New LiFeP04 Batt upgrade charging issues

[RustyRhodes]

Hi. New here and new to Rv'ng. Recently bought a TT and replaced the two existing batteries with a LiTime Li 200 Ah and changed out the converter to a 14.4 Li capable WF-8955-MBA. It will charge the battery but VERY slowly. I have 14.4v at the disconnected batt cables but when connected it only charges at 13.4v and 8.5 amps. I'm getting these numbers from the LiTime BT app that monitors the performance. As you can see on the screenshot it is taking 16 hours to go from 29% to 100 and its probably longer. Bad Battery, bad charger, settings on the charger??? I know it is supposed to be a 40a charger. The 13.4 v may be because I've not drained it low enough to charge in the Bulk mode and docs say the Absorption mode is 13.6v but that doesn't explain the low charge rate.
Thanks for any help in trouble shooting this. Surely this isn't the normal charging times.
Rusty

[Visionquest2]

First thing I would do is check the wiring between converter and battery, including frame ground connections. Check the voltage at the converter while connected to the battery. If 14.4 (or close) then you have major wire integrity issue.


I'm not familiar with the LI Time BMS or displays. Better to use an external shunt and battery monitor to know exactly the current in/out of the battery.

[SafariBen]

Any connection that is dropping that much voltage will cause enough heat to feel it.


Check the settings also, I don't know that charger, but "lithium capable" does not mean it comes set up that way.

[Mark_K5LXP]

Don't base your entire faith on a single measurement point and a phone app. A few verification measurements with a multimeter will confirm or refute this information, and also could offer the why - bad converter, bad connection or other significant discovery.

Mark B.
Albuquerque, NM

[twinboat]

You need to meter the volts at the converter and then at the battery. To light gauge a wire will give you voltage drop and that's how to check for it. Your going to want at least 8 gauge wire between the charger and battery, both positive and negetive.

[ra_weiss]

Originally Posted by RustyRhodes

Hi. New here and new to Rv'ng. Recently bought a TT and replaced the two existing batteries with a LiTime Li 200 Ah and changed out the converter to a 14.4 Li capable WF-8955-MBA. It will charge the battery but VERY slowly. I have 14.4v at the disconnected batt cables but when connected it only charges at 13.4v and 8.5 amps. I'm getting these numbers from the LiTime BT app that monitors the performance. As you can see on the screenshot it is taking 16 hours to go from 29% to 100 and its probably longer. Bad Battery, bad charger, settings on the charger??? I know it is supposed to be a 40a charger. The 13.4 v may be because I've not drained it low enough to charge in the Bulk mode and docs say the Absorption mode is 13.6v but that doesn't explain the low charge rate.
Thanks for any help in trouble shooting this. Surely this isn't the normal charging times.
Rusty

The WF-8955-MBA is not lithium compatible. Oh, it'll work but at a lower charge level, like absorb is preset to 13.6v. The WF-8955-AD-MBA is the lithium model and auto-adjusts to what kind of battery it's attached to. For lithiums its absorb voltage set at 14.6v.

[Persistent]

Originally Posted by ra_weiss

The WF-8955-MBA is not lithium compatible. Oh, it'll work but at a lower charge level, like absorb is preset to 13.6v. The WF-8955-AD-MBA is the lithium model and auto-adjusts to what kind of battery it's attached to. For lithiums its absorb voltage set at 14.6v.

I agree. In addition, WFCO AD models don't always "Auto Detect" the lithium battery. Sometimes you have to draw the batteries down really deep to trigger the lithium setting.

I recommend a different brand that does not "Auto Detect". Get one that has a switch or menu setting to get the lithium charging profile.

[d23haynes57]

Who said that charger is lithium capable? From experience it is not even a great choice for lead acid. What is happening is that the high open circuit voltage of the lithium is faking the charger out and having it go right into float mode of 13.4 to 13.6 volts. This charger is also a power supply. At 55 amps it is also a bit large for only a 200 A/H battery. But with a better profile it should work being able to charge that battery at a 4 hour rate.

[RustyRhodes]

It said Lithium on the Amazon listing and came with a sticker on the unit that said Lithium

[Duster73]

Originally Posted by ra_weiss

The WF-8955-MBA is not lithium compatible. Oh, it'll work but at a lower charge level, like absorb is preset to 13.6v. The WF-8955-AD-MBA is the lithium model and auto-adjusts to what kind of battery it's attached to. For lithiums its absorb voltage set at 14.6v.

This was my thought also. It could be in a float mode.

[glwinger]

I don't trust most of the descriptions on Amazon. I often get a good laugh reading some of them. Some aren't eve in good English.
As far as the sticker that may have been added by the seller.
Check the actual model number on the WFCO website for the specs.

[RustyRhodes]

Originally Posted by Persistent

I agree. In addition, WFCO AD models don't always "Auto Detect" the lithium battery. Sometimes you have to draw the batteries down really deep to trigger the lithium setting.

I recommend a different brand that does not "Auto Detect". Get one that has a switch or menu setting to get the lithium charging profile.

Any recommendations on one that isn't AD? Everything I've looked at says auto detect.

[ra_weiss]

I'm not attesting to these chargers but since you already bought from this merchant you may be able to do a clean exchange. They also have available: https://www.amazon.com/Saree-WF-8955.../dp/B0CRNDC4X6

Also comes in a 55 amp model if you prefer.

[Persistent]

WFCO made an extensive line of lead acid battery converter/chargers. A few years ago, they added a limited set of converter/chargers with a switch for lithium profile.

Soon after they launched a whole new set with "auto detect". These models all have "AD" in the model number.

WF-8955-MBA is a replacement charger module. It does not have a lithium profile.
WF-8955-AD-MBA is a replacement charger module. It does have a lithium profile.

Double check the model number printed on your unit. If it has a switch or "AD" then it is lithium compatible.

The AD units check voltage and current when the 120 volt input turns "ON". A micro-processor decides whether it is connected to lithium or lead acid. These units have been reported to charge using lead acid profiles even though the battery is lithium.

The system works, but you don't always get a full charge or cell balancing. It will charge a deeply discharged lithium fast until it gets to a high state of charge. It then slows down.

The non-AD models do not provide a full charge and do not balance the cells. It will charge a deeply discharged lithium faster until it gets to a high state of charge.