Residential fridge off battery power?

[rcharrette]

Hi all, we've had our current camper (Kodiak 240BHSL) for 3 years now and have been traveling in it full time for the past year. Now we are looking for something bigger, a 5th wheel. The one we are looking at is a Gateway GW3800RLB. What we are finding is that when buying new you can opt for a 2 way fridge (propane/power) but all the used ones we've come across seem to have the residential fridge (no propane) with 1000 WATT inverter. We do ALOT of dry camping and the salesman told us the stock batteries could power the fridge for about 6 hours. That would not even get through a night!

Anyway the nice thing about the residential fridge is it's large so I'm wondering if it would be possible to reasonably get enough battery power to the fridge to power it for a day or so (we have a generator to top up) or should we just stick with propane and go worry free? I don't want to have to run a generator constantly just for the fridge.

Thanks,

Randy

[NoDirectionHome]

I'm a proponent of solar if you are going to boondock. You need to do a power budget. If you get to choose the fridge, the newer variable frequency drive ones (26 cu-ft) only use 650 watts/day, so pretty easy on the overall power budget.

[Yarome]

I prefer propane/power/solar/worry free, but a residential reefer is MORE than doable. As you mentioned.. more space and typically more reliable, but you give up length of stay (generally speaking) or have to rely more heavily on your genny. I wouldn't rely on a dealer to quote battery length times.

 

As Stekay mentioned.. first step is an energy audit to determine what size of heart (battery bank) you'll need. Some rigs have very limited battery compartments. Space limitations might be a factor on how much you'll actually be able to pack without modifications.

 

If you full-time and generally boondock, solar makes a great deal of sense... if you're budget allows... but battery bank should be first and foremost on your list.

[Daveh]

You have asked what seems like a simple but is really a very complicated question. Many of us began our education here http://www.jackdanmayer.com/rv_electrical_and_solar.htm. I like the option of propane but since you are a boondocker and going to a bigger unit now is the time to consider a budget for a battery upgrade and solar. Also, be sure you have a very good battery monitor such as the trimetric (http://www.bogartengineering.com/products/trimetrics/) because the real question is not how much your batteries can handle but how much they can safely handle without destroying them.

[Al F]

......... Anyway the nice thing about the residential fridge is it's large so I'm wondering if it would be possible to reasonably get enough battery power to the fridge to power it for a day or so (we have a generator to top up) or should we just stick with propane and go worry free? I don't want to have to run a generator constantly just for the fridge.

Thanks,

Randy

The simple answer is "yes you can reasonably get enough battery to power the fridge". The complicated answer is you will need more battery than the 1 or 2 batteries that typically come with the stock 5th wheel.

 

Since you do ALOT of dry camping just running the generator to top off your batteries is not a practical solution. If you have the typical lead acid wet cell or AGM batteries you really need to bring the batteries to 100% charge, or at least very close to 100% every week. If you don't you will start loosing the capacity of the battery bank. It can take 12-24 hours of generator power to get a battery bank to a 100% charge especially if you typically discharge to 50% capacity. BTW you should never discharge beyond 50%. This is one reason why solar works so well. A day of full sunshine gets you close to 100% or it can be at 100% if you haven't discharged your battery bank beyond about 25%. Also for longest battery life, not discharging beyond 25% discharge (75% full) is best.

 

I complement your salesman for being direct with you about the battery life. If the trailer only has 1 battery, the 6 hours is probably correct. Even with 2 batteries you will spend lots of generator time trying to keep the batteries charged.

 

As mentioned earlier many of us started our RV electrical and battery education at Jack Mayer's website Jack Mayer RV Electrical

 

Here is a list of websites with excellent info about RV elect & batteries. This list starts with pretty basic info and gets more detailed the farther down the list you go.

The 12volt Side of Life (Part 1) Batteries

The 12volt Side of Life Part Solar & Inverters

RV Dreams Electrical Systems

Jack Mayer RV Electrical

Jack Mayer Battery & Charging

Deep Cycle Battery Information

Deep Cycle FAQ, Battery Mfg Names List, and

[oldjohnt]

rc, you ask a great very typical and relevant question

 

" I'm wondering if it would be possible to reasonably get enough battery power to the fridge to power it for a day or so (we have a generator to top up) or should we just stick with propane and go worry free? I don't want to have to run a generator constantly just for the fridge.

 

Of course ONLY YOU can answer it and the answer depends on YOUR needs and YOUR budget.

 

A) If you require the "larger" fridge ??,,,,,,,,,,,If you are wiling to invest in more solar panels, a quality charge controller, enough batteries (and space to store them safely) and a quality Inverter big enough to power the fridge HEY ITS VERY DOABLE AND I SAY GOT FOR IT. Its going to require more money DUH but you have that huge fridge if needed for extended dry camping. PLUS you have solar energy for other RV uses.

 

If you can get by with less fridge space and run an LP Gas/Electric fridge, then you can get by with less solar and batteries which saves some serious bucks.

 

OF COURSE you need to research the current draw and time the residential fridge might be required to run in a typical day. I did that on my small compressor powered fridge using a Kill A Watt meter so I obtained how many AMP HOURS of energy was required in 24 hours. Once you have that figure you can calculate how many batteries (total AMP HOURS) and how many solar panel watts is required STILL SUBJECT TO HOW MANY HOURS AND SUNLIGHT AND ANGLE.

 

When sizing batteries and solar remember NOT to discharge your batteries over 50% and I prefer no lower then 20% to 30%. Then there's the whole other decision to run conventional flooded lead acid batteries (requires proper venting and maintenance) or AGM or Lithium !!!!!!!!!!!!!

 

Then there's the decision to utilize permanent flat mounted solar panels or a safe and structurally sound tilting arrangement which can get you by with less watts due to increased harvest versus permanent flat BUT SAFETY AND STRUCTUE IS A CONSIDERATION

 

YOU MUST DO THE MATH TO OBTAIN HOW MANY AMP HOURS OF ENERGY USE THE FRIDE PLUS OTHER DEVICES REQUIRE,,,,,,,,,Then (first choose type) size batteries to have the energy storage Amp Hour capacity such that you don't discharge them too much over 20% to 30% if possible on a typical day,,,,,,,,,,,Then size your solar panels (and mounting method) so on a typical day you can fully recharge the batteries OF COURSE SUN AND ANGLE AND TIME IS A FACTOR and factor in generator size and battery charger size and type for use in the worst case like not much sun.

 

If you do a lot of extended dry camping I can envision the use of at least AGM battery technology and even the more expensive Lithium based, but you're talking huge up front bucks remember !!!!

 

Sooooooooooo run an energy audit,,,,,,,,,,Then price out the LP versus residential fridge cost,,,,,,,,,,,Then calculate and price out Solar and Batteries and Inverter,,,,,,,,,,,THEN THE CHOICE WILL LIKELY JUMP OUT AT YOU SUBJECT TO YOUR BUDGET.

 

I'm operating a small compressor fridge 24/7 weeks at a time dry camping and keeping charged with only 470 flat mount solar watts and 450 Amp Hours of battery energy storage and a 2 KW PSW Inverter BUT YOU NEED MORE THEN THAT TO RUN A LARGER FRIDGE.

 

You gotta do the math then the answer will be right in front of you

 

John T