Basic battery/solar question...

[woe_bonnet]

Hi there! Our Manley Extreme trailer came with a Volta VT12100 (12V, 100AH deep cycle) battery installed in the tongue toolbox. The rig is wired to power two 5v USB receptacles (one 1A and one 2.1A), a 12v marine/"cigar lighter" receptacle, and a pump that pulls water from the onboard reservoir to a small fold-out sink.

We will likely be running some outdoor LED lights for a few hours each evening, an electric water kettle, and would occasionally need to charge an iPod, small wireless speaker, and a phone or laptop. We would run all of these appliances off the battery/from the USB and cigar lighter receptacles.

We're interested in investing in a solar panel to charge the battery. Am I correct in understanding that we would simply be looking for an appropriately sized panel(s), and a charge controller? We wouldn't need an inverter or anything, as the solar setup is just being used to recharge the battery?

I requested a package recommendation from Renogy for one of their suitcase setups, and the rep I spoke with wanted to know the consumption needs of all the aforementioned appliances, and the daily duration of their use, before making a recommendation... but wouldn't the power needs and duration of use just determine how fast the battery will discharge itself? I figured we'd just need to determine how many watts of solar panel would be required to recharge the battery over a reasonable amount of time (5 hours, something like that?) under ideal weather conditions?

Am I missing something? (probably yes)

 

[Sparksalot]

For what you’re after, the panel and charge controller would do it. If you want to use the controller to monitor the loads, they would have to be routed through the controller, but that isn’t required to do the basic charging.

 

[grubworm]

i have a 5x8 square drop camper and it has a 100ah battery that runs everything, including 65qt dometic fridge. i mounted (2) 100w renogy panels on top and a charge controller in the tongue box and zero problems. the only big load you might have is the electric water kettle. i guess its 12v? anyway, led lights and that kind of load is not a big draw...anything with a compressor or heating element is going to have a huge draw. intermittant use of the kettle should be fine, but heating elements just draw a lot of current. i have a yakima cargo rack on top of the camper and mounted my panels under the cross bars so they are protected and i can still use the rack. im sure the renogy rep is very knowledgable, but usually folk like that just complicate things...get you a 100w panel and a charge controller off amazon, around $150 or less for both and see how it does. you can always add another panel

 

[woe_bonnet]

Thank you both for your replies! I agree that the rep has complicated things a bit (ultimately recommended x4 100w panels!)

I did end up getting a single 100w and charge controller, and I can expand if/when needed.

Thanks again!

 

[Kerner]

We mounted a 100W panel on our teardrop hatch and it would easily keep our battery charged for the load you're describing. Our total system is 400W but it is designed to charge a large battery quickly and powers a fridge all the time + laptops when working remotely.

 

[old_man]

Nothing other than the hot water kettle pulls that much power.

 

[Road]

.
Is your hot water kettle 12v? And does your laptop charge from a 12v or USB socket? Some will, many won't. Many Macbooks, like mine for example, want 18v and will not charge from a power pack or 12v socket. They may maintain, like on an airplane, but will not charge. They want 110 and their 85w charging block to convert the 110 appropriately, which means having an inverter.

Otherwise, if your kettle is 12v, then yes, as has been mentioned, 100-150w of panel should suffice for keeping your 100ah battery going.

I see you've already purchased a 100w panel and a charge controller. You may find you want to bump that a bit down the road, depending on number of people charging their devices and how much you run everything. That's why the Renogy rep asks those things; he's trying to steer you to the right amount of panel for best use so you're not running your batts too low regularly.

I use 120w folding panel charging my 100ah of battery on my trailer, and it's worked so well for me for years I am duplicating the whole thing on my van, down to same exact folding panel. Though I just found a great deal on a larger 250ah battery and some new flat panels with Sunpower cells, so may modify my plan and not have to worry as much about panel positioning, etc when under forest canopies.

Good luck with yours . . .I'll be interested to see how it all works out. Don't forget to fuse everything properly!

.

 

[tractor to trail]

I have the Renogy and love it here's a link to a test I did.

 

[woe_bonnet]

Thanks for the replies everyone. The kettle is 12v... not sure about those laptops, though? It would just be this Microsoft Surface I use, most likely... I'll have to do some research and see if an inverter is required. Thanks for the heads up!

Definitely going to keep in mind the notion of adding panels, as an electric fridge could easily make an appearance in the future...

 

[Billiebob]

i have a 5x8 square drop camper and it has a 100ah battery that runs everything, including 65qt dometic fridge. i mounted (2) 100w renogy panels on top and a charge controller in the tongue box and zero problems. the only big load you might have is the electric water kettle. i guess its 12v? anyway, led lights and that kind of load is not a big draw...anything with a compressor or heating element is going to have a huge draw. intermittant use of the kettle should be fine, but heating elements just draw a lot of current. i have a yakima cargo rack on top of the camper and mounted my panels under the cross bars so they are protected and i can still use the rack. im sure the renogy rep is very knowledgable, but usually folk like that just complicate things...get you a 100w panel and a charge controller off amazon, around $150 or less for both and see how it does. you can always add another panel

View attachment 200264

This is exactly where I am, ready to order but still hesitant.
I'm looking at 2 100W Renogy panels and controller too to a 100ahr battery.
So far my only regular draw will be a 37L cooler off a cigarette lighter plug.
It includes 2 USB ports too but I find I can charge the cell and tablet while driving.
So far my lighting is all free standing LED lights with AA or AAA batteries. They are 5 yearsold and still on the original batteries so I'll likely never hard wire lighting.


plus


and maybe this.... altho I have a $10 Kooltron which has not failed me yet.

 

[Billiebob]

I have the Renogy and love it here's a link to a test I did.

great video, all the questions I had, answered.... kinda

 

[tractor to trail]

Thanks.

 

[leeloo]

This is exactly where I am, ready to order but still hesitant.
I'm looking at 2 100W Renogy panels and controller too to a 100ahr battery.
So far my only regular draw will be a 37L cooler off a cigarette lighter plug.
It includes 2 USB ports too but I find I can charge the cell and tablet while driving.
So far my lighting is all free standing LED lights with AA or AAA batteries. They are 5 yearsold and still on the original batteries so I'll likely never hard wire lighting.


plus


and maybe this.... altho I have a $10 Kooltron which has not failed me yet.

it is a bit of an overkill, one 100 w panel is enough. You will do fine, had the same setup, 35 l fridge. I stop, I connect the solar panel ( 100 W foldable ) , when the sun is down the battery is still full, that means the panel more than covers what ever the fridge is drawing. During the night, the kid puts his tablet and phone to charge as well. In the morning at sun up the battery is about 75- 80 % , and it starts to charge, either from the panel or the driving. What ever the weather is, the battery will get full eventually even with heavy clouds. At clear sky in a couple of hours is full.
At 75% max discharge my AGM will have about 2000 cycles easy , that is a lot of years of camping.

 

[phxdsrtrat]

I'm going to throw my 2 cents in here as I've spent a fortune and done a lot of experimentation with portable off grid power for camping. With my current setup I have the ability to power 2 12 volt fridges and even a small 350 watt space heater for my teardrop off grid.

The Gear:
120 watt folding soft case solar panel (charging trailer battery)
100 watt folding soft case solar panel (charging King Power station)
Redarc BCDC1225D DC to DC charger (MPPT Solar and 12 volt DC vehicle input)
100Ah LiFePO4 house battery
King Power 1000Wh Power station (2000 watt peak inverter, built in MPPT solar charge controller)
700/900 watt propane generator

When I dry camp, I try to rely on solar. However, that is not always feasible. The amount of sunlight available is dictated by location and mother nature. The Redarc DC to DC charger gives me the ability to charge my trailer battery fully from my vehicle. This can not be achieved using just the hot wire in the trailer plug. It also has a built in MPPT solar charger also. I found running my vehicle to charge my trailer battery when solar just wasn't getting it done took quite a bit of time. I didn't like running the truck for hours. So, I picked up an inexpensive, propane only 700 watt generator to accomplish this same task. Propane is clean and doesn't go bad. I rarely use the generator option and some of my small propane tanks are years old. It's nice to have it available though.

Power wasn't all that important until I made the switch to 12VDC fridges (one of the best decisions I have made). However, running out of power for these fridges is not an option which is what drove the above final solution.

I would personally ditch the 12VDC kettle. Unless they have improved significantly in the last few years they take forever to heat water and require about 15 amps. Most cigarette lighter outlets are 10 amps. I actually added a 15 amp plug to my trailer for this. It's a power hog and a jet boil or equivalent works so much better. I assume you will have a stove in your setup so a plain old kettle works well also.

The King Power Station and its 100 watt solar panel is a little bit of overkill. I only bring it when I know the wife will want to run the space heater in the trailer when its cold.

-Curtiss

 

[woe_bonnet]

Great information here, thanks everyone.