Basics of Lithium conversion... I'm lost!

[C_Schomer]

I did a search and it's mostly Greek... to me. I'd like to know the key points for, hopefully, a straight across lead/acid to lithium conversion.
My old Flow-Rite watering system just overflowed 2 cells (GRRRR) and I'm thinking this might be the time to convert.
So far I see that SiO2 is better than Li but I don't know why or what the difference is, and charging is much simpler for lithium and not so fussy.
I currently have 2 of the bigger Sams 6gc's that have dimensions and specs similar to T-105s, 2 X 120 watt panels and a Morning Star controller with remote panel/setpoint, that the PO installed.
I don't use an inverter for any 120ac loads. I'm nearly always plugged in to 120. I have no big 12vdc loads... my 5er has full LED lighting but I use a 12vdc bipap for very rare boondocking. The biggest addition might be a 12vdc fridge, someday.
Is there 6v and 12v lithium batteries? I seldom need the capacity I have now but I don't want to give it up, for the times I need the 12vdc bipap. Can I get similar capacity with lithiums and also fit the 2 x 6gc foot print? How much capacity to run a 12vdc fridge? Do I need a different solar controller or just reprogram my existing one? Thanks bunches! Craig

[SV_K]

The OP left the room pages ago.

Why anyone would listen to the opinions of people with no experience is beyond me.

Kinda like asking the group of boys off to the side at a party, too scared to even talk to Mary-Lou, if she is a good dancer.

[3_tons]

Well, the disinformation Luddites have kinda got me thinking about making my rebuttals a bit more pointed...

3 tons

[FWC]

Itinerant1 wrote:
If the color of the sky is blue and someone insist it's green let them call it green if it makes them feel better.

These lfp threads are getting old with so many done already showing proof of the attributes and myths busted or proven wrong, yet more proof is wanted.

I'm just going to lurk and read these threads for now on while using my lfps and I guess doing everthing wrong now for 5 years everyday with over 1,600 cycles. Enjoy.

Nicely said, and I agree with your sentiment.

The problem that I see (which is illustrated in this thread) is that these dubious ideas are becoming mainstream on RV.net. No where else is there really even a serious discussion of 'SiO2' as it is fringe at best, but here on RV.net folks who are genuinely seeking guidance are starting our with 'I hear SiO2 is best....'. As far as I know, BFL is the only one who has gone as far as actually buying one, but who knows what the lurkers have done. If you leave it unchallenged, people will start to believe it.

[3_tons]

Considering these near desperate attempts to berate LFP’s, it appears that ‘SiO2-ism’ is approaching near cult levels...

3 tons, having recollections of Jonestown...

[Itinerant1]

If the color of the sky is blue and someone insist it's green let them call it green if it makes them feel better.

These lfp threads are getting old with so many done already showing proof of the attributes and myths busted or proven wrong, yet more proof is wanted.

I'm just going to lurk and read these threads for now on while using my lfps and I guess doing everthing wrong now for 5 years everyday with over 1,600 cycles. Enjoy.

[FWC]

I am not sure why I would need to provide backup to refute your un-backed up opinions.

That is great that SiO2 will work for your specific situation. However, I feel like you are doing the community a major disservice by recommending SiO2 in almost every situation, even when they are clearly not the right tool for the application. Furthermore, you have no idea whether they even live up to their fantastical claims.

pianotuna wrote:
Thanks for the opinions. But, since you don't back them up--that is all they are.

Thanks for bringing up SiO2. Until Li titinate are competitively priced, because of the ONE claim you approve of (-4f) I need to use SiO2.

[3_tons]

FWC, Earlier, I too thought about a rebuttal, but then with all sincerity it began to occur to me that this is not about LFP reality, so I opted to disregard...

3 tons

[pianotuna]

Thanks for the opinions. But, since you don't back them up--that is all they are.

Thanks for bringing up SiO2. Until Li titinate are competitively priced, because of the ONE claim you approve of (-4f) I need to use SiO2.

[FWC]

For best life span take no lower than 40% state of charge, do not charge to more than 90%
This is a truism - for any and all batteries the less you use them the longer they last. However for lithium you can use them from 100% - 0% SOC 2000 - 3000 times, which is far more cycles that 99% of RVers will ever use and is far better than any alternative - thus they are less fussy than lead acid in this regard.

do not float charge, store at 50% state of charge, do not charge below -4 f, have a dc to DC charger to protect the alternator,

There is no need to float charge (less fussy than lead), there is an ever so slight advantage to storing near 50% SOC, but this far less important than storing lead acid at 100% SOC (again less fussy than lead acid). The cold weather charging is a legit concern, unless you have a dumb alternator connected with a really short fat wire, the requirement for a DC-DC charger is also not true.

have a good battery management system, do not use above 140 f (irrc), do not draw power at greater than 0.5 C (not for all makes), have a high voltage (14.8 volts) source available to "reset" the battery management system if it "shuts down" the battery
Assuming we are talking about drop ins, then the BMS is included, the user doesn't have to do anything, there is no need for a 'high voltage source' BMS low voltage disconnect will reset at normal charge voltages, most drop in's will discharge at 1C with far less Peukert issues and voltage drop than lead (again less fussy). High temperature use will shorten their lifetime, but again this is not specific to lithium and is true of any battery.

Charge to 100% to rebalance the cells every so often, do not discharge to 0 soc, do not use temperature compensation charging, do not wire in series and initial cost is quite ridiculous unless you roll your own.

Depending on how the BMS is configures you may or may not need to charge to 100% to balance the cells, but in any case this is requires less often than lead requires it to avoid sulfanation (less fussy). You can discharge to 0% SOC somewhere in the range of 2-3000 times (less fussy), you don't need temperature compensated charging (less fussy) but as long as your max voltage is range it won't hurt. With most lithium batteries you can wire in series, but in general there is no need as lithium is available in 24 or 48V batteries if that is your desire (less fussy).

Yes they are more expensive upfront than generic lead acid, but they are significantly cheaper over their lifetime and the prices are falling fast. The upfront costs are also now about the same as your vaunted SiO2 (and way cheaper over time).

[3_tons]

“All most all of these statements about lithium are mostly or completely untrue (except maybe the -4f one). If you make up a bunch of requirement, then yes they appear fussy.”

A Mystic’s construct 2.0??....Seems we’re drifting into the realm of Witchcraft...

3 tons

[pianotuna]

FWC thanks for your opinion.

Tell us more about how your system is configured. How long have you been using LiFePo4? Have they lost any capacity yet?

And do be specific about which of my opinions are completely untrue. Of course, I'll ask you to back up your statements with reliable information. I do not wish to spread incorrect information.

[FWC]

pianotuna wrote:
thewoldwizard1,

Li have many good attributes. But they are a maze. For best life span take no lower than 40% state of charge, do not charge to more than 90%, do not float charge, store at 50% state of charge, do not charge below -4 f, have a dc to DC charger to protect the alternator, have a good battery management system, do not use above 140 f (irrc), do not draw power at greater than 0.5 C (not for all makes), have a high voltage (14.8 volts) source available to "reset" the battery management system if it "shuts down" the battery, Charge to 100% to rebalance the cells every so often, do not discharge to 0 soc, do not use temperature compensation charging, do not wire in series and initial cost is quite ridiculous unless you roll your own. I'm sure there are items I missed. I think that qualifies my statement that they are fussy.

Because each time I mention, or some one else mentions the many requirements for ideal cycle life in Li, that person is subjected to disbelief.

I should add, Li can be a great bank to own, and may offer excellent service.

All most all of these statements about lithium are mostly or completely untrue (except maybe the -4f one). If you make up a bunch of requirement, then yes they appear fussy. On the other hand many of us have been running lithium just fine with a dead simple single stage charger with far less 'fuss' than lead acid.

[time2roll]

Well for storage lithium is less weight to carry inside to survive the depth of winter. 😉

[3_tons]

pianotuna wrote:
3 tons,

-37 C and storage for months below -20 C. Li can be great banks--but they don't fit my RV needs.

I do have an Li that I use. I did notice that it lost 1% state of charge over a 12 month period, according to the battery monitor. That is truly impressive.

But then Mex has posted an AGM that was last charged in 2013, which under a light load showed 12.68 volts.

Yep, saw that too, not sure how typical that is, but I’d say truly impressive for AGM - GOOD for Mex!!

3 tons

[pianotuna]

3 tons,

-37 C and storage for months below -20 C. Li can be great banks--but they don't fit my RV needs.

I was answering a question of why I believe Li fussy.

I don't think the OP needs SiO2 unless he has deep pockets. He wants something he can just use with no fuss or muss.

I do have an Li that I use. I did notice that it lost 1% state of charge over a 12 month period, according to the battery monitor. That is truly impressive. I guess that makes me a "have".

But then Mex has posted an AGM that was last charged in 2013, which under a light load showed 12.68 volts. (oops I'm wrong--he has been using it since 2013, so it has been charged and used regularly)