Confused in Solar & fridges
Submitted: Sunday, Jun 10, 2007 at 10:42
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Member - Brian H (QLD)
Went to the
Brisbane Caravan and Camping show and was looking at buying a fridge and also a 80 watt solar panel to help charge the battery for the fridge while at rest.
I was looking at two fridges either a trailblazer or the Outback. This is not a fight of which is the best fridge :) yet lol mind you has anyone got an Outback please comment :)
I run a 150 amp battery and figured at best charge I deduct 20 % leaving it 130 amps the trailblazer from all accounts uses 1.9 amp per hour fridge and 1 as freezer (could be the other way around) and the outback was similar but he said average it out at 3 amps per hour.
Anyway I'll just work with the trailblazer I figure over 24 hours on the higher setting lets say it uses 48 amps a day (leaflets says 30 odd) so I assume it will get 2 days safely if conditions are right without going for a drive.
Now specking to 3 different
places for solar one said I could use the 80 watt and that will do, another said no I will need 2 x 80 watts = 160 watts if used as a fridge and 3 x 80 watts = 240 watts if used as a freezer. The other did not show to much interest and shoved a leaflet in my hand and said read this and it should explain it. He lost me there.
Now as I understand it ( I may have misunderstood) but an 80 watt delivers about 4 amps an hour so why will one 80 watt not do the trick. I understand if i park in the shade and its cloudy etc etc but if panel is in full sun I'm guessing I can look at getting 6 hours sun a day giving me 24 amps back in the battery.
Basiclly I did not buy a fridge (bit bleep off really) or anything cause if solar will not do it will have to look a small gen set (not my preferred option).
The reason not to buy the fridge was basiclly the trailblazer was 60 litre was 1600 (approx) and the outback I would have got 2 at $680 at 55 litre each one as a freezer and the other as a fridge and would have been $1320 was the amps draw and solar tossed my out and did not want to go down a wrong path. Id rather get it right first time.
So I ask the people (with hands on experence) whom have fridges how long does yours last and does solar charge your batteries or not worth going that way.
Your assistance most welcomed.
Brian
Reply By: obee - Sunday, Jun 10, 2007 at 11:25
Sunday, Jun 10, 2007 at 11:25
One has to ask ones self how often the rig will be used. Will the motor be run every day and for how long. Point is, the alternator on the vehicle pumps out an enormous amount of amps even at idel, and a cranking battery that is not run down too much will absorb same without cutting off too much of the overall life of the battery.
Ok, how much fuel is used by the motor at idle and how many times a year are you going to be doing this?
A small gennie like
mine (1000 watts) will only pump 4 amps an hour and consider the noise at the same time plus space.
Friends I traveled with had two 80 watt panels and after two days the battery would not crank the motor. The conditions were not ideal and seldom are. The battery, by estimation would have lost much of it's useful life and that equals dollars.
Traveling the way most people do, on the road every day, I reckon the car battery will manage (I should say diesal battery. Theyre bigger) with a top up from the motor close to end of day. The battery wants to be fairly new and in good shape but. Otherwise the gennie is a good back up or an extra battery like the one that sits in the boat doing nothing most of the time.
If you are going to spend the hols in one location then the solar panels are an option but they are expensive for what they do and fragile to boot. Deep cycle batteries are probably better in this situation. The yachties find them useful because they are out in the sun every day and only set up once. They also favour wind gennies which are only set up once and supply a lot of amps. I havn't seen mention of this option in these columns tho. Probably would be a pain to set up at every stop and you wouldn't want one to fall on you going at full kilt either.
All this is what I have learned from reading these columns and the articles on the subject also on this site. There are other intenet sites that deal with the subject too like this one, Site Link.
I invite critism of any of my
views, way to learn. But leave my typos and spelling out of this. LOL
Good luck
Owen
AnswerID:
245863
Follow Up By: Member - Syd R (QLD) - Sunday, Jun 10, 2007 at 13:25
Sunday, Jun 10, 2007 at 13:25
Hi Owen, I have an Australian Off-road Camper Cross Terrain with 2 x 85watt Sony solar panels connected to 2x120amp/hr gel batteries via a digital controller.
We have been travelling the outback SA and NT now for 6 months. We run a Eva cool 60litre Fridge and freezer compartment and we have had no trouble. The solar panels work
well even if we are
free camping for 5 days or more the batteries show full charge at the end of the day. I also run a 40 litre Engel for the drinks and 35 litre Waeco on low setting for the Fruit and Veges off the Exide Extreme auxiliary battery in the Landcruiser.
When the auxiliary battery gets low I plug in the solar panels via an Andersen Plug extension lead I had made (Heavy Gauge) into the fitting on the rear LC and the solar panel trickle charges the Exide Extreme auxiliary in the LC.
It works
well so far. But we have had a lot of sun where we have been.
FollowupID:
506848
Reply By: Member - joc45 (WA) - Sunday, Jun 10, 2007 at 11:59
Sunday, Jun 10, 2007 at 11:59
Hi Brian,
At best, the 80W panel will extend your stay before having to recharge it.
-The 80W quoted is for max sunlight, so unless you are tracking the sun all day, you will not get your calculated current into the battery.
-Then there are the days when it is overcast but hot as one finds in the tropics (so the fridge is working overtime) and you may see only 1 amp going into the battery. Very frustrating.
-And then there is temperature; the 80w is quoted at 20deg C, and you will find in full sun that as the panel temp increases, so the output drops. I proved this by chucking a bucket of cold water over the panels and watched the output climb by about 20%. (I briefly thought about concocting some machine where I could keep the panels cool with continuous water flow, but gave up on the idea!).
But two 80w panels should cope with what you are doing, esp if you are using a pretty efficient Trailblazer, which has excellent insulation.
I use a 39L Autofridge and three x 42W panels, and I get by fine, but must leave it out in the sun all the time. And that includes the use of 2-3 CFL flouros at night, which sucks a few more amp-hours out of the battery. And occasionally the lappie as I watch a dvd or update the journal.
Also to be considered if recharging the battery (and it's a large one!) is the recharge time, roughly calculated (stating the obvious) as amps x hours to give amp-hours. If running a gennie, the 12v output does not have a very high output - probably around 5 amps, which translates to an all-day job to recharge the battery. Consider a decent high-output charger running off the 240v output of the gennie.
Check the budget again and reconsider - in years to come you'll be pleased with the choice of solar, with the total silence you get out in the bush, and no smelly containers of fuel.
cheers,
Gerry
AnswerID:
245871
Follow Up By: richor - Sunday, Jun 17, 2007 at 12:29
Sunday, Jun 17, 2007 at 12:29
Gerry,
I am interested to know how you tilt your panels. I can't see any stays etc. from the photograph of your vehicle. Can you vary the angle of tilt? I have two 80w panels on top of my vehicle and want to tilt them as you are doing.
Regards,
Bob
FollowupID:
508252
Follow Up By: Member - joc45 (WA) - Sunday, Jun 17, 2007 at 16:55
Sunday, Jun 17, 2007 at 16:55
Hi Bob,
I only use one stay, which is hidden in the photo on the far corner. I mainly use it to prop up the panel when accessing stuff stowed underneath, but on days when the fridge is working overtime or it's cloudy, I will prop it up to maximise output. The panel can flex a bit, but this is not a problem provided the wind is not too high. When sitting down, the panel is still at a 10deg angle due to a spare tyre stowed at the back of the roof rack.
Basically, the three panels are set in a 40x40mm aluminium angle frame, which, along with bolting the panels together, makes a good strong structure. At the front and rear is a section of 20mm square steel tubing, with end plates on the front tubing which make a hinge. A picture would be best here to describe it, but it's all dismantled at the moment - email me at gezza90 at amnet d0t net d0t au and I'll try to put together some pics.
Gerry
FollowupID:
508281
Reply By: Member - Syd R (QLD) - Sunday, Jun 10, 2007 at 13:45
Sunday, Jun 10, 2007 at 13:45
Hi Owen, I have an Australian Off-road Camper Cross Terrain with 2 x 85watt Sony solar panels connected to 2x120amp/hr gel batteries via a digital controller.
We have been travelling the outback SA and NT now for 6 months. We run a Eva cool 60litre fridge and freezer compartment and we have had no trouble. The solar panels work
well even if we are
free camping for 5 days or more the batteries show full charge at the end of the day. I also run a 40 litre Engel for the drinks and 35 litre Waeco on low setting for the Fruit and Veges off the Exide Extreme auxiliary battery in the Landcruiser.
When the auxiliary battery gets low I plug in the solar panels via an Andersen Plug extension lead I had made (Heavy Gauge) into the fitting on the rear LC and the solar panel trickle charges the Exide Extreme auxiliary in the LC.
It works
well so far. But we have had a lot of sun where we have been.
AnswerID:
245885
Reply By: Member - Brian H (QLD) - Sunday, Jun 10, 2007 at 17:07
Sunday, Jun 10, 2007 at 17:07
Thanks for the advise. I missed a bit of info ........ I have a duel battery set up and my 2nd battery is the "150 amp deep cycle" and is maintained at
home on a smart charger all the time. This battery is what i was gauging my run on.
I don't have an issue in setting up 2 panels but of course if i can do it with one all the better and I save around a grand :).
I was a bit confused in if i drove to
my spot say 2 -3 hours (most more) and opted to stop I could simply stay there for a day or so without driving around to charge up the batteries of course if the weather is not on my side thats a different thing. I guess it would help to have a third battery to save any short comings in what i am thinking of doing.
I was thinking of doing the two Outbacks but they seem to draw 6amps and hour and that would be a big drain in my eyes and the Trailbalzer would be more efficient.
So much to think of so little time
Brian
AnswerID:
245923
Follow Up By: michael & lisa - Sunday, Jun 10, 2007 at 18:12
Sunday, Jun 10, 2007 at 18:12
go trailbalzer fridge & you wont go back. I run 2 trailbalzer & 2 80wat panels now.
I have got with 1 Fridge 3 day out n70 start battery with no panels not without moving.
But i have up grade now to 2 fridge a wife a camper & to kids
now i run 2 fridge one in the camper as a freezer hock to 180amp battery.
one in the car as a fridge on a n70 start battery
I have run trailbaler for 11 years now.
last year at
cape york the freezer was pull down to -16 degrees in a box on the camper at 55 degrees. that are tested at 42 degrees.
FollowupID:
506889
Reply By: Axel [ the real one ] - Sunday, Jun 10, 2007 at 18:51
Sunday, Jun 10, 2007 at 18:51
Salesmen vs Users ? lol , I run 2 fridges when camping , an 80lt Waeco as fridge freezer and a 15lt Engle as the drinks/beer fridge ,the Waeco chews up an average of 2.6amps per hr and the Engle 1.9 per hr , ergo using 4.5amps per hr every hr in 24 , 4.5x24= 108 amps ,so I have to replace those amps , now I have 2 solar panels , 1x 125w Kycera + a 64w Unisolar , in perfect conditions both panels combined give me up to 12amps per hr , problem is of course the old "peak sun hrs" , 12amp x 6hrs = 72 amps , throw in another 10 or even 20 amps produced in the pre and post peak hrs and I still end up with less amps than I use in a 24hr period , start to throw in the variables of day / nite temps , cloud cover ect ect and genny looks more and more attractive , this is Not a "dont go solar " or a pro generator response , thing is to become totally self sufficient using solar only more output is required than generally thought , fridge amp usage is not a "day" but 24hrs.
AnswerID:
245951
Reply By: Motherhen - Sunday, Jun 10, 2007 at 22:45
Sunday, Jun 10, 2007 at 22:45
Brian - Leaving all the technical facts aside, this is what worked for us.
A few years ago we bought our first caravan, an old windup camper. We threw out the defunct 3 way fridge. We bought an Engel upright 12/240v caravan fridge (around 130 litre), 1 deep cycle battery and an 80 watt (i think - I'm not that technical) solar panel. We were confident it would work, so left the genny at
home. The battery did trickle charge from the tow vehicle, but did not charge near as fast as the sun - even a glimpse of sun. We also had 2 fluro 12 v lights. We had the panel on a frame and stand, so when we stopped late in the afternoon we would put it out to face the sun, go for a walk and return to find it in shadow, but the battery
well charged. We usually turned the fridge off at night; if we ran it all night, the battery level was very low, but, leaving the panel ready to face the rising sun, at first glimpse of sunrise, the battery charge would rise. We have now moved the panel onto the F250, where we hope it will keep our battery charged for the Engel car fridge and what ever else we need to run off 12 v when camping without the caravan.
AnswerID:
245992
Reply By: Mainey (WA) - Monday, Jun 11, 2007 at 23:50
Monday, Jun 11, 2007 at 23:50
Brian,
I use a 200+ Watts Solar system and 200+ ah Deep Cycle battery system, it runs a (claimed) power hungry 10amp (3ah) 70Lt fridge/freezer, 365 days a year, in the bush for many weeks at a time, stationary in the same spot without starting the motor.
I originally had an 80Wt Solarex panel, (same as BP) and found it did not last the number of weeks I required so I added a SHARP 123Wt ND-L3EJEA low light solar panel and have not looked back.
The basics of solar is you MUST replace in 8 hours what you use in 24 hours or your going backwards. The Aux battery bank is just a power supply bank and can be run down to 60% if need be over a few days of no sun, but why would you
camp where there is no sun.
Using 'low light' technology the Sharp panel works from sun-up till sundown putting power into the Aux battery system, cheaper solar panels don't give the same performance!!
AnswerID:
246242
Reply By: Member - Matt M (ACT) - Tuesday, Jun 12, 2007 at 08:03
Tuesday, Jun 12, 2007 at 08:03
Brian,
If you can afford the two 80W panels, it sounds like the way to go. We travel with one 80W panel powering a 50 Litre Waeco through a bank of AGM batteries (210 Ah total).
I tracked the fridge consumption (running as a cold fridge, but not quite freezing) over a three month period which took us from
Broome through WA, SA and NSW, a fair range of weather and sun conditions. Fridge figures varied from 13 Amps per day (absolute best) to about 37 Amps. The average usage was closer to 22-23 Amps per day. On the input side, obviously the figures varied wildly, but on an 'average' sunny day I could rely on about 26-28 Amps from the panel.
With the batteries also charging from the alternator when on the move, the bottom line was that we didn't need to plug into 240v for over three months. If I could keep the camper (and the fridge) in the shade and get the panel into full sun, then we could maintain ourselves pretty much indefinitely in average weather conditions.
Four days of rain might cause trouble, but I guess you would be looking to move on under those conditions anyhow.
A genny is a fairly fail-safe option, but often it comes down to personal choice. I just like the concept of solar panels sitting quietly doing their business while you are off walking or exploring. Horses for courses I suppose.
Cheers,
Matt.
AnswerID:
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Follow Up By: Member - Brian H (QLD) - Wednesday, Jun 13, 2007 at 23:04
Wednesday, Jun 13, 2007 at 23:04
I agree and what your saying with 2 80 watt gives you enough to sit for a few days is all I need.
Thanks
Brian
FollowupID:
507489
Follow Up By: Mainey (WA) - Thursday, Jun 14, 2007 at 00:11
Thursday, Jun 14, 2007 at 00:11
Brian,
It's not only the number of Watts that you need to look at....!!!!
"Oils ain't oils" and Watts just ain't whats !!
Some panels will give you far better performance on a daily basis than some others, and they will both be rated at the same number of Amps, eg; both 80Amp panels.
Do the sums and see what you actually use in a 48 hour period and then go for a Solar system that will replace that number of Amps, plus a few extra (for insurance) over a similar 48 hour period.
Generally speaking a "budget" priced 80 Watt panel will put out ~4.9 Amps @ BEST PERFORMANCE.... eg full sun and low ambient temp, something that is not fully attainable in the world of camping and traveling, where you can realistically expect to get 3.5 to 4.5 Amps for a number of hours of the day if you move the panel to face the sun at regular intervals, and those Amps will not start till the sun is
well into the sky and fades with 'low light' as stated by the 5 to 6 'sun hours' shown on most graphs of 'sun hours' in Australia.
However the more expensive and higher performance 80 Watt panels will give more Amps for more hours per day due to their much higher technical specifications, and as I said will initially cost more, but they are better built also.
FollowupID:
507500
Reply By: Ron173 - Thursday, Jun 14, 2007 at 09:33
Thursday, Jun 14, 2007 at 09:33
ok heres my hands on experience.
I run a 40ltr Engel, 60w panel, just upgraded my battery to a 120ah, so will talk on the old one which i have experience of, which was 85ah deep cycle.
I usually run as a freezer, and do the rotating blocks thing with my esky as a fridge.
temp is usually -10 or colder even in 40deg heat. I run through a 10amp solar regulator, and I usually move my panel around midday to capture best of afternoon sun.
I find that the panel DOES put back in what the fridge is drawing out, and will maintain this indefinetly, now heres the catch, providing its in full sun.
I find that overnight it drops a bit, but by about 10am, the panel has it back up fully charged.
Where it falls down is when you have a cloudy day, I can make it thru one cloudy day, but if a second cloudy day occurs i would need to run the vehicle.
So thats why i have upgraded my battery, as this is when your battery capacity comes into it. i cant answer how long new one will go yet as not done it.
so in answer to your question, yes solar works, works very well when sunny, which is the majority of the time. Just get the biggest battery you can afford and fit in to see you thru the cloudy periods.
Ron
AnswerID:
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Follow Up By: Member - Brian H (QLD) - Thursday, Jun 14, 2007 at 20:45
Thursday, Jun 14, 2007 at 20:45
Thanks also good info
Brian
FollowupID:
507676
Reply By: Member - Brian H (QLD) - Thursday, Jun 14, 2007 at 20:34
Thursday, Jun 14, 2007 at 20:34
Mainey,
I run a deep cycle battery which is used for my electric motor on my boat so is a dedicated deep cycle and does accept a fast charge phewww one right :).
Your info on solar panels IE not all are the same even if they say 80 watts was a bugger lol not unexpected really.
So this opens up another question what makes a good panel I assumed BP panels were a good panel so are there others ? kinda scared this will be like asking the best tyre type question lol ....... dressing in armour plate and standing by :) ......... I am happy enough to spends more $$$$ to get the right thing BUT to simply spend extra $$$ and say this cost the most does not say its the best or most suited.
I really need to sit down and do some consideration on WHAT I really need including fridges, batteries (1 or 2) apart from main battery, what I also run off the batteries (accessories) work out the draw, as you say over 48 hours, and then look at a panel/s with a suitable regulator to delivery enough input plus some.
LOL camping used to be simple.
The problem I have is I listen to sales people to get the correct and best advise of course I don't know what they are saying is right or wrong if you know where I'm coming from.
AHHHHH the fun of yet anothe expensive hobby lol
Need more beer
Brian
AnswerID:
246856
Follow Up By: Mainey (WA) - Friday, Jun 15, 2007 at 13:52
Friday, Jun 15, 2007 at 13:52
Brian,
#Amorphous solar (cell) technology is used in Uni-solar panels.
#MONO-crystalline solar cells are made from a thin slice cut from a single crystal of silicon.
#MULTI-crystalline solar cells are made from material composed of many small crystals.
#POLY-crystalline cells are used in the ND-L3EJEA system by Sharp who have been developing solar cells for 45 years, the surface of these panels look similar to Unisolar panels from a distance.
Some companies make panels from more than one of the above examples.
Some solar cells work in low light - some will not
Some solar cells are heat resistant - some are not
As to batteries, AGM deep cycle and cranking batteries will fully recharge much faster than any conventional wet cell battery..!
FollowupID:
507870