How much Solar do you have?

[adventureduo]

We run an 80 watt Carmanah

 

[762X39]

We purchased a Siemens 20 watt panel for our travel trailer about 24 years ago and it is still going strong.I switched to cfl (and now a couple of 117 volt LED ) lamps for the trailer so the only other things I run (from a 400 watt true sine-wave inverter) is the vent hood over the stove and a laptop/speakers for watching movies.The fridge runs on a 30 lb tank of propane.I often camp at primitive sites and always try to camp where there is an opening because I hate shade (maybe if I was a mushroom I would feel different).

As far as distance from panel to charge controller and battery, the shorter the better unless you want to lose a lot of power to heat.This is where a higher voltage (like 24 or 48 volts) lowers the amount of loss in the system (assuming you have a high voltage battery bank, charge controller and inverter).:camping:

 

[Jim K in PA]

As to backfeeding the panel at night, the new panel we just bought already has the diode to prevent this. Older panels did not have the diode, and if left connected to a battery will discharge it overnight.

All the controllers that I have come across have the diode and/or a ss relay to disconnect the panel once output drops below a certain point. I was concerned about OVER charging the battery, which is why I got the controller. That certainly would have happened on our last trip.

 

[CSG]

I'd use solar if I understood it and had enough need for it. Meanwhile, I run two G27 batteries in the camper van and I cannot recall when I've stayed more than one night in one location. I'm about the traveling, not the staying.

In our fiver (nothing to do really with Expo) we run two G31 batteries and carry a Honda EU2000.

I remember someone telling me some time back that a genset like the Honda was a lot simpler than solar and probably cheaper in the long run.

Where solar would be interesting to me is with the Cruiser where I only have the engine battery but want to run a fridge and, maybe later, a RTT with a light. But I just don't get how to set it up and reading about it makes my head swim.

 

[Corey]

Where solar would be interesting to me is with the Cruiser where I only have the engine battery but want to run a fridge and, maybe later, a RTT with a light. But I just don't get how to set it up and reading about it makes my head swim.

This is exactly what my system is for what you describe above.
Keeps the batteries topped off while powering the fridge and a light in the roof top tent.
It was very simple to install.
I read about Adventureduo's setup, then I set out on a quest to get the parts, and the rest was easy.
http://expeditionportal.com/forum/showthread.php?t=28712

When I camp, I pretty much setup for one location and use the rig as a base camp so I can go out hiking, mountain biking, ect.

 

[Pest]

I remember someone telling me some time back that a genset like the Honda was a lot simpler than solar and probably cheaper in the long run.

I'm not 100% convinced it would be cheaper over many years. But I am more interested in solar since solar is silent. Even "quiet" generators are noisy...and stinky...and require another gas can.

 

[Tony LEE]

I have 2 x 180W 24V panels - one on the drivers cabin roof and one on the crew cab of the OKA. Feeds 2 x 12V 256Ah batteries in parallel via a 24V 40 Amp MPPT controller.

Might be a lot for some but with 2 x Waeco fridges - one as a freezer, Webasto cooktop, webasto thermoTop HWS/space heater, two computers with satellite internet, 1200W electric kettle and 1500W inverter for quick coffee at roadside stops, no generator (and never will be) and as yet, no charging of house batteries from the engine alternator, it only takes three days of cold weather without decent solar charging and the batteries are getting low.

Also this trip is for at least three months and mains power will rarely be available so the only charger I carry is one of those cheepie 4 amp ones. It is in use at White Cliffs at the moment because we have had so much rain (that the roads are all closed) but that is likely to be the last time for many weeks.

Weekend or even a few days - who needs power, but for two people full-time need at least some of life's luxuries and that means power - especially as I don't really believe in burning wood collected out of sparse scrublands just for camp fires (during high fire danger periods)

 

[Tony LEE]

Well knowing very little about solar I have to ask what might be not the brightest of thoughts! How much distance w/ the right cable of course can you put between the panel and the batteries. Feel free to answer as if i was a 7 yr. old.:smiley_drive:

The short silly answer is there is no limit to the distance because any voltage drop can be controlled just by increasing the size of the cable. gets expensive too.

Several metres between the panel and the controller are no problem with moderately-sized cable - say 6 square mm conductor area for a 120W panel, but it is important to have the controller as close to the battery as possible (but not in the same compartment unless the batteries are sealed.
Two reasons for this. The panels put out around 19 volts so you can afford to lose a little voltage on the way to the controller, but any voltage drop between the controller and the battery means that the battery doesn't get up to the specified voltage levels in each charging stage. The controller thinks it is putting out 14.4volts, but by the time it gets to the battery it might only be 13.8V if the cables were very light and the current high. Not a big deal normally but if the voltage drop at the rated controller charge rate was 1 volt then the battery would likely be seriously undercharged during the bulk and absorption stages. Another reason is that the controller needs to know the battery temperature to adjust the voltages according to temperature so if they share the same ambient temperature it is better.

Both problems can also be solved by having battery terminal voltage sensing and remote battery temperature sensing, but not all controllers have that facility anyway.

 

[bobDog]

The short silly answer is there is no limit to the distance because any voltage drop can be controlled just by increasing the size of the cable. gets expensive too.

Several metres between the panel and the controller are no problem with moderately-sized cable - say 6 square mm conductor area for a 120W panel, but it is important to have the controller as close to the battery as possible (but not in the same compartment unless the batteries are sealed.
Two reasons for this. The panels put out around 19 volts so you can afford to lose a little voltage on the way to the controller, but any voltage drop between the controller and the battery means that the battery doesn't get up to the specified voltage levels in each charging stage. The controller thinks it is putting out 14.4volts, but by the time it gets to the battery it might only be 13.8V if the cables were very light and the current high. Not a big deal normally but if the voltage drop at the rated controller charge rate was 1 volt then the battery would likely be seriously undercharged during the bulk and absorption stages. Another reason is that the controller needs to know the battery temperature to adjust the voltages according to temperature so if they share the same ambient temperature it is better.

Both problems can also be solved by having battery terminal voltage sensing and remote battery temperature sensing, but not all controllers have that facility anyway.

Thank you Tony. That does make a bit of sense to me. I wondered if I could camp in the shade but put a panel in the sun.
I find that Aussies always have clear cut answer to things...I have a cousin in Cairns and he always cuts to the chase when I ask him questions about my jeep.:sombrero:

 

[Azlugz]

I'd use solar if I understood it and had enough need for it. Meanwhile, I run two G27 batteries in the camper van and I cannot recall when I've stayed more than one night in one location. I'm about the traveling, not the staying.

In our fiver (nothing to do really with Expo) we run two G31 batteries and carry a Honda EU2000.

I remember someone telling me some time back that a genset like the Honda was a lot simpler than solar and probably cheaper in the long run.

Where solar would be interesting to me is with the Cruiser where I only have the engine battery but want to run a fridge and, maybe later, a RTT with a light. But I just don't get how to set it up and reading about it makes my head swim.

I have a 15W panel on our 5th wheel to keep the batts topped off in storage and to top them up during the day when we are out of the rig. We had an Onan 5500 installed for main power and will feed the full 50amp system, but so far, for lighting and small stuff, we have done good on battery and solar.


I have a blue top to put in the back of the Cherokee to run all the extras and was considering mounting a panel flat on the roof under the roof rack to keep everything topped off. I know flat is not the best, but we have a LOT of sun here in AZ

 

[Tony LEE]

Here in Oz it is quite common for those in caravans (travel trailers to you) and smaller poptop vehicles with limited roof area or loading capacity to carry a pair of 80W panels hinged together for deployment when camping.

Usual mistake made is to have the regulator mounted on the panels (because it is easier for the manufacturers that way) and then 20 yards of thin cable running to the batteries.

Much better to mount the regulator on the battery end of the cable because it minimises undercharging due to voltage drop.

Requires shifting a couple of times a day and of course the props need to be strong enough that it doesn't all collapse in a gust of wind. Means you can park in the shade and have the panels in the sun angled at their most efficient orientation and that will allow you to generate perhaps double what a flat panel would at high latitudes.

Other disadvantage is that they are a lot easier to steal and more prone to getting run over by others.

See http://www.solazone.com.au/PVpanels.htm near the bottom of the page for a typical setup.

Cheaper versions on ebay

Anything less than 50W is likely to be of limited benefit unless your usage is pretty low.

BTW - with mono and polycrystalline panels, you need to watch any shadows falling on a panel. Putting a hand-sized shadow anywhere on even a large panel can drop the output markedly. Antennae, hatch covers and the like can cast shadows that might halve your collection over the course of a day.

 

[bobDog]

Thank you for the useful info :smiley_drive:mate!

 

[z3r0]

i have mine on the dash right at the bottom

it's a 20w so it's a trickle charge. but my batt has gone dead and at work and after work it will start right up.

i hope to upgrade to one on top of the tool box, and the whole dash.
after i upgrade to a multi battery system

 

[lostworldexpedition]

Sorry, I voted in the 100+, my bad. I carry a Sunpower SPR 90 Watt panel paired with a Morningstar SunSaver 6 amp charge controller and a group 31 deep cycle battery. So far I am happy with the set up, except for some battery issues we are having (long story).

My current set up is a revised version... my main suggestion in general is: upgrade wiring to the largest gauge you can and get the best battery you can afford.

At the moment we store the panel in the RTT when we drive, but I would like to mount it somewhere permanently.

 

[TimS]

Right now, a 15 watt panel. I am going to get a 60 watt panel soon. This will beused for camping and to keep some batteries charged for power outages. When we loose power, the trend has been for 5 or more days at a wack.