My Dometic refrigerator stinks (literally).

[bobioknight]

I plan on switching my 1993 cc over to a domestic 24" wide apartment style refrigerator today. Looks like the ones available draw about 300w. I have 4 6v house batteries, a generator and am wanting to add two 300w solar panels. I have an original Heart inverter/converter, and separate charger with a a little wizard on the wired controller. I am pretty handy with construction including electrical and mechanical once I get my head around what needs to be done. So the questions are:

With winter coming are solar panels going to be enough to keep the refrigerator running and cold?

Are two panels enough?

Will I regret messing with a domestic refrigerator, and since we desert camp a lot would I be better off just biting the bullet and stick to a 2 or 3 way refer?

Any suggestions on what parts to buy?

Does traveling up and down hills and slight parked unevenness hurt domestics?

[Skip426]

Just finished helping with a couple of conversions on the 24" fridges. Can't help with the solar question ; BUT; in the spec's on the fridges, there was a warning , about use with an inverter.
Both were in 5ers that didn't move out of their sites , so the inverter wasn't an issue with them.

[Smitty77]

No right or wrong way to go on this between all electric, or the 2/3 way method of refrigeration. If you go the all electric route, then for sure the math needs to be done to determine how you will feed it power while boon docking.

A few suggestions:
-Add a dedicated PSW inverter to just feed the fridge. This does two things for you: 1) PSW seem to feed most fridges a power they like more then MSW; 2) You then turn off your higher consumption inverter, until you need it, without shutting off the power to the fridge.
-Four 6V batteries are not a great deal of power. You don't say it, but if the are standard GC wet batteries you probably have 480AH (+ or - 25AH, depending upon actual brand). Which gives you about 240AH of usable power down to 50% SOC (Note, I like to use 70-75% SOC as my drop down to point. So for me, that would have been about 120AH available usage. Just my way of trying to have reserves, and also keep batteries alive a bit longer, as it is simple math of in/out on battery life cycles, that can determine how long batteries will live.)

So, you are probably on the light side of have enough AH's to span the overnight period, unless you do severe energy conservations overnight.

Bottom line here, is you may want to consider an upgrade of the battery bank size. And, of course to help you spend more money, AGM's have and advantage for boon docking and recharging from Solar Panels, as they can take a higher charge, and recover their charge faster then standard wet cells. (But, good chance your current inverter/charger will not properly be able to take advantage of this faster recharging, when the generator is running, or plugged in.) On the Solar Panel from though, if you pick a controller that has the ability to recharge AGM, it will be able to support them. (Even if you don't go to AGM's now, spend a bit extra and get a controller that has the ability to support AGM's. Money well spent for future upgrades down the road.)
-On Solar Panel. I like to look at my total demand all up. I then size my battery bank based upon supporting that 70-75% overnight discharge. I then recommend a minimum of 25% more Solar Panel wattage then the total of your battery bank AH's.

We do not conserve power in anyway, though I have shifted key lighting over to LED. But we run the microwave, many power warts, watch TV and power the DirecTV DVR along with running surround sound amp, and in the AM, still run a pot off coffee off of what I call the 'total overnight' AH consumption. And we are 8 times out of 10, between the 70-75% SOC range in the after the coffee pot has stopped brewing. And we do have the Samsung 18F fridge in our coach.

We do this with 800AH of Lifeline AGM's (X's 4 L16). I went ahead and upsized my solar panels to 1200W (X's 5 240W Panasonic/Sharp 48V high efficiency panels). I probably would have been fine the bulk of the time, with only 4 of these, at 960W (A bit less then my recommended 25% over AH bank size.). But the place selling me the panels, said they only would have 1 of these panels left, and made me a pretty good deal, so I went with the 5th panel.

The MidNite Classic 150 controller is set for the Lifeline AGM setting (A bit higher charge then other AGM's, so many chargers and solar panel controllers, come with two AGM options. One is for only Lifeline, and the other is for all other AGM's. And most of the newer chargers and controllers, provide an option to also customize the settings if you desire.)

We have a personal goal to start the night (non solar producing) at above 95% SOC. I'd again say 8 times out of 10 we are at 100% SOC via Solar Panel charging, by around noon, or early afternoon during the winter angles of the sun and shorter days. Very seldom need to run the generator. If in a place with shading, we'll do the heavy lifting in the AM with the generator, then let the Solar Panel top things off. This is where having the extra panel solar capacity, can offset the shading and less then ideal solar charging places that you can come upon along the way.

I also follow the standard recommendation, of not going over three days without getting to full 100% SOC. So if I run two days and are only at 95% SOC at the start of the evening, the third day I run the generator enough to be sure by the end of the day, that we're at 100% SOC. Keeps the batteries in good shape. Same thing is something happens, and I find we're down to 50% SOC, or even below (which we have never been), I'll do whatever I need to do to get back to 100% SOC ASAP. (We had the coach in for work, and the fridge was running, and they had it in a bay for three days. Somewhere along the way, it was unplugged form the shore power, and I just happened to pop in to review an item of repair, and noted we were down to 59% SOC, the lowest it's ever been on this bank of batteries. The owner of the shop noted my concern, walked out and saw that thought he power cord was plugged in, that that power outlet had no power to it... He was embarrassed, and apologetic - not typical of my experience with the shop, and it was very unusual as shop construction was in progress, and the electrical contractor had not informed them that that power outlet was 'without power'.)

OK enough, I've probably bored the heck out of you. Suggest you do a bit more reading in both the Boon Docking and Green forums, and you will find many informative threads. Some high knowledge resources available!

My best to you, and by the way. Nothing wrong with running the generator for a few hours. Or even going with say a Honda generator if you want something a bit more quiet. For sure, many ways to go!!

Have fun!!
Smitty

[bobioknight]

Thanks Smitty, that is a lot of information and helps with my wish list...

We do not run much power, keeping our phones and ipads charged, xbox and a small 20" lcd tv, wifi, coffee maker in the morning, a few minutes of microwave at lunch. Mostly we are outside, bbqing and riding. Night time, 1 hour of tv then out goes the lights. Our 4 batteries last us a few days without charging. But adding an electric fridge may be too much for them, I expected that 600 watts of solar would keep the batteries topped off during the day while we are outside while supplying the fridge with enough voltage to keep things cold until dark when everything cools down and the fridge may not run as often.

My Batteries are the wet kind and I would not be able to fit those monsters that you have in my coach, The battery trays are short allowing just enough space for 2 large chassis batteries and 4 standard house batteries.

Would 600 watts of solar have enough power to run the 115 watt fridge during the day while charging batteries so there is enough power to run everything through the night?


Frigidaire 11.5 cu. ft. Top Freezer Refrigerator - White 115V / 60Hz / 15A

Morningstar SureSine-300 Inverter 2680215300 W12 VDC115 / 600max VACPure sine wave $220

3x Sharp ND-240QCJ-BAA 240W Poly SLV/WHT US Solar Panel $250 each

[Smitty77]

Very general rule of thumb I was given to use, think the gent got this from reading solar info on AM Solar site (Good source of online info.), is to plan on 6amps per 100w of solar panel. And about 5-6 hours of peak sun per day (Of course, shading and clouds and time of the years make a difference in this.). So 36A X 5Hours = 180amps to the positive. (Reality, is even in not peak time, your putting out power early in the AM, and late into the day, just not peak output. So if no shading. Your going to be greater then this 180Amp by some amount.)

Is it 300W or 115W of usage for your fridge? Suspect you meant to say 115V, as in the first thread you referenced 300W? At 300W, that is about 2.5amp draw. So figure 3amp. (If it is 115W, then just under 1amp.).

It does not run 7/24, but when it is running, you should still have 36A - 3A = 33A available to feed other demands in the coach, and feed the charger to the batteries too. And of course, the Morningstar consumes power to, so take this also off of the power available to feed the charging.

We have 5 of the Panasonic/Sharp 240W 48V panels. So if you went with the X's 3 of the Sharp 240's, that would give you 720, for north of 42Amps available to you.

I'd also budget in, or plan for it in the future, a meter/monitor. The Bogart Trimetic line are very popular, and do a good job of keeping you informed on your battery health.

Another great resource, is Larry (Batterypro handle, Going Green section of the forum.) and his Starlight Solar out of the Yuma area. You might give him a call, have him help you double check your numbers, and give him a shot at providing you with a kit. This way you have an expert with a good reputation, to review things with, and assist in any trouble shooting that maybe needed in the future.

Best to you,
Smitty

[bobioknight]

Smitty, yes Volts... uggg, see why I need help. Ok will give them a call, but your explainations have really helped me understand the process, Thank you sir.

[twinboat]

My 7.5 c.f. Avanti apartment size refrigerator draws .9 amps AC.

That converts to 9 amps DC + the .5 amp inverter draw, thru my Xantrex PS2000 inverter.

This is real time data as I am sitting in front of my battery monitor.

If you are getting your data off the fridge, I believe it includes the defrost cycle and both doors open with the lights on.

I use 10 amps for my calculations and a 50% runtime.

That works out to 5 AH, or 120 AH a day for refrigeration.

Add in the 600 watts of solar and you will charge your batteries and cover your refrigeration use for 6 to 7 hours a day even with partial sun.

I am charging 13 amps thru 675 watts of solar on an overcast day as we speak, here in the FL. Keys.

What you are planning should be an economical and usable system.

Here is a pix of the sky.

[birdhunter]

If you Boondock a lot propane fridge is the only way to go. I suppose if you want to invest in a massive amount of solar panels compressor fridge would be ok boondocking.

[twinboat]

Originally Posted by birdhunter

If you Boondock a lot propane fridge is the only way to go. I suppose if you want to invest in a massive amount of solar panels compressor fridge would be ok boondocking.

I don't nessessery agree with your statement.

I'm sitting on my deck looking out at over 250 moored, liveaboard boats, who stay for the winter. (No hookups out here ).

Over 90% have refrigeration. 75 to 80% have solar power and Zero have propane refrigerators. ( No unattended propane devices allowed by insurance regs).

I only see 1 boat with a "massive" 1000 watt solar array. Yet we all keep our food cold. Yes we have backup generators, just like RVs, but limit there use.

It also seems as though the RV industry is moving away from gas refrigeration, with more effecent compressor systems.

[Smitty77]

Originally Posted by twinboat

My 7.5 c.f. Avanti apartment size refrigerator draws .9 amps AC.

That converts to 9 amps DC + the .5 amp inverter draw, thru my Xantrex PS2000 inverter.

This is real time data as I am sitting in front of my battery monitor.

If you are getting your data off the fridge, I believe it includes the defrost cycle and both doors open with the lights on.

I use 10 amps for my calculations and a 50% runtime.

That works out to 5 AH, or 120 AH a day for refrigeration.

Add in the 600 watts of solar and you will charge your batteries and cover your refrigeration use for 6 to 7 hours a day even with partial sun.

I am charging 13 amps thru 675 watts of solar on an overcast day as we speak, here in the FL. Keys.

What you are planning should be an economical and usable system.

Here is a pix of the sky.

That's great that you have real numbers to share, and that is a thrifty consumption levels for sure! And great to point out what you're seeing as far as actual runtimes. In hot weather, with the refrigerator side of the coach baking in the sun, I'm seeing our Samsung run about quite a bit more during the daytime hours. And, I also use the daytime hours to generate ice cubes, which uses more power to. Always turn off the ice maker at night, and yeah, don't need to make ice ever day.

As far propane only for boon docking, no question it is a very efficient way to go for power management... But, a properly size battery bank and solar panel system, can easily support long period of boo docking too. We spent 7 days boon docking in one stretch last year, and grey tank was our main restriction for going longer. Ran the generator two times, both times are when the DW was cooking for more then 30 mins in the Convection oven. (Under 30 mins, we just run off the batteries. And she does cook earlier on those days, 2:30-3:00PM - to allow more time for the solar panels to recharge back up.) And while we do have a moderately good size AH Bank of Lifelines at 800AH, and the same on the solar panels at 1200W - these are for sure no where near some of the systems being installed in some coaches today. (I know one gent with a 42' coach, that has 1200AH battery bank, and 1600W of solar. Due to medical equipment needs.)

The world of Lithium banks, are also making a positive change on going all electric too.

Best to all,
Smitty

[bobioknight]

Originally Posted by birdhunter

If you Boondock a lot propane fridge is the only way to go. I suppose if you want to invest in a massive amount of solar panels compressor fridge would be ok boondocking.

I understand what you mean, but these days with the low power consumption refrigerators, especially in the size that fits my rig 10-12cf 2 door, the voltage draw seems to be low enough that the high volt panels even on cloudy days should be able to handle it. Probably not in state parks full of big red woods, so that is a consideration I need to think about, but boondocking I have a feeling these days that it will be possible. I have asked a irv2 member to set me up with a system so let's see what the pros think I get some feedback, the times are a changing.

[birdhunter]

Originally Posted by twinboat

I don't nessessery agree with your statement.

I'm sitting on my deck looking out at over 250 moored, liveaboard boats, who stay for the winter. (No hookups out here ).

Over 90% have refrigeration. 75 to 80% have solar power and Zero have propane refrigerators. ( No unattended propane devices allowed by insurance regs).

I only see 1 boat with a "massive" 1000 watt solar array. Yet we all keep our food cold. Yes we have backup generators, just like RVs, but limit there use.
It also seems as though the RV industry is moving away from gas refrigeration, with more effecent compressor systems.

I have about 400 watts of solar + 6 T105 Trojans. I have a 3 cubic foot Energy Star rated freezer in addition to my large Dometic fridge. I have Dish Network DVR, the inverter is on from about 4 p.m. all night. I have to also run my Hurricane a bit at times in the summer since it gets cold at night. When I run the freezer which uses significantly less energy than one of those Samsung refrigerators that everybody is putting in, it leads to significantly increased generator time. Yes if I had 800 watts of solar and 800 amp hours of life lines it would probably be ok. In my book that's a fairly massive setup, but that's just my opinion.

[BRex45]

Smitty 77

Could you advise where you purchased your high powered solar panels?
Any recommendations where to buy in the Pac northwest?

Thanks for replying, our Intrigue has ZERO = NONE solar panels and would at least like to get started on that route.

Thanks!

[deandec]

Just an observation.

I have found that my 100W solar panel does not keep up with the energy draw of my propane sniffer and my link 2000 direct wired volt meter during Sacramento winter. My four 6V batteries decline to about 12.3dcv over a period of 4 days if I leave the house battery switched on.

A separate inverter just for the new refer and a separate battery shut off switch for that circuit might be more efficient for your solar application (ie shut off the house battery for everything but the refer).