Yes, you can keep the reefer cold for extended time while plugged in at home.
If the converter charger is not very good, it still will not actually "over charge" the house bank, but it can cause the electrolyte to leave. It is not boiling, but it is turning to gas and leaving none the less. A good 3-stage unit will not do this nearly as much.
Adding a second battery, assuming what is there is a 12V deep cycle, will not get you double the capacity. Sorry, just a fact of paralleling lead acid batteries. If that battery was OE is near five years old, think about trading up to two 6V golf cart batteries.
A pair of golf cart batteries and a good converter charger is one of the best upgrades an RV owner can do - IMHO and years of experience.
Matt & Mary Colie
A sailor, his bride and their black dog going to see some dry places that have Geocaches in a coach made the year we married.
I leave my trailer connected to the house using a 50-foot long 10-gauge (10-3) extension cord plugged into the garage 120VAC Receptacle. On the trailer end i use a RV30A-15 18-inch long adapter (Walmart) to plug the trailer shore power cable into it. I cant use the small round RV30A-15A adapters as they always start getting hot on me.
This keeps my batteries in good shape and I sometime run an oil-filled electric heater in the trailer during the winter months to get some heat in them.
I do have a smart-mode converter/charger unit and used to check my batteries fluid level every month but with the smart-mode charger it never needs filled. I only check every couple of month or more now. The smart-mode chargers take care of the boiling out of battery water for you.
We sleep-over in our trailer sitting in CAMP BACKYARD all the time. It is a great get-away even at home. Its great for the grandkids when they stay over night. The 15A/20A service you can get from your garage will operate everything in your trailer including HDTV and all the appliances. You just have to watch what you have on at the same time. Having the air conditioner running and go turn on the microwave will result in a breaker to trip in the garage for us.
This way I know everything is working when we are ready to us it on trips.
I feel lucky to live where they allow you to keep your RV's at home so I use them at home when-ever we can.
My Posts are IMHO based on my experiences - PM me Roy and Carolyn
RETIRED DOAF/DON/DOD/CONTR RADIO TECH (42yrs)
K9PHT (Since 1957) 146.52M
2010 F150, 5.4,3:73 Gears,SCab
2008 Starcraft 14RT EU2000i GEN
2005 Flagstaff 8528RESS
Just a "THANK YOU" to the OP for the reminder!
After I posted, it occurred to me that I had not checked my batteries for a while, so I went out and did that. The electrolyte was in the "OK" range (above the plates), but a little low. It took 2 to 3 baster fulls per cell to top them off. It was definitely time to check them!
I gave up on the "little round" 30 to 15 amp adapters. They just seemed to be too cheaply made to be worth buying. I have a "dogbone" style adapter now, and while it is a little more expensive it seems to be worth it for the lack of trouble.
CM1, USN (RET)
2002 Fleetwood Southwind 32V, Ford V10
Toad: 2006 Jeep Rubicon LJ
Other toad: '06 PT Cruiser, Kar Kaddy dolly
Toy: 1977 Dodge W100 CC SWB, 3/4 ton axles & springs
"When seconds count, help is only minutes away!"
The standard equipment converter/charger used by Winnebago on a C motorhome can boil the battery dry, not necessarily the same thing as overcharging it. You can prevent this by using the battery disconnect when the motorhome is plugged in. The disconnect is wired to separate the battery from both charger and loads while the house 12-volt is still supplied from the converter.
If you need to do something that requires more current than the converter is designed to supply, like move slideout rooms or start the generator, you can either bring the battery back in, or start the engine to get additional current from the alternator, which has worked for me when the batteries were low or going bad.
If you don't have slideouts to move, and don't dry camp off the grid, then you probably don't need the second battery. A second battery in parallel has cost and maintenance issues you might prefer to avoid if you can. If one battery goes bad, especially if a cell shorts, it will quickly take down the other battery, as a parasitic load, and as a problem for the charging circuits. Combine this with the need to keep them balanced in capacity and age, almost anytime you need to replace one, you need to replace both, even if one of the two still has some life left in it. A new one hooked to one several years old but still good, will take down the new one. Personal experience on this.
* This post was
edited 05/09/12 11:58am by tatest *
I will be a bit more specific.. In days of old when RVers were bold and 12 volt systems were kind of new.
There was a popular converter/charger, The Magnetek 6300 line, This unit consited of both a converter that supplied power to the lights and such INDEPENDENT of the battery when plugged in and a Charger to charge the battery... Slowly.. And a relay to cross connect them when not plugged in so the lights worked off the battery.
The problem is that it did not know when to STOP charging the batteries and thus once they were full up it kept on cranking out the amps.. Boiling the batteies dry and killing them.
Today.. Many RV's have 3-stage converters such as the Progressive Dynamics 9200 line, or IOTA with IQ-4 or (Long list of others too long to type).
However there is still at least one SINGLE stage out there, The parallex 7300
(And a two stage, the Parallex 7300T)
The "T" is the minimum I'd consider leaving plugged in full time.
I have a PDI (Progressive Dynamics INC) 9100 with optional charge wizard (This makes it a 9200) and I do keep plugged in most all the time.. As a result I have to water my GC-2's annually.
Nothin adds excitment like something that is none of your business
Kenwood TS-2000 housed in a 2005 Damon Intruder 377
I wouldn't run the fridge when not occupied for weeks. Those fridges have a limited lifetime and are very expensive. When left for the winter I might plug it in for a couple of hours every month to top up the batteries. Or start the engine for 15 minutes to charge all the batteries.