Draining Battery! ARGH!

[joep218]

So, quick question for the group again, sorry just learning lots here. Anyway, something is draining the battery in my Palomino 1251 and I don't know what I should do or best practices here but the rig was rocking and rolling for about a 5 hour drive and have been hooked up to my house AC power for the week before with the fridge on and running, switched to DC power on the fridge for the drive and then got to our spot, and turned the fridge off for the night just to try and conserve battery but wake up in the morning and the low battery beep is blaring in the Carbon Monoxide detector.

I am wondering is my fridge running that much power down if it is on DC? Should I be running it mainly on propane? Just wondering how much I need to prepare when heading out on the road.

I then started the truck and it charged just a bit ran for about 20 min at idle and stopped the beeping. Needless to say I didn't run the fridge on DC anymore. But then I took off and began to drive home, turned the fridge back to DC power while driving, when about an hour and a half and then stopped for lunch and sure enough the low batter is beeping again right after turning the truck off.

Here is the long and short:
-What is the best way to use the fridge?
-What is the length of use for the truck camper to run without needing to be charged, so how many days in the backcountry? 1/2?
-Does the heater pull a lot of energy? I used it only once but maybe that is it?

Just a bit bummed as I was hoping that this would last me a weekend two night before needing to plug in. I have nothing else really going on, no water heater or anything just wanting some cold beers and enough propane to cook a couple meals! haha!

Any advice would be AWESOME!

Thanks for all the help!

[Black]

I usually go without power for a weekend easily on my battery.
Why don't you operate your fridge on propane ? That's what I do, even while driving, the truck should keep your battery charged.
Maybe you need a new battery ?

[RSchleder]

The frig will "chew-up" your battery when camping without 110V coming into the RV. I am surprised, however, that your battery didn't charge up enough during the 1 1/2 hour drive to allow you to stop for lunch without a low battery reading.
Tho answer your question, here's how we run our frig:

Running down the road---12V
Parked with land line-- 110
Parked without a land line--propane

This has worked for us for the past 25 years on 10 different RV's. Good Luck!

PS- are you sure that you have a 12v charge line running thru the 7 pin connector from the tow vehicle to the trailer?

[bikendan]

joe, in case you don't know, out all the FR brands, only one makes a truck camper. Palomino.

so, there aren't a lot of truck camper owners here to help you.
but we can help with general RV things that are common to all types.

i'd say you need to have how much charge your alternator is sending to the fridge. the fridge on DC may be using up battery power quicker than your truck can recharge it.

you should be switching it to propane when you stop driving. propane goes a long way.
yes, the furnace is the biggest eater of battery power in your rig.

[bubbubouy]

As stated above a fridge is hard on a battery when running on 12v. Just a word of caution, if the 12v feed from your truck is hot all the time as apposed to being switched with the ignition be careful not to drain both the camper and truck battery.

My truck is hot all the time, but I am not sure all trucks are.


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[Witch Doctor]

All above are true statements, but if I'm not on 110v I'm on propane. I do not have the 12v option as yours being a 5th wheel, but even driving my refer is on propane. Propane is the economical and best way 12V will drain your battery quick. It's resistance heating. In other words it's like turning on a heat strip.

[joep218]

Awesome crew! Thanks for the quick replies. I will keep you posted and do some tests in the driveway this week and see what comes of it! Great to know on the propane that it should be the go to.

Appreciate it!

[wagonrd]

The furnace fan quickly kills the batter in my Lance slide in. When this happens I can't start the propane fired Onan generator. I therefore installed a Bodiak front hitch on my Dodge dually and mounted a 2000 watt Honda generator. Now I can lay in bed in the morning reading the news on my Droud with the furnace on. On getting out if bed I fure up the Honda to recharge the battery. As the day heats up and I want airconditioning, I fire up the 4000 watt Onan and keeo the camper cool

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[JD4x4]

I have an older Starcraft slide in, and I always use propane for the fridge when not hooked up to and using 110v. The refrigerator heater element draws a lot of current and can kill a battery pretty quick.

The fan in the propane heater probably draws about a quarter as much (or less) than the fridge element, but if I run my heater all night (like in 30 degree weather) I still try to run the engine for 15 or so minutes in the morning to recharge the camper battery.

The rough math is that it takes 10 times as many amps to run something on 12v as it would on 120v. I think my small Dometic 2310 draws 10 or 12 amps on 12v.

[garbonz]

The RV frigs are ammonia absorption units that use a heating element and heating elements use a lot of amps. I remember my last 3 way as pulling 8 plus amps on 12 volt. AND that is ALL the time 24/7 not cycling. SO a typical 12 volt group 24 battery of 80 amp hours would only last 6 or so hours before the low voltage would kick on.

RUN on propane unless plugged into shore power. That is why many newer units are only 2 way, without the 12 volt heater.

Ironically, a conventional compressor frig with 12 volt power uses probably only 25% as much power as a RV model.


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[pgandw]

Originally Posted by garbonz

Ironically, a conventional compressor frig with 12 volt power uses probably only 25% as much power as a RV model.

I wish that were true. Even the smallest marine compressor fridges drew 5 amps running. The trick was to insulate the fridge enough to drive the "on" time to less than 50%. The rule of thumb was you had to add 2" insulation, and preferably 4" around the stock ice box to get a reasonable (non-battery killing) duty cycle. Just like in our campers, space for insulation comes out of space for the fridge or other valuable storage. A close friend installed one of the units in his camper, but had horrible results due to lack of insulation.

If you wanted a decent-sized fridge (or a freezer) on a sailboat, you either had to go to an engine-driven compressor with hold-over freeze plates (again loses space in the fridge) or 110 volt generator power.

Even though compressor units are more somewhat more efficient, the requirement for electricity to drive the compressor is a killer in small campers. The electricity issue is why much of the less-developed world still uses ammonia absorbtion refridgeration. It's simple, it works, and it's much easier to carry enough LP than it is to maintain a battery bank. In the marine world, LP is a frowned-upon fuel, and open flames are a no-no.

just my experiences
Fred W

[Witch Doctor]

Originally Posted by pgandw

I wish that were true. Even the smallest marine compressor fridges drew 5 amps running. The trick was to insulate the fridge enough to drive the "on" time to less than 50%. The rule of thumb was you had to add 2" insulation, and preferably 4" around the stock ice box to get a reasonable (non-battery killing) duty cycle. Just like in our campers, space for insulation comes out of space for the fridge or other valuable storage. A close friend installed one of the units in his camper, but had horrible results due to lack of insulation.

If you wanted a decent-sized fridge (or a freezer) on a sailboat, you either had to go to an engine-driven compressor with hold-over freeze plates (again loses space in the fridge) or 110 volt generator power.

Even though compressor units are more somewhat more efficient, the requirement for electricity to drive the compressor is a killer in small campers. The electricity issue is why much of the less-developed world still uses ammonia absorbtion refridgeration. It's simple, it works, and it's much easier to carry enough LP than it is to maintain a battery bank. In the marine world, LP is a frowned-upon fuel, and open flames are a no-no.

just my experiences
Fred W

My boat unit with the plates where R-12 when installed, I was able to get that all over the world, but when I returned to the USA I had to convert to r-134, mine also was 110v and ran off a inverter with a 3 stage charger(pure sine wave) supplied by 4 battery banks of D-8's charged by solar plus a water maker that produced 7 gals per hr. from sea water. Plus ran my navigation system, short wave and weather fax. All done by solar, if I didn't produce enough juice because of clouds, I had to kick on my 50 hp engine with a 150 amp alternator. for 2 hr's per day. Those were the good old days.

[garbonz]

My point is that a DC heater element on 24 hours with an 8 amp draw uses at least 4 times more energy than a 4 amp compressor that cycles on and off. Please compare dc to dc and not DC to Propane.

A RV refrig with Ammonia absorption, should not be used on 12volt unless no propane is available. That was the OP original Q.

USE the PROPANE for an RV frig, unless plugged into shore power.


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[garbonz]

Originally Posted by pgandw

I wish that were true. Even the smallest marine compressor fridges drew 5 amps running. The trick was to insulate the fridge enough to drive the "on" time to less than 50%. The rule of thumb was you had to add 2" insulation, and preferably 4" around the stock ice box to get a reasonable (non-battery killing) duty cycle. Just like in our campers, space for insulation comes out of space for the fridge or other valuable storage. A close friend installed one of the units in his camper, but had horrible results due to lack of insulation.

If you wanted a decent-sized fridge (or a freezer) on a sailboat, you either had to go to an engine-driven compressor with hold-over freeze plates (again loses space in the fridge) or 110 volt generator power.

Even though compressor units are more somewhat more efficient, the requirement for electricity to drive the compressor is a killer in small campers. The electricity issue is why much of the less-developed world still uses ammonia absorbtion refridgeration. It's simple, it works, and it's much easier to carry enough LP than it is to maintain a battery bank. In the marine world, LP is a frowned-upon fuel, and open flames are a no-no.

just my experiences
Fred W

it is true when on 12 volt.


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[pgandw]

Originally Posted by garbonz

it is true when on 12 volt.


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I disagree. Make sure you are comparing like cooling capabilities - watts/BTU, or at least same size fridges. A 5 amp/12 volt freon compressor - I've never seen one actually draw less than 5 amps - won't cool more than 3 cubic feet, and less if you want a 50% or less duty cycle. I can cool the same 3 cubic feet with a 75 watt (6.25 amp) element running continuously on ammonia absorption. So at best, the freon compressor rig is slightly more than twice as efficient.

As things scale up in size, the freon compressor does better and the ammonia absorption does worse, particularly on 12 volts. As size of cooled space goes up, the ammonia absorption needs added fans and heavy duty wiring to maintain performance. Freon compressors don't scale down well below a minimum size - the dorm refridgerators compared to a full size fridge are an example of how much less efficient small freon systems are.

I assume that because this thread is located in the truck camper section that we are talking a small fridge, certainly less than 5 cu ft. And in that size range, a freon compressor rig is just not 4 times as efficient as ammonia absorption.

Fred W

[garbonz]

Gosh Fred, I sure don't want to disagree. But you are being ENTIRELY theoretical. and it could be as easily 4 times as 2 times.

THE POINT IS TO NOT RUN YOUR AMMONIA FRIG ON 12 VOLT, which is the OP's Concern.

Lets let it go.

I've been sailing for 40 years and have had a variety of compressor frigs and NON of them have drawn more than 4 amps, either holding plate units such as the technautics or the adler barbour conventional. And mostly they have a 25% duty cycle, not 50%.

Your experiance may vary, obviously, but let me have mine.



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[pgandw]

For the OP, that's a very nice unit. However, all the add -ons may have parasitic electric draws that add up (in addition to the heater and refridgerator). I'm talking items like the propane and CO detector, battery monitor, fire detectors, any tank level indicators, stereo, etc. Those combined can add up to an amp or two continuously. Which is why the battery should be disconnected when the unit is not being used.

The amp draw of the fridge can be found from the specs in the fridge manual - take the DC element wattage and divide by 12. Typical draws for the smaller fridges without freezers in fold-down campers are 5-6 amps when running on DC. Your heater fan also draws 4-5 amps when running.

The problem is that your battery is likely a single size 24 (unless you deliberately upgraded). The capacity of said battery when fully charged to fully discharged is about 80 amp hours. Usuable capacity (that doesn't ruin the battery) is only 40 amp hours. As you can see, you can run out of battery real fast with both the heater and fridge.

I have an A-frame (A122) where the only 12 volt loads when dry camping are smoke alarm, propane and CO alarm, LED interior lights, water pump, and the biggie - the heater. Fridge is running on propane in that situation. We realized a single size 24 battery was not going to cut it for a long weekend in Colorado fall/spring weather. So we added a second size 24 battery to double our reserve for running the heater.

Because it is a towed trailer, battery charging while driving is a natural with the tow vehicle fully wired with the 7 pin connector. So I arrive at the site with a fully charged batteries, and with the fridge on DC. I switch off the fridge before I disconnect and then re-start it on propane or AC after disconnecting and leveling.

Other have said it - use AC for the fridge when available. Use propane when vehicle is not in motion, and no AC available. Use DC when driving. This assumes your Palomino battery is being charged by your truck alternator when the engine is running.

I'm not familiar with truck bed campers, so I'm not sure that the electrical connection between camper and truck is actually happening. The brochure talks about a battery charging station and battery quick disconnect - are those correctly set up for your camper battery to charge while driving? If the truck is not supplying power to the camper, putting the fridge in DC mode while driving will eat the battery in a matter of hours.

OTOH, I would not want to drive a truck with camper attached in the bed, and a fridge with open flame running (propane operation). I would certainly want to turn the fridge off of propane while refueling the truck. So making sure that the truck is charging the camper while driving is important (to me).

for garbonz, from the Adler Barbour Cold Machine Manual:

AC/DC O

PERATION

For the ColdMachine, figure approximately 5 amps when running. The average draw, as the ColdMachine cycles on and off, is 1.8 to 2.4 amps for most 4 to 8 cubic foot/0.11 to 0.23 cubic meter iceboxes with average (3 inch/7.6 cm or more) rigid polyurethane foam insulation.

(My comment) The duty cycle calcs based on these figures come out a minimum of 36% for the 4 cu ft fridge with 3" (or more) rigid foam insulation.

[garbonz]

Just make sure you have a diesel truck and don't worry about it. Unless someone has a major whoops of spillage, it is infinitesimally rare for the lower explosive limit of gasoline in air to be reached during refueling, even relatively close to the point of flow.

Among the things there are to worry about, that would not be one. If you are smart and have a diesel truck, your problems are solved. I don't even like driving in a gasoline vehicle AT ALL, they are just a bomb waiting to happen.

MOST truck campers are wired exactly like a trailer is, and use their own running, brake and turn signals since the back of the camper blocks the truck lights. Many have a standard 7 pin plug on them and a short pigtail to run from the truck trailer plug to the camper. Lance have their own proprietary plug with high gauge wire to carry the current and thus are well equipped to handle the refrig load.

Most recent Refrigs (my 2005 included) don't even have a 12 system.

I don't know what the point of the comments on the Adler Barbour are, but I gave up on going down that dark alley.

Regards