Solar revamp/upgrade opinions

[ShullsinUtah]

We've got about 100 watts of solar on our trailer. I'm unsure of the exact wattage because we bought the coach used and it was already installed. My guess is the panel is about 10 years old.

In bright sun, we normally see around 6-7 amps on the solar controller. Since we do alot of boondocking, I'd like to double or triple the amount of wattage we can produce. In my mind, two 150W panels would be ideal. We aren't really power hungry, but we do camp where it gets warm in the daytime and cold at night. We run the lights (most updated to LED), our fans (both roof fans and the furnace) and charge our cell phones. Occasionally, we'll run the DVD player and TV during dinner.

For us, the reason to spend the extra money on more on extra solar isn't for the good days, it's an insurance policy for the bad days. The days when the daylight hours are short or it's cloudy. FWIW we do have a 2000w inverter generator that we can top the batteries off with if needed. However, we try to run that as little as possible.

What I'm milling over in my head is how I would like go about this refresh/upgrade. My constraints are that I would I would like to put as few (new) holes in the roof as possible and I would like as small a footprint with the panels as possible. I also imagine that Moore's law also applies to solar and the efficiency of panels has increased since the one on our roof was purchased.

So Do I,

1) Simply add a panel(s) in parallel to what up there already? I'm not sure if this will lead to compatibility issues, so I'm not ruling that out at this point. The advantages of this option is that it is likely the lowest cost option (and would require the least amount of work. (This option could also include using a non-attached movable solar array, but I'm not so keen on that one.)

2). Remove the panel that is up there and replace it with totally new panels. I think this would be the cleanest option. This option would require the most work and would be more expensive. I would also likely have to patch holes in the roof of the trailer. Best case scenario would be to find panels with the same dimensions as what up there now, so I could do a plug and play on the one panel, and simply install the other(s) in a suitable location. As I said above, I think two 150W panels in parallel would be ideal for us but would do three 100w panels if push came to shove.

3). Option 3 would be do nothing and get better at power management.

Regardless, I'm going to be running all new wire on the roof of the trailer and I assume I'll have to install a junction box to join everything. I also think it would be smart to add a 30 amp breaker somewhere between the panels and the solar controller. Thoughts on the location of that one? When they installed the solar controller, they placed it beside the fridge above the TV. The existing wires are routed in via the fridge vent on the roof.

Thoughts of the group? Am I missing anything?

Edit: Any recommendations on cost per watt and good panels would be highly appreciated.

[Lumatic]

I will follow this thread as I have a similar concern.

I have a Go Power Weekender system that I am moving from one trailer to another. It has one 180 watt collector. I asked Go Power and I can add more collectors up to a total of 500 something watts without changing any of the major components. I will have to buy a gizmo that the collectors will plug into.

[Mattirs]

Originally Posted by ShullsinUtah

We've got about 100 watts of solar on our trailer.

So Do I,

1) Simply add a panel(s) in parallel to what up there already? I'm not sure if this will lead to compatibility issues, so I'm not ruling that out at this point. The advantages of this option is that it is likely the lowest cost option (and would require the least amount of work. (This option could also include using a non-attached movable solar array, but I'm not so keen on that one.)

2). Remove the panel that is up there and replace it with totally new panels. I think this would be the cleanest option. This option would require the most work and would be more expensive. I would also likely have to patch holes in the roof of the trailer. Best case scenario would be to find panels with the same dimensions as what up there now, so I could do a plug and play on the one panel, and simply install the other(s) in a suitable location. As I said above, I think two 150W panels in parallel would be ideal for us but would do three 100w panels if push came to shove.

3). Option 3 would be do nothing and get better at power management.


Thoughts of the group? Am I missing anything?

Edit: Any recommendations on cost per watt and good panels would be highly appreciated.

Option 4 Is to get a solar panel and make it a portable one tying it into your existing system. This allows you to park in the shade and chase the sun.

Matti

[ShullsinUtah]

Originally Posted by Mattirs

Option 4 Is to get a solar panel and make it a portable one tying it into your existing system. This allows you to park in the shade and chase the sun.

I think I had that listed as option 1b.

1) Simply add a panel(s) in parallel to what up there already? I'm not sure if this will lead to compatibility issues, so I'm not ruling that out at this point. The advantages of this option is that it is likely the lowest cost option (and would require the least amount of work. (This option could also include using a non-attached movable solar array, but I'm not so keen on that one.)

When I said I wasn't keen on that one, I hadn't thought of the shade sun thing. Of course, where we do 90+% of our camping, there aren't that many trees.

I have already thought about this option though. I could install a connection point on the drivers side of the coach where the outside access panel for the fridge is located. It would be easy to do, and would require little to no modification of the trailer, which is a bonus. However, the downside is security when you are not at the campsite (which is often for us.)

[alano]

Originally Posted by ShullsinUtah

We've got about 100 watts of solar on our trailer. I'm unsure of the exact wattage because we bought the coach used and it was already installed. My guess is the panel is about 10 years old.

In bright sun, we normally see around 6-7 amps on the solar controller. Since we do alot of boondocking, I'd like to double or triple the amount of wattage we can produce. In my mind, two 150W panels would be ideal. We aren't really power hungry, but we do camp where it gets warm in the daytime and cold at night. We run the lights (most updated to LED), our fans (both roof fans and the furnace) and charge our cell phones. Occasionally, we'll run the DVD player and TV during dinner.

For us, the reason to spend the extra money on more on extra solar isn't for the good days, it's an insurance policy for the bad days. The days when the daylight hours are short or it's cloudy. FWIW we do have a 2000w inverter generator that we can top the batteries off with if needed. However, we try to run that as little as possible.

What I'm milling over in my head is how I would like go about this refresh/upgrade. My constraints are that I would I would like to put as few (new) holes in the roof as possible and I would like as small a footprint with the panels as possible. I also imagine that Moore's law also applies to solar and the efficiency of panels has increased since the one on our roof was purchased.

As long as you're asking, here's what I would consider:

1. Keep your existing panel, it seems to be working well.
2. Add more panels. Check out the Grape panels from AM Solar, or buy the Renology panels on Amazon/eBay. Use VHB tape and Sikaflex-221 to fix the panels to the roof without screws.
3. Add a "roof c-box" from Am Solar to tie the panels together on the roof. You can also buy the wire and waterproof connectors you need from Am Solar. Reuse your existing wiring if it's 8 AWG or larger.
4. Buy a MPPT controller to handle the total power you intend to install. I'd look at Blue Sky or Victron controllers.
5. You don't need a 30 A breaker between the panels and the controller. However, it's recommended that you add a SPST switch, so you can cut the power from the panels to the controller for any reason. The MPPT controller's manual will specify a fuse to be inserted between the controller and your batteries.
6. Make sure you get a battery monitor with a shunt, so you can easily monitor the state-of-charge of your batteries.

[Trout Bum]

A couple of questions to answer first, methinks.
1. How often do you really use your genset to replenish your batteries?
2. What type and how old are your current batteries? Total AH available?
3. What gauge wire and how long is the run from your current PV to your existing controller?
4. What type and size is your existing solar controller? Fused?
5. What's the budget?

[ShullsinUtah]

Originally Posted by Trout Bum

A couple of questions to answer first, methinks.
1. How often do you really use your genset to replenish your batteries?

If it's sunny and warm, not often. If cloudy and cold about 1x per day for an hour or two.

Originally Posted by Trout Bum

2. What type and how old are your current batteries? Total AH available?

Duracell group 24 Deep Cycle. About 150 AH total.

Originally Posted by Trout Bum

3. What gauge wire and how long is the run from your current PV to your existing controller?

About 3' to 5' and 10 gauge.

Originally Posted by Trout Bum

4. What type and size is your existing solar controller? Fused?

I was kind of forced into a box on this one when our old "specialty concepts" controller failed, we already had an existing cutout above the TV and beside the fridge for a solar controller. My controller had to fit into that spot. The one we previously had had been discontinued. We were leaving on a trip and a couple of days, so only one I could find with the right dimensions was a 30amp controller made by Sunforce. Getting it to our house on time was a battle with Home Depot that enervated me beyond belief (paid for 2 day shipping to make sure it arrived before we left on a trip, only to have it delayed...)

I don't think it's currently fused (so lets say it's not).

Originally Posted by Trout Bum

5. What's the budget?

I'd say $300 to $400 based on the equipment we already have.

[gator.bigfoot]

Originally Posted by ShullsinUtah

We've got about 100 watts of solar on our trailer. I'm unsure of the exact wattage because we bought the coach used and it was already installed. My guess is the panel is about 10 years old.

In bright sun, we normally see around 6-7 amps on the solar controller. Since we do alot of boondocking, I'd like to double or triple the amount of wattage we can produce. In my mind, two 150W panels would be ideal. We aren't really power hungry, but we do camp where it gets warm in the daytime and cold at night. We run the lights (most updated to LED), our fans (both roof fans and the furnace) and charge our cell phones. Occasionally, we'll run the DVD player and TV during dinner.

For us, the reason to spend the extra money on more on extra solar isn't for the good days, it's an insurance policy for the bad days. The days when the daylight hours are short or it's cloudy. FWIW we do have a 2000w inverter generator that we can top the batteries off with if needed. However, we try to run that as little as possible.

What I'm milling over in my head is how I would like go about this refresh/upgrade. My constraints are that I would I would like to put as few (new) holes in the roof as possible and I would like as small a footprint with the panels as possible. I also imagine that Moore's law also applies to solar and the efficiency of panels has increased since the one on our roof was purchased.

So Do I,

1) Simply add a panel(s) in parallel to what up there already? I'm not sure if this will lead to compatibility issues, so I'm not ruling that out at this point. The advantages of this option is that it is likely the lowest cost option (and would require the least amount of work. (This option could also include using a non-attached movable solar array, but I'm not so keen on that one.)

2). Remove the panel that is up there and replace it with totally new panels. I think this would be the cleanest option. This option would require the most work and would be more expensive. I would also likely have to patch holes in the roof of the trailer. Best case scenario would be to find panels with the same dimensions as what up there now, so I could do a plug and play on the one panel, and simply install the other(s) in a suitable location. As I said above, I think two 150W panels in parallel would be ideal for us but would do three 100w panels if push came to shove.

3). Option 3 would be do nothing and get better at power management.

Regardless, I'm going to be running all new wire on the roof of the trailer and I assume I'll have to install a junction box to join everything. I also think it would be smart to add a 30 amp breaker somewhere between the panels and the solar controller. Thoughts on the location of that one? When they installed the solar controller, they placed it beside the fridge above the TV. The existing wires are routed in via the fridge vent on the roof.

Thoughts of the group? Am I missing anything?

Edit: Any recommendations on cost per watt and good panels would be highly appreciated.

I was in the same position as you a few years ago with the same thoughts.
My usage is similar to yours and my trailer is also similar to yours in age. The only difference in my case was that my solar controller no longer worked, which I changed first and then the following year I started to change other things. In my case I added 2 new solar panels to the roof (2 x 100 watts). I upgraded the wiring to the back of the fridge (since any further I would have to remove the fridge) then I replaced the batteries with new ones (same Lifelines as before). I found that the 2 batteries were not quite enough storage when it rained for days on end so I added 2 more shortly after.

If I had to do it again I would do the same but just change the solar controller. Currently I have a PWM, but the MPPT would give me a little better charging current. But overall I am happy with the system and I have not run out of power yet with the type of usage that I do (which is similar to yours). Even after days of rain with heavy overcast sky's it works well. I also added a Trimetric to monitor the usage which helps me identify the loads. Currently I am considering using the Victron MPPT controller since it has the built in monitoring and can also be monitored remotely which is useful when the unit is in storage.

If you are considering this route (which I think is the cheapest) for roof top installation then this works well. The portable panel also works well, but you have the hassle of moving it and setting it up (not to mention the storage), but then you can get it into the sun and at the right angle. Personally here I would use the flex panels since those can be stored under the bed and don't break if knocked over by wind.

I made my own combiner box (which all parts are easily obtained from you local big box store) and also made my own solar panel mounts from aluminium angle from HD. Double sided tape holds everything to the roof. I added my combiner box in between the existing roof connector and the existing panels.

As for costs the panels and the batteries were the most expensive then the controller and the battery monitor. The wiring and incidentals (connectors, wire tie downs, combiner box items, solar mounts, heat shrink, etc.) added up, but if you look around you can get some good deals. I also added a pair of breakers before and after the controller to isolate things.

You can also get most of these items in a "package" from a number of suppliers, but where I live that wasn't an option without paying through the nose for shipping and duties.

Good luck.

[ShullsinUtah]

Thanks Gator. Some good info there.

FWIW, I have an old Battery box that I used in my inflatable pontoon boat when I did more lake fishing. I have also thought of putting a 3rd battery in that, running a pigtale to that from the battery box, and running 3 batteries in parallel for more amp hours. Obviously, I'd only hook it up when stationary, and would have to keep it topped off with a charger at home when not in use....

[Trout Bum]

Okay, now we’re getting somewhere. Based on what you’ve written, you most likely have an existing poly panel with 100 watt output. 100w/6Amp output=16.7Volts which is in the ballpark. And, based on 75Amp hour battery useful capacity (50% of 150 A/h) that appears to need replenishment on a daily basis you are definitely under powered in both the solar and the storage department for your daily requirements.


So, what to do with the $400 budget limit? Two 150w poly PV’s will cost about $370 without mounting brackets. Make your own mounts from aluminum or stainless? Some MC4 electrical connectors, VHT 4950 tape for mounting and a half tube of Sikaflex 221 and you’re right on the money. You do not need to upgrade your wire run. Your existing PWM controller will be able to handle this PV upgrade without problem. You can add a disconnect switch, fuse and an MPPT controller later after you refill the money magazine.
However, this doesn’t address your storage capacity. All the solar power in the world won’t help if you can’t store enough to meet your needs especially if your power usage is outside of solar supply hours. So, either more batteries or, less electrical usage after the sun sets.

[gator.bigfoot]

I think the budget might be better utilized purchasing new batteries. Then perhaps next year you can look at upgrading the solar. Although I'm not sure it is enough for really good batteries.

If you upgrade the solar first you will have lots of power while the sun shines, but no where to store it. Unfortunately some of this solar stuff goes hand in hand. You really want to purchase your batteries together or at least in close proximity otherwise you mix old batteries with new which reduces their overall storage and efficiency.

[ShullsinUtah]

Alright,

Talk to me about batteries...

Edit: FWIW, I've always felt somewhat limited by the Group 24 size battery (given the "average" Ah's they are "limited" to.) Additionally, I do like the concept of two 12v DC batteries in parallel vs two 6v DC batteries in series because of the built in redundancy in the parallel setup...

[AirMiles]

Talk to me about batteries: https://marinehowto.com/what-is-a-deep-cycle-battery/

The best budget deal on a battery is the Duracell EGC2 at Sam's Club for $117.52 each. They were on sale on Saturday for $97.52 each! These are the high quality Deka/East Penn GC15 batteries described in the above article. There are cheaper 6V batteries, $77 for a GC2 this weekend, but the above article suggests choosing the higher quality Duracell EGC2 (Deka GC15) over the budget GC2 (Deka GC10) version. I am really happy with these Duracell EGC2 batteries in my Airstream as described and pictured here: http://www.airforums.com/forums/f42/...ml#post2079369

[Rocinante]

We were never happy with our flooded group 24 and later group 27 batteries. Just not. Possibly because we didn’t have a battery monitor and relied on voltage measurements. So, maybe start by putting in a good monitor solution that gives more than a SWAG regarding the state of charge for the batteries?

[ShullsinUtah]

Thanks Miles.

I get the basics of batteries, and they physics behind them (I am a scientist by training, FWIW). I was looking more to what folks prefer/recommend and how do folks squeeze the most out of the batteries.

If I'm not mistaken, the Group Size EGC2 batteries require a modified battery box? I've been reluctant to do that in the past, but I'm going into this with an open mind (and at 12 y/o our battery box is likely in need of some rehab anyway. I went with the current (no pun intended) batteries because they were available locally, came well recommended online and had the most Ah's for the lowest price. I'm guessing this is where I get the talk about not all Ah's are created equal.

Thanks again to everyone who's taken the time to respond.

[ShullsinUtah]

Originally Posted by Rocinante

We were never happy with our flooded group 24 and later group 27 batteries. Just not. Possibly because we didn’t have a battery monitor and relied on voltage measurements. So, maybe start by putting in a good monitor solution that gives more than a SWAG regarding the state of charge for the batteries?

Excellent idea. I'm also open to suggestions on what folks like in regards to battery monitoring...

And I should say (or say again), our current mode of operation works just fine for us. Worst case scenario is I run the generator for a hour or two (and often we don't even have to do that). I'm conceptualizing trying to get us a point where that hour or two becomes zero on all but the very worst days we are camping.