Alternator Damage & Lithium Battery Conversion

[imnprsd]

al1florida: I flip-flop.

Yes, I would like to have another 100-200AH of lithium batteries, and yes I would be willing to spend $1700 - $2700 to get it, but then someone said Lithium charging is not that straight forward.

I was thinking I could charge my RV-Lithium batteries like to do my cell phone, but apparently this is not the case.

So while I'm a little tired of monitoring my lead acid batteries, I'm not willing to spend this much money in less I can install lithium an just forget about them!

I found a way to save some money, but it's not an "automatic" system. To get that it sounds like I have to spend $3,500-$4,000; and then I still will not have a PSW inverter, which would be another $1,500-$2,000 if I wanted that.

I'm also not sure about Lithium-Iron vs. Lithium-Phosphate performance trade offs and safety or how to store Lithium when I am not around to monitor the battery.

...And this raises concerns when outside temperatures drop below 32F; and concerns on how to NOT charge lithium batteries beyond 70% SOC in general.

HUMAN NATURE

What I have learned over time is that when people spend $2,000-$4000 or more on any upgrade, they are reluctant say anything negative about their purchase. And many can't even be objective, but that's often because they really don't understand the technology and base their understanding what a good friend told them.

One engineer I worked with like to say: "The truth does not take that long to tell."

So my questions are meant to find out what new technology can and cannot do!

My questions also help me and hopefully many learn what are the features and benefit and tradeoffs if any there maybe. And then we can talk about ROI or just simple "comfort" benefits that make life easier and have value.

MY SPECIFIC SITUATION

I also just spent $500 on a new set of 4-6V-GC2-420AH batteries; so if if dump these for a direct replacement of 200AH of lithium, I will not be happy if I have to baby them or if I choose not to baby them then I will be shortening the useful life of my very expensive lithium battery bank to ~5 years.

So I really want to know of I can beat the sh*t out of my lithium battery bank and still count on them lasting 7+ years?

And while I came up with a methodology to save some money, and while this approach also upgrades my refrigerator power supply to a dedicated 1000W-PSW inverter -- and I like that -- but who wants yet another sub-system to deal with?

So at the end of the day, I can see pulling the trigger for $2,000 but not for $3,700; and let me be clear, these numbers do not include labor as I would be installing this system myself.

That said, if you others plan on upgrading to lithium I'm sure you will need to add another $1,000 for labor!!!

And let's not forget, you always can just run your generator vs. spending this lump sum of cash! ...And every time you need to turn on your air conditioning we all know this will require you to run your generator anyway. So during these times, who cares how fancy your battery bank is or is not!

I also flip-flop, because I only boondock 10% of my time. So spending this much money for so little ROI makes pulling the trigger that much harder.

As an owner of a 40' DP-RV, with a residential refrigerator, and 420AH of lead acid ready to go, and 400W of solar on my roof, I'm not really that challenged when I boondock.

Now if you only have 2-12V deep cycle batteries for a total of 210AH, then that's a different concern; and this would include many Class-A gas rigs, most Class-C and trailers I think. Now these guys probably would benefit much more from lithium than I would.

[Rick 99037]

For any participant in these conversations, it is helpful if you go into your account on this site; and add a signature; if you have not. In it, denote what year, make, and model you have, and in some non-Winnie owners, the brand.
Cruise through this string, and see what others put in their signature before you do yours. Some are just the bottom line, while others are more expansive; but in ether case, it is helpful information, to then get context for your remarks and questions.

[al1florida]

Originally Posted by imnprsd

al1florida: I flip-flop.

Yes, I would like to have another 100-200AH of lithium batteries, and yes I would be willing to spend $1700 - $2700 to get it, but then someone said Lithium charging is not that straight forward.

I was thinking I could charge my RV-Lithium batteries like to do my cell phone, but apparently this is not the case.

So while I'm a little tired of monitoring my lead acid batteries, I'm not willing to spend this much money in less I can install lithium an just forget about them!

I found a way to save some money, but it's not an "automatic" system. To get that it sounds like I have to spend $3,500-$4,000; and then I still will not have a PSW inverter, which would be another $1,500-$2,000 if I wanted that.

I'm also not sure about Lithium-Iron vs. Lithium-Phosphate performance trade offs and safety or how to store Lithium when I am not around to monitor the battery.

...And this raises concerns when outside temperatures drop below 32F; and concerns on how to NOT charge lithium batteries beyond 70% SOC in general.

HUMAN NATURE

What I have learned over time is that when people spend $2,000-$4000 or more on any upgrade, they are reluctant say anything negative about their purchase. And many can't even be objective, but that's often because they really don't understand the technology and base their understanding what a good friend told them.

One engineer I worked with like to say: "The truth does not take that long to tell."

So my questions are meant to find out what new technology can and cannot do!

My questions also help me and hopefully many learn what are the features and benefit and tradeoffs if any there maybe. And then we can talk about ROI or just simple "comfort" benefits that make life easier and have value.

MY SPECIFIC SITUATION

I also just spent $500 on a new set of 4-6V-GC2-420AH batteries; so if if dump these for a direct replacement of 200AH of lithium, I will not be happy if I have to baby them or if I choose not to baby them then I will be shortening the useful life of my very expensive lithium battery bank to ~5 years.

So I really want to know of I can beat the sh*t out of my lithium battery bank and still count on them lasting 7+ years?

And while I came up with a methodology to save some money, and while this approach also upgrades my refrigerator power supply to a dedicated 1000W-PSW inverter -- and I like that -- but who wants yet another sub-system to deal with?

So at the end of the day, I can see pulling the trigger for $2,000 but not for $3,700; and let me be clear, these numbers do not include labor as I would be installing this system myself.

That said, if you others plan on upgrading to lithium I'm sure you will need to add another $1,000 for labor!!!

And let's not forget, you always can just run your generator vs. spending this lump sum of cash! ...And every time you need to turn on your air conditioning we all know this will require you to run your generator anyway. So during these times, who cares how fancy your battery bank is or is not!

I also flip-flop, because I only boondock 10% of my time. So spending this much money for so little ROI makes pulling the trigger that much harder.

As an owner of a 40' DP-RV, with a residential refrigerator, and 420AH of lead acid ready to go, and 400W of solar on my roof, I'm not really that challenged when I boondock.

Now if you only have 2-12V deep cycle batteries for a total of 210AH, then that's a different concern; and this would include many Class-A gas rigs, most Class-C and trailers I think. Now these guys probably would benefit much more from lithium than I would.

A different perspective:
I wish I didn't have to monitor:
-- My fresh water tank to be sure I don't run out of drinking water.
-- My black & gray water tanks so I don't overflow, even when I am on full hookups

Then there are the hassles of:
-- dealing with dumping the black & gray tanks.
-- Every time I pull into the RV Park I have to hook up my water hose. Oh yeah, I if the park has too high water pressure I may blow out the plumbing in my RV.
-- The wonderful RV Parks. I am crammed in next to the RV next to me. My only view is the RV in front and the RV's beside me. What fun!!

And to top it off, when I dry camp I have to make sure I don't run my lead acid batteries down so far I'll ruin them in just a month or two.

I guess I'll just stay in motel rooms. Just drive up, check in and go to my room. No mess no fuss and no big expense of an RV. Oh, yes I spent lots of dollars on the rig and it just drops in value week after week, year after year.

BTW, Other than needing to monitor my lithium batteries SOC, I don't feel I have all the concerns you have itemized about maintaining lithium batteries. I have almost 5 years on my batteries and they are going strong.

Keep in mind it is not the outside temperature needing to be above 32*. It is the internal temperature of the battery. If you have the batteries in an enclosed area, the outside temp can go quite a ways below freezing and you can still charge the batteries. Also charging and discharging the batteries does generate some heat so that helps to keep the batteries above freezing. Better yet, put the batteries in the living area of the RV.

[imnprsd]

al1florida: I guess I don't understand your sarcasm and you really did not answer any of my questions. What I can glean from your last post is this:

Keep in mind it is not the outside temperature needing to be above 32*. It is the internal temperature of the battery. ...So I thank you for that.

And many thanks to all who have posted, because I think I can now figure out the trade offs of adding lithium to my existing lead acid power grid on my own, but I would like to know what will happen to a lithium battery if I leave it fully charged and UNCONNECTED, in storage, for 7-9 months? ...And does it matter if this battery does not have battery maintainer connected to it when outside temperatures fall into the teens?

Usually... I do have shore power where I store my RV, so is this a mute point if I can connect a lithium battery maintainer?

Do they make a lithium battery maintainer that only charges the battery to 50% or 70%? I.e., is there a setting on this charger for this option?

Side Question: If I want to upgrade my inverter from MSW to PSW, and I also need to buy new house batteries, is this the time to convert to 24V or 48V house batteries... and buy a 24V/48V inverter only... plus a 12V converter to power my Intelletec EMS/PMS and 12v interior lights? ...The point being I want to maximize my Amp-hours of battery storage with the available battery tray storage (footprint) currently being used by my 4-6V-GC2-golf cart batteries.

[Old Navy]

I don't think it's worth stressing about keeping a LiFePO4 battery within a narrow SoC range while you are using it. For long term storage, you want to discharge them to 40%-50%. They do not self discharge like FLA batteries, so no "trickle" charger is needed.

I'm in a similar situation as you, with brand new GC2 batteries. I wouldn't even consider building a separate 12V system. If you think you want to upgrade to Lithium, just start using your FLA batteries more aggressively. A good GC2 battery can handle deep discharges. Trojan rates their T105 at 1,000 cycles at 80%DoD. That might be overly optimistic for RV usage, but 500 cycles @ 80% DoD should be realistic with good maintenance. That's 336Ah's of "usable capacity", more than if you used 50% DoD plus 100Ah's of lithium.

Also, the "100W light bulb" example is not correct. With a simple load like a light bulb, voltage and current are directly proportional. Decreased voltage means decreased current and power. In a more complex load like an inverter, that won't be true. In fact, inverters are designed for maximum efficiency at their designed input voltage. They will be less efficient above and below that voltage, but the actual efficiency would best be derived by "real world" testing.

[imnprsd]

What I proposed for us residential refrigerator owners who are finding 420AH of lead acid batteries is not optimal, especially after the 1st year of use, because lead acid SOC drops as the batteries degrade due do sulfation is this:

Build a separate power grid for $1700 and build it using a 1000W-PSW-Inverter and 1-100A lithium battery, plus 2 more solar panels. And then if you want 200AH of lithium you can spend another $1,000 if that makes sense.

Personally, I wish my residential refrigerator runs on a PSW inverter, but I'm getting by with my Dimensions Quasi-sine Inverter.

However, for those owners with a Magnum or Freedom MSW inverter, who want to add a residential refrigerator, then adding a separate PSW-inverter and separate LiFePO4 battery bank may make more sense.

...And I don't think anyone has ever pointed this out until now!

However, the other option (I believe you and a few others are pointing out) is to just keep replacing your lead acid bank of 4-6V-GC2 at $500 a pop and see how long you own your RV.

My 4-6V-GC2 battery bank of (420AH) only lasts 2.5-3 years and I always recharge them between 40% -50%. But hey! Even if I replace my battery bank 3x that still means I would break even vs. the cost of this lithium upgrade over 8-9 years of ownership.

So in the end, if you want the latest and greatest.... it's only money, right? ...And this is why I am a "flip-flopper."

To repeat: Can beat the sh*t out of my lithium battery bank and still count on them lasting 7+ years?

I want to know I can charge them like my cell phone and know I'm not sacrificing lithium battery life, because if I am, I think I will just keep my lead acids and replace them as needed over time.

[Wyatt]

Originally Posted by imnprsd

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?

At 55 seconds into the video, they admit that they ARE NOT using the required battery management system.

Then, their scientific test takes another turn as they don’t compare the two alternators at the same speeds.

Now I’m not an expert in this, by any stretch of the imagination, but I’d like to see a more robust test, as outlined above.

So, if you’re REALLY worried about your alternator overheating when leaving a campground with your Lithium batteries somewhat discharged, then why not run your generator? Kills two birds with one stone. It will exercise the gen set, as one should, and take the weight off of the alternator? Like I said, I’m not an expert on charging, just throwing that option out there for debate...

[imnprsd]

The video is just a data point. It's not meant to scare you!

The solution as I understand it to add a DC-DC charger. ...No big whoop! ...And not expensive.

===

As an alternative to a full replacement of your lead acid batteries, I proposed the idea of SUPPLEMENTING your existing FLA battery bank with a SEPARATE LiFeO4 bank and 1000W-PSW-Inverter and 2 extra solar panels (200-250W). This option has not been discussed to my knowledge, but it seems to have merit, especially for those owners who want to add a residential refrigerator to their rig without the extra cost of upgrading their MSW-inverter.

The challenge to any upgrade, IMO, is to a) Do it as safe and robust as possible; vs. b) Doing it as cheap as possible!

And the outstanding questions I have have to do with how to "baby" your LiFeo4 bank when charging them; and how to store these lithium batteries without shortening their useful life? And it is these subjects that are still open questions for me.

[Wyatt]

Originally Posted by imnprsd

The video is just a data point. It's not meant to scare you!

The solution as I understand it to add a DC-DC charger. ...No big whoop! ...And not expensive.

===

As an alternative to a full replacement of your lead acid batteries, I proposed the idea of SUPPLEMENTING your existing FLA battery bank with a SEPARATE LiFeO4 bank and 1000W-PSW-Inverter and 2 extra solar panels (200-250W). This option has not been discussed to my knowledge, but it seems to have merit, especially for those owners who want to add a residential refrigerator to their rig without the extra cost of upgrading their MSW-inverter.

The challenge to any upgrade, IMO, is to a) Do it as safe and robust as possible; vs. b) Doing it as cheap as possible!

And the outstanding questions I have have to do with how to "baby" your LiFeo4 bank when charging them; and how to store these lithium batteries without shortening their useful life? And it is these subjects that are still open questions for me.

We switched out our two FLA batteries for two Battle Born Lithium batteries, after this forum swayed me away from AGM’s. Why? Weight, for one. I lost 60#’s with the swap.

Longevity.

Draw down on reserve,

These last two times longer due to the ability draw the, down below 50%.

They charge fast.

We keep them on our shoreline power 24/7. The power center in our unit offers three stage charging, to eliminate overcharging them.

Battle born told us, with our setup, and converter/charger model we have, they were plug and play.

Now, we don’t have solar, or any use for that, so THAT could be the cog in the wheel for you.

And so we did so. They work great, no issue with the alternator or anything else. Move on done...

[imnprsd]

Wyatt: Good to know.

Please clarify your RV setup and if you have a large residential refrigerator?

As a lithium owner, when charge your LiFeO4 bank, do you:

a) Routinely charge them above 70% SOC?

b) Do you think constantly charging them to 100% will reduce the life of your lithium batteries?

c) Do you use a lithium battery maintainer when you put your RV in storage?

d) What is the amp output of your alternator and how many amp-hours is your lithium battery bank?

e) Do you have a residential refrigerator?

f) How long can you go between charge cycles?

g) When you boondock do you need to run your generator every day or every other day?

[al1florida]

For storage of Lithium batteries, I did an internet search for "storage of lithium batteries" and this is one of the hits: https://www.solacity.com/how-to-keep...e%20batteries.

Quote from the above link:

Storing Lithium-Ion Batteries
The very low self-discharge rate makes it easy to store LFP batteries, even for longer periods. It is no problem to put a lithium-ion battery away for a year, just make sure there is some charge in it before placing it in storage. Something between 50% – 60% is ideal, that will give the battery a very long time before self-discharge brings the Voltage close to the danger point.

Storing batteries below freezing is fine, even at very low temperatures such as -40 Centigrade (that is the same in Fahrenheit), or even less! The electrolyte in LiFePO4 cells does not contain any water, so even when it freezes (which happens around -40 Centigrade, depending on the particular formulation) it does not expand, and does not damage the cells. Just let the battery warm up a bit before you start discharging it again, which is OK at -20 Centigrade and above. You will see an apparent loss of capacity when discharging at below-freezing temperatures that reverses when the battery gets above freezing, and there is a slightly accelerated effect on aging. Storing them at low temperatures is certainly much better than storage at high temperatures: Calendar aging slows down dramatically at low temperatures. Try to avoid storing them at 45 Centigrade and above, and try to avoid storing them completely full if possible (or nearly empty).

If you need to store batteries for longer periods, be sure to simply disconnect all wires from them. That way there can not be any stray loads that slowly discharge the batteries.

The above supports the info I have read about for the last 5 years about storing lithium.

[al1florida]

For inexpensive LiFePO4 batteries here is an excellent video about two drop in batteries and a DIY option. About $1000 for 200AH for the least expensive.

https://www.youtube.com/watch?v=RxMI...ature=youtu.be

[Wyatt]

Originally Posted by imnprsd

Wyatt: Good to know.

Please clarify your RV setup and if you have a large residential refrigerator?

As a lithium owner, when charge your LiFeO4 bank, do you:

a) Routinely charge them above 70% SOC?

Yes, I keep them connected to shore power 24/7, so they are float charged as needed by the converter/charger.

b) Do you think constantly charging them to 100% will reduce the life of your lithium batteries?

No. So long as you have a three stage smart charger.

c) Do you use a lithium battery maintainer when you put your RV in storage?

No, mine is never in storage, it sits in our driveway. If I couldn’t do that, I’d simply disconnect them (when fully charged) if stored off site.

d) What is the amp output of your alternator and how many amp-hours is your lithium battery bank?

110 each amp hours. Not sure about the alternator output, but it’s on an f53 Ford v10 motor.

e) Do you have a residential refrigerator?

Yes. And I wired our outdoor kitchen fridge to run off the inverter, and a third Alpicool compressor refer/freezer. So we have three compressor fridges running 24/7.

f) How long can you go between charge cycles?

Depends on usage. We’re often plugged in somewhere. But my Victron monitor has told us two days on several occasions.

g) When you boondock do you need to run your generator every day or every other day?

I haven’t boondocked per se yet, but we’ve been without power. I’d imagine I’d have to run the gen set every other day at least.

See my answers inline...

[imnprsd]

al1florida: Great video. Thanks!

After watching it I learned a lot. The young battery expert hosting the video is also very informative and easy to watch. He certainly has a bright future ahead for himself.

Apparently, the cost of lithium not as expensive as I/we first thought? ...Or maybe there will be a trend towards lower prices and by the time I hit the road again in May-2020 as more lithium suppliers will be offering lower cost RV lithium battery solutions.

The video referred me to this website where you can find tons of information on lithium since lithium has been used widely in home solar applications and on boats much more so than RVs at this point:

https://diysolarforum.com/forums/diy...tery-banks.22/

Then I went to Ebay add found a $839, 12V-200AH LiFeO4 RV bank of batteries, with BIS, and a home charger included, plus free shipping! WOW! ...So who wants to be the ginny pig to verify it's reliability?

https://www.ebay.com/itm/Lithium-12v...MAAOSwpYhfYtkI

The lithium box below measures 7-1/2"W by 10" tall by 16" long.

And if you have 6V-GC2-Golf Cart batteries a typical dimension is: 7-1/8"W by 11" tall by 10-3/8" long.

==> So I can't say for certain you an put two of these 12V-200AH lithium boxes in your current battery tray is not at least 15-1/4" wide, but it looks like the height and the length will be okay. (TBD) If you can get two of these boxes in your current battery tray, when you might be able to have 400AH of 12V-Lithium battery storage for ~$1700.

...What's the size of your battery tray? ...Can you fit 2 of these lithium boxes in that foot print?

[al1florida]

Originally Posted by imnprsd

.......................Then I went to Ebay add found a $839, 12V-200AH LiFeO4 RV bank of batteries, with BIS, and a home charger included, plus free shipping! WOW! ...So who wants to be the ginny pig to verify it's reliability?

https://www.ebay.com/itm/Lithium-12v...MAAOSwpYhfYtkI .............

The battery is for sale on Amazon for the same price and it would come with a reliable return policy for 30 days, plus the mfg warranty.

The battery looks good, nice bus bars to interconnect the cells.

[Elkman]

A BIM like the ones from Precision Circuits enable the coach charging systems to first charge the house batteries and then when they are at 100% to have the charging sent to the crank battery. The RV should already have a isolation device so that the house batteries do not draw power frorm the crank battery (or batteries) but this does nothing to keep the crank or starter batteries fully charged.

The advantage of having even 100W of solar is that it will keep the house batteries charged when the RV is not in use. With the BIM the solar can also provide battery tender charging of the crank battery as well.

With a 100 AH AGM or FLAT type battery it provides 50 AH for the coach without damage. Drawn down further and the number of life cycles is reduced so intead of 500 cycles it may only provide 300 charge cycles. With a 100 AH lithium phosate battery the battery can be discharged by 80% (for 80 AH of power) and still provide more than 2000 charge cycles for use.

Two 100 AH AGM or FLAT batteries provide a total of 100 amp hours of current as compared to up to 160 amp hours for a lithium phosate pair of batteries. The lithium provide 200% more power from the same amound of space. Lithium output is specified in Watts and most batteries produce 1200 Watt hours as compared to 600 WH for AGM battery) but the Lithionics batteries are available in a Group 31 size and these produce 1600 What hours of power to the RV.

The Lithionic batteries cost 50% more than the Battle Born batteries but for anyone who wants to maximize their RV's dry camping capabilities the extra $1000 is a worthwhile investment. Having 3200 WH instead of 1200 WH from the two battery bank is a big gain and the $2900 cost for them is something I can amortize over the years with less anxiety when dry camping and having little if any need to run the diesel generator.

Having a LPG fridge would alter the math quite a bit as the Norcold fridge in my RV is DC only and draws about 5 amps on average.

[Old Navy]

Originally Posted by Elkman

With a 100 AH AGM or FLAT type battery it provides 50 AH for the coach without damage. Drawn down further and the number of life cycles is reduced so intead of 500 cycles it may only provide 300 charge cycles.

Small 12V AGM and FLA batteries are not a great choice for RV's, and really aren't "deep cycle" IMHO. Plates are too thin, not enough lead. Much of the "you only get 50% usable Ah's" comes from these small 12V batts. Large AGM's, 6V GC2's and other larger capacity batteries do much better. Two 6V GC2 batteries will get over 2X as many deep discharges as typical 12V RV batts, and can provide 500 or more cycles at 80% DoD. Not nearly as many cycles as LiFePO4, but @ $300 for 225 Ah's, they are nowhere near the price either. Add in the cost of upgrading your converter/charger, maybe adding a DC-DC charger or BIM, possibly moving the batteries from outside to inside, etc. The return on investment for lithium might well exceed the time you own the RV, or the lifetime of the lithium batteries.

Still, I'm considering LiFePO4 batts in the next few years, especially if they continue to drop in price. Lower weight, no maintenance and even more important, fast charging, are pretty big advantages. I'm a bit of a geek, and like new technology.

[AJMike]

Originally Posted by Elkman

The Lithionic batteries cost 50% more than the Battle Born batteries but for anyone who wants to maximize their RV's dry camping capabilities the extra $1000 is a worthwhile investment. Having 3200 WH instead of 1200 WH from the two battery bank is a big gain and the $2900 cost for them is something I can amortize over the years with less anxiety when dry camping and having little if any need to run the diesel generator.

I am really not disagreeing with your post, but I think it would be better to be comparing the Lithonics batteries to the Battle Born batteries since both are Lithium, and then the comparison is 200 AH vs 250 AH or, if you prefer, 2560 WH vs 3200 WH.

The question then becomes whether or not the $1100 difference is worth it for 50 more AH (or 640 more WH), and that depends upon each individual's needs when camping. As for me, I would certainly like another 50 AH in the bank, but I am not sure that it would be worth that much extra, especially considering that the price of Lithium batteries appears to be dropping. I used the $1100 figure (rather than $1000) because I got a deal on my BB batteries, getting them for $900 each.

Personally, if I were going to spend the extra money I would prefer to get a 3rd BB battery. That would give me an extra 100 AH rather than just 50 AH and would do so for a bit less cost.