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 > Lifepo4 float setting?

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pianotuna

Regina, SK, Canada

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Posted: 05/13/22 10:07am Link  |  Quote  |  Print  |  Notify Moderator

Time2roll,

It is true my rv is modified for cold use. That was the determining factor for the number of house batteries, so I could run a block heater for 3 hours at -40. I have boondocked at -37c (-34 f). Moving Sue and Photomike have me beat--they have both done -40.

One of my modifications is a magnetic block heater for the generator.

But -20 (-4 f) is quite common where I live.

Again Li are super batteries when full time, or no low temperatures.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

3 tons

NV.

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Posted: 05/13/22 10:30am Link  |  Quote  |  Print  |  Notify Moderator

StirCrazy said:

“I wish some of these resellers would just stop trying to put out information about LiFePO4 batteries as they are putting out half truths and in some cases outright BS and then certian people take it as gospel and spout off on the internet.”….

Maybe I’m misunderstanding here, but I sense that the info you seek has been offered here (dismissing usual confusion…), trust that it’s not even close to rocket science, and I believe all that remains is a well advised dose discernment (IMO…) and you should be good to go - from my non-theory sourced, hands-on experience, LFP charging is simpler than other types - but ironically, maybe it’s this level of uber simplicity is what leads to such confusion - lol [emoticon] JMO

3 tons

time2roll

Southern California

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Posted: 05/13/22 10:41am Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Time2roll,

It is true my rv is modified for cold use. That was the determining factor for the number of house batteries, so I could run a block heater for 3 hours at -40. I have boondocked at -37c (-34 f). Moving Sue and Photomike have me beat--they have both done -40.

One of my modifications is a magnetic block heater for the generator.

But -20 (-4 f) is quite common where I live.

Again Li are super batteries when full time, or no low temperatures.
And the thread is about float values of LFP.

Best to start a new thread about low temperatures and the effect on batteries etc.


2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
675w Solar pictures back up

3 tons

NV.

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Posted: 05/13/22 11:05am Link  |  Quote  |  Print  |  Notify Moderator

More ‘Friday funnies’ from the SiO2 battery camp:

BFL said, “ I got that from the Solacity guy.” (LOL on that, but what about actual LFP experience?) - while it seems PT can’t resist making the topic about SiO2’s vs LFP’s (huh?)…

Time2roll rightly states, “Best to start a new thread about low temps and the effect on batteries, etc”,

Agreed, but (with regards to SiO2’s…) this has been tried before, but as the old saying goes, “how do you start a party if nobody shows”?? - Just saying [emoticon]
3 tons

2oldman

NM

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Posted: 05/13/22 03:33pm Link  |  Quote  |  Print  |  Notify Moderator

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!

StirCrazy

Kamloops, BC, Canada

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Posted: 05/14/22 08:59am Link  |  Quote  |  Print  |  Notify Moderator

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


2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100

3 tons

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Posted: 05/14/22 09:07am Link  |  Quote  |  Print  |  Notify Moderator

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..

* This post was edited 05/14/22 09:47am by 3 tons *

StirCrazy

Kamloops, BC, Canada

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Posted: 05/14/22 09:09am Link  |  Quote  |  Print  |  Notify Moderator

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.

BFL13

Victoria, BC

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Posted: 05/14/22 10:04am Link  |  Quote  |  Print  |  Notify Moderator

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. [emoticon] 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.

* This post was edited 05/14/22 10:15am by BFL13 *


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3 tons

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Posted: 05/14/22 10:28am Link  |  Quote  |  Print  |  Notify Moderator

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

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