solar

[Akraft]

GHen - Please read before commenting. As I all ready explained in the previous post. It all depends on your battery size. I'll make it nice and simple.

Battery Rating (amp-hrs) / 2 = Usable Power (amp-hrs)

Sunny Day: 100 watts charges at 6 amps. Five good hours in direct light gives you 30 amp-hrs of charge per day. 200 watts charges at just under 12 amps that yields you 60 amps hrs per day. 300 watts charges at 18 amps that yields you 90 amps hrs per day.

Hazy Day: 100 watts charges at approximately 3.6 amps. That same panel location should yield you about 18 amp-hrs of charge per day. 200 watts charges at just under 7.2 amps that yields you 36 amps hrs per day. 300 watts charges at 10.8 amps that yields you 54 amps hrs per day.

If you are dry camping you want to make the most out of your battery capacity. No braine.

[GHen]

Thanks AKRAFT.
What your saying is right on and should be easy for most to understand.
What brand panels do you use? I can’t find any 100 watt panels that deliver over 5.6 amps.

[Akraft]

I have a Ecoworthy 120 watt portable that charges at 6.67 amps and I just purchased a Portable Sunwanderer 200 watt that charges at 11.43 amps.

I was only estimating the 6 amps. I was also estimating the 5 hours of sun light. Different manufactures claim different daily yields. Ecoworthy estimates 0.5KWH/day from my 120 watt kit on a sunny day. That translates to 120 watts panels producing 41.6 amp-hrs per day.

As you know there are a lot of variables. Position of panel, angle of panel, and the amount of shade are the ones off the top of my head.

What I said is an estimate. The point I was trying to make was instead of doing what everyone suggest and guessing at how much you will use it might use, it would be smarter to look and your planned battery capacity and basing your size panels on getting the most out of your storage capacity.

[Akraft]

The reason I am using portable panels is the location I park my RV is 300 feet from the house so I have no shore power. I am in a area that is shaded most of the day but I was able to cut enough trees to set my panels in front of the RV so I can get good sunlight from 2:00 pm to 6:00 pm.

If they were mounted on top of the RV I would only see less than two hours light with none being direct. With my new 200 watt panel the batteries always seems topped off even if I have been using the furnace. I only use the RV 3 to 4 times a week (a couple hours each time) at home. When traveling I always am able to connect to shore power.

[sullivanclan]

I have the same set up but one battery, it recharges within about three hours sometime less each morning with full sun.

[daveobieone]

Hazy Day: On a hazy day figuring only 60% output current that would reduce to 18 amp-hrs per 100 watts. So if you want to insure you can replace 107.5 amps hrs on a hazy day that comes out to 560 watts.

Well stated!
That's exactly the reason we have 600 watts on the roof. It wouldn't be really unusual for us to burn through almost 100 amp-hours over-night what with TV, lights, water pump, C-pap, air filter, fans, etc running. That's about 1/2 of the capacity of our 2 Trojan T-105 6 volt golf cart batteries. We wanted to make sure that even on a partly cloudy, hazy day, we could still be back up to fully charged...Which we usually are by early afternoon on overcast days.

With this set-up, we are never short of power.

One must also take into consideration that in most RV installations, the solar panels are not at an optimal angle for capturing the most power from the sun. So, you won't get quite the full power rating from your panels. The most I've gotten from my 600 watt set-up is about 560 watts. That's with the sun straight overhead, and a very clear sky. Those panels are just flat mounted to the roof.

You will never be sorry for putting more panel power on the roof. You might be sorry if you put to little up there.

I also wanted my batteries to last a good while. They are going on 4 years now, and still working great. Over-depleting your batteries every night is an invitation to short battery life.

Dave O.

[01tundra]

Originally Posted by GHen

I’m not aware of any 100 watt solar panel that will generate more than 5.6 amp hours.

I see quotes above at 7.5 and 8.3. You either of you have a specific product that generates that much?

Our Renogy 100W solar suitcase is rated at a max operating voltage of 18.0V and 5.56A, but I rewired the panels in series and use a Victron 75/15 MPPT controller.

The Victron takes the higher input voltage and converts it down, which results in a increase in amperage. More is always better to an extent, but I don't want to give up the bed space to go with a larger solar suitcase.

Since we only use an average of 10AH in a 24 hr period while dry camping our 100W panel can top off our single BattleBorn 100AH battery in under 2 hrs in good conditions....and when it's cloudy the Honda 2200 can bring it back up to 100% SOC in about 15-20 minutes max.

That's why a lot of people respond with "depends" when asked about how much solar a person needs, for our particular set up a 100W solar suitcase is more than ample.

[Pikespeakfamily]

I get jealous how well these guys understand solar. It baffles me!

[Screwby]

Originally Posted by 01tundra

Our Renogy 100W solar suitcase is rated at a max operating voltage of 18.0V and 5.56A, but I rewired the panels in series and use a Victron 75/15 MPPT controller.

The Victron takes the higher input voltage and converts it down, which results in a increase in amperage. More is always better to an extent, but I don't want to give up the bed space to go with a larger solar suitcase.

Since we only use an average of 10AH in a 24 hr period while dry camping our 100W panel can top off our single BattleBorn 100AH battery in under 2 hrs in good conditions....and when it's cloudy the Honda 2200 can bring it back up to 100% SOC in about 15-20 minutes max.

That's why a lot of people respond with "depends" when asked about how much solar a person needs, for our particular set up a 100W solar suitcase is more than ample.

My 400w Renogy kit on the roof of my camper produced 146aH yesterday sitting in the sun. I need to get a better monitor like the Victron but for now I rely on the Renogy Bluetooth app. I can’t imagine a situation where I’d use 146aH of my 215aH (50% of my 430aH bank) available but I do like having more than I need and enough solar I can almost put it all back during ideal conditions in if needed.

[01tundra]

Originally Posted by Screwby

My 400w Renogy kit on the roof of my camper produced 146aH yesterday sitting in the sun. I need to get a better monitor like the Victron but for now I rely on the Renogy Bluetooth app. I can’t imagine a situation where I’d use 146aH of my 215aH (50% of my 430aH bank) available but I do like having more than I need and enough solar I can almost put it all back during ideal conditions in if needed.

I've been toying with the idea of building a 200W solar suitcase, even have all the pieces and parts in my Amazon shopping cart, I just still can't justify it yet.....even though it's going to cost around $250 including a case. At this point the only way I can justify it is because I want a project to work on.

Since we're old tent campers, when we go dry camping somewhere we really only use the trailer as a base station - cooking outside, use the bathroom, a few lights, refrigerator on propane and recharge center for our phones and son's tablet. Other than for sleeping, we're outside. Last time we were dry camping we "splurged" with using a lot of lights and still only used about 14AH in a 24 hr period. With the BattleBorn being new I wanted to see how far we could stretch it, after five days and no recharging we were still slightly above 50% SOC, I think we could get at least 8 days out of it.

Really for the way we camp a second BattleBorn would be the best spent money, but all that would really gain us is maybe not having to bring along the Honda 2200. Since most of our camping is in the woods and heavily shaded, solar doesn't gain us near as much. I can run the generator for 15 minutes each morning and have our SOC back up to 100%. So the real right answer for us is "do nothing"....which is incredibly boring !

[Screwby]

Originally Posted by 01tundra

I've been toying with the idea of building a 200W solar suitcase, even have all the pieces and parts in my Amazon shopping cart, I just still can't justify it yet.....even though it's going to cost around $250 including a case. At this point the only way I can justify it is because I want a project to work on.

Since we're old tent campers, when we go dry camping somewhere we really only use the trailer as a base station - cooking outside, use the bathroom, a few lights, refrigerator on propane and recharge center for our phones and son's tablet. Other than for sleeping, we're outside. Last time we were dry camping we "splurged" with using a lot of lights and still only used about 14AH in a 24 hr period. With the BattleBorn being new I wanted to see how far we could stretch it, after five days and no recharging we were still slightly above 50% SOC, I think we could get at least 8 days out of it.

Really for the way we camp a second BattleBorn would be the best spent money, but all that would really gain us is maybe not having to bring along the Honda 2200. Since most of our camping is in the woods and heavily shaded, solar doesn't gain us near as much. I can run the generator for 15 minutes each morning and have our SOC back up to 100%. So the real right answer for us is "do nothing"....which is incredibly boring !

Same here with the tent camping mindset. If I’m honest with myself, I way overbuilt this system. We’d had the camper for 2 months and I was slapping 4 panels on the roof and 4 6v batteries on the tongue. Not that I’m complaining but we don’t use an 1/8 of our capacity even with my two little ones watching cartoons on rainy days. I might have a solar addiction too so that doesn’t help. I’ve got a system on my cargo/mobile workshop, just helped a buddy get his cabin setup with a small system, and looking to fab a baby kit for my Ham Radio box I’m building. I’m all about self sufficiency and self reliance and solar fits that bill nicely.

[01tundra]

Originally Posted by Screwby

I’m all about self sufficiency and self reliance and solar fits that bill nicely.

Yes it does !

[ttavasc]

Originally Posted by 01tundra

I've been toying with the idea of building a 200W solar suitcase, even have all the pieces and parts in my Amazon shopping cart, I just still can't justify it yet.....even though it's going to cost around $250 including a case. At this point the only way I can justify it is because I want a project to work on.

Since we're old tent campers, when we go dry camping somewhere we really only use the trailer as a base station - cooking outside, use the bathroom, a few lights, refrigerator on propane and recharge center for our phones and son's tablet. Other than for sleeping, we're outside. Last time we were dry camping we "splurged" with using a lot of lights and still only used about 14AH in a 24 hr period. With the BattleBorn being new I wanted to see how far we could stretch it, after five days and no recharging we were still slightly above 50% SOC, I think we could get at least 8 days out of it.

Really for the way we camp a second BattleBorn would be the best spent money, but all that would really gain us is maybe not having to bring along the Honda 2200. Since most of our camping is in the woods and heavily shaded, solar doesn't gain us near as much. I can run the generator for 15 minutes each morning and have our SOC back up to 100%. So the real right answer for us is "do nothing"....which is incredibly boring !

In the scheme of things this isn't a bad reason. I recently finished a 200 watt portable build. It was a fun project and I got something useful out of it but I'm ready to do something else now. Given how you camp have you considered adding a higher capacity charge line to your tow vehicle? I've got the heavy duty alternator on my F-250 and getting started now on adding a new charge line to the truck using a Victron Energy 30amp DC-DC charger and an 85a continuous duty solenoid tied into the ignition system. With that capability you wouldn't have to worry about bringing the generator along - hook up to the truck in a pinch or just let it give a proper charge traveling between destinations.

[01tundra]

Originally Posted by ttavasc

In the scheme of things this isn't a bad reason. I recently finished a 200 watt portable build. It was a fun project and I got something useful out of it but I'm ready to do something else now. Given how you camp have you considered adding a higher capacity charge line to your tow vehicle? I've got the heavy duty alternator on my F-250 and getting started now on adding a new charge line to the truck using a Victron Energy 30amp DC-DC charger and an 85a continuous duty solenoid tied into the ignition system. With that capability you wouldn't have to worry about bringing the generator along - hook up to the truck in a pinch or just let it give a proper charge traveling between destinations.

I've been studying Victron 12/12-18 and 12/12-30 DC-DC chargers every day for the past couple months. I've talked myself off the cliff about a dozen times now.

The first reason I bailed was because I don't want to do any wiring on our GMC 2500, but then I realized that I could simply use the trailer running lights as a trigger since we always travel with lights on to power the back-up camera....so that excuse has fallen flat. I haven't checked yet, but since we have a dedicated 30A fuse for 12V+ in the truck I would think that the wire is 10AWG.

I installed a switch on the trailer that allows me to kill the 12V+ from the tow vehicle for when the battery is charged. From the trailer's 7-way we have 10AWG in the pigtail and once it enters the junction box on the frame it goes through a 40A breaker and then is 8AWG all the way to the rear of the trailer where it lands on a power post. If I could get away with mounting a 12/12-30 in the rear of the trailer behind the converter and trigger it with the rear running light I would likely pull the trigger on that option, I just haven't worked through the voltage drop from an alternator almost 40' away from the DC-DC charger.

[ttavasc]

Originally Posted by 01tundra

I've been studying Victron 12/12-18 and 12/12-30 DC-DC chargers every day for the past couple months. I've talked myself off the cliff about a dozen times now.

The first reason I bailed was because I don't want to do any wiring on our GMC 2500, but then I realized that I could simply use the trailer running lights as a trigger since we always travel with lights on to power the back-up camera....so that excuse has fallen flat. I haven't checked yet, but since we have a dedicated 30A fuse for 12V+ in the truck I would think that the wire is 10AWG.

I installed a switch on the trailer that allows me to kill the 12V+ from the tow vehicle for when the battery is charged. From the trailer's 7-way we have 10AWG in the pigtail and once it enters the junction box on the frame it goes through a 40A breaker and then is 8AWG all the way to the rear of the trailer where it lands on a power post. If I could get away with mounting a 12/12-30 in the rear of the trailer behind the converter and trigger it with the rear running light I would likely pull the trigger on that option, I just haven't worked through the voltage drop from an alternator almost 40' away from the DC-DC charger.

That is a bit further of a run to get to the charger than what I'm dealing with so I understand the dilemma. I'm looking at around 25 feet on the truck which will be 2 gauge, and then about 7 feet or so of 6 gauge to the charger which I am mounting in a small electrical access area inside the enclosed underbelly right behind the batteries. From the charger to the battery probably another 2.5-3 feet of 6 gauge. All told I should be able to keep the voltage drop about 2%, maybe just a hair over.

[lefoster]

just a follow up.........got my Renogy 100W suitcase solar panel last week. On saturday, i was sanitizing my fresh water system, water pump running, and had radio going, even tried my TV on a 12V plug inverter. It ran down the batteries one dot on gauge on wall. (which I know doesn't tell you much) but, hooked up the solar charger on Sunday, so easy, and they were charged back to full in about 5 hours and it was slightly cloudy all day.
so, for what it's worth......there you go!
I have two 12V/80AH batteries in series.

[Screwby]

Originally Posted by lefoster

just a follow up.........got my Renogy 100W suitcase solar panel last week. On saturday, i was sanitizing my fresh water system, water pump running, and had radio going, even tried my TV on a 12V plug inverter. It ran down the batteries one dot on gauge on wall. (which I know doesn't tell you much) but, hooked up the solar charger on Sunday, so easy, and they were charged back to full in about 5 hours and it was slightly cloudy all day.
so, for what it's worth......there you go!
I have two 12V/80AH batteries in series.

Careful, once you dip your toes into solar there’s no turning back. You’ll be thinking of all kinds of ways to utilize it.

[TaftCoach]

Originally Posted by Pikespeakfamily

I get jealous how well these guys understand solar. It baffles me!

I think often times people come into the discussion in the middle and get lost and never recover.

There are only three elements.
1. The battery
2. The solar panels
3. The (controller) regulator (sits in the middle)

Analogy to your car
1. The fuel tank
2. The gasoline station's fuel tank
3. The gas station fuel pump

If you are driving a long distance you will need a large 1 and 2. If you are using a lot of electricity you will need a large 1 and 2.

Gas is measured in gallons -- electricity in amp hours.

You can go further with more gallons of gasoline. You can go longer with more amp hours of electricity.

Solar panels refill your tank (battery). The controller acts like the pump at the gas station and regulates how fast the electricity flows and when it should shut off.

The wire size is like a leaky gasoline hose. Leaky in the sense that electricity is lost through heat as it travels down the wire. Heavier wire doesn't heat up as much and allows more electricity to flow with less loss. The smaller the number the thicker the wire (cable).

The rest is just bits and bobs to make it pretty.

So all you need is a

Solar Panel---> Controller ---> Battery

A simple 100 watt system can be put together for about $150 at Amazon. If you are willing to go with two batteries and swap them when one gets low you can put a 100W panel in the back of your truck with a controller and recharge the battery there and then swap it as needed. No holes in the roof. No chasing wires through the trailer. That seems like the biggest challenge for most people. And it makes sense because drilling holes in something that is suppose to keep water out is always a risk.

[lefoster]

I can see that happening!

[lefoster]

Originally Posted by lefoster

just a follow up.........got my Renogy 100W suitcase solar panel last week. On saturday, i was sanitizing my fresh water system, water pump running, and had radio going, even tried my TV on a 12V plug inverter. It ran down the batteries one dot on gauge on wall. (which I know doesn't tell you much) but, hooked up the solar charger on Sunday, so easy, and they were charged back to full in about 5 hours and it was slightly cloudy all day.
so, for what it's worth......there you go!
I have two 12V/80AH batteries in series.

OOPS! I mean two 12V/80AH batteries in PARALLEL