Solar Experts-Does this sound right to you?

[al1florida]

About just how large a number of people with RV's dry camp as versus stay with hookups.

For the last 3-5 years the RV manufactures have been shipping between 400,000 and 500,000 RV's each year. That equates to around 1.5 million to possibly more than 2 million new RV's on the road in the last 4-5 years.

I find it hard to believe that all these RV's are in State Parks (w/o hookups), National Parks, National Forests, BLM areas or just boondocking.

I'm sure a number of them are dry camping since most if not most all these areas are full on the weekends and some places full during the week in the summer.

[imnprsd]

Thanks Al1Florida for sharing your Lithium upgrade story. And I like how you categorize RVers into 3 groups. I also think the sub-groups pointed out by everyone is very relevant.

By sub-groups I think the size of the RV may define that somewhat since size often determines how an RV is "outfitted" with more creature comforts and power hungry devices like a 16+ sq-fr residential refrigerator or not. And then there is climatic factors often based on where you RV that play into your power needs.

For example, if you boondock your RV in hot or humid weather, where you need to run your house air conditioning system, the only way to do that is to turn on your generator. Consequently, you this lithium and solar upgrade talk goes "out the window."

On the other hand, I think if I traveled like Al1Florida I would look into lithium myself; and I think lithium is the wave of the future. So much so more and more states are passing legislation requiring all cars to be electric in 20 years!

...Maybe that will mean diesel fuel will be super cheap since there will be far less demand for gasoline! (TBD)

Al1Florida: How long do you you think your lithium batteries will last?

* And thanks for reminding me that lithium is not as heavy as lead acid.

* I'm still unclear about what needs to be done to your alternator if you upgrade to lithium? Are you saying you just need to connect your alternator output to a DC to DC converter? How is it wired?

* I also lost you on the whole solenoid distance issue being a long ways away from your alternator. Isn't there some other work around for this?

* What about wind generators? I would think this type of renewable energy might be a very good option if you boondock a lot in one place; but I'm not sure why more people have not gone this route? Can anyone tell me why?

[AJMike]

Originally Posted by al1florida

About just how large a number of people with RV's dry camp as versus stay with hookups.

For the last 3-5 years the RV manufactures have been shipping between 400,000 and 500,000 RV's each year. That equates to around 1.5 million to possibly more than 2 million new RV's on the road in the last 4-5 years.

I find it hard to believe that all these RV's are in State Parks (w/o hookups), National Parks, National Forests, BLM areas or just boondocking.

I'm sure a number of them are dry camping since most if not most all these areas are full on the weekends and some places full during the week in the summer.

I have only anecdotal evidence for this, but it is convincing to me.

We normally take a couple of trips to one of the California ocean RV parks during the Winter. We don't need reservations because the place is always half empty from October through March and only full during the high summer months, but since my wife wanted one of a small number of specific sites I logged on to make a reservation but could not find an open space until late December, probably January now since that was a couple of weeks ago. It is a dry camping park.

We went to a local Arizona mountain National Forest about a week ago. We don't even bother making reservations because it is empty this time of year. We got there and only found a handful of sites not already taken. It is a NF campsite so it is dry camping.

We go boondocking in the mountains here in Arizona, and we generally go to places that are empty, but can no longer find those "empty" boondocking sites as they are now full of RVs.

In July we made a trip to Bryce Canyon NP and made a reservation because there were only 2 sites available. Again, dry camping.

I believe that many of the new RVers are dry camping. Whether or not that will be true 12 months from now will be interesting.

[DavidM]

Here in the NE we have noticed the same thing as AJMIke. Our season typically ends after Columbus Day when virtually all public campgrounds close. In prior years we could always find a nice site after Labor Day particularly during mid week. Not so this year.

Campgrounds seem to be 90% full even up to Columbus Day. I attribute this to new RV owners getting away from home bound Covid restrictions as well as existing RVers.

That really doesn't say much about the percentage of dry campers to full hookup campers. It seems that in the west and the NE there are lots of dry campers about. But in the SE it seems to be mostly commercial RV parks with full hookups. Also in the NW and SE there seem to be more State Parks with at least power hookups available. Not so here in the NE and from what AJ says not so many in the west either.

All in all my take is that there are about the same number of dry campers as full hookup campers if you consider the country as a whole. But there are specific differences regionally as noted.

David

[Winterbagoal]

Originally Posted by DavidM

That really doesn't say much about the percentage of dry campers to full hookup campers. It seems that in the west and the NE there are lots of dry campers about. But in the SE it seems to be mostly commercial RV parks with full hookups. Also in the NW and SE there seem to be more State Parks with at least power hookups available. Not so here in the NE and from what AJ says not so many in the west either.
David

Some of the variations between the number of dry campgrounds, and serviced, is probably climate related. It has to be much easier to maintain water and sewer lines/systems in climate conditions that are warmer year round, than it would be closer to the poles (North, in this case) as the weather there turns colder.

[imnprsd]

I just looked at this lithium battery on Amazon, and the information suggests a lithium battery will last 3x-10x longer than a lead acid battery.

Is this true?

https://www.amazon.com/dp/B08CJYSG3H...ing=UTF8&psc=1

If so, then I would take a second look at lithium option since I'm tired of changing my 400AH deep cycle bank every 2-3 years at $500 a pop. So at 6 years I will have spent $1500.

So paying $1500 for 200AH of lithium sounds like an advantage if 200AH of lithium has an equivalent recharge cycle life to 420AH of lead acid (based on lead acid SOC issues over time); and the lithium battery bank can truly last 8+ years without any degradation in SOC. Is this true?

I.e., if these numbers hold true, then any time a lithium battery bank lasts more than 6 years... this is money saVed! ...And that would make me a Flip Flopper... if these numbers are true. Are they?

* And now I would like to know if I put 2 LiFePO4 batteries in parallel, in the same battery tray as my 4-GC2 lead acid batteries?

* Do I need some sort or special battery management device?

* And I'm still not clear what you have to do to your alternator?

* Is there a fire concern with these things?

So please let me know what you need to upgrade to lithium?

...Because right off the bat I can see those light weight LiFePO4 posts are not sufficient to handle my battery cables. So do I also need to create an isolated "+" and "-" strip?

[al1florida]

imnprsd, you have lots of good questions.

Al1Florida: How long do you you think your lithium batteries will last?

* And thanks for reminding me that lithium is not as heavy as lead acid.

* I'm still unclear about what needs to be done to your alternator if you upgrade to lithium? Are you saying you just need to connect your alternator output to a DC to DC converter? How is it wired?

* I also lost you on the whole solenoid distance issue being a long ways away from your alternator. Isn't there some other work around for this?

* What about wind generators? I would think this type of renewable energy might be a very good option if you boondock a lot in one place; but I'm not sure why more people have not gone this route? Can anyone tell me why?

* And now I would like to know if I put 2 LiFePO4 batteries in parallel, in the same battery tray as my 4-GC2 lead acid batteries?

* Do I need some sort or special battery management device?

* And I'm still not clear what you have to do to your alternator?

* Is there a fire concern with these things?

So please let me know what you need to upgrade to lithium?

I'll work on answering to the best of my knowledge, however it will be a day or two before I can respond.

[Winterbagoal]

Originally Posted by imnprsd

I just looked at this lithium battery on Amazon, and the information suggests a lithium battery will last 3x-10x longer than a lead acid battery.

Is this true?

https://www.amazon.com/dp/B08CJYSG3H...ing=UTF8&psc=1

If so, then I would take a second look at lithium option since I'm tired of changing my 400AH deep cycle bank every 2-3 years at $500 a pop. So at 6 years I will have spent $1500.

So paying $1500 for 200AH of lithium sounds like an advantage if 200AH of lithium has an equivalent recharge cycle life to 420AH of lead acid (based on lead acid SOC issues over time); and the lithium battery bank can truly last 8+ years without any degradation in SOC. Is this true?

I.e., if these numbers hold true, then any time a lithium battery bank lasts more than 6 years... this is money saVed! ...And that would make me a Flip Flopper... if these numbers are true. Are they?

* And now I would like to know if I put 2 LiFePO4 batteries in parallel, in the same battery tray as my 4-GC2 lead acid batteries?

* Do I need some sort or special battery management device?

* And I'm still not clear what you have to do to your alternator?

* Is there a fire concern with these things?

So please let me know what you need to upgrade to lithium?

...Because right off the bat I can see those light weight LiFePO4 posts are not sufficient to handle my battery cables. So do I also need to create an isolated "+" and "-" strip?

Lab/bench tests suggest they will last up to 10X longer than FLA/AGM.
Check the various top end makes/models websites for more info.
Try internet searches on your questions. There are many blogs/forums/videos that can answer them.

[DavidM]

Yes, they may very well last longer than true deep cycle batteries. The main cause of FLA batteries failing is sulfation- lead sulfate that is produced when a battery is discharged falls to the bottom of the battery, doesn't get resolublized when recharged, builds up and finally shorts the plates.

But that is a function of how you use them and particularly not recharging fully every 3 days or so. I have gotten 7-8 years out of my golf cart batteries by taking care of them and always recharging fully. Solar is a great help towards fully recharging.

David

[AJMike]

Originally Posted by imnprsd

I just looked at this lithium battery on Amazon, and the information suggests a lithium battery will last 3x-10x longer than a lead acid battery.

Is this true?

Battle Born warrants their batteries for 10 years, one of the other Lithium battery companies (I don't remember if that is Lion or Relion) does so for 11 years, and I think that the BB warranty is for replacement, not pro-rated. That should give you some idea of how long they expect the batteries to last.

[creativepart]

It's Dekota that has an 11 year warranty on Lithium batteries and they are priced between $849 and $899 each, depending on special offers.

The pluses for Lithium are pretty great. Increased depth of discharge. Rapid recharging. Holding charge when stored and 2 to 3 times the practical lifespan overall.

The negatives are mostly the high initial cost and the need for care in charging (low temp charging and alternator charging).

Another thing to consider is how long you plan to continue RVing. And, if you move to a new RV will you move your Lithium batteries to the new RV. Or, will your Lithium batteries increase your RVs resale value to any meaningful extent.

My AGMs are 3-years old. I haven't seen noticeable reduction of the existing amp hours available, but I also don't dry camp all that much.

I doubt that I would replace my AGMs with more AGMs. If I did I would expect to pay about $1,000 to $1,200 for 4 AGMs. At today's pricing I could replace my 4 batteries with just 2 Lithium batteries and be close to equal in available amp hours for $1,900. So, that wouldn't be too much of a premium. But I'd likely want three LiPo batteries, not two and that would add another $900 or so to the replacement cost.

I can't really see replacing AGMs with AGMs - though it may be something to consider at the time.

I'm 70 years old. So, my wife and I talk about having UP TO 10-years or so of RVing left in us. Surely, many people RV into their 80's - but it's hard to count on that at this point.

We can afford the batteries any time we want them - but I'll not make that decision until I start to see problems with my current 4-100 amp hour AGMs.

[AJMike]

Originally Posted by creativepart

It's Dekota that has an 11 year warranty on Lithium batteries and they are priced between $849 and $899 each, depending on special offers.

Yes. That is right. Now I remember calling them before I decided on which batteries to buy and they told me that they had an 11 year warranty, although I don't think if I asked if that was full replacement or pro-rated replacement. I chose Battle Born because the guy who I was going to have install them was a BB dealer and gave me a good deal and, of course, at our age a 10 year warranty seemed more than sufficient.

The one hidden issue with Lithium batteries, at least for us, is that with all of this extra power my wife decided that she could use her small kitchen utilities off of the inverter without worrying about running out of power. That added quite a bit of draw from our batteries (tea kettle 3 times a day, toaster once or twice a day) so the ability to draw them down turned out to be a big plus.

[al1florida]

Replying to inmsprd's questions:

My replies are in green.

* I'm still unclear about what needs to be done to your alternator if you upgrade to lithium? Are you saying you just need to connect your alternator output to a DC to DC converter? How is it wired?
I have not installed or used a DC to DC converter, but the consensus seems to be that is the way to go. There are some threads in this forum of people installing them. There is a thread about 2-4 months ago involving AJMike and his install of a DC to DC converter.
Basically the install involves wiring one side to the chassis battery and the other side to the house battery and then a small gauge wire (14 AWG?) to detect that the ignition switch is on. You should be able to find the instructions on a website that manufactures the converter.

* I also lost you on the whole solenoid distance issue being a long ways away from your alternator. Isn't there some other work around for this?
Sure you just use large gauge wire from chassis battery to converter to house batteries. You need fuses cutoffs, etc as well.
About my RV, it is just the way the mfg set it up. Chassis batteries in the back, the solenoid in the front with the generator and the house batteries in the back. That makes for a long cable run. A long cable run with fairly high current creates a voltage drop, limiting the power that gets to the house batteries.
Do you really need the DC to DC converter. What I have read in various forums is that some people install them and some haven’t.
I just tested my RV. Lithium batteries are about 60% full. Battery voltage is about 13.1V. No 120V source charging batteries. Chassis batteries at 12.6V I started the engine, alternator/chassis batteries voltage came up to 13.7V. Activated the solenoid to connect the house batteries to the alternator. Alternator voltage still at 13.7V, voltage at house batteries 13.3V, amps going to the house batteries is fluctuating between 10amps and about 17amp. I have no idea just why the amps are fluctuating. This low amount of current is not going to harm the alternator.
Bottom line, you really need to determine just how your RV is setup and works. Does the alternator have a fixed voltage of 13.8 or so volts? How long is the wire and what size is the wire going to the house batteries? How far discharged are you going to take your batteries before charging. The lower the house batteries voltage the more amps the alternator is going to try to push to the batteries.

* What about wind generators? I would think this type of renewable energy might be a very good option if you boondock a lot in one place; but I'm not sure why more people have not gone this route? Can anyone tell me why?
The work of putting up the windmill blades? Where are you going to store the stuff when not in use?

* And now I would like to know if I put 2 LiFePO4 batteries in parallel, in the same battery tray as my 4-GC2 lead acid batteries?
The drop in lithium batteries can go in the same place as your lead acid batteries. Just don’t charge them when the internal temp of the battery is below freezing. That could mean the outside temp is 28* but the battery internal temp is still above 32*.

* Do I need some sort or special battery management device?
Your charger has to be able be set up to charge Lithium batteries. I don’t charge my batteries above 14.2V, but Battle Born says their batteries are OK up to 14.6V. (I think this is correct)

* And I'm still not clear what you have to do to your alternator?
Others have written that the lithium can draw so many amps it will damage the alternator. So a DC to DC converter is needed.

* Is there a fire concern with these things?
All the major sources for lithium batteries I know of have a built in BMS (Battery Management System). That keeps the battery from being over or under charged as well as being charged when the battery temp is below freezing.
Also the LiFePO4 (Lithium Iron Phosphate) batteries have been shot with a gun, stabbed with a tool and otherwise beat up and have not caught fire, exploded, etc.
These are not the batteries that Boeing put in their planes or the batteries that are in cell phone or are in the toys that have burned up.

So please let me know what you need to upgrade to lithium?

Much to general a question for me to know where to begin. I read lots of forums and did other research before installing my lithium and solar.
A lot of what is needed to know about installing has been covered in this ongoing thread.

Here are some links to info about others who have installed lithium:
https://www.technomadia.com/lithium/
Sailboat Tech – Lithium Batteries & Why We Chose Them
Lithium Battery project
The following is a link to my forum topic in 2016. I included lots of link for info about lithium as well as my thoughts.
Lithium Versus Lead Acid for RV’s

[AJMike]

Originally Posted by al1florida

Replying to inmsprd's questions:

My replies are in green.

* I'm still unclear about what needs to be done to your alternator if you upgrade to lithium? Are you saying you just need to connect your alternator output to a DC to DC converter? How is it wired?
I have not installed or used a DC to DC converter, but the consensus seems to be that is the way to go. There are some threads in this forum of people installing them. There is a thread about 2-4 months ago involving AJMike and his install of a DC to DC converter.
Basically the install involves wiring one side to the chassis battery and the other side to the house battery and then a small gauge wire (14 AWG?) to detect that the ignition switch is on. You should be able to find the instructions on a website that manufactures the converter.

To clarify:

As I understand it the issue with Lithium batteries is that they can take a lot of current for charging, much more than wet cells, so there is the danger of your alternator running at too high a state for too long and being damaged by the high drain. You need some way to protect the alternator, and you have 2 choices. A BIM (Battery Isolation Manager) or a DC-DC charger with the BIM generally being the older and less expensive option. I am not an expert on this but here is what I understand. If this is wrong I am sure someone will post to correct the information.

1) A BIM works by allowing the alternator to charge Lithium batteries at its full and high charge rate, but limits the time it can do so by interrupting the connection between the alternator and the charger after specific times. That is, it serves as a circuit disconnect first allowing the charge for xxx minutes, then interrupting the circuit for yyy minutes, then starting the cycle over. The one positive thing about this is that I understand it to be the method that Winnebago is using in their Lithium upgrade, or at least that is what the service tech at an authorized Winnebago dealer told me.

2) A DC-DC charger works as a limiting transformer. It sits in the connection between the starter battery and the house battery and only draws enough current to provide the rated output to the house batteries, thus limiting the current draw from the alternator. Renogy makes 20 amp, 40 amp and 60 amp DC-DC chargers and Victron makes 18 amp and 30 amp models. There are other manufacturers as well although I have no experience with those. Battle Born sells a charger by Sheffield, although it is very pricey.

The Renogy models have 3 connections - an input from the starter battery, the output to the house battery and an enabling input that turns the charger on when the engine is running. The Viltron models have 2 connections, an input from the starter battery and the output to the house battery and uses the difference between the resting and charging voltage of the starter battery to know when the engine is running to turn itself on. For both models, of course, when I talk about input and output connections I am generally talking about 2 wires for each - positive and ground - although Victron makes several charger models for both 18 amp and 30 amp.

There are some other differences between the Renogy and Victron chargers - I believe that the Renogy charger uses an onboard fan to cool itself while the Victron uses a heat sink to dissipate the heat. I have used both and found that the Renogy charger tended to overheat so I installed a muffin fan to blow cool air over it to keep it cool. Someone also posted that the heat sink in the Victron was not really large enough and that it tended to overheat so I kept the fan when I changed from the Renogy to the Victron models when my Renogy charger failed.

In my Winnie Fuse I located the charger inside the RV under the dining area seat so I know about what the air temperature blowing over the charger is. I guess they can also be installed outside the RV in some outside storage cabinets (I saw an RV-ing with Tito video where he did that) but here in Arizona I believe that it is often too hot outside the RV for the air to provide sufficient cooling.

If there is anything else I can tell you that will help please just let me know. I have done this, but I am not an expert and there are surely others on this forum who know more than I about the process.

[tjwoody]

Another good source for LiFePO4 is Will Prowse. He’s done tons of YouTube videos and has actually torn down several batteries, bot cheap and expensive. Of particular interest is his discussion with the CEO of Battleborn batteries https://youtu.be/ywn-vBjKblI

I hope this helps.

[JoeC]

My $.02. I believe that you have a very unbalanced design here. You have too much solar for the solar controller, not enough inverter power, period, and not really enough battery for a residential refrigerator, unless it's a very small one. Solution: Bigger solar controller to match the 600W of solar and a minimum 2000W pure sine wave inverter, which is important for powering electronic equipment (mounting space for it may be an issue, so compromise to 1500W) and 300+ ah of lithium battery power plus a good, name-brand, shunt-style battery monitor preferably with Bluetooth for remote monitoring and control.

First, calculate your presumed daily ah power consumption from just the refrigerator (70% duty cycle, run time), all other loads are minor and/or optional, and convert that to Watt hours by multiplying by 13.2. Your solar will need to be able to supply this amount daily. Calculate your solar Watt hours by assuming about 50% output over the number of useable daylight hours (not dawn to dusk), more in summer, less in winter and depending on latitude. You'll do a bit better in the Sun Belt and worse in other parts of the country. But at least you will know approximately how long your system will hold up to the refrigerator, the primary load by a long shot. Now factor in loss of solar through clouds or shade. Again, location is key. There are tables available that will tell you how much useable solar you can expect on average at various locations and times of year throughout the country. Any leftover power is what you get to use for the other DC loads, which I recommend you prioritize, as lighting is more important than television and coffee pot. You can do without TV and can make coffee on the stove. If you plan on boondocking in colder weather, you will need to factor in the heater's blower motor consumption. Having a shunt battery monitor is priceless when it comes to seeing actual device power consumption.

You may have noticed that I did not mention battery capacity in the above paragraph. That's because batteries don't generate power, they only hold on to it temporarily. However, they need to be able to get you through the dark hours. 2,000 ah of battery capacity is useless if you can't get them charged back daily. They too will eventually discharge to zero without adequate daily solar charging and will take forever to charge back to full. The take-away here is: know your daily load and be sure your solar can provide it, otherwise you will be destined to running the generator or alternator or both to get back to full. And yes, you can do that. You can even be on shore power at the same time on a well-designed system. I've done it. Pushing nearly 100 amps (30+ amps per battery) back into my 300ah of battery. I have 400W solar, 30 amp controller, 300ah batteries and 2,000W pure sine wave inverter with a small (75W) compressor refrigerator conversion, which has been working out quite well for over a year without being in the sun belt.

[Van]

Watts = voltage times amperage. So.

Watts/ voltage= amperage.

There will be loss so it won't be exact. Remember 9 amps at 12 volts won't power much for long. There is significant loss through an inverter as power is required to operate the inverter as well as the load. I used 9 15 watt panels to charge a battery and was not able to run a 6000 btu window ac for even 15 minutes.

[MadMaxWinny]

First of all, bravo! There is an impressive body of electrical system knowledge on this forum! I was involved in marine system design, and dabbled in remote cabin systems, as well. When designing a system, there are two important considerations: Individual component sizing, and using each component as it was designed, sized and intended for.

These have both been touched on in previous posts, but failure in either will result in a system which is not robust. The design progression should be: calculate ALL electrical loads for a 24 hour duration, size banks (2-3x load) and charge inputs (varies) accordingly. Your converter/charger is generally your largest input.

As mentioned, inverters are amazing devices, but if you are counting on your charger and either the genset or a high output (100-130 amp) alternator, run them when you know you will have your highest loads and do your charging at the same time. We would design most systems to include a 90 minute alternator/genset run time, since with most battery chemistries, you can get from a 50% discharge to 85% of charge in this time (with properly sized components = 25-35% of total capacity).

Solar (and wind generation on boats/cabins), is best used for that last 15% of charge (absorption/float). While you "can" size solar to do more, it's not the best use of the technology unless you've got a LOT of panels.

This is all great stuff! I'll try to dig up some of the worksheets I used to hand out at seminars.

[MadMaxWinny]

Oh, one more thing...

Several people have mentioned getting 2-5 years from various battery chemistries. Even a wet cell Trojan can last well over 10 years if the system is balanced and charge/discharged correctly. I had wet cells last 12 years in my cabin, Gel Cells last 13 years on one boat, and I've got a set of AGMs that have been in two boats and are now going into the RV (12 years and no sign of degradation).

As my mentor once said: "Most batteries do not die. They are MURDERED!"

[JoeC]

Originally Posted by Van

Watts = voltage times amperage. So.

Watts/ voltage= amperage.

There will be loss so it won't be exact. Remember 9 amps at 12 volts won't power much for long. There is significant loss through an inverter as power is required to operate the inverter as well as the load. I used 9 15 watt panels to charge a battery and was not able to run a 6000 btu window ac for even 15 minutes.

The typical loss with today's inverters is around 10%. When you get to splitting hairs on loading, factor that in. When you rough out a design, you never want to run close to the limits and expect it work out just fine. If you are close, bump up the power requirement a bit or cut back on optional loads. Running air conditioners on battery power in an RV should not be a consideration, ever. It makes no sense at all to use a generator to charge a battery through a converter (DC power supply) to run an air conditioner through an inverter. With all the conversion losses you are dumping energy all over the place. Just run the A/C directly off the generator and leave out the "middle men", the converter/battery/inverter. Follow the physics; you will never get something for free. Losses are everywhere, even in the cables and wires, but these are really minor in a good design.