Good Sam Club Open Roads Forum: Are lithium batteries worth the cost?
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 Truck Campers

Open Roads Forum  >  Truck Campers

 > Are lithium batteries worth the cost?

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 8  
Prev  |  Next
Grit dog

Black Diamond, WA

Senior Member

Joined: 05/06/2013

View Profile


Offline
Posted: 04/26/21 12:05pm Link  |  Quote  |  Print  |  Notify Moderator

Interesting. I thought the loss of capacity was similar to the charging loss and not better than lead acid. That’s encouraging


2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29

otrfun

On The Road

Senior Member

Joined: 09/08/2012

View Profile



Good Sam RV Club Member


Posted: 04/26/21 05:52pm Link  |  Quote  |  Print  |  Notify Moderator

FWC wrote:

Grit dog wrote:

Keeping on topic and out of Kayteg land....
Anyone have practical experience using them at low temps?
I only know what I’ve read and what I’ve experienced with my Snowbike lifepo4 battery.
Seems this is the one practical Achilles heel of them.
Yes, I have used my lithium pack in low temperatures discharge down to about -15C and charging at ~ -10C. The voltage was definitely lower at low temperatures, and I assume they loose some capacity (I have plenty to spare, so I have not tested this). The loss of capacity with temperature is true of all batteries, and is actually less severe with LiFePO4 vs AGM/FLA:
[image]
My concern with LifePo4's would not be so much reduced discharge current capacity at lower temps, but the chance of permanently damaging the cells with *excessive* charge (and discharge) current at or below a given temp. I've always heard you should dramatically reduce charge current (or not even charge at all) below 0c (32f) with LifePo4 cells. I've heard -18c (0f) is a very similar type of cut-off for discharge current.

Did a cursory look for a graph that shows the maximum charge (and discharge) current and temperature relationship for LifePo4, but couldn't find one. Have you seen one?

time2roll

Southern California

Senior Member

Joined: 03/21/2005

View Profile



Good Sam RV Club Member


Posted: 04/26/21 05:59pm Link  |  Quote  |  Print  |  Notify Moderator

Generally the BMS will halt charging at about 0c and halt discharge about -10c.
Of course no reason to get below 5c as you would want to add a heater if going that cold. However your battery would be protected if an unexpected cold snap was to slam down suddenly.


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

otrfun

On The Road

Senior Member

Joined: 09/08/2012

View Profile



Good Sam RV Club Member


Posted: 04/26/21 07:12pm Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

Generally the BMS will halt charging at about 0c and halt discharge about -10c.
Of course no reason to get below 5c as you would want to add a heater if going that cold. However your battery would be protected if an unexpected cold snap was to slam down suddenly.
According to BattleBorn you can safely charge LifePo4 cells below 32f (0c), but you must reduce the charge current accordingly. I would prefer the option to reduce/limit charge current when temps get down to say, -3 or -5c, rather than rule out all charging below 32f (0c). That's one of the reasons I'm hoping to find a LifePo4 charge current/rate vs. temperature chart. Of course, to pull this off you need a programmable BMS. A nice advantage of a DIY LifePo4 cell pack.

time2roll

Southern California

Senior Member

Joined: 03/21/2005

View Profile



Good Sam RV Club Member


Posted: 04/26/21 08:31pm Link  |  Quote  |  Print  |  Notify Moderator

BMS does not throttle power. On or Off with a MOSFET or Relay. BMS is really the last resort to save the battery. You should have a voltage alarm to reduce power or keep track of the state of charge and temperature with the BMS APP. There is no load shed like there is for 120 volt systems that I know of.

Similar can happen to lead-acid but there is no limit to discharge and possibly freezing up and killing the battery. So it is the same type of monitoring if you are in extreme conditions. Possibly need a generator auto start in either case.

Dodgemahal

Idaho

New Member

Joined: 09/29/2019

View Profile



Posted: 04/27/21 12:20am Link  |  Quote  |  Print  |  Notify Moderator

I just finished converting to lithium. Two 100 AH battle borns moved to the basement storage in our Bigfoot. I also put a 40 amp Renogy DC to DC charger to charge off the truck. Monitoring is with a Victron 702. Also a Progressive Dynamics 55 amp lower power center conversion to a lithium compatible charger. All new 4 GA cables. I used a hybrid vehicle high amp connector to penetrate the camper hull. Over kill yes but the lack of resistance and the smaller hole to drill made it worth the extra costs. It was an expensive conversion. I could not keep our wet cell deep cycles charged. We only boon dock. No hook ups for us. I only need to run the 4 GA from the truck battery to the fuse, relay and back to the bed to the pollack 200 amp bed side connector. That is all that is left to do. We will head out soon after. Was it worth it? Absolutely it was. No longer will I be carrying a fluke meter around while I should be relaxing by the fire.
My old batteries were a pain.
I also found some issues while studying all this.
The Renogy will pull up to 60 amps while making 40 amps to charge your batteries. Even with the current limiting switch activated for the 20 amp, the unit will still draw up to 60 amps. More expensive DC to DC chargers don't draw so much to create the power they are rated for.
Not putting a DC to DC charger in the system carries the risk of two things. Discharged lithiums can pull max current from your (non smart) alternator which will burn it up and possibly cause a fire. Ending up on the side of the road is a big possibility.
Also the nature of lithium power and wet cell batteries in your truck, leaving home with charged up lithiums has the potential to back drain into your trucks battery system. Either through the 7 way plug or if directly hooked to the charging system. I am disconnecting the power lead in the 7 way plug. Smart alternators will back off the charge current and lithiums loose energy to the truck system. This is not discussed much but it can be found if you search long enough. It provided interesting reading. I also discovered using 4GA battery cables from batterycables.com meant getting very high quality high purity copper cables.... but, trying to run heavy jacket cables in the power converter compartment was difficult. Using regular sheathed 4GA would be less of a wrestling match. Using the battery cables to run down the dodge frame and also on the entire wiring system of the renogy DC to DC system was fine. I had hoped to post several pictures. But I am having issues with a new security feature the site has that stalls out while I am trying to post. EDIT: just posted a pic with no issues. I will try to post up some of the lithium upgrade. Anyway..
I can't wait to hit the trail. I don't wonder if it will be worth it. I already know it totally is.

* This post was edited 04/27/21 01:05am by Dodgemahal *


Almost new to truck camping. Truck is a 2001 Dodge 3500 Dual rear wheel with a few performance mods. Camper is a 2005 Bigfoot 2500 9.6 with Lithiums. The trailer carries gear, one quad, two kayaks, two bicycles, and a 3700kw generator.

otrfun

On The Road

Senior Member

Joined: 09/08/2012

View Profile



Good Sam RV Club Member


Posted: 04/27/21 04:16am Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

BMS does not throttle power. On or Off with a MOSFET or Relay. BMS is really the last resort to save the battery. You should have a voltage alarm to reduce power or keep track of the state of charge and temperature with the BMS APP. There is no load shed like there is for 120 volt systems that I know of.

Similar can happen to lead-acid but there is no limit to discharge and possibly freezing up and killing the battery. So it is the same type of monitoring if you are in extreme conditions. Possibly need a generator auto start in either case.
I only mentioned the BMS in this scenario because it must be reprogrammed to allow charge current below 0c. I would use a programmable charger or possibly a small bench-top regulated power supply to limit charge current while charging at these lower temps,

otrfun

On The Road

Senior Member

Joined: 09/08/2012

View Profile



Good Sam RV Club Member


Posted: 04/27/21 05:09am Link  |  Quote  |  Print  |  Notify Moderator

Dodgemahal wrote:

I just finished converting to lithium. Two 100 AH battle borns moved to the basement storage in our Bigfoot. I also put a 40 amp Renogy DC to DC charger to charge off the truck. Monitoring is with a Victron 702. Also a Progressive Dynamics 55 amp lower power center conversion to a lithium compatible charger. All new 4 GA cables
. . .
I can't wait to hit the trail. I don't wonder if it will be worth it. I already know it totally is.
Nice upgrade! Can’t go wrong with those Battleborns!

We did a very similar upgrade on our Northern Lite. Installed a single, group 24 size 200ah DIY LifePo4 cell pack and a Renogy 40a dc to dc charger.

Used 2 gauge cable for our Renogy install. Surprisingly, it allows 40a of charge current with only a 43a load on the alternator. Also installed a battery isolator to isolate the Renogy (and the truck’s battery) when the alternator is off-line.

Elected to keep our standard 3-stage (13.2/13.6/14.4) 45a Progressive Dynamic converter (and Charge Wizard) to charge our LifePo4 cells vs. using the single stage (14.6v) 45a PD lithium converter. We prefer the option to float the LifePo4’s at 13.6v with the Charge Wizard.

Like you, we’re thoroughly pleased with our upgrade. Well worth the time and money for the added stability and performance.

StirCrazy

Kamloops, BC, Canada

Senior Member

Joined: 07/16/2003

View Profile



Posted: 04/27/21 06:29am Link  |  Quote  |  Print  |  Notify Moderator

Dodgemahal wrote:



Not putting a DC to DC charger in the system carries the risk of two things. Discharged lithiums can pull max current from your (non smart) alternator which will burn it up and possibly cause a fire. Ending up on the side of the road is a big possibility.


Lets clear this one up before it starts spreading as fact.

The only way this is going to happen is is some one took the fuse out of your charging line for your 7 way. Or if some person who didnt have a clue installed there own because it want a factory option and didnt put a fuse in.

I think most of this stems from the youtub video of a guy hooking a li pack directly to an altnator with large wires and started it up using an electric motor. no fuse now voltage loss and yes it did start stuf burning.

having said that I still would encourage the use of a LFP compatable DC to DC charger and proper wiring to provide the LFP battery its best charging.

Steve

Steve


2014 F350 6.7 Platinum
2016 Cougar 330RBK

FWC

The Wilderness

Senior Member

Joined: 09/12/2020

View Profile



Posted: 04/27/21 08:53am Link  |  Quote  |  Print  |  Notify Moderator

otrfun wrote:

My concern with LifePo4's would not be so much reduced discharge current capacity at lower temps, but the chance of permanently damaging the cells with *excessive* charge (and discharge) current at or below a given temp. I've always heard you should dramatically reduce charge current (or not even charge at all) below 0c (32f) with LifePo4 cells. I've heard -18c (0f) is a very similar type of cut-off for discharge current.

Did a cursory look for a graph that shows the maximum charge (and discharge) current and temperature relationship for LifePo4, but couldn't find one. Have you seen one?


As with most things, low temperature charging of LiFePO4 batteries is not black and white, it is shades of grey. Yes in general you need to be careful when charging much below -5C, and you should limit the current at these low temperatures (0.1C or so). Charging at higher current at low temperatures will decrease the battery life (but so will taking it below 50% SOC), but unless you go to the extreme it is not like it will be destroyed in the one cycle. This is not exactly what you are looking for, but it gives you an idea that even under 1C cycling, the increased aging at -5C is only very slight:
[image]

The whole paper is here: Journal of thermal analysis and calorimetry

As for discharging, besides decreased capacity at low temperature I am not aware of any cycle life issues discharging at low temps. If you can read the paper above, storage at low temperature (-20C) is actually beneficial to battery lifetime.

* This post was edited 04/27/21 09:05am by FWC *

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 8  
Prev  |  Next

Open Roads Forum  >  Truck Campers

 > Are lithium batteries worth the cost?
Search:   Advanced Search

Search only in Truck Campers


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.