Is this sensible: Portable Solar / Controller for RV

[Chateau_Nomad]

You essentially have the equivalent of a battery tender... that's what a typical "solar prep" package comes with. It's intent is so RV lot sales staff don't have to constantly deal with dead batteries.

IMO, like Star Link, solar panels on an RV are strictly "off grid" tools. And just like any tool they have a place. There's absolutely no need for either of those on an RV that's rarely off-grid.

There's the often used argument that using a generator which only drinks a half-gallon per hour makes more sense. But the counter argument generally isn't about the fuel usage.

The draw to off-grid is the silence and remoteness encountered when FAR away from the noise and bustle of everyday life. It's NOT for everyone. Those are the experiences we seek... miles away from any civilization... where there's NOTHING to do. No stores... no cell signal, no electric... nothing. Nothing but quiet - and that's a huge part of the experience.

Our daughter doesn't understand that. She's a dedicated "big city" girl who'd be comfortable in New York City. Remote "glamping" doesn't even compute for her. There are many folks who feel the same as her. If it wasn't for all those folks, our special remote retreats would be crowded!

It's an awesome feeling to be able to take our little self-contained hotel room our to the middle of nowhere and exist in near silence... with nothing but the sound of nature. Yes... the generator is there if needed in rare cases - AND we'll use it, but ONLY as a last resort.

Basic rigid solar panels are cheap nowadays... much less than $1 per rated watt. Batteries are cheap now too... as you know. Both are excellent off-grid tools.

The reason for the explanation of our camping "style" was to lend an understanding of why we use solar as a supplemental tool. It contributes to the sense of solitude. I'm not an anti-generator zealot... quite the contrary. But neither am I a "solar fan boy". Like solar, Star Link and LiFePO4 batteries, a generator is just another tool which has its place.

 

[dkoldman]

You essentially have the equivalent of a battery tender... that's what a typical "solar prep" package comes with. It's intent is so RV lot sales staff don't have to constantly deal with dead batteries.

IMO, like Star Link, solar panels on an RV are strictly "off grid" tools. And just like any tool they have a place. There's absolutely no need for either of those on an RV that's rarely off-grid.

There's the often used argument that using a generator which only drinks a half-gallon per hour makes more sense. But the counter argument generally isn't about the fuel usage.

The draw to off-grid is the silence and remoteness encountered when FAR away from the noise and bustle of everyday life. It's NOT for everyone. Those are the experiences we seek... miles away from any civilization... where there's NOTHING to do. No stores... no cell signal, no electric... nothing. Nothing but quiet - and that's a huge part of the experience.

Our daughter doesn't understand that. She's a dedicated "big city" girl who'd be comfortable in New York City. Remote "glamping" doesn't even compute for her. There are many folks who feel the same as her. If it wasn't for all those folks, our special remote retreats would be crowded!

It's an awesome feeling to be able to take our little self-contained hotel room our to the middle of nowhere and exist in near silence... with nothing but the sound of nature. Yes... the generator is there if needed in rare cases - AND we'll use it, but ONLY as a last resort.

Basic rigid solar panels are cheap nowadays... much less than $1 per rated watt. Batteries are cheap now too... as you know. Both are excellent off-grid tools.

The reason for the explanation of our camping "style" was to lend an understanding of why we use solar as a supplemental tool. It contributes to the sense of solitude. I'm not an anti-generator zealot... quite the contrary. But neither am I a "solar fan boy". Like solar, Star Link and LiFePO4 batteries, a generator is just another tool which has its place.

Remember, I did not buy the Power Station or Solar Panel for the RV. I got the Power Station for an incredible good price Memorial Day weekend and I bought the solar panels just because I have always said if I were to get solar it would be portable. I felt that 200watts was twice what I see in basic solar offerings of only a 100 watt system. At 18 lbs, the 200 watts is my limit.

The fact that I can charge my house or chassis battery on demand is appealing. I am with your daughter, but don't view us as dedicated big city.

I have had my RV's power off now about a week. I may drain the RV down to 75% to see how long it takes to recharge back to 300ahs?

 

[Chateau_Nomad]

In reality, the ONLY reason I bought 300Ah of LiFePO4 batteries was for the scenario I described in my previous post. It wasn't a curious novelty, but a necessity... a tool to make it happen.

However, with pedestal power always available or running my generator at will, all I would have needed was that pair of 6-volt lead-acid batteries. Even today given that scenario, I would just replace those lead-acid batteries with a single 100Ah LiFePO4 battery when they failed because the battery is just a buffer. I probably never would have upgraded the converter either. And solar panels? They would be totally unnecessary.

So... when you could just as easily plug in your power station to recharge it, why go through the hassle of setting up a solar panel? And same for your motorhome. If power is always readily available for battery charging via shore, alternator or generator why fuss with solar?

Would it be safe to say you view the solar panel as a novelty not a necessity? I could see the power station as a convenience - like a situation where you didn't want to string an extension cord,

Or... maybe you're dipping your toes in the water for the future. I remember all too well when you were bordering on disdain of LiFePO4 batteries vs your AGM ones... and I suspicion it wasn't just about price. Then LiFePO4 prices fell through the floor and several folks on the forum bit the hook of LiFePO4.

Now you're "experimenting" with solar. Am I seeing a pattern here? I'll be curious in a few years where these experiments lead.

 

[dkoldman]

In reality, the ONLY reason I bought 300Ah of LiFePO4 batteries was for the scenario I described in my previous post. It wasn't a curious novelty, but a necessity... a tool to make it happen.

However, with pedestal power always available or running my generator at will, all I would have needed was that pair of 6-volt lead-acid batteries. Even today given that scenario, I would just replace those lead-acid batteries with a single 100Ah LiFePO4 battery when they failed because the battery is just a buffer. I probably never would have upgraded the converter either. And solar panels? They would be totally unnecessary.

So... when you could just as easily plug in your power station to recharge it, why go through the hassle of setting up a solar panel? And same for your motorhome. If power is always readily available for battery charging via shore, alternator or generator why fuss with solar?

Would it be safe to say you view the solar panel as a novelty not a necessity? I could see the power station as a convenience - like a situation where you didn't want to string an extension cord,

Or... maybe you're dipping your toes in the water for the future. I remember all too well when you were bordering on disdain of LiFePO4 batteries vs your AGM ones... and I suspicion it wasn't just about price. Then LiFePO4 prices fell through the floor and several folks on the forum bit the hook of LiFePO4.

Now you're "experimenting" with solar. Am I seeing a pattern here? I'll be curious in a few years where these experiments lead.

It is actually very simple, I bought the Bluetti AC180 power stations because of a fire sell, they were brand new and very cheap, I bought 4 of them, my mother, my two kids and got one for the house. These things can run 1800 watt compliance and they are awesome. I gave my 3500 watt portable generator away last year to our Mobile Tech so I was wanting to do something anyway, no plans to buy another portable gas generator. Given I had the new AC180 Power Stations which by the way make my new Navigator more of a real Electric vehicle without the hybrid cost, I decided to buy one portable solar panel. Just to see what they can do, thus my probing questions. I am using my power station in the house daily and charging in the sun and in some days with no sun daily. Just to see what it can do.

If you notice, it has NOTHING to do with my RV. However, I did make a special MC4 cable with alligator clips and bought a Victron 75/15 Solar controller that I can charge any type of battery I want with the solar panel (including the RV). Will I ever need to, not likely; but I could. Panel is portable and only 18 lbs so I will travel with it.

So for now I am just trying to make sure the panel I bought is working properly for what solar panels do. 130 watts seems to be the peak and the ACE has stated that is all I can expect. Do you agree with that assessment? Also, why do the Solar Panels state to be 23.5% efficient when I see 65 to 70% efficiency? It just seems like all lies to me, so I am just asking somebody that can speak the truth in straight talk

 

[Chateau_Nomad]

The 23% is the cell efficiency. That's generally science across the board. The 70% is the particular panels overall efficiency.

So... yes solar panels are VERY inefficient. But compared to what? A gasoline engine is terribly inefficient... 30% at best. Like the tungsten light bulbs used for a century, most of the energy produced is wasted as heat. Heck, the entire realm of energy storage is mind blowing inefficient.

So the "efficiency" argument can be a very deep rabbit hole. I keep going back to the tool analogy. Use the best one you have for what you're trying to accomplish.

 

[dkoldman]

The 23% is the cell efficiency. That's generally science across the board. The 70% is the particular panels overall efficiency.

So... yes solar panels are VERY inefficient. But compared to what? A gasoline engine is terribly inefficient... 30% at best. Like the tungsten light bulbs used for a century, most of the energy produced is wasted as heat. Heck, the entire realm of energy storage is mind blowing inefficient.

So the "efficiency" argument can be a very deep rabbit hole. I keep going back to the tool analogy. Use the best one you have for what you're trying to accomplish.

Just comparing across other 200 watt solar panels.

i.e. If my manual had said the 200watts of rated power is 70% efficiency, I would not have a question. Rather it rave about how great the 23.5% efficiency is / was without saying it was cell efficiency. Now that I know it is cell efficiency it has no intrinsic value to me, maybe there is correlation with actual efficiency.

You keep tying the question to a functional application when it is only intended to understand how solar work snad how marketed / sold.


I think I have it now...

1. At best solar panels may yield 70% of the rated wattage
2. Mfg show the efficiency based on cell efficiency, which has correlation to overall panel efficiency.

So I can conclude my recently purchased 200 watt solar panel is working properly, and that a replacement 200watt panel or another brand of 200 watt solar panel is not going to give me any significant results? The latter is the question I am trying to resolve.

Bluetti sells thousands panels, I only have this one. I am sure some can be defective, but how would I know if it were defective if I have never looked at solar. The fact that I am just now learning how inefficient they really are is a byproduct of my purchase. I don't want a panel that does 120 watts peak when most others with the same panel model is getting 160 watts peak. I hope this make sense as to what I am getting at?

 

[Scubawise]

I have two of the vMax Tanks AGMs 125ah each and one OEM Aux14 stop/start battery that all work fine but nothing to use them for. I did not trade them in. I think the Aux14 can run the lights in shed solo. But the vMax tanks should power any AC tools I have grid free. I may only need to charge once a month or longer depending upon usage.

You know the expression, build it and they will come. That is how I got here. I was just wanting to get confirmation on what size controller I needed. I don't see myself in such a need for power that I would need two panels, but if I am somewhere off the grid, if I have the time I can setup and get 10 amps sent to the House or Chassis battery if needed. I don't think I will even bother to have inline fuse. I believe the Controller has a 20 amp fuse anyway.

I am thinking of buying the exact same Yitranic 2200 watt inverter I bought last year for the RV. It is working really well and I love the remotes. If I make the 2nd one portable for shed etc., it would be plug and play backup for the RV, but with the new power station, I don't need that much power from inverter in the shed. I just wish to put those batteries to use.

Someone offered me $300 for both my
vMax Tanks AGMs 125ah
If it works my 300 ah lithium will cost $69!

 

[Chateau_Nomad]

Just comparing across other 200 watt solar panels.

i.e. If my manual had said the 200watts of rated power is 70% efficiency, I would not have a question. Rather it rave about how great the 23.5% efficiency is / was without saying it was cell efficiency. Now that I know it is cell efficiency it has no intrinsic value to me, maybe there is correlation with actual efficiency.

You keep tying the question to a functional application when it is only intended to understand how solar work snad how marketed / sold.


I think I have it now...

1. At best solar panels may yield 70% of the rated wattage
2. Mfg show the efficiency based on cell efficiency, which has correlation to overall panel efficiency.

So I can conclude my recently purchased 200 watt solar panel is working properly, and that a replacement 200watt panel or another brand of 200 watt solar panel is not going to give me any significant results? The latter is the question I am trying to resolve.

Bluetti sells thousands panels, I only have this one. I am sure some can be defective, but how would I know if it were defective if I have never looked at solar. The fact that I am just now learning how inefficient they really are is a byproduct of my purchase. I don't want a panel that does 120 watts peak when most others with the same panel model is getting 160 watts peak. I hope this make sense as to what I am getting at?

Will knowing a gasoline engine is only 25% efficient affect your next automobile purchase? Doubtful. Neither should knowing how inefficient solar panels are affected your purchase of them.

If you do decide to purchase another one, if you're concerned about efficiency... just purchase the cheapest rigid monocrystalline you can find. Because there's no REAL WORLD way to compare. If you want portability get the folding type, but beware of issues with those. Wires don't like to be bent back and forth... which (read reviews) can make them fail. You'll pay a convenience premium, won't get any better performance AND will get a product that has a higher failure rate.

 

[16ACE27]

Someone offered me $300 for both my
vMax Tanks AGMs 125ah
If it works my 300 ah lithium will cost $69!

Wow! is that pond stocked? Seems to grow big fish.

 

[Scubawise]

Wow! is that pond stocked? Seems to grow big fish.

I know! He said I will come see today.
I listed for $305

 

[Chateau_Nomad]

Wow! is that pond stocked? Seems to grow big fish.

If you want the REALLY BIG older fish, ya gotta find those hidden gems spots.

 

[dkoldman]

Will knowing a gasoline engine is only 25% efficient affect your next automobile purchase? Doubtful. Neither should knowing how inefficient solar panels are affected your purchase of them.

If you do decide to purchase another one, if you're concerned about efficiency... just purchase the cheapest rigid monocrystalline you can find. Because there's no REAL WORLD way to compare. If you want portability get the folding type, but beware of issues with those. Wires don't like to be bent back and forth... which (read reviews) can make them fail. You'll pay a convenience premium, won't get any better performance AND will get a product that has a higher failure rate.

I will try one more time because your analogy proves you do not follow what I was asking. I don't want to ask you to re-read, but it may help if you do a brain dump and just follow what I was getting at.

In simpleton terms... if one buys ANYTHING they never had or knew little of. How would they know it is working like it is suppose to?

Take you Solar glasses off for a minute. I was simply saying that I am experiencing 100-130 watts for a new Solar panel rated for 200watts. Ace has already told me that was normal, and I think you have too, but if so; I am a tad confused.

My question was asked specifically because if ACE or you had said I should expect 150 watts, I would return my solar panel to have replaced or ask around wh makes a 200 watt panel that can get 160 watts? Has nothing to do with whether solar is useful or not, nor better than a generator or etc.

Now given that information, I was also saying that out of all of the talk crowing about solar, I never heard anyone mention about the inefficiencies one should expect. These inefficiencies are in ideal sun conditions. Imagine if it panels were fixed on roof, or under shade tree or clouds. That 65-70% will drop a lot lower.

Again this was NOT about me buying Solar. This was about me buying my family power stations. They don't own RVs. With that said, I now have a 1152wh power station in my house, so I just bought a panel to see what it could do. I didn't buy based on # of watts, but what Bluetti sold as a single portable panel to go with my Power Station. So I got what I wanted, now what I need to know.... is it is working like it is suppose to? There is where I thought you may help. Maybe not. The question came because I don't know enough about solar to know, I do know I was expecting to see a lot more than 130 watts at peak ideal conditions for a 200 watt panel, but that expectation was based on lack of information. Next time I will just have to take The Ace's word as Law and move on.

 

[16ACE27]

if one buys ANYTHING they never had or knew little of. How would they know it is working like it is suppose to?

Research the product
Read reviews
Watch reviews
Watch installation and test/use videos
Compare your results to what everybody else gets.

If everybody else gets 65-70 watts on a 100 watt panel and you do as well, then .............................

 

[dkoldman]

Compare your results to what everybody else gets.

Which is what I was trying to do. Other than your response, not much feedback. Just a surprising to me because I read so much about Solar on this forum, but until I got a solar panel it never crossed my mind that a 200watt solar panel was NOT capable of 200 generating 200 watt of power. I buy a 100watt bulb, I expect 100 watts not 65 watts.

When I discussed this with Bluetti a few days ago, they were willing to refund me or allow me to return to replace. But I have the newest PV200L refurbished model and they say they don't currently have that in stock refurbished.

What I find odd and I think Chateau is missing my questioning, is that Bluetti is not acting like the 100 - 130 watts peak is normal? I like the panel, but I don't want their older model. I would in fact pay more for new non-refurbished if they said the replacement when will do maybe 160 watts.

Seems like when I first got the Victron hooked up and put on the bench I saw 150 watts on Victron Connect app not the Bluetti app. But that was with my smaller 12v Aux battery that came out of my daughters Jeep for START/STOP. I have since tried that Victron on my old vMax Tanks and barely get 100 watts, but I think those batteries are end of life. I have had my RV unplugged for about a week now. I am trying to drain the house batteries down to 70% or so and I will connect the Victron to see what it does.

Also, I watched one video on Bluetti Solar and the guy said Bluetti did not like him because he created a video earlier where he just toasted Bluetti because the Solar panels were not putting out satisfactory watts. He said after that video they replaced his panel and he said the replacement panel worked flawless. But he failed to say what his actual performance was in the new video I saw. The new video he spoke highly of Bluetti.

I was kind of hoping someone would say "you only getting 130 watts peak, do this do that and you should be able to get 150 - 160 watts off a 200 watt panel". Or they say, "you are seeing 130 watts of 200watt panel, that is great, I wish I could get that", but nooooooooooooo I just gets crickets and double talk you not withstanding.

 

[Chateau_Nomad]

Sorry dude, but you completely lost me on what you're trying to accomplish. If it's just understanding why manufacturers call a panel 200 watts when it can only produce 100 (or whatever)... after all that's been said all I can suggest is there's a wide knowledge base of hundreds of videos about solar panels on YouTube.

 

[dkoldman]

I got what I was looking for today.

According to Bluetti, the PV200L model Solar Panel I have should have a Power Output of 160 - 165 Watts if in direct path to the sun with no clouds or shade. They had me do some testing on VOC. For now they are saying my open circuit voltage should be 24.62vdc or at least 24.0 vdc. I am getting 21.4 - 22.9 vdc

They are suppose to get back to me on what to do. The issue looming may be that I bought brand new refurbished direct from them, and as of now they have no more new refurbished stock to replace with. I bought on special memorial day sale and the brand new price is outrageous. I would never buy. So my days of solar may be short lived.

Even if it were doing 150 - 160 watts it wouldn't make that much difference. But I was just wanting to know if what I was seeing is what it really was designed to do. Hopefully they tell me how to fix or it is replaceable. With said, it would be kind of crappy to have a panel that peaks at 125 watts and other customers with the same panel can get 160 watts. While it is new and still under warranty is the time for me to push this point, especially when it is the Mfg saying it should be doing 160 -165 watts.

 

[PS89]

I finally saw my "1170 watts" of solar max out my 60A MPPT SCC at about 860 watts delivered this week.

"Noon in June".. lol Back in Jan-Feb in the Keys, I was doing well to see a max of 600-700 watts occasionally with 400-500 watts more typical.

I suppose If I installed tilt mounts I could improve things somewhat since a fair amount of solar energy gets reflected instead of absorbed in less than perfect angular positions. After all, these aren't laboratory standard test conditions out here in the real world.

 

[dkoldman]

Update:

So I heard back from Bluetti today who's technical support confirmed that the Solar Panel is not putting out what it should. They are sending me another unit of the same model that is confirmed to be efficient to their expectation of 165 watts of output on their 200 watt panel with optimum sun.

They didn't say anything about returning the existing panel rather they asked me to patient with them and I will soon see tracking info. I should note they know I recently bought 4 of their brand new AC180s

I will be patient and I am pleased. Don't know what will happen in the end, but I can't wait to see. Worse case may be that I may make new cables and put the two together and have 250 watts or so ( maybe 290 watts peak?)

========================

Solar Scattershooting: I still don't see how Solar is efficient at all the vast majority of time on a RV or Home roof? I mean the panels don't move. Most of the day with perfect sun and no shade; you get no good charging due to the angles.

My RV at home would never get optimum sun because it is parked under a tree. if I am at a campsite that has no trees, I am pissed trying to find another site or contemplating leaving. I mean do people purposely park their RVs in hot sun to get maybe 4 hours of good sun?

Yesterday I could not solar charge at all I am learning we may have rain for a full week. But I will see when the Power station goes to zero. My goal at home is to use Power Station at home and to only recharge with Solar or via DC from an engine alternator. Thus far I was recharging back up to 100% SOC every day but not yesterday.

 

[dkoldman]

So I received the brand new panel today, took out of the box and with impromptu setup, some clouds and haze I got 151 watts of output. That is significant from the original panel. suppose to rain later, so I will just let it charge in full.

Since the new one is also the PV200L, I can wire both in series and have 400 watts or maybe at least 260 to 330 watts output. Time will tell, but I am happy now regardless of actual output because I can always double up to 400 watts if in a hurry.

My plan is to wire in Series if I need to double up. No new cables required, no change required on power station because it can handle 60vdc input. The Victron Controller can handle 75vdc, but I am not sure if I need to change anything with the profile program? I think if I wanted to 24 vdc output through the Victron Controller I would need to tell it, but as long as incoming DC voltage is less than 75, I hope I will be ok.

Can't wait to give Bluetti a positive review and 5 star rating

 

[dkoldman]

I have questions about how the Solar Charge Profiles work?

So I have both sets of portable panels connected in series. About 45 volts combined and about 10 amps max from both of the panels in series.

The Victron can handle 75 volts and 15 amps max inputs.

What I am seeing looks to be the Victron is controlling everything, so short of maybe the two fixed hours for absorption, until the Victron drops absorption in favor of float the 2nd panel seems useless?

Based on my battery's specifications:

Charge Voltage: 14.6V​

Equalize Charge Volt: 14V​

Boost Charge Volt: 14.4V​

Float Charge Volt: 13.8V​

I have set Float - 13.8vdc in my Custom created Profile for "Bluetti Solar Panels"
Absorption - 14.4vdc it is not clear to me what the Mfg mean by Charge voltage: 14.6? I have Equalize disabled.

So I ask these questions because real world( yesterday & today) I have observed the following.

I left my RV disconnected from shore power in Use mode with lights on for 2 weeks and I got down to 54% SOC per Victron on 300ah Lithium. By contrast, the Newtipower said 74% SOC?

I connected to the panels and Victron yesterday. SOC finished at 69% before dark & shade. Maybe 7 hours in total, but most of the time was in Float mode.

This morning I put out in a good morning sun and it is now up to 84%, but again in Float mode. When in float mode the watts are always low like 90 watts etc. Even though the watts are low, the voltage 13.8vdc is dead on. So it looks like Victron is dialing back the watts to make the voltage work? Is that correct?

I would think a solar controller would try to pump as much AH capacity in that battery it could when it had available Sun? Seems like it is allowing some of the harvested energy from the sun / panels go to waste in favor of a long running Float that could take days to fully charge at such a low voltage.

i.e. Why wouldn't I change the absorption time from 2 hours to 6 hours or longer? My solar setup is portable not 24/7 around the clock when if sun may be available. Seems like if I decide to charge, it should run at some max absorption voltage until 100% SOC and then NOT go to Float but to turn itself off. I want my panels to cool down so I may put them back up. I may not need again for a two months.

What am I missing?