I have not had to deal with a float setting so far with PWM controllers but I have a Victron 75/15 coming tomorrow and reading up on the settings,it is confusing especially the float setting..Some say float will shorten the life of a LFP battery and others say hogwash..Float at what setting for a 100ah LFP battery that settles at 3.3+..?Any input welcome...

Shouldn't the battery maker have that info?

2oldman wrote:Shouldn't the battery maker have that info?For this particular battery,there impossible to communicate with and the reason why I did not buy another one of there batteries when I needed another..The battery I did get instead of there brand says float 13.8 which is higher than recommended everywhere I look..I don't think some of these cheap batteries have very good customer service,some do,some don't.

Then I wouldn't bother floating it. It's a miniscule amount more charge and Li's don't care if they're fully charged.

It's been said a bunch...pick your posion. Are you cycling them daily or storing the trailer for awhile then using it? It will interesting after a 2-3 years with many new folks getting lfp what the survival rate will be of said batteries. With so much mixed info being regurgitated of how to use (charging, absorb, float) the batteries. As long as you can get the cells to balance and have your SOC meter sync to the capacity of the battery bank occasionally life should be good. What voltage is need for "your" batteries to accomplish this?

Don't see what PWM vs MPPT has to do with it. The battery doesn't care--solar is solar. Voltage goes down every night, which sort of counts as floating for any type of battery, depending on the scenario.The concern over float voltage with LFPs seems to be more with converters left on for long periods. With solar, float voltage settings should also depend on the scenario? Is this just for when camping or for when the RV is sitting at home for long periods?If the latter, the usual story is run the LFP down to 50% SOC and disconnect. Get your 12v from the converter.While camping off grid on solar I guess it depends on how many days/weeks in a row and whether you get to full charge or not and even when during the day that is. It still gets dark at night though.

Lifepo4 float setting? | Good Sam Community

3_tons
Explorer III
May 14, 2022
As a practical matter, looong running LFP personal testaments and anecdote's are no substitute for extensive bench testing, therefore I believe the only possible way satisfy BFL’s thirst at nuance (based on past threads and continuously evolving goal post - IMO…), may be for him to obtain his own LFP and conduct his own extensive test regiment and report back*… However, I presume that soliciting funds to this end is against forum rules…

*(hopefully improved over the Vector-dueling charge controller test…)

3 tons
3_tons
Explorer III
May 14, 2022
BFL said, “ I am still getting abuse from 3-tons… Meanwhile he just used the Solacity guy as a reference in a recent post in this thread (13 May at 0732), and then when after that, I used the Solacity guy as a ref, he said that guy is not to be believed! Makes you laugh.”

True enough - My bad, I didn’t mean in any way to discredit Solacity’s info, I was only pointing to one’s lack of hands-on LFP evaluations…In my view, theory IS important, but Hands-on often trumps the theoretical, and to BFL (and others), therein lies my distress …Sorry for any unintentional keyboard confusion…

3 tons
jaycocreek
Explorer II
May 14, 2022
Itinerant1 wrote:
That's because I'm living off my system and don't have the time to be a weekend worrior scientist making graphs, there is recorded data that time after time shows the same thing after 6 years of everyday use and many cycles in whatever SOC using high draw item for long periods. It works what I'm doing.

I find these threads amusing when everyone is bringing in different beliefs from different websites or blogs or sales page's.

I know one thing for sure, right or wrong, which I believe is good enough for "my" prupose of living off of solar/ lfp batteries with solar being the main charging source. 14.1v absorb 10 minutes tops but 6 minutes is usally when it switches to flaot at 13.6v. I have constant draws of 2ah from inverter (never turned off) and a humidifier 7ah on 24/7, total of 9ah always drawing then add in all the other comforts of life. I don’t scimp on power, some might even say wasteful but it's there to waste without worry. ;)

Pretty much..Even though I am not living off grid as I did for years in fifth wheels/motorhomes and travel trailers now,I run my TC 24/7 as if I was using battery power and solar connected to two 12v compressor fridges and occasional microwave use and lot's of TV/DVD use..

The reason for my questions or questions,is after a year using LFP as portable power stations in smart battery boxes,I decided to replace my house AGM with one of the LFP,which I just did a while back..I unhooked shore power and 100% on solar with an extension cord ran in for the little heater I use when it is cold..

I haven't hooked up the shore power to the system yet because of the old converter I have and screwing up my alternator maybe..It will work but not just as well as a proper one for LFP..I plan on disconnecting the charge wire to the lance camper and just use solar and portable chargers to keep them up without worry of my alternator if rumors are correct about the damage LFP can cause...

If you don't ask a question you will be guessing,so I ask here knowing there is some real LFP knowledge here as stated above..

Thanks for the answers,much appreciated..
BFL13
Explorer II
May 14, 2022
Itinerant1, yes you are not in a position to do the sort of testing and make the kind of graphs I would like to see. Some other guys could though. Just not the kind of thing many guys would like to do it seems.
Itinerant1
Explorer
May 14, 2022
That's because I'm living off my system and don't have the time to be a weekend worrior scientist making graphs, there is recorded data that time after time shows the same thing after 6 years of everyday use and many cycles in whatever SOC using high draw item for long periods. It works what I'm doing.

I find these threads amusing when everyone is bringing in different beliefs from different websites or blogs or sales page's.

I know one thing for sure, right or wrong, which I believe is good enough for "my" prupose of living off of solar/ lfp batteries with solar being the main charging source. 14.1v absorb 10 minutes tops but 6 minutes is usally when it switches to flaot at 13.6v. I have constant draws of 2ah from inverter (never turned off) and a humidifier 7ah on 24/7, total of 9ah always drawing then add in all the other comforts of life. I don’t scimp on power, some might even say wasteful but it's there to waste without worry. ;)
Itinerant1
Explorer
May 14, 2022
BFL13 wrote:
StirCrazy if your claim is that the Solacity guy's info is just a sales pitch with wrong info about LFPs, it is your job to provide links to the correct, more credible, version of that information to prove your claim.

FWIW, I don't read it as a sales pitch, and I am one who got all kinds of abuse from you LFP guys on here last year or so for my complaints about LFP sales pitches having bogus info.

I am still getting abuse from 3-tons. :) Meanwhile he just used the Solacity guy as a reference in a recent post in this thread (13 May at 0732), and then when after that, I used the Solacity guy as a ref, he said that guy is not to be believed! Makes you laugh.

When I posted test results of my various field tests of various RV equipments to show what they did, I had to explain how I measured things to indicate how credible those results were.

It is no good making arm- wavy claims about LFP performance without any graphs , tables, and especially the whole scenario for how those measurements were made.

EG, if I had LFPs I would already have run some cycles and made graphs to see what really happens at various charging rates same as I did years ago to make my ugly graph using FLAs. Barre's book on 12v taught me how to do that.

So let's see some graphs and tables you LFP guys have made from your measurements and indicate how you got those numbers so they can be peer reviewed here by guys who can see if your results are credible.

itinerant1 has posted many tables of how his system performs, but they don't show graphs of charging profiles at various rates with times, which the Solacity guy claims to have seen but did not show.
3_tons
Explorer III
May 14, 2022
StirCrazy wrote:
time2roll wrote:
pianotuna wrote:
Stir find me an Li battery that provide 9C for 5 seconds, 4C continuous, and be charged at -40. You may find that is unobtainable.

As to size, I have room for 7 Group 31, so that is not an issue.
Why would I need 9,000 amps, or even 4,000 for that matter??

If my battery actually drops to even -20 my energy and heating systems have failed to the point I am already rolling out. I mean propane does not even vaporize at -40. I would have to assume utility power is available at these temperatures(no battery required). Temps at -40 is an expedition vehicle and preparation is far beyond virtually all RVs. No reason to proclaim this as an ordinary criteria for an RV on this forum. Better suited to an expedition vehicle forum.

https://www.globalxvehicles.com/uxv-max.html

dont want to go there, I went there and searched SiO2 and here is a quote from the first post that came up .

"With the exception of cold weather charging, the specs on these are almost identical to any other flavor of lead acid battery. They are not really comparable to lithium with regard to cycle life, energy density, recharge rate etc. There do appear to be some folks shilling these on some RV themed sited that are making some very unrealistic claims about their performance. In the end, they are just extra jellied gel-cells.

The low temperature charging 'issue' with lithium is a bit overstate and fairly easy to address if it does apply."

Steve

Thanks very much for highlighting this valuable information!!….FWIW, I’d made several attempts to gain a better understanding of SiO2’s nature, but my search efforts always failed to yield even a single independent White Paper (except for a CAN vendor’s in-house paper…), and unfortunately, this lack of independent findings may have stung (??) a poor few who’ve already taken the SiO2 plunge…I’ve never once ‘knocked’ SiO2’s for others (but doesn’t work for me…), though may now warrant a re-evaluation for some - JMHO

It’s definitely kinda sad to see Caveat Emptor raise it’s ugly head again (ugg)…

3 tons
BFL13
Explorer II
May 14, 2022
StirCrazy if your claim is that the Solacity guy's info is just a sales pitch with wrong info about LFPs, it is your job to provide links to the correct, more credible, version of that information to prove your claim.

FWIW, I don't read it as a sales pitch, and I am one who got all kinds of abuse from you LFP guys on here last year or so for my complaints about LFP sales pitches having bogus info.

I am still getting abuse from 3-tons. :) Meanwhile he just used the Solacity guy as a reference in a recent post in this thread (13 May at 0732), and then when after that, I used the Solacity guy as a ref, he said that guy is not to be believed! Makes you laugh.

When I posted test results of my various field tests of various RV equipments to show what they did, I had to explain how I measured things to indicate how credible those results were.

It is no good making arm- wavy claims about LFP performance without any graphs , tables, and especially the whole scenario for how those measurements were made.

EG, if I had LFPs I would already have run some cycles and made graphs to see what really happens at various charging rates same as I did years ago to make my ugly graph using FLAs. Barre's book on 12v taught me how to do that.

So let's see some graphs and tables you LFP guys have made from your measurements and indicate how you got those numbers so they can be peer reviewed here by guys who can see if your results are credible.

itinerant1 has posted many tables of how his system performs, but they don't show graphs of charging profiles at various rates with times, which the Solacity guy claims to have seen but did not show.
StirCrazy
Moderator
May 14, 2022
BFL13 wrote:
time2roll wrote:
BFL13 wrote:
You need 14.x to get those ions moving better. Once there you can lower the voltage

Lower charging voltage than 14.6 needs more time so keep
Float voltage same as Bulk longer too till desired SOC is reached
I respectfully disagree.

I got that from the Solacity guy.

ya that is how a lot of the misconceptions around here got started. prople taking a sales pitch as gospel. you don't know how many stores and websites I have been to where people are giving the information for older nickel cadium batteries and saying that is for LiFePO4. they are starting to get better but for a couple years it was just horrable.

there are a couple handycaps to workaround with LFP like cold weather use and charging, but this is very easily solved by moving the batteries into a conditioned space or insulating them and useing heateres (weather there home built or come intagrated into the battery) if some one is unwilling to do the work then the batteries shouldn't be blamed but rather the person who shills them as bad because they are not willing to do the work nessasary. not saying this is you in anyway, I think you are just trying to read to much into sales papers.
3_tons
Explorer III
May 14, 2022
2oldman wrote:
3 tons wrote:
You didn’t mention your stats, but it’s entirely possible with my 400a/hr LFP and 660w of solar - with 400a/hr LFP concurrent with harvest, and 2/3rds duty cycle
835w solar, 100ah@48v li battery. If I ran air with that during the day I may not have much left over for evening use!

As I stated, I calculated it out at roughly 5 hrs (with a manageable reserve till next harvest period), 2/3 duty cycle concurrent with harvest drawing 9.5 ac amps (post comp warm-up) …Even my old GC’s (two 6v) would run it for a max of 1.5 hrs, 2/3duty cycle (to 50-55% SOC) with just the previous 440w of solar…But I just try to take the edge off the heat, 10 or so degrees lower does the job for me…

3 tons

Upon edit, I need to point out that this scenario is with a 10’ single slide truck camper..

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