RV.Net Open Roads Forum: Lifepo4 cold temp cut off 23F or 32F?

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

 > Lifepo4 cold temp cut off 23F or 32F?

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 4  
Prev  |  Next
Sponsored By:
StirCrazy

Kamloops, BC, Canada

Senior Member

Joined: 07/16/2003

View Profile



Posted: 11/22/21 05:36pm Link  |  Quote  |  Print  |  Notify Moderator

Lwiddis wrote:

I've seen some manufacturers say it is ok down to 24 but no experts. They say 32.


and who are these experts and what makes them that? youtube?

personaly I think 32 was chosen because of lack of knowledge and a carry over from other Li chemistry. also since the LFP only gave them a extra 5 degrees C , and who realy camps when its 0 (sarcasm, but its how assembliers/branders would probably think) why change it. and if they leave it at 0 degrees C that gives them a 5 degree buffer for warenty claims.. win win win..

Steve


2014 F350 6.7 Platinum
2016 Cougar 330RBK

3 tons

NV.

Senior Member

Joined: 03/13/2009

View Profile


Offline
Posted: 11/22/21 05:45pm Link  |  Quote  |  Print  |  Notify Moderator

Oops, please disregard…

jaycocreek

Idaho

Senior Member

Joined: 12/28/2013

View Profile


Offline
Posted: 11/22/21 05:55pm Link  |  Quote  |  Print  |  Notify Moderator

StirCrazy wrote:

23F is -5C, which is the lowest cold weather charging temp listed by the Prismatic cell manufactures, so thats not the brands limit thats the actual cell manufctures limit. most rebranders/assemblers would put that to 32F to give them self a bit more protection from warenty claims.

Steve


That really makes sense to me,kinda like the truck manufacturer axle ratings vs the actual axle manufacturer ratings,both different numbers..

Thanks

time2roll

Southern California

Senior Member

Joined: 03/21/2005

View Profile



Good Sam RV Club Member


Posted: 11/22/21 06:05pm Link  |  Quote  |  Print  |  Notify Moderator

StirCrazy wrote:

personaly I think 32 was chosen because of lack of knowledge and a carry over from other Li chemistry.
Two of the largest manufacturers, EVE and CATL, give 0c as the minimum to charge.
Ignore factory specifications at your own risk.


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

Itinerant1

Itinerant

Senior Member

Joined: 05/23/2017

View Profile



Posted: 11/22/21 06:52pm Link  |  Quote  |  Print  |  Notify Moderator

Manufacturers seem to have their own recommendations. My GBS cells recommend -20C (-4f) to 65C (149f) for discharging, 0C (32f) to 65C (149f) for charging. Which the BMS protects for these temps.


12v 500ah (5,120Wh usable), 20 cells_ 4s5p (GBS LFMP battery system). 8 CTI 160 watt panels (1,280 watts)2s4p,Panels mounted flat. Magnum PT100 SCC, Magnum 3012 hybrid inverter, ME-ARC 50. Installed 4/2016 been on 24/7/365, daily 35-45% DOD 1,800+ cycles.

S Davis

Western WA

Senior Member

Joined: 08/11/2005

View Profile


Offline
Posted: 11/22/21 09:34pm Link  |  Quote  |  Print  |  Notify Moderator

I am heating my two 12v 280ah batteries, will be using a separate small agm charged by the trucks alt. I don’t plan on letting them get below 40 under normal conditions but will probably test after they cold soak once for a idea just Incase.

Twin 280ah LifeP04

Tom_M

New Hope, MN

Senior Member

Joined: 04/24/2011

View Profile


Offline
Posted: 11/23/21 06:12am Link  |  Quote  |  Print  |  Notify Moderator

jaycocreek wrote:

[image]
From ExpertPower web site:

Discharge: -4 — 140°F
Charge: 32 — 140°F

https://www.expertpower.us/products/ep12100-100ah

The Amazon listing is a typo.


Tom
2005 Born Free 24RB
170ah Renogy LiFePo4 drop-in battery 400 watts solar
Towing 1978 VW Bug convertible
Minneapolis, MN


jaycocreek

Idaho

Senior Member

Joined: 12/28/2013

View Profile


Offline
Posted: 11/23/21 07:19am Link  |  Quote  |  Print  |  Notify Moderator

You would think they would fix there typo..lol

My cheapo 100ah lifepo4 battery is pretty generic temp wise as I assume most of them are...The 23F cutoff just caught my eye...

[image]

otrfun

On The Road

Senior Member

Joined: 09/08/2012

View Profile



Good Sam RV Club Member


Posted: 11/23/21 11:24am Link  |  Quote  |  Print  |  Notify Moderator

I believe there's general agreement the majority of lifepo4 manufacturers specify >32f as the minimum temperature you can "safely charge" a lifepo4 at it's maximum rated charge current. Safely charge defined as charging that results in no reduction in a lifepo4's long-term performance---the ability to deliver 3000-4000 charge cycles while maintaining at least 80% of the original ah rating of the battery.

As StirCrazy alluded to earlier, if a particular manufacturer specs their lifepo4 as capable of maximum charge current at <32f, my guess, it's just a marketing strategy. Their bean-counters have probably determined any increased costs for warranty claims (to support the lower charge cut-off temp) is more than offset by the increased sales to folks who actually believe they have a better lifepo4. Again, more than likely marketing strategy vs. a battery/cell with any real added capability.

Lastly, some see the lifepo4 32f low-temp charge cut-off as all or nothing in terms of charging--ok to charge at 33f---not ok to charge at 32f. That's not necessarily the case. It is possible to safely charge at <=32f . . . if you're willing/able to reduce the charge current (and have a BMS which permits charging at <=32f). I find it very interesting that Trojan actually specs the maximum allowable charge current for their 110a Trillium lifepo4 down to -4f (-20c).

BFL13

Victoria, BC

Senior Member

Joined: 02/15/2006

View Profile



Posted: 11/23/21 12:01pm Link  |  Quote  |  Print  |  Notify Moderator

Previously, Trillium info was to limit charging amps on a sliding scale from just under freezing to well above freezing, but their data sheet now shows full 110amp charging right from freezing on up, and reduced charging amps below freezing to a lower temp than before.

No idea if anything new with the LFPs that take heat from a charger before allowing charging, but it was 5C/40F before they allowed charging to start.

I kept asking on here about what to charge at between freezing and 5C and how you could throttle the amps of your charger to do that, but got nowhere. Seems Trillium has changed their story lately. if true for all LFPs now, it is moot.

Perhaps there has been more experience /data with LFPs or they have changed the formula a bit for making the cells, not a clue.

Lesson is to keep up with the latest on all this, because what you learned last year might now be wrong. Eg I see Trillium has "retired" the Trillium Owners Guide, but do have the new charging guide in the Data Sheet


1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 4  
Prev  |  Next

Open Roads Forum  >  Tech Issues

 > Lifepo4 cold temp cut off 23F or 32F?
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:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.