LiFePO4 Battery Charger - is it needed?

Buckster

While researching which lithium battery to purchase for our 2022 320 CS-S, I've noticed that many people indicate that after purchasing a battery online, the first thing they need to do is charge them.  I was under the impression that (once installed on the TAB) the battery would charge when connected to shore power.  Is that true for LiFePO4 batteries?  Is a portable charger needed as well?

[Deleted User]

Hi Buckster, the battery will definitely charge installed in the T@B on shore power but slower. Maybe others were in a hurry to charge them up for a trip or something?  

Dutch061

Your 2022 should have a switch to adjust the WFCO converter to address the higher desired voltage levels of LifePO4. If not, you will need to consider how you wish to charge them, because a converter for SLA or AGM will not do the job efficiently or properly.

Brad

Buckster

TabbyShack said:

Hi Buckster, the battery will definitely charge installed in the T@B on shore power but slower. Maybe others were in a hurry to charge them up for a trip or something?  

Thanks TabbyShack.  Do you know if there is any difference (other than charging speed as you mentioned) in Lithium batteries being fully "topped off" on a charger versus shore power?

[Deleted User]

Oh yes I forgot about the switch. I have a photo of mine.  I will find and add to this post.  

[Deleted User]

Here is the photo. It's the little red and white button that says on. Button should be pushed to the LI side.  Pic is upside down. It is not in correct position for lithium in the photo.

pthomas745

Lithiums do have different charging profiles. The "older" WFCO's didn't have the appropriate "profile", so a lithium battery might only get a "90 percent" charge. (Or 80, or 85, or whatever the internet number is today.)  Any of the newer solar controllers (which many owners also have in their Victron) are capable of fully charging a lithium battery.  Another method of charging a lithium would be to have any of the dozens of battery charging devices (NoCo, Battery Tender, etc) that are capable of charging a lithium.

So, it is nice that the newer trailers have the "lithium switch", but there were plenty of good ways to charge the lithiums without it.

mail4vaughn

Is this switch present in a 2021 T@B 320 S BD?

Denny16

Sorry, it is only on the 2022 year model TaBs as far as I know.  A few late model 2021s may have the new converter, you could check your unit and see.  But this is a 2022 model year feature.
 Cheers 

TNOutback

Here is what Battleborn said about the charger in my 2020 400, which was not optimized for Lithium Ion batteries:

The WF8955PEC will charge our batteries, but only to 13.6v. Our batteries need to be charge to a voltage between 14.2v and 14.6v for cell rebalancing. I recommend replacing the converter section with a Progressive Dynamics PD4655LIV. This is a direct replacement converter section that will charge our batteries to 14.4v.

Horigan

Another option is adding a DC to DC charger between the converter and the Li battery.  There's isn't much savings though over just replacing the converter.

Sharon_is_SAM

Just found this over on the TaG forum.  Have those of you with lithium and the stock, non-lithium WFCO converter noticed a higher SOC if you have a load present? 

JamesDow Member Posts: 495

 March 2021 edited March 2021 99.178.134.185

Real life update using WFCO-8725 converter charging Renogy 100Ah smart lithium battery.

My initial tests indicated I could reach a 84.1% State of Charge (SoC) just using my stock WFCO converter.

In real life use I have found that I can reach a 94% SoC just using the converter alone. I am pleased with those numbers. The difference came by having the T@G battery switch ON and under a small load (Norcold NRF-30 refrigerator). I assume this made the converter run more in the "Absorption Mode" (13.6 Vdc) or the "Bulk Mode" (14.6 Vdc) as opposed to the "Float Mode" (13.2 Vdc). 94% is good with a 100 Ah lithium battery. 

I will be curious how much of an increase of SoC I will get using my solar suitcase. I should be able to get up to 100%. 

Since my shore power camping is limited (less than 3-5 trips a year), I wonder if changing to the new WFCO-8725Lis will be worth the effort.

Time will tell.

gulfarea

@Sharon_is_SAM YOU brought up a very good question. Should we nit pick the battery electrical system to death or just go camping with what we have? I also wanted to go with those batterys but changing the charger system just to do it seems like a lot of work. Please keep us informed as we might find the factory charger system that came in our older T@BS might just do us OK unless you are the type that boondocks for extended times. Art 

WayneW

Yes, interesting question.  I recently installed a 100ah lithium in our 2021 320S Boondock with the non-lithium converter. 

A basic question I have is without a lithium charger how do you know when you're at 80% or 90% or 100%? In the initial setup my battery monitor requires me to tell it where the battery is in its charge cycle.  The only known points are either no charge (0%) or full charge (100%).  I charged the battery as best I could with the controller and told the monitor it was 100% - but I don't know where it truly is.  

We went boondocking for 3 days last week.  I have the stock rooftop solar and a Renogy 100a solar suitcase.  I was hoping to get a full charge from those because both have lithium settings and I would then be able to define 100%.  But alas, it was cloudy and rained.

Regardless, I did notice that the converter would charge to about 85% and then reduce charging to a float mode.  It I disconnected the battery with the battery switch in the tub and then re-connected it again, the converter continued to put a charge in the battery and it reached close to 100%.  Or at least what I defined as 100%.

I ordered a lithium capable battery charger yesterday.  I have other batteries to charge as well so it's not just for the trailer.  When I get that I'll be able to get the battery to 100%, reset the battery monitor, and be better able to tell what the on-board charger is doing.

dsfdogs

@WayneW here is the cheat sheet for volt vs % full for lithium. When using a lithium compatible charger, it will actually show 14.4, which is 100% and where balancing occurs. Immediately upon disconnecting/turning off the charger, my multimeter reflects the 14.4, then shortly thereafter, it drops to 13.6.

13.6V = 100%

13.4V = 99%

13.3V = 90%

13.2V = 70%

13.1V = 40%

13.0V = 30%

12.9V = 20%

12.8V = 17%

12.5V = 14%

12.0V = 9%

I was reaching high 90% state of charge with the stock 8735 converter, but most of the time this was at home charging and not necessarily with any higher load than parasitic drain. 

PixandMsBee

Dutch061 said:

Your 2022 should have a switch to adjust the WFCO converter to address the higher desired voltage levels of LifePO4. If not, you will need to consider how you wish to charge them, because a converter for SLA or AGM will not do the job efficiently or properly.

Brad

This is a direct reply from Nu_camp regarding lithium batteries in a 2022 T@B "

The unit will be Lithium ready. You will not need to do anything to get your unit ready for lithium. You will want to go into the Victron app and change a setting to make the solar work more efficiently with the lithium. But nothing else would need to be adjusted or changed. "

Sharon_is_SAM

@PixandMsBee - you still need to make sure the switch is turned to the lithium option, otherwise, you will not be able to fully charge a lithium battery.  The 2022 TaBs are lithium ready because nuCamp changed the converter to lithium capable and you simply need to install a lithium battery instead of a lead acid battery.