Upgrade to Lithium FE battery question

[EnzoColorado]

I currently have two Renogy AGM batteries, hooked to a Renogy PWM Solar Charge Controller and also charging from the converter.  

I just scored on a pair of LiTimes LiFEO4 batteries.  Plan to install them in the spring.  

I know I need to upgrade the Renogy PWM Solar Charge Controller.  Do I also need to upgrade the converter?  The trailer is a Starcraft 2017 model.  Currently parked in storage and can't remember the mode of the converter.  

[bigfootford]

I recommend that you consider a Victron Smart shunt to go along with those Lbatts.  The 712 is the best.  I did get the gauge too but the phone app for it is very good and you can do without.  Then you can keep track of the AH in and out of the batteries and the voltage status along with state of charge.   You did not say that your new Ltime batteries are 12vdc but I am assuming they are.

You did not tell us the model of your WFCO converter.  If it is an older non Lbatt compat it might not give you  the boost mode due to the higher at rest and the differences in the voltage of these Lbatts. 

[EnzoColorado]

The Victron controller already have bluetooth and I can see how many watts are coming in and going out, battery voltage and solar voltage.  Not sure what functionality a Shunt will add.  

I mentioned below the converter is WFCO wf-8735-p.  It's made before LiFeO4 days and it'll bulk charge at 14.4V.  My LiTime manual says bulk charging voltage is 14.4.  Only the absorption phase is where the WFCO convert falls short at 13.6V where the LiTime wants 14.4V for aborption as well.  That's where I think the solar Victron will be able to top off the battery in absorption phase.  

[EnzoColorado]

Installed the LiFeO4 batteries today with a Victron MPPT charger, and verified the charger is charging the battery and all 12V appliances work inside the trailer.  

My current converter is a WFCO wf-8735-p which charges in bulk mode at 14.4V for up to 4 hours before dropping to absorption mode at 13.6V.  The only issue I see with this converter is that it'll not able to top off the battery in one shot.  Since I have 200W of solar panels, the solar MPPT charger will top off the battery.  So I'm thinking I can save the $ and using the existing converter.  Anyone see any issues with that thinking?  

[StirCrazy]

thats what I did for over a year, actualy still doing it.  I have more solar (325watts) but I don't plug in very often, I just let the solar handle it.  for winter storage I just turn off my battery and leave it plugged in, but I am looking at a replacment for the converter section, the wife wants 120V power for a couple things so I am looking at a inverter / converter unit to take that over

[EnzoColorado]

Thanks StirCrazy.  I live in Colorado and mainly go camping in Colorado and Utah.  Sun is very good here.  With my old two AGM 100Ah batteries, they're usually topped off by the 200W solar by 10 AM or so.  

We also have a Jackery 1000.  We use that for coffee maker and microwave when needed and Jackery can usually handle 2 to 3 days of coffee and Microwave without charging.  Having a build in inverter in the camper would be more convenient but no need to spend that money now is nicer.

[StirCrazy]

ya, I used to have two 6V 208AH batteries in the camper and was in the same boat, if it was early spring or fall (temps about -5C at night) it might take till noon as I was running the furnace 24/7 haha.  riht now I am building a new 304AH LFP to replace the 280AH LFP I put in there last year..  the 280 is going to go into the 5th wheel.  

[Tango424]

Dont forgert to check the max input amps and output amps on those batterys some of the bms's will omly allow yuo to charge at half the rated amp hours so say 100 ah might only charge at 50 and also make sure the bms will output 100AH  some wont it will state that in the specs of the batteries 

You might have 200 AH but can only use up to 100 AH but for a longer period of time

[StirCrazy]

---

@Tango424 wrote:

Dont forgert to check the max input amps and output amps on those batterys some of the bms's will omly allow yuo to charge at half the rated amp hours so say 100 ah might only charge at 50 and also make sure the bms will output 100AH  some wont it will state that in the specs of the batteries 

You might have 200 AH but can only use up to 100 AH but for a longer period of time

---

since he told us the battery he bought we don't have to speculate and put generic warnings out.. here is the charge section for his batteries

"

BMS：

100A

Max. Continuous Output Power：

1280W

Max. Continuous Charge Current：

100A

Max. Continuous Discharge Current：

100A

Max. Discharge Current 5 Seconds：

280A"  

so he said he bought two so they can handle up to 200amps of charging

and as for this statment 

"You might have 200 AH but can only use up to 100 AH but for a longer period of time"

that is totaly wrong, you can use 100% of the charge in a LifePo4 and get at minimum the rated life out of them so long term he can use 200AH 

[bigfootford]

Which Renogy Charger/Inverter...  Sounds like a good solution to the maintenance needs for Lbatts.  Jim.

[StirCrazy]

This one

I never realized how it worked untill I started downloading manuals from various ones to look at custom settings.  the factory Li will charge to say 14.6 then not charge again untill say 12.3V I want to say, but if you do a custom Li profile it lets you change thoes numbers so you could do 13.6 if you are not worried about balancing and put your bottom at 12V.  I just like the fact that it isn't constantly trying to charge so I could leave my camper pluged in over the winter and turn off the solar it will initial charge it to my top level then not send any power back to the battery till my lower limit, but I can still use 110 power if I am doing stuff in there.

[StirCrazy]

you need to find out what converter is in it first, then you will know if it has a setting for Li, if it doesnt then it is best to upgrade it.  you can get away with anormal one but you won't get a proper charge and will not be able to access your full capacity of the battery. 

renogy actualy makes a nice charger inverter combo that I am looking at. it charges to your set point then shuts charge off and won't charge again untill you hit a lower voltage that you set.  so what this means is you can let it charge to full then not worry about a float chage and the only thing that will be charging is your solar and then if that can't keep up the charge will start up again when you hit your lower limit if you are plugged in.  its kind of the anwser for people like me who leave their rv's plugged in all the time when your not using it.