple swap unless I’m missing something. Yes, I’ll be close to maxing out my gopower inverter, but I did install a softstart on the A/C and the EMS is showing 10-11amp draw at 115v. I should be well within the limits of the current battery and inverter. I’m also looking at a pair of SOK 200AH batts too which would increase run time.

Thoughts?

[BobG]

I think you have a good idea and a good understanding of what to expect. If it doesn't work then just switch it back to Shore power only or get a larger inverter. If you can manage it for some level of comfort then you can use it either on inverter or shore power.

The air conditioner comes in handy for short periods, especially at bed time. You may be surprised at how long you can run the AC because once the trailer is cooled the on cycle may only be a couple minutes followed by a 10 minute off cycle. It just depends on the the outside weather; temperature, wind, and direct radiation. Of course after sunset the wind usually dies as does the the sun's radiation resulting in more AC effectiveness.

I would make sure all the DC wiring and connectors between batteries and inverter are up to standards for the inverter's maximum current draw at a 3% or less voltage drop. It is easy to check the wire sizing with an internet app and then confirm with a multimeter to make sure the system including connectors are in deed operating as expected. You can measure the voltage drop across connectors or check them for excessive heat.

[Mjschwart]

Great points, but now I’m massively confused. Escape ships the full lithium package with a 200amp fuse on the positive side (both batts in parallel can exceed 200amp for short periods). They use 2awg cable, which is only rated for 115amp. Too close for comfort since my observations show the a/c consuming 10-11a at 120v and the inverter is 91% efficient. OTOH, wouldn’t that 2awg cable melt well before the 200 amp fuse blows?

[John in Santa Cruz]

cable amp ratings are proportional to the LENGTH of the cables. you can run 200 amps down a short AWG 2 cable just fine as long as the cable isn't in a dense bundle of other cables.

[John in Santa Cruz]

If you run your batteries way down low with 1 or 2 hours of A/C, how do you plan to recharge them? I have dual SOK 206AH batts, and intentionally ran them down to 50% (about 2600 watt*hours). It took the better part of 2 days at 360 W solar to fully charge the batteries again, I get about 2000 watt*hours per day of solar, but it takes more power to charge the batteries than you get back out..

[Mjschwart]

Originally Posted by John in Santa Cruz

If you run your batteries way down low with 1 or 2 hours of A/C, how do you plan to recharge them? I have dual SOK 206AH batts, and intentionally ran them down to 50% (about 2600 watt*hours). It took the better part of 2 days at 360 W solar to fully charge the batteries again, I get about 2000 watt*hours per day of solar, but it takes more power to charge the batteries than you get back out..

I’m using this chart, https://www.therangerstation.com/wp-...tion-chart.png.

Doesn’t look like 200a is acceptable at any length on 2awg. Can you provide a different source.

The a/c usage would be for “on the road” in limited conditions where the final destination has electricity.

[Mjschwart]

Originally Posted by John in Santa Cruz

If you run your batteries way down low with 1 or 2 hours of A/C, how do you plan to recharge them? I have dual SOK 206AH batts, and intentionally ran them down to 50% (about 2600 watt*hours). It took the better part of 2 days at 360 W solar to fully charge the batteries again, I get about 2000 watt*hours per day of solar, but it takes more power to charge the batteries than you get back out..

Id only use it “on the road” on the way to the campsite that had electricity.

BTW! How do you like the SOK batts?

[John in Santa Cruz]

Originally Posted by Mjschwart

Id only use it “on the road” on the way to the campsite that had electricity.

BTW! How do you like the SOK batts?

so far, totally happy with them. well made, and they are performing to specifications. I have a classic Escape 21, with the rear "U" shaped dinette, so I removed the original dual GC2 box, and installed the two SOK batts in the curbside rear corner, like this



with this panel of Victron power management goodness under the rear bench...



and put a Renogy 2000W puresine inverter under the street side bench...



currently wired to its own dedicated outlet,



but I'm toying with getting a subpanel and a transfer switch so I can use the inverter for any of the outlets...

the rest of this upgrade was replacing the original 160W polycrystalline solar panel with a 360W monocrystalline panel,




and replacing the broken RMD8555 with a Norcold N2175 DC compressor fridge.

[Mjschwart]

I love it. Great setup!

[hugh]

Originally Posted by Mjschwart

I’m using this chart, https://www.therangerstation.com/wp-...tion-chart.png.

Doesn’t look like 200a is acceptable at any length on 2awg. Can you provide a different source.

The a/c usage would be for “on the road” in limited conditions where the final destination has electricity.

John is actually referring to two current capacities: The capacity to run equipment without excessive voltage drop, and the maximum safe current carrying capacity.

The voltage drop based rating is different for different lengths, as longer runs have higher electrical resistance, and cause a higher drop in voltage. With a longer run, you may need thicker wire to reduce the voltage drop to an acceptable level. If you exceed this rating, the wiring wouldn't be unsafe, but your equipment would not function properly.

The safety rating does not vary based on length. This rating is the amount of current your wire can carry before it reaches an unsafe temperature. Typically, that's temperature at which the insulation on the wire would begin to soften / break down. That's why when you see these ratings, they vary based on the temperature rating of the insulation. They also vary based on whether the wiring is enclosed, run in a bundle, etc, as this can cause more heating of the wires.

Most people use the ABYC ratings to determine the wire gauge needed to safely carry a certain current. According to the ABYC, 2AWG wire is rated to carry up to 210 amps, if it has 105C rated insulation. With 90C insulation, it would only be safe up to 180 amps. These ratings assume single conductors run in "open air" in relatively cool ambient temperatures.

A copy of the ABYC rating chart is here:
https://www.bluesea.com/support/refe...e_Sizing_Chart

[cpaharley2008]

Hugh,
I see you have 2 more weeks before your Escape delivery or pick up?

[BobG]

Michael, the link Hugh provided also gives access to the BlueSea's Circuit Wizard which allows you to enter the allowable voltage drop. Usually a 3% voltage drop is used in marine applications but you can enter different allowable voltage drop.

My previous response to you was based on my erroneous understanding of what you wanted to do. I was thinking you had the solar package too. After reading your initial post, I see that you never mentioned solar.

I also have a 2021 21NE.

[Mjschwart]

Originally Posted by BobG

Michael, the link Hugh provided also gives access to the BlueSea's Circuit Wizard which allows you to enter the allowable voltage drop. Usually a 3% voltage drop is used in marine applications but you can enter different allowable voltage drop.

My previous response to you was based on my erroneous understanding of what you wanted to do. I was thinking you had the solar package too. After reading your initial post, I see that you never mentioned solar.

I also have a 2021 21NE.

I have all the things. 2 panels and 2 lithium batts w/inverter.

[John in Santa Cruz]

another way of looking at it...
using formulas: ohm * amps = volts, volts * amps = watts (ohms law, and watts law, respectively).

AWG 2 copper is 0.16 ohms per 1000 feet. so a 5 foot run would be 0.0008 ohms (0.16/1000 * 5). at 200 amps, thats a 0.16 volt drop, or 32 watts loss in the 5 foot wire. 32 watts over 5 feet of heavy gauge wire will get warm, but not hot enough to melt anything as long as that wire is not buried in a bundle.

[hugh]

Originally Posted by cpaharley2008

Hugh,
I see you have 2 more weeks before your Escape delivery or pick up?

Yep, the trailer is done, and I'm just waiting on a final ship / arrival date to pick it up in Maryland.


As everyone says, these last few weeks seem like the longest wait!

[GregWCIL]

Originally Posted by John in Santa Cruz

with this panel of Victron power management goodness under the rear bench...

and replacing the broken RMD8555 with a Norcold N2175 DC compressor fridge.

Looks good John. I'm using mostly Victron components on my new solar build. We just got our 5.0 June 15 and already have it in the shop doing the upgrades.

Wow, your fridge looks huge. We went with the Norcold compressor option from Escape and in our 3 week "shake-down trip" my wife decided it is just fine for our needs. It is an absolute miser on power usage and keeps Ben and Jerry's Ice cream rock hard when set on 4 out of 6. And impressively without freezing anything in the fridge compartment.

I sure appreciate the pioneering work you and others have done on upgrades. You all have been helpful as well as inspiring.

Take care,
Greg

[John in Santa Cruz]

Originally Posted by GregWCIL

.... We went with the Norcold compressor option from Escape ...

just curious, what model Norcold do they use?

[BobG]

DC558 is the one I went with from Escape. I believe the also install a larger one.

[John in Santa Cruz]

Originally Posted by BobG

DC558 is the one I went with from Escape. I believe the also install a larger one.

k, that one is about 7-8" shorter in height than the N2175, and about 0.7 less cubic feet (5.5 vs 6.2 cu ft). I think its an earlier model, the N series are fairly new.

[BobG]

I got the shorter one to make room for microwave above it.