Lithium Batteries are NOT Worth the Extra Cost?

[Isaac-1]

Mark, to stay on point of overall LiFePo4 vs Lead acid at this point in time can we agree that Lead acid charge / discharge cycle are measured in hundreds of cycles and that LiFePo4 are measured in thousands of cycles, and that certain sometimes different care / abuse can shorten or lengthen those numbers?


Can we also agree that for many / most RV applications the practical lower cut off point for battery discharge is when the voltage sags under load to the point that it will no longer power a furnace blower (rather they furnace blower slows enough to trip the sail switch safety cut off) or power an inverter at a substantial load, and that this tends to happen when discharged to around 11.7 - 11.9 VDC or circa 30-40% state of charge? Not 0% state of charge when the last glow goes out of the light bulb.


If so can we agree that LiFePo4 batteries don't drop below this 11.7-11.9VDC range until they are in their last few percent of charge, circa 5% or less.


If so this gives us a reasonably fair comparison ratio of comparing a circa 150Ah LiFePo4 to a 210Ah Lead acid. Since all is not equal this may not be an entirely fair sizing comparison, but given that it seems to give every benefit of the doubt to lead acid, it is at least something.


As to the topic of comparing a basic Costco GC2 to a generic made in China LiFePo4, I think that is a lot more fair than trying to compare that same Costco GC2 with a 6-12 month warranty to a $800 Battleborn LiFePo4 battery with Bluetooth BMS interface and a 10 year warranty.


If you want to compare a lead acid battery to a Battleborn, you should be using something like a Crown, or at least a Trojan lead acid, which typically sell for more than double the price of the discount club GC2's, probably more like 3-4 times for Crown batteries.

[Marine359]

Originally Posted by corn18

You can't fit 412 Ah of usable FLA in this spot. And it only weighs 96 lbs. That's why I went LiFePO4.

AND, you can’t mount them inside at all. It would take three FLA @ 150lbs mounted on the tongue to equal what I have with a single 35lb 170ah LiFEPo4 which is mounted in my heated pass thru. Travel trailer owners towing with 1/2 ton or smaller tv don’t have enough payload for those lead acid beasts. LiFePo4= no more worries and zero effort. And no hernias if you want to pull it out for storage. Best bang for your buck you can spend for any towable upgrade.

3x Trojan Group 31 100ah = $990 @ 210lbs
1x Bigbattery 170ah =$800 @ 35lbs

Tell me again how much more than FLA LiFePo4 costs.

[jharrell]

Originally Posted by Isaac-1

Can we also agree that for many / most RV applications the practical lower cut off point for battery discharge is when the voltage sags under load to the point that it will no longer power a furnace blower (rather they furnace blower slows enough to trip the sail switch safety cut off) or power an inverter at a substantial load, and that this tends to happen when discharged to around 11.7 - 11.9 VDC or circa 30-40% state of charge? Not 0% state of charge when the last glow goes out of the light bulb.

This is one of those things that you don't really get until you use LFP's yourself, they feel much more like gas tanks than batteries, you run them down and they hold voltage right up until they are empty even under heavy load, then you charge them up at full bulk current until almost full then a short optional absorb, charge them to less than 100% no big deal actually lengthens their life. It's really the way a battery should be but everyone is so used to leads characteristics they don't think it a big deal, its really is.

[Bylandorsea]

Originally Posted by Isaac-1

s.

If you want to compare a lead acid battery to a Battleborn, you should be using something like a Crown, or at least a Trojan lead acid, which typically sell for more than double the price of the discount club GC2's, probably more like 3-4 times for Crown batteries.

"What each person has to decide is where do they choose to strike the balance between cost, build quality, warranty and support. Do you mind buying from a fly by night, no name brand with no contact information in the US for warranty claims, if they even have a warranty. How about the small shop, one man show selling customized batteries, do you prefer a bigger company like Renogy who has been active in the US selling solar panels and other solar accessories for about a decade, or maybe you prefer a dedicated LiFePo4 premium brand with premium level of support and very long warranty like Battleborn, that is somewhere between a one man shop, and a big company."

From what I can see the big box discount 6V 215AH GC2 deep cycle lead acid golf cart batteries are manufactured/sold by someone that has been in business many years and has a US phone # if not a dealer near by for warranty /returns. Good luck calling China.

[Mark_K5LXP]

Originally Posted by jharrell

The true cost of ownership even for a single expensive Battleborn is pretty close to two cheap SAM's club lead acid if you run the BB down to 0% and the GC batteries down to 50% of over the life time of the batteries but if you do 2 Battleborns to 50% at 8x the cost vs 2 GC's you get 20X the life and you can see how LFP just pulls away from lead. SOK's are nearly half the cost of Battleborns and LFP's are still dropping in price, there are ones coming on the market at 29c per Wh the economics can't be denied forever.

But those very economics are based on some pretty specific, high cycle use cases. If you only put 50 cycles a year on a battery, your cost of ownership for LFP will be higher than lead because you will never use all the cycles before the battery expires or you're done with it. You may also leave cycles on the table with lead but your acquisition and thus opportunity cost is less. So while LFP is "better", whether it's more cost effective is highly application specific. For some LFP couldn't come too soon, for others it's a don't care or it's a premium solution to a pedestrian problem. The numbers are out there, and everyone can decide the best solution for them. Data should always drive the decision, not a limited use case.

Mark B.
Albuquerque, NM

[Mark_K5LXP]

Originally Posted by Isaac-1

can we agree that Lead acid charge / discharge cycle are measured in hundreds of cycles and that LiFePo4 are measured in thousands of cycles, and that certain sometimes different care / abuse can shorten or lengthen those numbers?

Agree.

Can we also agree that for many / most RV applications the practical lower cut off point for battery discharge is when the voltage sags under load to the point that it will no longer power a...

Disagree. Many/most is an assumption. When equipment does not operate correctly as a system then that's a design deficiency or component failure.

can we agree that LiFePo4 batteries don't drop below this 11.7-11.9VDC range until they are in their last few percent of charge, circa 5% or less.

Solving an equipment/system issue by replacing the battery with a better performing one is a perfectly valid solution. But replacing the offending component would also be a valid solution.

If you want to compare a lead acid battery to a Battleborn,

It doesn't matter what batteries are compared as long as it's based on facts and data. The proponents of LFP seem to have a need to artificially increase the performance of LFP and diminish the performance of lead which is the point of my post. Going forward the cost disparity between LFP and lead will likely flip and there'd be no reason at all to bother with lead for most any application. But that's not today. Lead is not as good as LFP in many respects but for many, and I would offer millions of end users today, it's "good enough".

Mark B.
Albuquerque, NM

[Isaac-1]

Mark, that argument is a bit like saying I don't need an engine that will go 300,000 miles because I am only going to keep the vehicle for 50,000



Bylandorsea, How much added value is there really in a 6-12 month warranty on a Costco GC2 vs buying a discount LiFePo4 battery on Amazon with a 3-5 year warranty from the sometimes admittedly questionable manufacturer / seller, and a 30 day no questions asked return policy from Amazon themselves.


The other question there will you be near a Costco when the battery dies and you need to exchange it, this would be a real issue for me, as the nearest Costco is a 200 mile round trip drive from my house, where if my LiFePo4 battery fails, I can ship it back to the seller for warranty claim, something you can't do with lead acid.


p.s. you suggest replacing offending components like inverters and furnaces, this is not exactly cheap to do, and sure I know people that advocate for exposed flame propane heaters inside RVs to save battery power, and know just as many people that are against them. Either way the face remains that as delivered from the factory most RV's have power hungry propane furnaces, and most people get upset when their furnace dies in the middle of the night, with 30% of battery capacity left due to voltage sag. As to inverters I know of none that continue to operate at much below 11.0 VDC seen at the inverter, which equates to around 11.8-11.9 VDC at the batteries at rest even with large, short battery cables.

[jharrell]

Originally Posted by Mark_K5LXP

But those very economics are based on some pretty specific, high cycle use cases. If you only put 50 cycles a year on a battery, your cost of ownership for LFP will be higher than lead because you will never use all the cycles before the battery expires or you're done with it.

Thats assuming you actually take care of your cheap FLA's by adding water, keeping them fully charged and doing equalizations as well, also don't pull too much current when discharging or you won't even get the 50% or 80% capacity out of since its above the 20 hour rate.

LFP batteries don't "expire" they have cycle aging and calendar aging, if you're not cycling much its dominated by calendar aging which is a function of SOC (minor) and temperature (major). There isn't a lot of clear data on the calendar aging of LFP but everything I can find shows easily more than 10 years to 80% unless the are kept at high temps constantly, low temps actually slow down calendar aging ending up with 20 year projected lifespans in standby applications.

I would venture most lead batteries in RV's are cycled less than 50 times a year and still need replacement every few years due to under charging or running them dead, not doing good temp compensated charging and equalizations along with not keeping up on the water. I went with AGM's originally to avoid maintenance as it was worth it to me have once less thing to keep up with, lithiums are similar except even less fussy about always keeping them charged properly to extend life.

If RV's came with LFP's for house batteries there is good chance they can last the lifetime of the RV for a small overall additional cost when purchasing while not have to spend any money later on replacements when they go dead at the worse time on vacation and adding resale value. I think most people would prefer that along with all the other nice attributes of LFP batteries, time will tell, but the economics are starting to make sense for a much wider audience now and continuing to get better.

[CRV2]

I suggest one aspect that has been mentioned but not as much as I would have thought, is that with limited space and cargo carrying capacity in many RV's (especially like in a larger Class C like I own), it is almost impossible to get ~400ah of battery capacity without going to LifePo4. When it comes to the aspect of size and weight then the choice is much easier. It is hard to deny that they are between 1/3 to 1/2 the weight and room they take up compared to la batteries. On the other hand, if I was good with the AH capacity that one single la deep cycle battery provides then I would have stayed with a single large la battery. ~CA

[Biljol]

Where are all the used 12 sealed lead battery’s coming from …..

All us IT people swapping them for lithium

Why

Because the lithium will last 15-20 years and the sealed lead only 4 years if we are lucky.

We used to use SLA in alarm systems for backup power never lasted more than 3 years have now swapped them to lithium and have not had to change one in the 7 years since we started the swap.

I would rather get a Chinese lithium than FLA because it works… Warrantee is not an issue as much because they work.

Why can the manufacturer put 5-10 year warranty on the lithium because they work. If FLA was as reliable and as good at lithium they would also have 5-10 year warranty.

All the extra cost is for build quality and warranty service.

Also if my lithium goes out I can also run down to Costco or sams buy a FLA and get me up and running till I have the replacement lithium.

[Winemaker2]

Biljol
"Because the lithium will last 15-20 years and the sealed lead only 4 years if we are lucky."

My boat AGMs have finished 8 yrs and still going strong. Owners are not maintaining g them if they die at 4 yrs.
I'll wait to see how many LFP are still around in 20 yrs.
Those claims are nice to quote but they are unsubstantiated. Besides how many still have their same cars, trucks, MHs, boats, etc after 20 yrs?
I won't luve that long and agree they are not for everyone... some maybe... time will tell.

[Isaac-1]

Its not about still owning the RV in 20 years, if the LiFePo4 batteries still have 10+ years of life when you sell the RV in 5-10 years it also becomes a selling point.



As to being unsubstantiated, LiFePo4 has been around in some applications like medical equipment for well over a decade, and those take out batteries were / are actively being sold on the used market, and testing out with 80%+ of their rated capacity.


See this video from a couple of years ago, so information on prices are out of date

https://www.youtube.com/watch?v=L43bArxyszU

[CRV2]

Originally Posted by Isaac-1

Its not about still owning the RV in 20 years, if the LiFePo4 batteries still have 10+ years of life when you sell the RV in 5-10 years it also becomes a selling point.



As to being unsubstantiated, LiFePo4 has been around in some applications like medical equipment for well over a decade, and those take out batteries were / are actively being sold on the used market, and testing out with 80%+ of their rated capacity.

In fact I made a purchase of 15~20 50ah used medical Lifepo4's a couple of years back at a super low cost ~$50 each and they still test to have close to 85% capacity now and are ~10 years old. One thing to know is that Lifepo4 batteries degrade faster earlier in their life so I should be able to get another ~10 years out of them with around 10% further loss of capacity. LifePo4 testing indicates that they can even last a lot longer than 20 years, with understanding that you will lose about 1% capacity per year after the first 10 years (~15% in the first 10 years). A FLA battery can't do that, once it hits around 75% of its capacity then it is done in most cases, even if you would be happy to have a working battery with less capacity for more years.

One other thought, if I was to sell my 11 year old RV now (no plans to do so), I wouldn't leave my LifePo4 bank of batteries in it and there is no reason for anyone else who has invested in LifePo4 to have to sell their RV with them and instead you can simply place them in your new RV and put a low cost battery in what you are selling. ~CA

[jharrell]

Originally Posted by Winemaker2

My boat AGMs have finished 8 yrs and still going strong. Owners are not maintaining g them if they die at 4 yrs.

You're obviously not cycling very often to get 8 years, 4 years is a couple full cycles per week for a perfectly maintained lead battery. When was the last time you did a full capacity test on your 8 year old bank? I would be surprised if it had 80% of its original capacity left which is what we are talking about with cycle life, my Lifeline AGM's had probably 50% capacity at 6 years and only at low draws, they could no longer stay above disconnect voltage at high draws. LFP's don't just stop working at the end of their cycle rating just like lead, they just keep losing capacity albeit much more slowly than lead and keep a much lower internal resistance.

Good deep cycle AGM's aren't sub $100 batteries either, my Lifeline AGM where $350 batteries, you could probably get a much smaller AH capacity LFP bank for less money than the AGM's and have similar capacity and better life at this point. I quadrupled my capacity in the same space for about three time the cost and should not have to buy another house battery for this RV ever and neither should the next owner.

Originally Posted by Winemaker2

I'll wait to see how many LFP are still around in 20 yrs.
Those claims are nice to quote but they are unsubstantiated. Besides how many still have their same cars, trucks, MHs, boats, etc after 20 yrs?
I won't luve that long and agree they are not for everyone... some maybe... time will tell.

Its not unsubstantiated there have been studies done but of lot of it is modeling since they haven't been in widespread use for 20 years and the ones that are out there seem to just keep going and going, there is already a secondary used LFP market, note this is comparing to ultra long life OPzS lead batteries:

https://www.proquest.com/docview/2483958114

For the studied standalone PV-battery system with Li-ion batteries and low temperatures (much lower than 20 °C), the typical value of 20 years for stationary battery systems can be considered as the battery lifetime. However, if the average temperature is higher than 20 °C (as in Tindouf), the battery life is significantly reduced to 13.7 years.

Summarizing, comparing a similar battery bank size in a PV-battery standalone system, the LiFePO4 battery life is expected to be around two times the OpzS lead-acid one. As the LiFePO4 battery cost at the end of 2020 can be around two times the OPzS cost, this means that economically LiFePO4 batteries can be competitive with the OPzS technology. Considering the expected reduction in Li-ion battery cost, we can expect that Li-ion batteries will be widely installed in PV-battery standalone systems in a few years.