chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 23, 2015 18:03:33 GMT -8
This Norcold 12V refrigerator, which draws 3.75 amps: Link: NR751
and, 2 of these 6V batteries connected in series: Link: T-105 | Trojan Battery Company
Can any of you electrical buffs give me an idea of running time the 12V Norcold will give me on those batteries if it were the only 12V operating in the trailer? Thanks!
|
|
yas
Active Member
Posts: 422
Likes: 162
'63 Shasta Airflyte
Currently Offline
|
Post by yas on Feb 23, 2015 19:15:08 GMT -8
First a rough calculation. Capacities are roughly 200 amp-hours at differing rates of discharge. 200 amp-hours / 3.75 amps yields 53 hours. So the capacity we'll really use is between the 20 and 100 hour discharge rates, closer to 20. Estimate from the table 235 amp-hours. Divide by 3.75 amps results in ~63 hours.
It's recommended to only discharge the batteries between 50-85%, less being better for battery life. 50% is just over 30 hours.
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 23, 2015 20:38:57 GMT -8
Yas…. Whewww! Thanks for saving me hours of research…
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 24, 2015 8:51:18 GMT -8
...50% is just over 30 hours. So, accounting for the compressor cycling on and off as needed… perhaps 50 hours of refrigerating time? Considering that I am more of an off grid camper, going with 110/12v only model may put some pressure on the management of the batteries (even with modest daytime charging with solar panels). In addition to the 12v demand of the fridge, there will be 12v LED lights (not much draw from that) and a Fantastic Vent fan in the ceiling. Also consider, charging of phones, some computer use/charging, small sound system, 12v water pump, etc. It may be wiser for me to consider a 110/12/LP type and consider the LP as the primary source (I have two 20# bottles on the tongue), with 12v maintaining fridge temps while driving and the occasional 110v use at campsites with service. I guess that's the beauty of the 3-way… but man, they're kind of pricey w/ shipping. I'm looking at the Norcold N306 3 way. LINK: N305/306 .
|
|
yas
Active Member
Posts: 422
Likes: 162
'63 Shasta Airflyte
Currently Offline
|
Post by yas on Feb 24, 2015 11:16:57 GMT -8
I didn't realize it was a compressor fridge, so I didn't include the duty cycle (which I don't have a feel for anyway!). You've got it right.
I want a nice, new 3-way too - and you're right, they're expensive!
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 24, 2015 17:20:24 GMT -8
Thanks Yas… With all that LP sitting out there on the tongue, why worry about conserving the batteries… right? I also like the idea of switching to 12V while towing. With my current, very old LP only fridge, I have issues with the pilot blowing out, even though it's in a shielded box. I like the Norcold 3-ways a lot, but I called them today and the smallest dimension is about 1-1/2" wider than my door!
How are your Airflyte and Compact doing these days?
|
|
yas
Active Member
Posts: 422
Likes: 162
'63 Shasta Airflyte
Currently Offline
|
Post by yas on Feb 24, 2015 18:08:10 GMT -8
We finished and sold the Compact in the summer. We've got the Airflyte resealed and waterproof, and repaired the (very little) rot that we found. Now it goes slowly as work, life and the weather interfere. We'll have it in shape to camp by summer!
I've got an older Norcold 3-way (a 3163 I think) in a VW Eurovan Camper. We like it a lot. The electrical power doesn't run a compressor, but heats the working fluid just like the propane.
Have you measured the fridge that's in your trailer? You may have trouble getting it out, too. Many are wider than the door.
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 24, 2015 18:51:22 GMT -8
We finished and sold the Compact in the summer. We've got the Airflyte resealed and waterproof, and repaired the (very little) rot that we found. Now it goes slowly as work, life and the weather interfere. We'll have it in shape to camp by summer! I've got an older Norcold 3-way (a 3163 I think) in a VW Eurovan Camper. We like it a lot. The electrical power doesn't run a compressor, but heats the working fluid just like the propane. Have you measured the fridge that's in your trailer? You may have trouble getting it out, too. Many are wider than the door. Nice… on your Shasta progress! The Morphy Richards Astral fridge has a fairly shallow depth, so it will get out easily. It's not what Mobile Scouts came with originally, so someone got it in. Right now, the trailer is being prepped for some serious frame repair etc… so there may be an opportunity to slip a new fridge in with the doorway trim removed… also the Norcold itself may have a mounting flange that can be removed… we'll see. A fraction here… a fraction there. I know that NovaKool has some similar 3-way models that are a couple of inches trimmer… but they're not as well designed as the Norcolds IMO.
|
|
turbodaddy
1K Member
Posts: 1,086
Likes: 462
17' 1965 Fan "Sunseeker"
Currently Offline
|
Post by turbodaddy on Feb 25, 2015 4:31:58 GMT -8
Here is a link with manuals and a lot of Norcold info: linkwww.rialtainfo.com/winnebago/refrigerator.htmWe have a Norcold model 300 (3 way). There is no built in thermostatic control for 12 VDC operation...it is meant to ONLY maintain temp while underway. (you fill it with food get it cooled down with AC or LP) The PO of our camper never wired for !2VDC . (I think for fear of killing the batteries because it draws over 10amps.) If you do wire it be sure to run directly off the tow vehicle alternator, NOT tow vehicle battery or find some way to make it impossible to inadvertently drain all of your batteries. LP is very efficient and with 2 bottles you will not have to worry. Another safe method is to do like on a boat, install a battery selector switch and carefully manage the use and charging of the individual batteries. I installed 5 LED puck lights, 1 dome light, and 2 reading lights (Scandvik svk-41366) They are awesome!
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 25, 2015 9:13:24 GMT -8
Turbo… thanks. The Rialta link is a fantastic cache of user information far beyond what Norcold provides.
Regarding 12V operation: yes, I was aware that it is only for maintaining temps while underway. And at 10 amp draw, it would be a battery killer in short order! I suppose the easiest way to protect the tow vehicles battery in this case would be to disconnect the 7 pin when stopping and shutting the engine down (of course, remembering to reconnect later!). But would the fridge immediately start drawing on the trailer's battery under those circumstances? In other words, would you also have to shut off the refrigerator's DC mode when making rest stops?
Also: does your Norcold have a mounting flange on the face that can be removed temporarily? According to Norcold, the fridge's smallest dimension (the width) is slightly wider than the trailer door! I am trying to determine whether I can even consider this model and looking to steal an inch or two to get it through the door. Thanks.
|
|
pete3046
New Member
Posts: 13
Likes: 6
Currently Offline
|
Post by pete3046 on Feb 25, 2015 17:25:08 GMT -8
Although it might be a bit much, I installed what is known as an Automatic Charging Relay (ACR) in the boating world to protect the TV battery. Basically when the TV battery voltage drops below say 12.6 volts the ACR isolates the two batteries and when the TV battery is say above 12.6v, it connects the two batteries. So, if you are not pulling a large load on the camper battery, the TV will charge the camper battery and if the camper battery starts to pull too much on the TV battery it isolates the two batteries. It's a nice little system the boaters use all the time. Pete
|
|
|
Post by vikx on Feb 25, 2015 21:32:50 GMT -8
The Norcold I recently installed (300N) did not have a removable flange. It seemed to be glued/foamed in place. The door and hinges had to come off but we got it into the trailer. Most of the time, you can slip them in that way.
The trailer door and flange are pretty easy to remove. A bunch of screws and then new putty to re-mount. That should gain you 1/2 to 3/4 inch.
Check your windows. Some have a larger opening. Takes a little help lifting...
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 26, 2015 9:29:27 GMT -8
Check your windows. Some have a larger opening. Takes a little help lifting... Vikx… windows are out of the question on my trailer! Without the N300 in my hands, I think it would be a very close call in any case (door trim on… or off). If the non-flange portion of the body can squeak through (the specs tell me the cut-out width and my finished door opening are exactly the same!)… some diagonal maneuvering might get the rest of it through with the flange. From the info I have, I'd say a 50/50 chance. The question is: am I a betting man? There's always the N260 (2.4 cu.ft.), which is essentially the same inner works, but no freezer and the controls are in the back and accessible through the trailer's exterior vent door. I doubt if my very old Astral is as much as 2.4 cu.ft… but it does have a freezer compartment, darn it… and a lovely "dairy box" in the door. The exterior is all beige and extremely bland… but it does look like it is a blank slate for customizing with my own finish panel, which would be fun. Maybe even a 'vintage' look kind of thing. Here's the Astral I currently have.
|
|
|
Post by vikx on Feb 26, 2015 10:36:42 GMT -8
If the cut dimension is 20 1/2, the flange will be another inch or more...
I would definitely contact Norcold to find out how wide the flange actually is. We did have quite a tight squeeze as well, with the trailer door and frame removed...
|
|
chametzoo
Full Member
Posts: 585
Likes: 128
1960 Mobile Scout
Currently Offline
|
Post by chametzoo on Feb 27, 2015 11:24:01 GMT -8
If the cut dimension is 20 1/2, the flange will be another inch or more... I would definitely contact Norcold to find out how wide the flange actually is. We did have quite a tight squeeze as well, with the trailer door and frame removed… Well… MY tight squeeze may be even tighter than yours . Door way is 20-1/2" and Norcold measured an actual unit for me and it's 21-7/8" with the flange. A difference of 1-3/8" (or 5/8" per side). Skin (and door frame) will be off my trailer in the next couple of weeks, so I'll know for sure then.
|
|