Questions about solar power

[Carol H]

Originally Posted by MCDenny

I've been checking the consumption every morning and evening and find it is steadily rising, from 1.1 ah/hour the first night to 2.0 ah/hour the third night. I believe this is due to ice buildup on the evaporator coils. It has been six days since it was last defrosted and it was pretty frosty. I just defrosted it again and will know by this evening if the power consumption has dropped back to the previous level.

Build up of ice around the freezer compartment on my old fridge has a negative impact on its ability to perform well also. One of the side benefits of running without the fridge plugged in after dry camping for a number of days is it gives an opportunity for the frost to recede.

[blodn1]

I believe this is due to ice buildup on the evaporator coils.

Why do you suppose there is so much ice build up so quickly? Do you think it needs more ventilation?

[blodn1]

This raises the possibility of putting solar panels on awnings:

[MCDenny]

Originally Posted by blodn1

Why do you suppose there is so much ice build up so quickly? Do you think it needs more ventilation?

It was the ice. Second hour after defrost consumption is back to 1.4 amps per hour. It used 2.0 amps per hr last night.

Don't know why it built up so fast. We are in Fl where it is always somewhat humid. Yesterday was very humid with a few periods of rain.

There is no ventilation inside. Are you suggesting a little fan might help?

[MCDenny]

Originally Posted by blodn1

This raises the possibility of putting solar panels on awnings:

Those look like the panel I bought. I thought about the awning but the support struts aren't that stable, particularly in the wind.

With a strong awning the panel could be held on with Velcro. It's only supposed to weigh 3 lbs.

[blodn1]

The panels I'm looking at will self-adhere to the roof of the Snoozy. Those were on the canopy of a sailboat - 100W semi-flexible monocrystalline solar panels.

Carol says she has frost problems on her fridge, and since hers is (at least) dual, it has to be vented, so I'm not sure it is the ventilation. Maybe a seal isn't sealing properly? Just going over the possibilities. Trying to eliminate problems before my eventual build:-)

[Carol H]

Originally Posted by blodn1

The panels I'm looking at will self-adhere to the roof of the Snoozy. Those were on the canopy of a sailboat - 100W semi-flexible monocrystalline solar panels.

Carol says she has frost problems on her fridge, and since hers is (at least) dual, it has to be vented, so I'm not sure it is the ventilation. Maybe a seal isn't sealing properly? Just going over the possibilities. Trying to eliminate problems before my eventual build:-)

Actually the frost build up on at least on mine has nothing to with the seals on it or rear ventilation - all good. Has fairly new seals on it and as it is a 3 way and it does have rear ventilation as well as a fan which I added to the rear.

The reason that many/most of the small sized RV fridges tend to frost up is due to the fact they are not like your home fridge and are not Frost free, along with the fact they are small and if full there is not a great deal of air circulating inside them & they are impacted by moisture.

A small battery operated fan helps with the lack of circulation but you need to remember to move it and not cover it up with stuff so the air can circulate Best if the fan is placed on the bottom to one side with nothing directly above it on the shelves above.

Moisture is actually the biggest reason for frost build up - putting items that are moist (such as a head of lettuce you just washed) in the fridge will increase frost. Making ice in the freezer also compounds the moisture issue as does opening and closing the door a lot. Have found if I remove the ice tray from my freezer it does help to keep the frost build up down. Another reason for ice build up is the temp of the fridge is set lower than it needs to be to maintain it for safe food storage... what happens the fridge gets less efficient with frost build up and the first response is to turn it a little higher which only makes matters worse.

[blodn1]

Hi Carol - Thanks! I'm just trying to think through how to install the DC refrigerator for its best efficiency. If it needs to be ventilated, pre-build is where I want to catch it. If the main problem is humidity, I'll be able to address that after.

[Carol H]

Originally Posted by blodn1

Hi Carol - Thanks! I'm just trying to think through how to install the DC refrigerator for its best efficiency. If it needs to be ventilated, pre-build is where I want to catch it. If the main problem is humidity, I'll be able to address that after.

You may want to do a google or two on the topic before your build takes place but pretty sure in talking with other RV techie types over the years about the frost issue humidity seems to be the general consensus as to the cause of frost.

[carlkeigley]

Originally Posted by blodn1

This raises the possibility of putting solar panels on awnings:

Maybe a couple on top of a screen house.
Shade for the camper and full sun for the battery..

[MCDenny]

Carol has a propane fridge. The flame has to be vented. A dc fridge has no need for an external vent

The little fan to circulate air inside the box sounds like a good idea.

A dc fridge needs a flow of room temp air behind it to remove compressor heat. Truckfridge says 1" min at bottom, back and top.

[David Tilston]

It is clear that the solar cells on that boat have no support. I can't imagine what would prevent them from breaking. After all, they are essentially very thin glass sheets.

[Raz]

Originally Posted by MCDenny

A dc fridge has no need for an external vent

True but.... Some trailer manufactures ignore the fridge installation instructions and don't vent at all, so the heat sits behind the fridge. When I was offered a compressor fridge, that's what Trillium was doing. Others provide a gap below the fridge to vent into the living space. Since there are no combustion by products, this is fine from a safety point of view, however remember the fridge moves heat from inside the box to the back and from there into the living space. This makes that space hotter. If you have AC, it will have to work harder. And since heat rises, going down under the fridge can't work well. After noticing the side of his trailer was hot, one member added an outside vent to get rid of this heat. I bet the fridge efficiency improves as well. So an outside vent might not be a bad thing. Raz

[blodn1]

David,
This is what Renogy says about its flexible panels:
“The laminate coating on the exterior of the panel makes it impervious to saltwater splashing, rain, and other weather elements. While this panel may be damaged by sharp objects or scraping, there is no risk of shattering or cracking.”

[blodn1]

Thanks Raz, That's what I was trying to get to. Even if it isn't propane, that vent wouldn't be a bad thing. Since I'm planning to add a vent for the propane furnace to the other side, it wouldn't
be a stretch to put another small one near the top rear of the fridge during the build.

[David Tilston]

Originally Posted by blodn1

David,
This is what Renogy says about its flexible panels:
“The laminate coating on the exterior of the panel makes it impervious to saltwater splashing, rain, and other weather elements. While this panel may be damaged by sharp objects or scraping, there is no risk of shattering or cracking.”

While that is a fantastic claim, like I said, Monocrystalline solar cells are effectively very expensive thin glass. If you put enough stress on them, they will break. But since they say that will not happen, I hope they back that up with some kind of warranty.

I wonder why the flex cells are almost twice as expensive as the framed ones?

For my permanent install, this is now my leading contender. But it will be a while, the 40 W portable Coleman unit will do for now.

[padlin00]

Originally Posted by David Tilston

It is clear that the solar cells on that boat have no support. I can't imagine what would prevent them from breaking. After all, they are essentially very thin glass sheets.

They are not glass but plastic.

[David Tilston]

Originally Posted by padlin00

They are not glass but plastic.

I don't claim to be any sort of expert on the subject, but monocrystalline silicone is not plastic. Since glass is made of sand, (silica) they are very similar.

http://en.wikipedia.org/wiki/Monocrystalline_silicon

You may be thinking of amorphous solar cells, but these are not those.

[padlin00]

I was talking about the surface material, not the composition of the silicone cell.

"100W Mono-crystalline Semi Flexible Solar Panel Module
100W semi-flexible solar panel kit for yacht boat RV, boat ready for using. The revolution on producing technology of solar panel, cut 70% weight from the standard rigid solar panel 。
100w semi- flexible solar panel with 1m cables! with 4 holes, can install it very easily !
Features:
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Unbreakable (no glass);
Lightweight & thin(about 2.8+/-0.3mm)，bending up to 30 degrees
Be with anti-reverse charging function;
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Be with CE certificate"

[ruscal]

Originally Posted by MCDenny

Many solar controllers have an"equalize" function the operates manually or automatically maybe once a month. It over charges the battery a bit, the purpose being to remove lead sulphate crystals (I think).

My iota Dls 30 charger does not have an equalize function but my T105s are two yrs old and still have a fully charged resting voltage of 12.72 and the partially discharged resting voltage agrees with the state of charge calculation my Victron battery meter gives. So I think the battery's are still A-OK.

THe battery charger has been plugged in pretty much all the time we have been camping and once a month for 24 hrs when it's been in storage.

Denny,
The Iota DLS 30 can be upgraded by adding the IQ4 pendant which turns the unit into a 4 stage smart charger. The equalization cycle occurs every 7 days. The pendant plugs into the "phone jack" on the DLS. The IQ4 also can be installed on older DLS units without the jack. I'm using the Iota with IQ4 for my maintenance charger now and it is working well. Much better than the stock converter.
Russ