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Old 02-19-2019, 12:54 PM   #1
daveinaz
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Best way to wire inverter for fridge on 08 3400RL

I've read the pros/cons of hooking up dedicated inverter for the residential fridge and decided that the DW will be happiest if I install one. I understand the basic process but I am wondering about the specifics of how to go about this.

Our 5er, an 08 3400RL, has the fridge in a slide-out. The fridge is plugged into an AC outlet that I can access from the outside panel. I'm assuming that the AC power to this outlet is coming from the converter that is above the washer/drier in the closet near the entry door.

I'm hoping that someone else with this floorplan can give me some advice on how to best go about accessing the wiring to/from the fridge/converter to get it into the front of the rig for this fridge inverter thing.

Thank you.
 
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Old 02-19-2019, 04:08 PM   #2
jcurtis934
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I believe the 3400 was similar to lots of models that had fridge, cooktop, microwave, etc in the slide. All utilities for things in that slide are routed to the back end of that slide. You will see a plastic device that keeps 120 vac, 12vdc, propane, etc contained so that the slide can move in and out. The 120vac for the fridge is one of two lines so routed. These 120 vac lines have to transistion from the normal romex that you see in houses to special connectors that allow the lines to hook up to stranded cables in order to flex as the slide is operated...so you will not see romex underneath at the back of the slide. Then back to normal romex inside the frame at back end of rv and routed up to where the converter/breakers are for power. So, I would identify what loses power when the breaker for the fridge is flipped off. That will tell you what all would be powered by an inverter when travelling and what things you have to make sure are off, if you only wish the fridge to run while travelling. The inverter has to live in the pass thru area and a transfer switch to control whether shore power or inverter power runs to fridge. Romex wire on output of that breaker will have to run to a junction box so you have enough romex length to get to thealternate power connection inside the transfer switch. Then a new romex line is connected to the breaker that you took the fridge power lines off of. This romex runs to the transfer switch and hooks to the shore power connection. The input coonection of the transfer switch goes to the output of the inverter. If this sounds above your knowledge, best to hire the job out to someone that can assure a proper job is done that meets all the regulations.
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Old 02-19-2019, 04:24 PM   #3
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Thanks, JCurtis, that was helpful. I was thinking that the plastic holder going to the slider held the AC to it. That will give me a starting point to trace back the wires. Makes me wish there was a easier on/off method for that coroplast!
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Old 02-20-2019, 01:03 PM   #4
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So, it looks like our fridge only uses 1.4 amps... So if I multiply that by 120 = 168. Am I correct in thinking that it only needs 168 watts to operate?? And if I multiple that by 2 (336) or even 3 (504) for start-up surge, then a 1000 watt inverter should be plenty, correct? Or am I missing something?


And for those of you who are good at math (not me), I have two size 27 12V batteries in parallel. Each battery has these specs: 20 amp hour rate:90, Minutes at 23 amps:200, Minutes at 25 amps:175.


I know the fridge wouldn't be pulling juice all the time, but assuming a constant discharge rate of 1.4 amps, how many hours would my batteries provide juice to it?

Thanks.

(Is this right? Each battery has a 20aH rating of 90. That means it'll give 4.5 amps for 20 hours? or 2.25 amps for 40 hours? and since the amperage is doubled from batteries in parallel, the two of them would give 2.25 amps for 80 hrs?)
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Old 02-20-2019, 03:30 PM   #5
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You are correct. 1.4 amps at 120vac will translate to 17 amps of 12vdc from batteries. Your group 27 batteries are probably 65 amp hour rated, so that means with two in parallel that you have 65 amphr of power you can use before reaching the 50% limit of drawdown without affecting battery lifespan. I went with the xantrex prowatt sw 100 pure sine wave inverter and xantrex transfer switch. Using 150 amp circuit breaker by blue sea series 285 to feed battery power to inverter in passthru.
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Old 02-20-2019, 03:36 PM   #6
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In reality, you will have some battery charging from the truck while towing so you should never reach that 50% point while towing. If you had no charging going on, you could get 65 ÷ 17 = 4 hours of use if the draw was 17 amps all the time. But more than likely, the average draw of the fridge while towing will be more like 10 amps or less and you could get around 7 hours.
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Old 02-20-2019, 04:27 PM   #7
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I'm a little confused.

I think the battery is rated at 90 amp hour. (https://www.batteriesplus.com/produc...xoCx_kQAvD_BwE) So 90 / 17 = 5.3 hrs? Does the batteries in parallel double amperage, so doubling that 5.3 to 10.6?
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Old 02-20-2019, 04:44 PM   #8
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Quote:
Originally Posted by jcurtis934 View Post
You are correct. 1.4 amps at 120vac will translate to 17 amps of 12vdc from batteries. Your group 27 batteries are probably 65 amp hour rated, so that means with two in parallel that you have 65 amphr of power you can use before reaching the 50% limit of drawdown without affecting battery lifespan. I went with the xantrex prowatt sw 100 pure sine wave inverter and xantrex transfer switch. Using 150 amp circuit breaker by blue sea series 285 to feed battery power to inverter in passthru.
Is this the inverter you're talking about?

https://www.amazon.com/Xantrex-806-1...g%2C188&sr=8-5

And this transfer switch?
https://www.amazon.com/Xantrex-80809...gateway&sr=8-1
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Old 04-09-2019, 03:01 PM   #9
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Follow up:

Well, I'm working my way down the "to do" list and installing the inverter is coming up soon. I've gotten some really good advice and I now know what needs to be done (Thanks JCurtis!!), but I do have one more question that I hope someone who has a 3400RL can answer.

In our 08 3400RL, the Inverter is under the steps going to the bedroom. However, the distribution/breaker panel is in the bathroom over the toilet. The entryway closet where the washer/dryer are is on the opposite side of the wall it's mounted on. Does anyone know the best way to access the breaker panel? Just wondering if I should approach it from the bathroom or the closet.

Thanks.
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