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Solar panel & batteries?

PostPosted: Sun Sep 23, 2012 7:58 pm
by rando18
I'm putting a 100w solar panel on top of my 7x12 CTC.
I have 2 Deep Cycle batteries from costco. I want to run a small
thermoelectric cooler. Is this enough power and can the batteries
be kept inside the trailer?
Thanks in advance for all the replies.
Randy

Re: Solar panel & batteries?

PostPosted: Sun Sep 23, 2012 8:09 pm
by rando18
Sorry! I didn't mean to make this same post 3 times.

Randy

Re: Solar panel & batteries?

PostPosted: Sun Sep 23, 2012 8:13 pm
by Taco Jeff
Need more numbers to answer your question.
How many amp hours are the batteries, what does the refrigerator draw in amps and then truthfully, its a crap shoot.
It will depend on how efficient the frig is and how hot out it is and how much in hours you are getting in sun exposure.

Jeff

Re: Solar panel & batteries?

PostPosted: Sun Sep 23, 2012 8:23 pm
by rando18
[quote="Taco Jeff"]Need more numbers to answer your question.
How many amp hours are the batteries, what does the refrigerator draw in amps and then truthfully, its a crap shoot.
It will depend on how efficient the frig is and how hot out it is and how much in hours you are getting in sun exposure.

Jeff[/quote


Thanks Jeff
I'll look at the amps of the batteries and cooler.
Really wanted to know if batteries could be stored inside.
I see so many mounting batteries on outside of campers.

Re: Solar panel & batteries?

PostPosted: Sun Sep 23, 2012 8:54 pm
by OverTheTopCargoTrailer
I have 400 amp hour flooded batteries for 840 watt solar panels sitting inside

Have not blown up yet
:NC :NC


http://overthetopcargotrailer.blogspot.com/

Re: Solar panel & batteries?

PostPosted: Sun Sep 23, 2012 8:55 pm
by Taco Jeff
rando18 wrote:
Taco Jeff wrote:Need more numbers to answer your question.
How many amp hours are the batteries, what does the refrigerator draw in amps and then truthfully, its a crap shoot.
It will depend on how efficient the frig is and how hot out it is and how much in hours you are getting in sun exposure.

Jeff[/quote


Thanks Jeff
I'll look at the amps of the batteries and cooler.
Really wanted to know if batteries could be stored inside.
I see so many mounting batteries on outside of campers.



If the batteries are AGM or "Gel cells", they can go inside.
Wet batteries are a no go.

Jeff

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 6:05 am
by Shadow Catcher
The thermoelectric coolers use a good bit of power, looks to be about 5A and will only cool about 40 degrees below ambient temperature, my understanding is that they run for the most part constantly.
Conventional wet batteries can be kept inside safely only in a vented battery box, Hydrogen which is out gassed during charging can be explosive.
The output in USA will vary a great deal depending on the location. At the best locations an 100W panel output can be expected to be around 413Wh/day while there are locations where output will be as low as 250 Wh/day. This is with the panel angled and oriented to the sun etc.

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 9:30 am
by rando18
Shadow Catcher wrote:The thermoelectric coolers use a good bit of power, looks to be about 5A and will only cool about 40 degrees below ambient temperature, my understanding is that they run for the most part constantly.
Conventional wet batteries can be kept inside safely only in a vented battery box, Hydrogen which is out gassed during charging can be explosive.
The output in USA will vary a great deal depending on the location. At the best locations an 100W panel output can be expected to be around 413Wh/day while there are locations where output will be as low as 250 Wh/day. This is with the panel angled and oriented to the sun etc.


Thanks Shadow Catcher
Great info.
I have the batteries in a regular battery box that is vented.
I may have to add another solar panel and batteries in the future.
We get good sun here in Colorado usually.
Going too the Dakotas to look for work. Not sure if
the sun will be as powerful there. Guess I'll find out. :thumbsup:

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 9:43 am
by eamarquardt
Taco Jeff wrote:If the batteries are AGM or "Gel cells", they can go inside.
Wet batteries are a no go.

Jeff


21,000,000 VW Beetles were made. All of em had a flooded and non sealed battery in the cabin. VWs were famous for their being pretty much air and water tight. Never heard of a single one blowing up even though they had cigarette lighters and ash trays.

Never heard of a kid drowning due to cramps after swimming within an hour of eating either.

I wouldn't hesitate to put a battery inside a teardrop.

Cheers,

Gus

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 12:41 pm
by Shadow Catcher
Gus The bug generator at 30A, was not likely to charge the battery very quickly and the area under the rear seat was vented by the "heater". And yes explosions do happen http://mechanicsupport.blogspot.com/201 ... osion.html. It is like most things, you can get away with not venting "most of the time".
I passed a class C motor home yesterday on the way back from Atlanta on I 75, the back half had burned to the chassis. RV's are REALLY flammable, (Big fire engine
traffic backed up for miles).

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 12:50 pm
by bikeopelli
Rando,
I basically dealt with the same problem when I decided to go with and electric fridge and solar. As previously stated, its a 'crap shoot'. Its difficult to dial in exactly what you will need since there are so many variables including how, where, when you camp, ambient temps. total available amp hours, solar setup, etc.

My problem solving efforts lean much more toward the 'empirical' approach than the 'scientific' and my friends almost always accuse me of overbuilding. That said, here is the what, and the why of what I did, (and therefore what I recommend) once I decided on an electric fridge and solar.

1. Choose an honest-to-goodness compressor type fridge. Unlike thermoelectric units cooling is not related to the ambient air temp. So lets say you are camping in 90º weather. That thermoelectric unit is going to cool down to around 50º. Sub-optimal. I can only assume you do not enjoy drinking 50º beer any more than I do.
2. Install a lot of battery. I installed (4) 230 amp 6 volt deep cycle batteries. Go with pairs of 6 volt batteries. In testing I have found I can go about 3 days/nights before I start closing in on 12.07 volts if its not too hot out.
3. I went with a 140 watt panel but built a 'solar tracker' based on a cheap collapsible 1.5" PVC stand. Along with just being a lot of fun to muck around with, the tracker keeps the board facing directly into the sun all day.

One last thought on 'overbuilding'... I spent the first half of my life buying cheap, minimum effort stuff. Then after a while having to replace it once it proved to be sub-optimal. Obviously the cost and effort involved was almost always greater than if I would have 'overbuilt' in the first place.
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Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 2:11 pm
by rando18
eamarquardt wrote:
Taco Jeff wrote:If the batteries are AGM or "Gel cells", they can go inside.
Wet batteries are a no go.

Jeff


21,000,000 VW Beetles were made. All of em had a flooded and non sealed battery in the cabin. VWs were famous for their being pretty much air and water tight. Never heard of a single one blowing up even though they had cigarette lighters and ash trays.

Never heard of a kid drowning due to cramps after swimming within an hour of eating either.

I wouldn't hesitate to put a battery inside a teardrop.

Cheers,

Thanks for the inf Gus. Living in the State of Euphoria sounds nice. Randy

Gus

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 2:19 pm
by rando18
bikeopelli wrote:Rando,
I basically dealt with the same problem when I decided to go with and electric fridge and solar. As previously stated, its a 'crap shoot'. Its difficult to dial in exactly what you will need since there are so many variables including how, where, when you camp, ambient temps. total available amp hours, solar setup, etc.

My problem solving efforts lean much more toward the 'empirical' approach than the 'scientific' and my friends almost always accuse me of overbuilding. That said, here is the what, and the why of what I did, (and therefore what I recommend) once I decided on an electric fridge and solar.

1. Choose an honest-to-goodness compressor type fridge. Unlike thermoelectric units cooling is not related to the ambient air temp. So lets say you are camping in 90º weather. That thermoelectric unit is going to cool down to around 50º. Sub-optimal. I can only assume you do not enjoy drinking 50º beer any more than I do.
2. Install a lot of battery. I installed (4) 230 amp 6 volt deep cycle batteries. Go with pairs of 6 volt batteries. In testing I have found I can go about 3 days/nights before I start closing in on 12.07 volts if its not too hot out.
3. I went with a 140 watt panel but built a 'solar tracker' based on a cheap collapsible 1.5" PVC stand. Along with just being a lot of fun to muck around with, the tracker keeps the board facing directly into the sun all day.

One last thought on 'overbuilding'... I spent the first half of my life buying cheap, minimum effort stuff. Then after a while having to replace it once it proved to be sub-optimal. Obviously the cost and effort involved was almost always greater than if I would have 'overbuilt' in the first place.
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Thanks a lot bikeopelli.....Sincerely Rando

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 3:22 pm
by eamarquardt
Shadow Catcher wrote:Gus The bug generator at 30A, was not likely to charge the battery very quickly I'm not aware of too many chargers that will put out 30 amps and I've never seen a battery take that much current from a "conventional" charger that is likely to be used by an RV and the area under the rear seat was vented by the "heater". I've worked on many VW bugs and the underside of the rear seat is not, as far as I can tell "vented by the heater". The heater tubes enter there but exit without venting under the seat. And yes explosions do happen http://mechanicsupport.blogspot.com/201 ... osion.html. If you read the article the hydrogen gas was contained in a small battery box that was not properly vented. A VW or teardrop is not a small volume and I don't believe that the concentration would ever get to the level required for an explosion. It is like most things, you can get away with not venting "most of the time". Never heard of a VW exploding as a result of a hydrogen explosion. 21,000,000/0 is good enough odds for me, ha.
I passed a class C motor home yesterday on the way back from Atlanta on I 75, the back half had burned to the chassis. RV's are REALLY flammable, (Big fire engine
traffic backed up for miles) Nothing to suggest in your comment that the fire was a result of a hydrogen explosion. Most engine fires, that I have witnessed, have been a result of a gasoline leak. Hydrogen is quite light and dissipates too quickly to be a problem.


As I say, I wouldn't hesitate to get into a VW or a teardrop with a battery inside. I agree that it is better outside but primarily "just because". I did have a voltage regulator fail on my 67 Bug and the sulfuric acid fumes caused me to cough. I replaced the regulator and breathed a lot better, ha.

Cheers,

Gus

Re: Solar panel & batteries?

PostPosted: Mon Sep 24, 2012 3:55 pm
by droid_ca
What kind of refrigerator is that and how big do they come in