RV.Net Open Roads Forum: Tech Issues: Effect of no absorption on LiFePo4?

RV Blog

  |  

RV Sales

  |  

Campgrounds

  |  

RV Parks

  |  

RV Club

  |  

RV Buyers Guide

  |  

Roadside Assistance

  |  

Extended Service Plan

  |  

RV Travel Assistance

  |  

RV Credit Card

  |  

RV Loans

Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tech Issues

Open Roads Forum  >  Tech Issues

 > Effect of no absorption on LiFePo4?

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 3  
Next
Sponsored By:
Ramblin' Ralph

Central California Coast

Senior Member

Joined: 10/27/2005

View Profile


Offline
Posted: 01/21/23 04:33pm Link  |  Quote  |  Print  |  Notify Moderator

I bought a low end 100Ah LiFePo4 a couple of years ago. The manufacturer only listed charge and float voltages on their spec sheet. Later I asked them about absorption and they told me 14.4v. They also said it wasn't on the spec sheet because "it's not that frequently ask by our customer". [emoticon] I never got around to setting my solar controller for absorption. For 2 summers of extended summer travel the battery has performed very well and is only charged by my 225w solar system.

So what is the effect on the battery to not have absorption?

Thanks,
Ralph


Ralph
2006 GMC 2500HD, XCab, SB, 6.0L w/2001 Lance 845
Bilstein Shocks, TorkLift Stable Loads, 100 Ah LiFePo4, 225 watt solar
My RV Travels Webpage / Yearly Campsite Map / 740 Campsites / YouTube Videos /
Instagram


2oldman

NM

Senior Member

Joined: 04/15/2001

View Profile


Offline
Posted: 01/21/23 04:40pm Link  |  Quote  |  Print  |  Notify Moderator

Lifepo's don't have an absorption phase. Those are strange responses from the mfr.

* This post was edited 01/21/23 05:18pm by 2oldman *

time2roll

Southern California

Senior Member

Joined: 03/21/2005

View Profile



Good Sam RV Club Member


Posted: 01/21/23 05:52pm Link  |  Quote  |  Print  |  Notify Moderator

At 14.0 to 14.4 bulk volts there is no need for absorption time. Worst case the battery might be 2% or 3% undercharged which will not hurt anything ever.


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

Ramblin' Ralph

Central California Coast

Senior Member

Joined: 10/27/2005

View Profile


Offline
Posted: 01/21/23 07:03pm Link  |  Quote  |  Print  |  Notify Moderator

Thank for the info. Glad to know I'm damaging my battery. [emoticon]
Ralph

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 01/21/23 09:21pm Link  |  Quote  |  Print  |  Notify Moderator

Ralph,

Quite the opposite. LiFePo4 do not want to be charged to 100%. They do want to be balanced charged once per month.


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.

bighatnohorse

Cave Creek

Senior Member

Joined: 01/15/2005

View Profile



Good Sam RV Club Member


Posted: 01/22/23 08:22am Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Ralph,

Quite the opposite. LiFePo4 do not want to be charged to 100%. They do want to be balanced charged once per month.


Isn't a "balance charge" a 100% charge?
As I recall, it is said that over time, individual component batteries can develop slightly different voltages. Thus, charging the entire battery to a full charge and holding it at full charge for a period of time will equalize the individual component batteries.
Can you clarify?


2021 Arctic Fox 1150
'15 F350 6.7 diesel dually long bed
Eagle Cap Owners
“The best lack all conviction, while the worst
Are full of passionate intensity."
-Yeats

pianotuna

Regina, SK, Canada

Senior Member

Joined: 12/18/2004

View Profile


Offline
Posted: 01/22/23 08:42am Link  |  Quote  |  Print  |  Notify Moderator

Hi,

My (limited) understanding is that there is a specific voltage needed to balance the cells. That is set by the battery management system. I don't know what that number is.

time2roll

Southern California

Senior Member

Joined: 03/21/2005

View Profile



Good Sam RV Club Member


Posted: 01/22/23 09:39am Link  |  Quote  |  Print  |  Notify Moderator

Charging to 14.4 on any regular basis as described by the OP is sufficient to keep the cells balanced. There is no recommendation to periodically change the charging cycle for balancing. Yes if the battery is short charged to 13.6 or less it may or may not get any balancing from the BMS. Could go years like that without issue. The primary time balance can be a critical process is when the battery is first assembled to verify the cells are at the same level to start with.

3 tons

NV.

Senior Member

Joined: 03/13/2009

View Profile


Offline
Posted: 01/22/23 10:15am Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

Charging to 14.4 on any regular basis as described by the OP is sufficient to keep the cells balanced. There is no recommendation to periodically change the charging cycle for balancing. Yes if the battery is short charged to 13.6 or less it may or may not get any balancing from the BMS. Could go years like that without issue. The primary time balance can be a critical process is when the battery is first assembled to verify the cells are at the same level to start with.


X2….Mythology has it that LFP’s are in someway ‘fussy’ to charge when in fact (except for cold weather charge constraint) the opposite is true…

OP suggest he may have ‘damaged’ his batteries (how so??)…The basics are, don’t exceed 14.6v, don’t equalize, float at or below 13.6v (or not at all), don’t leave on charger for an extended period of time (say, once fully charged), no need for a full charge except for occasional cell re-balancing and (if applicable) SOC meter resynchronizations…

Applying this basic charge regime is a minor price to pay which negates conventional battery maintenance and achieve faster charge recovery times and a far deeper depth of discharge..

3 tons

* This post was last edited 01/22/23 11:42am by 3 tons *   View edit history

Grit dog

Black Diamond, WA

Senior Member

Joined: 05/06/2013

View Profile


Offline
Posted: 01/22/23 10:55am Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Ralph,

Quite the opposite. LiFePo4 do not want to be charged to 100%. They do want to be balanced charged once per month.


Correct but they’re not near as needy as described above.
Ralph, just when they are not in use, make sure they are not on a maintenance charge. If there is truly no draw. Ideal condition is NOT fully charged, however it’s only slightly less.
I don’t go out of my way to make sure my LFP batteries are drawn down some for storage nor do I maintenance charge them while not in use.
They probably end up fully charged. Like my MX bike. I’ve hooked up a little charger after it sitting for months 6-8 months even “just to see” and it literally takes 2 min or less to register full charge. (Small battery). Tells me it’s fully charged when I last shut the bike off.


2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 3  
Next

Open Roads Forum  >  Tech Issues

 > Effect of no absorption on LiFePo4?
Search:   Advanced Search

Search only in Tech Issues


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2023 CWI, Inc. © 2023 Good Sam Enterprises, LLC. All Rights Reserved.