How much draw on batts while cooling fridge?

[TitanMike]

Originally Posted by NXR

Not exactly. They both use the 433 MHz ISM (Industrial, Scientific, Medical) band for unlicensed transmitters. They’re actually on different frequencies within that band. At least mine are. I’ll dig the books out tomorrow because they did list the exact frequency.

Ray

Not only different frequencies (433 band extends from 433.050 MHz to 434.790 MHz) but there's also the specific coding of each device used in each system. How else would it be able to discern the signal from a RF tire or LR tire, as well as from a vehicle using the same system driving next to you on the Interstate?

[NXR]

Originally Posted by TitanMike

Not only different frequencies (433 band extends from 433.050 MHz to 434.790 MHz) but there's also the specific coding of each device used in each system. How else would it be able to discern the signal from a RF tire or LR tire, as well as from a vehicle using the same system driving next to you on the Interstate?

True, however it's far more likely that a strong or "dirty" transmitter physically close to a qwappy receiver would cause problems by overloading the receiver and blocking the signal it's expecting even when the two systems are not on close frequencies. If the signal can't get through then the coding or lack thereof is irrelevant.

I used to work in operational IT security and there have been some proof of concept hacks where a car driving next to one with deficient security controls was able to access the other car's data bus wirelessly through the TPMS system.

And they almost all have deficient security controls.

Ray

[babock]

Originally Posted by NXR

Not exactly. They both use the 433 MHz ISM (Industrial, Scientific, Medical) band for unlicensed transmitters. They’re actually on different frequencies within that band. At least mine are. I’ll dig the books out tomorrow because they did list the exact frequency.

Ray

The problem is that they are close enough that a receiver, not designed correctly, will get saturated with frequencies that are slightly out of its band. That's why they can possibly not play well together.


EDIT: see you actually wrote the same thing in your last post.

[Crusaderguy]

Our Primetime Crusader is kept in storage with no power available. The night before every trip we fire up the frig on propane, put water in the ice cube trays and fill up the frig with canned drinks etc. The next morning we have ice cubes and all drinks are cold. We have been doing that for 14 years and have had no problems with the battery. So I think the battery drain is minimal.

[Gonzo]

One of the things we do to start is take a large Ziplock bag of Ice and place it in the freezer. Then we place a a large solid frozen meat for a crock pot meal in the refrigerator. Then we turn on the refrigerator. This will help get things started and you are slowly getting a meal ready for your trip. You also have ice to use. Use less energy and makes your trip a little better.


Gonzo

[Dougmott]

I am a brand new newbie so I don't know if my suggestion will be any help or not. This won't answer your question directly, but . . .



I put several frozen ice packs in my fridge the night before going camping. It seemed to cool it a little so I imagine it took less time for my fridge to reach the proper temperature when I turned it on.



Enjoy camping!!

[vickyr]

Our unit is also stored off site. I put ice packs in my frig and freezer in among the items. Then while we are driving my frig in on and we haven't had a problem yet. The packs also help when we are traveling between sites to keep everything colder in hot weather. We have not electric and are asked not to use propane due to chance of fire and there are a dozen other vehicles in the building. Great seeing another Lexington. We have a 2008 GTS, very seldom see another. Love ours

[pt35cruiser]

If your TT is in storage for an extended time, you should consider taking your batteries home and keep them on a battery maintainer. This will ensure that you have a full charge when you go to turn on the fridge.

[Texan99]

Originally Posted by pmsherman

The Dometic fridge in my Georgetown has a heater element in the doors to prevent condensation. In addition to this, Using propane requires activating the propane shutoff solenoid that also draws around 1A/hour. When I'm cooling down the fridge or boondocking when I'm trying to conserve battery power, I disconnect the fridge interior light and door heater at the fridge control panel.



Phil

Just FYI, there is no such electrical unit as A/hour-it's just A (amps). There is amp-hours which is amps x hours to determine battery capacity.

[Texan99]

Originally Posted by Lexington 283

Lexington 283......2005......recently acquired

At storage site, I'm not able to plug in

In order to cool down fridge overnight, prior to a trip, how much draw is it on my batteries?

Thanks, I'm new

Jerry

My owners manual says the fridge draws 3 amps from battery. So an overnight run of 12 hours would use 36 amp-hours of the 180 amp-hour capacity of two Group 27 deep cycle batteries just for the fridge. There are other loads as well such as LP gas detector, entertainment center, leveling system which on my fifth wheel amounts to about 1/2 amp IIRC (I've never figured out why it's that high). Running the refer would draw 3.5 amps total allowing you to run for about 26 hours to use 50% of battery capacity, which is recommended I think. Hope this helps. I added a second battery to mine just to be able to run the fridge longer.

[TitanMike]

Originally Posted by Texan99

My owners manual says the fridge draws 3 amps from battery. So an overnight run of 12 hours would use 36 amp-hours of the 180 amp-hour capacity of two Group 27 deep cycle batteries just for the fridge. There are other loads as well such as LP gas detector, entertainment center, leveling system which on my fifth wheel amounts to about 1/2 amp IIRC (I've never figured out why it's that high). Running the refer would draw 3.5 amps total allowing you to run for about 26 hours to use 50% of battery capacity, which is recommended I think. Hope this helps. I added a second battery to mine just to be able to run the fridge longer.

Only 3 amps?

That's about 40 watts or half the power draw of a small dorm room refrigerator without freezer.

Sounds rather optimistic -- unless it' a real small refrigerator.

That is unless it uses a swing motor compressor like an Engel that runs on 1-2 amp hours. They are however the size of one of those throw away foam coolers.

Just guessing but the 3 amp number is more likely the AC current draw from an inverter or shore power. Of course a pic of the label or spec page in the manual showing the DC current could certainly make me a believer.

[emm-dee]

Originally Posted by TitanMike

Only 3 amps?

That's about 40 watts or half the power draw of a small dorm room refrigerator without freezer.

Sounds rather optimistic -- unless it' a real small refrigerator.

That is unless it uses a swing motor compressor like an Engel that runs on 1-2 amp hours. They are however the size of one of those throw away foam coolers.

Just guessing but the 3 amp number is more likely the AC current draw from an inverter or shore power. Of course a pic of the label or spec page in the manual showing the DC current could certainly make me a believer.

Here’s a pic. 10 or so cf Dometic.

[TitanMike]

Originally Posted by emm-dee

Here’s a pic. 10 or so cf Dometic.

My apologies. Somewhere along the line residential refrigerators were mentioned and that stuck in my mind.

Yours is cooled by either 120V AC (heater) or LPG flame.

Now the 3 amp makes sense.


For a compressor type refrigerator 3 amps on AC might be doable but then the DC current through an inverter would be more like 30 plus amps.

Maybe some day someone will build an Engel type, full size, refrigerator using one or two swing motor compressors drawing less than 6 amps @12v DC These compressors are low draw and because they are essentially a solenoid with a "bouncing" armature rather than rotor, startup current is the same rather than up to 7 times the starting current in a regular compressor.

[samTummo]

I just installed a v/amp/AH meter on my 235ah bank. the parasitic Load including the fridge totaled 0.781 ah draw. 235 / .781 = 300 hours or 12.5 days. No worries.

SamTummo

[babock]

Originally Posted by samTummo

I just installed a v/amp/AH meter on my 235ah bank. the parasitic Load including the fridge totaled 0.781 ah draw. 235 / .781 = 300 hours or 12.5 days. No worries.

SamTummo

Which you would never want to do. May want do half of that to stay below 50% SOC. Can likely get rid of 0.5A of that by disconnecting the heater strip around the door. My current draw is a little abobe 0.25 with just the fridge on.

[samTummo]

Originally Posted by babock

Which you would never want to do. May want do half of that to stay below 50% SOC. Can likely get rid of 0.5A of that by disconnecting the heater strip around the door. My current draw is a little abobe 0.25 with just the fridge on.

Yeah, I realize the 50% mark, thanks.
What would happen if I did disconnect the heat strip? Besides using less power. How would I disconnect it? My old dometic fridge had a switch. I never noticed a difference on or off, other than heat reduction around the door.

Samtummo

[TitanMike]

Originally Posted by samTummo

Yeah, I realize the 50% mark, thanks.
What would happen if I did disconnect the heat strip? Besides using less power. How would I disconnect it? My old dometic fridge had a switch. I never noticed a difference on or off, other than heat reduction around the door.

Samtummo

Look around the back of the refrigerator and you may find a wiring diagram. Look for how and where it's connected and either snip wire or add your own switch in series so you can use it if you wish while on shore power.

If you can't find the wiring dagram on a large sticker in the back, check an online service manual.

It's possible you don't have one. I haven't been able to find one on mine and I get a little frost buildup around freezer door. Nothing that a no scratch spatula and towel can handle every few days though.

[babock]

On my Dometic 2612 I was able to cut a wire where the light and switch is inside the fredgerator. There are two wires there. One is for the light and one for the heater.


Of course this is for a Dometic. If you have another brand, you may not have one.

[5picker]

On my Dometic RM1350 the TWO door area heater wires easily disconnected at a junction inside the lower, outer cover.

As mentioned, look for a wiring diagram and you'll easily tell how your model is wired.