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ericdiehl · 07-10-2017, 03:16 PM

OK, after rebuilding the Norcold with an Amish Dutch Aire cooling unit, new circuit board, fans, heating elements---and still not entirely happy with it---out goes the NoCold (wish I'd done that previously), and in comes the Samsung RF18.

We don't boondock, so the only time we'll be using the inverter is when we're traveling from campground to campground. At those times our 2-battery fiver will be plugged in to the 2-battery RAM 3500 with alternator charge, so I'm not anticipating problems with battery capacity.

The inverter is a 1200 watt Aims Power pure sine wave inverter, with auto-transfer. For the AC input , I plugged the inverter into an existing conventional 110 outlet in the basement, which presumably gets fed thru the breaker box.

For DC input, I used solid copper romex to piggyback off the DC connection of the rig's converter/charger. There was a doubled connector at both positive and negative connections on the charger, where the battery connected to the smart charger, and I used the vacant +/- connectors on the smart charger for the DC input to the inverter. Essentially, the same battery connection to both the smart charger and the inverter. This is the connection I wonder about; I've heard accounts of an odd constant charge/discharge cycle? Don't quite understand that.

For the inverter AC output, I pulled off the romex that fed the existing fridge outlet from the breaker box, and instead connected that romex to the inverter output. I was at first concerned that I was bypassing the breaker box to that outlet, but then it occurred to me that the 110 outlet I plugged the inverter into was undoubtedly also fed by the breaker box, and so no problem?

I don't have the Samsung yet, but plugging a shop lamp into the 110 outlet for the fridge shows that the inverter is feeding pass-through AC when plugged in to shore power, and switching to the batteries when shore power goes away.

Anybody see any problems with my setup? The one question I have is; why has the Intellipower smart charger not gone back to the float-charge state, an hour after my installation, and with shore power connected?

Sbrownstein · 07-10-2017, 03:29 PM

Not bad. You could have cut the feed from the power panel to the reefer outlet and wired the feed side to the feed side of the AIMS and the load side to the output side of the AIMS and your breaker would still work and would still power the reefer.

I also piggybacked off the the PD converter to my inverter. You said "solid copper romex" I presume you used #4 or #6 cable to the inverter inputs (and also put something like a 100 amp fuse in that line)

I wouldn't worry that the PD hasn't dropped back down yet...it is nothing you did unless the AIMS has a big idle current but I think it should be less than 1 amp.

powercat_ras · 07-10-2017, 03:36 PM

Quote:

Originally Posted by ericdiehl

OK, after rebuilding the Norcold with an Amish Dutch Aire cooling unit, new circuit board, fans, heating elements---and still not entirely happy with it---out goes the NoCold (wish I'd done that previously), and in comes the Samsung RF18.

We don't boondock, so the only time we'll be using the inverter is when we're traveling from campground to campground. At those times our 2-battery fiver will be plugged in to the 2-battery RAM 3500 with alternator charge, so I'm not anticipating problems with battery capacity.

The inverter is a 1200 watt Aims Power pure sine wave inverter, with auto-transfer. For the AC input , I plugged the inverter into an existing conventional 110 outlet in the basement, which presumably gets fed thru the breaker box.

For DC input, I used solid copper romex to piggyback off the DC connection of the rig's converter/charger. There was a doubled connector at both positive and negative connections on the charger, where the battery connected to the smart charger, and I used the vacant +/- connectors on the smart charger for the DC input to the inverter. Essentially, the same battery connection to both the smart charger and the inverter. This is the connection I wonder about; I've heard accounts of an odd constant charge/discharge cycle? Don't quite understand that.

For the inverter AC output, I pulled off the romex that fed the existing fridge outlet from the breaker box, and instead connected that romex to the inverter output. I was at first concerned that I was bypassing the breaker box to that outlet, but then it occurred to me that the 110 outlet I plugged the inverter into was undoubtedly also fed by the breaker box, and so no problem?

I don't have the Samsung yet, but plugging a shop lamp into the 110 outlet for the fridge shows that the inverter is feeding pass-through AC when plugged in to shore power, and switching to the batteries when shore power goes away.

Anybody see any problems with my setup? The one question I have is; why has the Intellipower smart charger not gone back to the float-charge state, an hour after my installation, and with shore power connected?

The wiring from your battery system to your converter charger, assuming it is a 45 or 55 Amp output one, is likely only 6 gauge, sized for 55 amps DC or less. There also may be a circuit breaker in line sized to 55 amps or less. Your 1200 Watt Inverter under full load could draw up to 120 Amps DC. Best practice would be to home run wire power and ground wires to the batteries using #2 wire with a 120 or 150 amp in-line fuse.

You are fine for powering the residential refrigerator but if you were planning to power other small appliances like a toaster, etc. off of it too from time to time you may need to consider running the inverter to the batteries as a direct wire run using #2.

Sbrownstein · 07-10-2017, 03:44 PM

Actually the #6 is rated for 75 amps and the reefer in question takes about 800 watts maximum (although it is an inverter reefer so it will generally only draw 80 watts or so.) Agree that if he wants to power something else a new run from the batteries would be beneficial, although I would run bigger cable but still run through the PD converter since it too can benefit from the larger wire when charging. Most manufacturers skimp on the converter to battery bank wire size and in my coach it costs me almost .75 volts and a lot a amps in boost mode.

twinboat · 07-10-2017, 03:48 PM

Agree with above.

Keep the inverter close to the batteries, use at least 2 gauge battery cables and run 14 gauge romex to and from your fridge connections.

With smaller gauge cables, the startup load may alarm the inverter and shut down for low voltage.

Sbrownstein · 07-10-2017, 04:13 PM

Quote:

Originally Posted by twinboat

Agree with above.

Keep the inverter close to the batteries, use at least 2 gauge battery cables and run 14 gauge romex to and from your fridge connections.

With smaller gauge cables, the startup load may alarm the inverter and shut down for low voltage.

Possibly, but the startup current of an inverter compressor is significantly lower than that of a conventional single speed induction compressor. The real key here is not the absolute wire gauge, but the length of run. Bigger is safer, but I bet that #6 will work.

ericdiehl · 07-10-2017, 05:00 PM

The pre-existing wires from batteries to charger seem fairly heavy gauge; 6 AWG, it's marked. I guess I need to study up on terminology. What I used today to piggyback DC from the charger to the inverter are 2 wires I stripped out of the 4-wire romex that I used to install 220 power to my back garage many years ago (I did study-up some back then, but I've since forgotten most of it). The romex is marked 12/20/06, and AWG 10, amongst other nomenclature. It will power only the refrigerator, nothing else. I would think it's sufficient for a fridge.

But the charger has still not gone back to float mode.

Hmmm

Sbrownstein · 07-10-2017, 05:13 PM

If the leads are short it might be ok, but #10 is only rated for 40 amps and will have a hefty voltage drop if the wires are very long. You can get premade #4 and #6 battery cables at most auto parts stores.

Doesn't take much to get a 3 stage out of float mode.

twinboat · 07-10-2017, 05:34 PM

How does that fridge handle it's defrost cycle ?
Does that run at 80 watts ?

Maybe it's me, but I would always recommend wiring it to the manufactures specs, even if not being run to max output.

Maybe the next owner will want to tap it's potential.

Sbrownstein · 07-10-2017, 05:49 PM

Quote:

Originally Posted by twinboat

How does that fridge handle it's defrost cycle ?
Does that run at 80 watts ?

Maybe it's me, but I would always recommend wiring it to the manufactures specs, even if not being run to max output.

Maybe the next owner will want to tap it's potential.

No, that 80 watts is a long term average. My 22 cuft runs up to about 600 watts for short periods ever 7 or 8 hours and then tapers way down for the longer haul as the compressor slows down. Defrost heater is 800 watts as well, but I presume the micro processor prevents max compressor and defrost from overlapping.

I would always wire for correct ampacity, hence recommending #6 or #4, but the voltage drop is another thing and it isn't necessary to go down to #2 or 1/0 unless the round trip is long.