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Old 10-28-2020, 08:45 AM   #1
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Alternator Damage & Lithium Battery Conversion

Hello, looking for some insight.


The question I have is whether I need to put a DC to DC charger in place to prevent damage to the alternator while charging batteries as I consider swapping out the flooded lead acid coach batteries for Battleborn LiFePO4 in our 2010 Journey Express 34Y.


Initial exchanges with Battleborn left me thinking I should while a conversation with a local RV tech who has done a number of these says I don't need to worry about in this coach.


So at this point I am not quite sure what to think and/or how to think it through. I am not looking to 'cheap out' but also don't want to install stuff that's not needed.


Thanks in advance for your insights and thoughts.
Brian
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Old 10-28-2020, 09:11 AM   #2
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This seems to be a common question. Many do nothing with alternator charging, some use a isolator device or switch and others a dc to dc charger.

I don’t know if there is a definitive answer to the question. It would be good if this was settled once and for all.
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Old 10-28-2020, 09:12 AM   #3
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It somewhat depends on the engine and alternator that you have. A Mercedes Sprinter based coach is limited to about 40 amps supply from its altrnator to an external battery, and the alternator will supply more than that if a lithium battery bank is connected to it. So I would use a 40 amp rated B2B charger to limit the current.

If it is a more robust pusher diesel or maybe an F53 Ford chassis, I would hook it up to the Battle Borns that are somewhat discharged and measure the alternator's case temperature with an IR gun. If it goes above 220F then you probably need a B2B to limit charging current from the alternator.

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Old 10-28-2020, 10:14 AM   #4
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I found this interesting and informative regarding Sprinter smart alternators and the numbers are about what I'd expect, and am probably getting with my 2018 Navion (2017 Sprinter cab chassis).
I have no additional hardware to protect what is already touted as being "smart" enough to self protect, in cases of high amperage draw, due to low battery impedence.
https://windinmyface.com/Sprinter-Al...r-Primary.html
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Old 10-28-2020, 10:29 AM   #5
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I wish that the tester in the link above had also measured the Sprinter's alternator case temperature during his tests.

At idle and with a low SOC large lithium battery bank, the alternator was putting out 100 amps. Alternators are roughly 50% efficient so another 100 amps or 1,400 watts is being output as heat.

Think about what that much heat is doing to an alternator idling with limited fan cooling. That is like a space heater running full blast inside the alternator.

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Old 10-28-2020, 11:47 AM   #6
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From the 2nd alternator discussion
"A 2nd alternator gets reduced cooling with a skid plate covering it, particularly up a steep grade on a hot day. Its higher output won’t be there when hot in such conditions, as it will self-protect by reducing output. The Nations 280XP has this self protective feature however. Still, such conditions are not typical and are relatively short term."

From this I inferred that in situations where the alternator(s) heat up to some upper limit threshold, the "smart" part kicks in, and it reduces it's output to safe levels to allow thermal output inefficiency by-product reduction. AKA "self-protect from over heating".
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Old 10-28-2020, 01:08 PM   #7
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You'll have a big investment in your batteries so spend a little extra and get the DC-to-DC charger. Even if not absolutely necessary, the peace of mind it will give you is well worth it. Plus, if you go with the DC-to-DC charger, you won't have to "battle" Battle Born if you have a warranty issue down the line.
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Old 10-28-2020, 05:03 PM   #8
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I am still confused about battery charging...They tell me to get a special charger when switching to a AGM style from my old add water battery..I always thought that an alternator wouldn't know the difference, but people smarter than me tell me otherwise..common sense says that you check your voltage and amperage so you don't cook your battery when charging...What is going on in the electronics world..sign me dumbo...
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Old 10-28-2020, 05:27 PM   #9
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You shouldn't need anything special if you use AGM batteries. Their impedance rises with increased charging voltage and as it gets full. No need for a B2B charger or any change to your existing converter, but see if it has an AGM setting and set if for AGMs.

You only need to consider a B2B (DC to DC) charger if you use Li batteries. These have a low impedance and will pull a lot of charging current from your chassis alternator, maybe too much. They also need a different Li converter or if you have a PD converter, get their dongle to boost the voltage for complete Li charging.

David

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Old 10-28-2020, 05:32 PM   #10
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Here's a video on alternator output concerns when charging Lithium batteries:




And here's a thread on solar and trying to get to the bottom of the benefits vs. cost of upgrading to lithium batteries.

https://www.winnieowners.com/forums/...-359162-2.html

Specifically, see "al1florida's" post #34 to get a good summary of his experiences with lithium batteries and how he describes himself as a "Group 3 RVer," which he defines as someone that boondocks for 10+ days at time.

I'm a "Group 2" type of traveler, which I will self-describe as being somewhat nomadic. I like to go to art museums, big city events, and I google famous jazz clubs to seek out. I love good food and I follow the good seasonal weather so I don't need to run my coach AC that often. My point is that I am always driving and that is my holiday experience as much as anywhere I go. (I live in Hawaii 9 months out of the year so I like to hit the road and I only stop here-and-there fro a few days at a time.)

As a "Group 2" traveler my alternator and 400W of solar (with my KeyLine VSR) keeps my house batteries at 100% SOC (on the gauge) or the first night and my 420AH of lead acid batteries last through the night very reliably without any generator assistance. (And I do have a 16.5 cu-ft residential refrigerator.)

My solar keeps me going to through day #2, but come that night I need to run my generator, unless I "hit the road again." So what I am saying is that my alternator and my Keyline VSR do 90% of the battery charging I need.

Therefore, for my type of traveling and boondocking, I don't see the ROI with lithium at today's price points.

However, I do replace my house batteries every 3 years, probably because I'm never properly charging them. Why? ...Because I don't have access to enough shore power.

TAKAWAYS

* When I spend $500 every 3 years for on my 420AH battery bank (4-6V-GC2). However, I'm really buying a 250AH/recharge cycle in year one; 210AH/cycle in year two; and 150AH after that. Then my batteries sulfate out or they short out; and this is both costly and labor intensive.

* By labor intensive... Yes, I am constantly monitoring my battery panel at bedtime and when I wake up. And if I ever need to run the heater (blower) or combination of cooling fans on a warm night, my lead acid voltage will be down to 12.0V in the AM if I am lucky; and if I'm not lucky, the whole inverter system will shut down when I wake up due to low voltage, which is annoying. ...And yes, this happens more in year 2, because a lead acid battery looses is ability to fully charge as is sulfates more and more over time.

* So called "smart chargers" attempt to fix sulfation, but you can never stop it. And they say your lead acid battery starts to degrade the moment it is made.

* Many have installed generator-auto-start functions to avoid this manual effort to keep your lead acid SOC above 40%, but I have not. Maybe I will do that someday, but if you don't want your generator running, then this option is not attractive.

* And buy the way, diesel fuel costs can add up over time since you are burning $3-$5/day just to keep your batteries charged.

* Solar cuts down on the cost of running your generator and it is not as noisy, but it's also just supplemental power. Eco-friendly too, but no one talks about the energy it took to make these things, or the environmental impact after we trash them some day.

* I think a wind generator might be a very good option if you boondock a lot in one place, and I'm not sure why more people have not gone this route? Can you tell me why?
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Old 10-30-2020, 07:15 PM   #11
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There is a school of thought that I have seen on various forums that suggests that the newer alternators are "smart" enough to limit current the output on their own and that for those alternators Lithium batteries do not need any other device. Personally I don't know if that is true or not, but I was convinced by Winnebago because their Lithium upgrade includes a BIM. If Winnebago believes that it needs to include a current limiting device, then I will assume they know what they are doing.

But I need to explicitly mention that I am not an expert and everything I have learned about this subject has been in the last 18 months or so since I have been researching this. And some of what I have learned may not be true under all circumstances and/or for all equipment.
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Old 10-31-2020, 06:45 AM   #12
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Quote:
Originally Posted by imnprsd View Post
* I think a wind generator might be a very good option if you boondock a lot in one place, and I'm not sure why more people have not gone this route? Can you tell me why?
1. You need a decent amount of wind. Something we usually try to avoid in selecting a campsite.

2. I come from a sailboating background, where wind usually isn't a problem and the turbines are usually permanently mounted. Although I never had one, the biggest complaint is the irritating noise.

You might find these informative:

https://rvlifestyle.com/experiment-p...-wind-turbine/

https://www.tripsavvy.com/rvers-go-g...d-power-505147
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Old 11-01-2020, 01:55 AM   #13
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Thanks BobC for discussing wind generators.

Here's Xantrex link explaining their approach to the burgeoning LiFE04 market:

Freedom e-GEN Powered by Xantrex

And here's some good videos by The RV Geeks on their efforts to upgrade to Lithium LiFE04 batteries:

https://www.thervgeeks.com/tag/xantrex/

And here's a video by Tito who installed Lithium House batteries in his trailer and switched his alternator through the battery-boost-solenoid so he can turn the alternator charge off when the LiFe04 battery back reached a full charge.



This is interesting because it suggests you can remove the momentary boost switch and go with a standard toggle switch to turn on and off the DC-DC charger. So this is a manual approach to turning off the charger. ...Alternatively, I would think they have some smarter DC-DC chargers you can install that would automatically open the circuit (turn off the DC-DC charger) when the LiFE04 gets full. ...Still this is a good video to get a good understanding of how to deal with your alternator when charging lithium batteries.

Note: For us RV owners who are thinking about upgrading to lithium and are willing to spend $2,000 on LiFE04 batteries (220AH)... with the hope these thing can last 7-10+ years vs. paying $500 (again) for a 2-3 year lead acid battery bank of 4-6V-GC2 Golf Cart batteries (420AH), with only 50% usable capacity per cycle); I'm still not sure what the least expensive and safest way is to go?

...And then if I want to spend another $1,500 to add a second LiFE04 (210AH) bank for a total of 420AH and a 90% utilization per cycle, with no voltage decline, then that's an added expense I will call "icing on the cake."
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Old 11-01-2020, 08:11 PM   #14
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I believe that the safest route is to use a DC-DC charger between the coach and chassis batteries to protect all devices involved. I'd probably be using one if I had space for it. However, you are not likely to damage the alternator circuitry as long as you have a lead acid battery to soak up any abrupt lithium shut-offs, which get down to really small draws before this happens anyway. Assuming no alternator malfunctions, your lithium batteries should be happy with the alternator charge. My issue with this type of setup was with the constant charging of my lithium batteries while driving. I don't want to be constantly keeping the lithium batteries at full charge as this is not the best way to operate them. My solution was to install a switch that disables the battery interconnect solenoid when it is not needed while driving. I might want to keep my coach batteries at a lower charge to help extend their life, which I understand is optimal between 50 and 70 percent full and only fully charge them when needed; like starting out on a boondocking adventure.
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Old 11-01-2020, 08:47 PM   #15
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My batteries have a max charge limit of 100A. My bank is rated at 200Ah. My alternator's output is rated at 220A. I have no DC > DC charger, as I felt it was unnecessary.
I may have the best set up because my alternator's max output is above the max input draw of my battery bank. I can see how someone with 600Ah of battery, in an extremely low SoC could be concerned about their alternator charging rate being too high to compensate, but the BMS of the battery bank should prevent excessive current draw. If it does, the alternator should be protected, by the battery's BMS, and it's own internal thermal protection systems.
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Old 11-01-2020, 10:01 PM   #16
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Just when I am starting to think I can upgrade to 200AH of lithium LiFeP04 batteries in the $2,000 range, JoeC sheds some more light on some additional challenges to optimal lithium battery charging.

I.e., I think JoeC is saying: Lithium batteries last longer when they are kept between 50 and 70 percent full; and that you really only want to fully charge them to 100% SOC just prior to arriving at your boondocking campsite.

So this suggests we need to have two different types of charging control over our lithium battery bank; and we need another method to control lithium battery charge when you store your RV.

1) When driving if you know you are going to end up in an RV park with shore power, then you really do NOT want your alternator to keep charging your lithium batteries to more than 70%.

2) When driving and you know you plan on boondocking, then you DO want to turn on your alternator charging circuit, based on "X-hours of driving time" so when you arrive at your boondocking location that you will reach 100% Lithium SOC.

3) And as a separate matter, when you store your lithium battery, is it okay to let it drain down to 0-V or do you need some sort of lithium battery maintainer that will turn-off at 50 or 70%? Do they make one?

MORE QUESTIONS

...And what happens to a lithium bank if all you can do is to leave a trickle charge on it or a battery maintainer for 7 months? ...Or do you just let it drain down over time, and it will not hurt anything to let it get to super low voltage?

Does the DC-DC charger only monitor the connection to the alternator?

Do they make a trickle charger and battery maintainer that will turn-off at 100% SOC or 70% SOC... and/or will turn-on at 5% or 10% SOC?
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Old 11-02-2020, 09:14 AM   #17
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Quote:
Originally Posted by Winterbagoal View Post
My batteries have a max charge limit of 100A. My bank is rated at 200Ah. My alternator's output is rated at 220A. I have no DC > DC charger, as I felt it was unnecessary.
I may have the best set up because my alternator's max output is above the max input draw of my battery bank. I can see how someone with 600Ah of battery, in an extremely low SoC could be concerned about their alternator charging rate being too high to compensate, but the BMS of the battery bank should prevent excessive current draw. If it does, the alternator should be protected, by the battery's BMS, and it's own internal thermal protection systems.
Don't forget to divide the charge current to you battery bank by the number of batteries that you have in that bank in order to calculate the charge current to each battery. That goes for discharge current also. Starting your generator will draw around 250 amps (270 for the Onan 4kW), possibly more, for a very short period of time in cooler weather. You do not want to exceed your lithium battery discharge rate either. And if you use your coach batteries to start the RV's engine in an emergency, expect even more discharge current. Your coach batteries need to be able to handle this. I'd hate to trash my $3k investment in lithium batteries because of an oversight. That is the reason why I paid more money to get RB100-HP batteries from Relion. They have a peak discharge of 800 amps each. The standard RB100 was too close for comfort for me, even though they would probably work just fine, which is not good enough for me.
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Old 11-02-2020, 10:35 AM   #18
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I'm no expert - and haven't used LiPo batteries, but I have researched the topic for the past year or more.

Here's my attempt to answer some of your questions:

Quote:
Originally Posted by imnprsd View Post
I.e., I think JoeC is saying: Lithium batteries last longer when they are kept between 50 and 70 percent full;
Many manufacturers state that depth of discharge of 80% is not a problem even for extended battery life and unlike LA batteries cannot "sulfate" so it's not imperative to recharge them immediately.

It is true that Lithium batteries like being charged to less than 100% better than constantly being recharged to 100%. Certainly electric car chargers do something like that.

You can achieve that by setting the charging profile of your charger. AGM settings work but not as well as a Lithium charge profile or custom charging settings.

Quote:
Originally Posted by imnprsd View Post
And as a separate matter, when you store your lithium battery, is it okay to let it drain down to 0-V or do you need some sort of lithium battery maintainer that will turn-off at 50 or 70%? Do they make one?

They cannot be taken to 0v - it will kill the battery. I've attached a video with a voltage chart.

Quote:
Originally Posted by imnprsd View Post
And what happens to a lithium bank if all you can do is to leave a trickle charge on it or a battery maintainer for 7 months? ...Or do you just let it drain down over time, and it will not hurt anything to let it get to super low voltage?
I don't think you trickle charge Lithium batteries. Once charged up they hold their charge well. You charge them up and remove the charge current. A good solution would be a lithium capable solar charge controller and a little bit of solar.

Quote:
Originally Posted by imnprsd View Post
Does the DC-DC charger only monitor the connection to the alternator?
Yes, the Alternator delivers it's output directly to the DC to DC Charger which then has a Lithium charge profile for your batteries. It limits the charge and isolates the alternator from the battery protecting both.

Here's a PDF of a Battleborn Battery User Manual:

https://www.solar-electric.com/lib/w...orn_Manual.pdf

And, here's a Will Prowse video showing a Battleborn voltage chart for state of charge:
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Old 11-03-2020, 01:39 AM   #19
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So you still have to care for lithium?

Great video.

I captured the Lithium-Iron SOC Chart and matched it up with a long time accepted Lead Acid Chart.

I then came to this conclusion based on the formula P=VI:

* For a 100W light bulb load, if the voltage drops, then you current has to increase.

I then charted a theoretical amp draw for a Lithium battery vs a Lead Acid battery under a 100W load; and found the lead acid batteries draw about 8.0% to 8.4% more amps.

Consequently, I think I can conclude a LiFeO4 battery will be at least 8% more efficient than a lead acid battery, but 8% of 100A or even 200A is really not saying much... but every little bit helps.

The cart did put this into perspective for me: I thought I could basically abuse a lithium battery bank, but apparently you have to care for it differently than you do a lead acid battery bank.

==> And I'm still not sure how I can care for my lithium batteries when I put my RV in storage for 7-8 months and never visit it? I mean what sort of charger will maintain the lithium battery at 50-70% SOC when I plug it into the RV storage lot 120V shore power? Or are you telling me a lithium LiFeO4 battery can hold a full charge for 7-8 months without dropping below 10% SOC?

OTHER OBSERVATIONS & QUESTIONS

* While you can constantly charge your lithium batteries above 70%, I would like to know how does this reduces it's operating life?

For example, if I constantly cycle my Lithium from a low of 10% SOC to a high of 100% SOC, does that lead to a shorter 5 year live or a 7 year life or can I still expect 10+ years of service?

* It sounds like owners are installing alternator OFF/ON switches to manually charge there lithium battery from 70%-100% SOC while they drive to their boondocking camp spot; and if their destination is not a boondocking sight... then this same owner many never have use their alternator to charge their lithium bank.

* Another plus would be to have 200-400W of solar panels dedicated to charge the lithium bank when the sun is shinning; and rely on the Solar Controller that is lithium compatible to manage it's SOC. ...With the alternator as a supplemental charging option and not a primary charging option.

* Having a DC-DC converter safeguards your alternator from overheating and this device sounds like a better way to go do nothing at all and rely on the specs of your lithium battery to now "over heat" your alternator when it is running. Is this correct?

* This suggest not all LiFEO4 batteries are built the same. And it sounds like some people have both Lithium-Iron and/or Lithium-Phosphate batteries. So how this this come to pass? Because, from what I read, Lithium-Iron Batteries are supposed to be much safer and more stable than Lithium-Phosphate. Is this correct?

* I understand my Inverter can handle 14.6V from a Lithium Battery Bank, but are there any concerns when it comes to the other RV components and subsystems (like my Itelletec PMS-EMS) and my inside lights in my coach that were built to run on 12.6V from a lead acid battery? ...My guess is that all I may see is a brighter 12V standard light bulb, but what about those fluorescent lights in my galley area that use a transformer? Will they be okay at 14+V?

* As an example, will a 100W or 400W of solar panels charge a lithium bank faster than a lead acid bank... for the same rated battery amp-hours. Is this true? ...The reason being: A lead acid bank of batteries has more internal resistance vs. Lithium.

HOW ABOUT THIS ALTERNATIVE TO ADD MORE AMP-HOURS OF LITHIUM BATTERY STORAGE TO MY EXISTING LEAD ACID POWER GRID?

Situation: I just bought 420AH of lead acid batteries (4-6V-GC2); and because I have a residential refrigerator, it would be nice to have additional Amp-Hours when I boondock (when I do NOT need a generator to run my house air conditioner). I only want to spend $1,800. What can I do?

OPTION ==> It seems to me I can supplement my lead acid power grid by adding a separate-dedicated LiFeO4 power grid that consists of:

* Buy 1 Lithium (LiFeO4) 100A battery I install it in the center of my basement. (Cost $750-800)

Note: You can add a second 100A battery for another $750, but that would increase your system total cost to ~$2700.

* Add a dedicated cheap-PSW-1000W-inverter to run my refrigerator and maybe one outlet I install and use for my computer, TV, or fan. ($200). Get one with a remote on/off switch as a minimum.

* And then add a supplemental Automatic Transfer Switch (ATS) to take the 120V out of my OEM-ATS and feed it to this supplemental ATS. This will all your refrigerator to run on inverter power or shore power or generator automatically. ($80)

* Run a new power wire from your supplemental ATS to your refrigerator... and additional wall sockets.

* Connect a Victron 17A charger to recharge the lithium battery when you have shore power ($150)

* Add 2 more solar panels (200W) and dedicated them to only charge the Lithium battery and let the solar charge controller manage its SOC. ($300)

* Then and a thick wire to the ALTERNATOR output post and make it manually switchable from the driver's seat -- on your way to your boondocking location. For this you will need a separate solenoid, switch, and voltmeter to monitor the Lithium battery SOC while you drive, like Tito did in his video posted above. ($100)

* Misc Expense: $50

BTW: This set-up might be a good idea for anyone with a square wave inverter who wants to install a residential refrigerator and/or run sensitive medical equipment off a PSW inverter, because it will save them money. Besides, your square wave inverter is not a problem for most applications.

However, going to all this trouble is a PITA, but it will save you $2000 and allow you to install a PSW inverter. Just know you now have yet another sub-system to deal with and operate. So if you have an extra $2,000 then spend it on a fully integrated system that works just like your current lead acid power grid you are familiar with; and learn how to care for your lithium battery bank differently than you do your lead acid battery bank.

I will look forward to your pro vs. con opinions on this supplemental approach to getting off cheap... if you consider spending $2,700 cheap?

Specifically, I can replace my lead acid battery bank 5x before I break even, but remember, this is boondocking and NOT having to run your diesel generator 2-4 hours/day, which is about $10/day in diesel fuel.

Nah... I think will just stick with my lead acid and beat the sh*t out of them and change them every 3 years! ...knowing I still have to care for a lithium battery bank (differently); and my only other alternative is to spend $1,800 to upgrade for a meager 100 additional AH of lithium or spend $2700 on a 200AH. (Which is cheaper than last years prices!)
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Old 11-03-2020, 06:36 PM   #20
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Great video.

I captured the Lithium-Iron SOC Chart and matched it up with a long time accepted Lead Acid Chart.

I then came to this conclusion based on the formula P=VI:

* For a 100W light bulb load, if the voltage drops, then you current has to increase.

I then charted a theoretical amp draw for a Lithium battery vs a Lead Acid battery under a 100W load; and found the lead acid batteries draw about 8.0% to 8.4% more amps.

Consequently, I think I can conclude a LiFeO4 battery will be at least 8% more efficient than a lead acid battery, but 8% of 100A or even 200A is really not saying much... but every little bit helps.

The cart did put this into perspective for me: I thought I could basically abuse a lithium battery bank, but apparently you have to care for it differently than you do a lead acid battery bank.

==> And I'm still not sure how I can care for my lithium batteries when I put my RV in storage for 7-8 months and never visit it? I mean what sort of charger will maintain the lithium battery at 50-70% SOC when I plug it into the RV storage lot 120V shore power? Or are you telling me a lithium LiFeO4 battery can hold a full charge for 7-8 months without dropping below 10% SOC?

OTHER OBSERVATIONS & QUESTIONS

* While you can constantly charge your lithium batteries above 70%, I would like to know how does this reduces it's operating life?

For example, if I constantly cycle my Lithium from a low of 10% SOC to a high of 100% SOC, does that lead to a shorter 5 year live or a 7 year life or can I still expect 10+ years of service?

* It sounds like owners are installing alternator OFF/ON switches to manually charge there lithium battery from 70%-100% SOC while they drive to their boondocking camp spot; and if their destination is not a boondocking sight... then this same owner many never have use their alternator to charge their lithium bank.

* Another plus would be to have 200-400W of solar panels dedicated to charge the lithium bank when the sun is shinning; and rely on the Solar Controller that is lithium compatible to manage it's SOC. ...With the alternator as a supplemental charging option and not a primary charging option.

* Having a DC-DC converter safeguards your alternator from overheating and this device sounds like a better way to go do nothing at all and rely on the specs of your lithium battery to now "over heat" your alternator when it is running. Is this correct?

* This suggest not all LiFEO4 batteries are built the same. And it sounds like some people have both Lithium-Iron and/or Lithium-Phosphate batteries. So how this this come to pass? Because, from what I read, Lithium-Iron Batteries are supposed to be much safer and more stable than Lithium-Phosphate. Is this correct?

* I understand my Inverter can handle 14.6V from a Lithium Battery Bank, but are there any concerns when it comes to the other RV components and subsystems (like my Itelletec PMS-EMS) and my inside lights in my coach that were built to run on 12.6V from a lead acid battery? ...My guess is that all I may see is a brighter 12V standard light bulb, but what about those fluorescent lights in my galley area that use a transformer? Will they be okay at 14+V?

* As an example, will a 100W or 400W of solar panels charge a lithium bank faster than a lead acid bank... for the same rated battery amp-hours. Is this true? ...The reason being: A lead acid bank of batteries has more internal resistance vs. Lithium.

HOW ABOUT THIS ALTERNATIVE TO ADD MORE AMP-HOURS OF LITHIUM BATTERY STORAGE TO MY EXISTING LEAD ACID POWER GRID?

Situation: I just bought 420AH of lead acid batteries (4-6V-GC2); and because I have a residential refrigerator, it would be nice to have additional Amp-Hours when I boondock (when I do NOT need a generator to run my house air conditioner). I only want to spend $1,800. What can I do?

OPTION ==> It seems to me I can supplement my lead acid power grid by adding a separate-dedicated LiFeO4 power grid that consists of:

* Buy 1 Lithium (LiFeO4) 100A battery I install it in the center of my basement. (Cost $750-800)

Note: You can add a second 100A battery for another $750, but that would increase your system total cost to ~$2700.

* Add a dedicated cheap-PSW-1000W-inverter to run my refrigerator and maybe one outlet I install and use for my computer, TV, or fan. ($200). Get one with a remote on/off switch as a minimum.

* And then add a supplemental Automatic Transfer Switch (ATS) to take the 120V out of my OEM-ATS and feed it to this supplemental ATS. This will all your refrigerator to run on inverter power or shore power or generator automatically. ($80)

* Run a new power wire from your supplemental ATS to your refrigerator... and additional wall sockets.

* Connect a Victron 17A charger to recharge the lithium battery when you have shore power ($150)

* Add 2 more solar panels (200W) and dedicated them to only charge the Lithium battery and let the solar charge controller manage its SOC. ($300)

* Then and a thick wire to the ALTERNATOR output post and make it manually switchable from the driver's seat -- on your way to your boondocking location. For this you will need a separate solenoid, switch, and voltmeter to monitor the Lithium battery SOC while you drive, like Tito did in his video posted above. ($100)

* Misc Expense: $50

BTW: This set-up might be a good idea for anyone with a square wave inverter who wants to install a residential refrigerator and/or run sensitive medical equipment off a PSW inverter, because it will save them money. Besides, your square wave inverter is not a problem for most applications.

However, going to all this trouble is a PITA, but it will save you $2000 and allow you to install a PSW inverter. Just know you now have yet another sub-system to deal with and operate. So if you have an extra $2,000 then spend it on a fully integrated system that works just like your current lead acid power grid you are familiar with; and learn how to care for your lithium battery bank differently than you do your lead acid battery bank.

I will look forward to your pro vs. con opinions on this supplemental approach to getting off cheap... if you consider spending $2,700 cheap?

Specifically, I can replace my lead acid battery bank 5x before I break even, but remember, this is boondocking and NOT having to run your diesel generator 2-4 hours/day, which is about $10/day in diesel fuel.

Nah... I think will just stick with my lead acid and beat the sh*t out of them and change them every 3 years! ...knowing I still have to care for a lithium battery bank (differently); and my only other alternative is to spend $1,800 to upgrade for a meager 100 additional AH of lithium or spend $2700 on a 200AH. (Which is cheaper than last years prices!)
Not to be rude, but do you really want answers to all your questions, based on the last statement in you posting?

Quote:
Nah... I think will just stick with my lead acid and beat the sh*t out of them and change them every 3 years! ...knowing I still have to care for a lithium battery bank (differently); and my only other alternative is to spend $1,800 to upgrade for a meager 100 additional AH of lithium or spend $2700 on a 200AH. (Which is cheaper than last years prices!)
BTW, you make lots of good question and thoughts the folks should think about went considering either lead acid or lithium batteries.

As in most things there are no really simple yes or no answers.
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2006 Winnebago Journey 36G
https://downtheroadaroundthebend.blogspot.com/
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