Recommendations for solar setup

[Shiltsy]

I have a Lance 825 truck camper that will be stored outside without electrical access starting this spring. I'd like to setup a solar system that will charge the batteries while in storage. I have all LED interior lights, no TV, no electric coffee maker, no AC, etc, so when I boondock I can easily make the battery last for 3-4 days. Space on the roof is limited because of a Thule cargo carrier and vents, so I'm really just looking for the most efficient panel that will keep my single 12 volt deep cycle charged during storage.

Love to hear your suggestions. I'm not afraid to spend some money for the right system including a controller.

Thanks!

[Shiltsy]

This is really great feedback. I may also explore adding a wifi hotspot and security camera that would run while in storage. It'll be interesting to see how much those two devices would draw.

Next step is to crawl up on the roof and map out potential square footage where panel(s) could be placed. Space/weight is always at a premium on our TC's!

After my storage shed was broken into last fall, I'm hyper sensitive to security...

[Jfet]

Do think a lot about shade. I am putting four 270 watt panels on our camper (1080 watts). I was messing around with one the other day with a resistive load (10 ohms) because I have not purchased a controller. It was producing 117 watts (Seattle sun) until I shaded just one cell with my hand and the power dropped to 77 watts. Shade three cells in the right place and the power drops to almost nothing.

[Camper_Jeff___K]

The batteries can be charged in just a couple hours, true, under good conditions. Often we are camping in the forest so our cumulative charge may take over 6 or 10 hours to achieve fighting shade and such. When under perfect conditions, we leave the fantastic vent running to keep the camper cool throughout the day, charging computers and phones etc or running other items. I would say to go for the higher power 140 + 140 watt panel setup. You can also setup a secondary load like charge your truck battery when the TC is full. A while back, somebody on the forum had a water heater element specially made for just such a purpose. I think it was dual 120AC and 12DC as a diversion load to heat the water. Perhaps not hot but warm. I think there is more reason to have a larger solar system than not to.

[Redsky]

I did as high end a system install as possible and it was overkill. The 200 Watts and MPPT controller recharge my two 110 AH 12v batteries in 2-3 hours, winter or summer.

Two places you can save time and money. First is to install a single panel and try to use the Lance factory wiring. It is 12ga which is not ideal but it is good enough. It is better with a 34 Voc panel than a 17 Voc panel as there is less current loss with the higher voltage but not a big deal if all you put up is a single Kyocera 140 Watt panel. The Kyocera and the 100 Watt panels from AMsolar.com are narrow and so fit in the limited space found on camper roofs and not going to be shaded by anything on the roof.

The Lance wiring will go to a cabinet space where you can install a small charge controller. From there the wiring will run near to where the battery is located and you want to install a switchable circuit breaker so you can switch off the power from the panel(s).

One easy place to install a solar panel is on the roof rack. I could not do this on my camper as the roof rack is directly over two of the roof vents.

You can save a great deal by going for a system that will be 80% as effective and cost a third of what a premium 99% system. It really will have little impact in real use when it take 4 hours to recharge the battery or batteries instead of 3 hours. You cannot do anything with the extra current produced once the battery bank is charged.

Do add a monitor like the Trimetric. The Lance gauges are about as useful as using a dip stick to know how much gas is in the truck's fuel tank.

[bka0721]

This is good additional information! You had only mentioned that you were looking for Solar to keep battery charged, during storage.

The easiest fix, would be to get two AGM Batteries and move them into the occupied area of your camper (In a cabinet, as I did). Batteries will lose considerable capacity when the temperatures drop. Having the AGM batteries in the heated area, would increase your battery capabilities, during colder periods.

There is lots of discussion on the Pros and Cons or the Flat Solar Panels (Flex or Film), but what might impact you more, is that you would not be able to take advantage of the low to the horizon sun’s position in the Late Fall into Winter time of the year, if you are attaching your solar to the roof, thus unable to tilt your panels.

Yes, a space case can take up some room. But, how many panels are you planning on putting up there? You could put your space case in the middle and then install two solar panels, one on each side of your space case. This would allow you to take advantage of the sun as it travels, negating the shadow across one of the panels, for a percentage of time.

I love my solar, but there are other options that should be considered when cost and amount of time of use, are added in. If you have the funds, do it all.

b

[mena661]

I think a couple of 100W panels and a cheap PWM controller would work just fine on a single 12V batt.

[shiltsy1]

Bka - that would work except that I need to keep my Thule cargo box mounted up there.

I need to get out to the storage unit and get some measurements in suitable install areas. I'd really like to make some flexible panels work if possible.

Side note, I did some camping in single digits when hunting last year. I didn't think battery drain would be an issue, but didn't account for how much the furnace fan would drain the battery running constantly. Huge drain and took my battery life down to a day or two if I remember correctly. Another reason to get as much panel up here as possible.

[bka0721]

Hi. Why don't you use your Thule Cargo Rack to mount your future Solar Panel? I did and it has been a great solution, too. My battery bank was located in the back of my TC, as well as the Cargo Rack too. This proximity made it very simple to route the necessary cables and some room in a cabinet for the monitors.

This is a link to a previous discussion of this type of solution; Maggie Roof Rack Post


My Thule Rack (Maggie Rack) solution;






If you are just trying to keep your battery from being discharged, during a short time, just disconnect the battery cable (-) lead from your battery and hit the disconnect switch that should be in your battery cabinet. If you are only leaving it for a month or two, typically you will not have sufficient discharge to be an issue, if the SOC was current at time of disconnect. The best solution would be just to remove the battery and take it home and charge it, periodically or put a trickle charger on it. It really comes down to whether you have the $$, Time, or wish to deal with the hassle of removing/reinstalling your battery.

b

[pianotuna]

Hi,

Here are some flexible panels. They may be a premium price as they are pretty new: http://gpelectric.com/company/news-and-updates/company-update/flexible-solar-kits-launch-early-2014

Shiltsy wrote:
I was just thinking the exact same thing. Gives me a bunch of space and also the added benefit of not having to drill into the roof of a camper that will now be stored outside!

Will keep the forum updated on my little project here.

[Shiltsy]

"Hum, I wonder if you could put a flexible panel (or lots of little panels) on the top of your cargo carrier? Might be worth looking into. Someone on here will know."

I was just thinking the exact same thing. Gives me a bunch of space and also the added benefit of not having to drill into the roof of a camper that will now be stored outside!

Will keep the forum updated on my little project here.

[RoyB]

Keep in mind that keeping a 90%-100% SOC battery fully charged is different than re-charging a 50% SOC battery bank.

Charging Batteries with a solar controller is much the same as using your on-board converter unit.

When I re-charge a 50% battery bank my converter supplies 14.4VDC to my 255AH battery bank. The three batteries in this bank then immediately want to draw around 53AMPS DC current for a good 15-20 minutes and then start dropping back. Then after two hours of the 14.4VDC charge period the batteries are demanding around 8AMPS of charge from the converter. Then after two hours the converter switches down to 13.6VDC which drops the battery demand down to around 6AMPS DC Current. This will continue for another hour before returning my three 85AH batteries to a 90% charge state.

A single 120WATT Solar panel with a controller will only give you around 6 AMPS of Dc Current so this will take many hours to obtain a 90% charge state on your battery bank. If you start out with your batteries discharged down to their 50% charge state it ain't going to work to get your batteries back up to their 90% charge state in the remaining high SUN DAY.

Keeping the battery fully charged using solar is another story if it starts out at 100% charge state. If your consumption is low a single panel should be able to keep the charge up during the 8 hours of the SUN DAY.

For me this would not work as my battery demand is too high between 8PM and 11PM along with the 24/7 parasitic drains which equates to around 250-300WATTS of use. My batteries will drop from 90% SOC to 50% SOC by 8AM the next morning as read on my installed Battery Meter Panel. I do not think a single 120WATT SOLAR panel will replenish this SOC in the 8 hours of full sun time available in the one SUn DAY.

My rule is too never start using my 255AH battery bank for the day/night battery run unless it is at the 90% SOC.

My plan is going to be to install 360WATTS (three 120WATT PANELs) and do the initial battery charge each morning using the generator to get over the high 53 AMP charge cycle for two hours and then allow the solar panels to finish my 90% SOC rate before I run out of time of the high SUN DAY. When my 255Ah battery banks drops to around 12.0VDC I will turn it off to keep from doing damage to my battery bank.

This is my plan at any rate... The Solar guys are telling I will probably do great with my 360WATTS of solar panels giving me around 18AMPS of usable DC current during the high SUN DAY (Maybe around 108AHs total re-charge capability).

Just my thoughts for my upcoming SOLAR PANEL Project

Roy Ken

[SteveAE]

Shiltsy wrote:

Basically want a system with max output per square foot of roof space consumed. If I can fit a 2x4' panel will 100w serve my purposes well?

Yes. Without any problem as long as there is sunshine. In the winter, you will want to knock snow off the panel.
As a side benefit, the number of days you can stay out without power may even double.

Hum, I wonder if you could put a flexible panel (or lots of little panels) on the top of your cargo carrier? Might be worth looking into. Someone on here will know.

Enjoy your solar system,
Steve

[Shiltsy]

Thanks for the quick feedback. I am really looking for a system strong enough to give me a full charge while the rig is in storage. The 3-4 days of dry camping will get me through most camping weekends. I just want the system to be topped off without plugging in during storage.

Basically want a system with max output per square foot of roof space consumed. If I can fit a 2x4' panel will 100w serve my purposes well?

[bob_nestor]

I have a similar problem dry camping with my Class B and I also have limited roof space. On a recent camping trip I experimented with a portable 120w panel and found it was capable of keeping my batteries fully charged. (Like you I could only go 2-3 days before needed to recharge.) There are some 100, 120, and 135W flexible solar panels available that are 21" wide and anywhere from 40 to 56" in length. Would they fit in the space you have available?

BTW, I think I have room to install two of the 135W panels on my roof and I'm looking at doing that to solve my dry camping power issues.