WFCO WF-8950L2-MBA Lithium Charger

[sportcoupe]

I upgraded to lithium house battery (280Ah) and also upgraded the RV converter and engine BIM.

The lithium converter I selected is the drop in replacement, WFCO WF-8950L2-MBA Lithium Charger.

This is a 2-stage charger, Bulk Mode charges at 14.2v up to 50 amps and Absorption Mode charges at 13.65v at around 10 amps and under.

What I am seeing is the charger picks one of these modes to start and sticks with it till either it ends charging at 13.65 volts if it chooses Absorption Mode or it stays in Bulk Mode (high amps) till my BMS disconnects the lithium battery.

Ending at 13.6v and I am not using all 280Ah of the battery. Bulk charging at high amps till BMS disconnects isn't great either.

Anyone else convert to lithium observe this strange action using the WFCO converter charger?

[DavidEM]

I have never been a fan of WFCO chargers. Their ubiquitous 8955 acts like a single voltage charger to me, ie is not a three step charger.

I would have used a Progressive Dynamics 9180L charger.

David

[sportcoupe]

LOL, I assumed the WFCO would operate to spec and it was plug and play.

No it is not advertised as a three step charger. It is advertised as a two step charger. It acts like a single step charger and it picks the mode used out of thin air.

I may have an expensive doorstop now if I further upgrade to the PD charger.

Does the PD charger fit in the same area as the WFCO?

[sportcoupe]

I did a little searching on the PD charger here with lithium batteries. Other have posted simpler problems with the PD charger. Seems the PD charger also charges to 13.6v at time, at half the current rating of the unit. Sounds exactly like the WFCO charger.

[The_Breeze]

Originally Posted by sportcoupe

LOL, I assumed the WFCO would operate to spec and it was plug and play.

No it is not advertised as a three step charger. It is advertised as a two step charger. It acts like a single step charger and it picks the mode used out of thin air.

I may have an expensive doorstop now if I further upgrade to the PD charger.

Does the PD charger fit in the same area as the WFCO?

I believe it does. @Judge would be your best contact for that. I believe that's the charger he used for his setup. Seek him out (PM). He's seems like a nice guy and would probably help you out.

[sportcoupe]

Originally Posted by The_Breeze

I believe it does. @Judge would be your best contact for that. I believe that's the charger he used for his setup. Seek him out (PM). He's seems like a nice guy and would probably help you out.

I researched sizes of the PD verses WFCO charger. It doesn't fit without modifications. That's ok with me.

If the lithium PD charger functions like the lithium WFCO charger, I wouldn't consider that an upgrade.

Maybe Judge will provide some facts.

[Judge]

I upgraded to three BigBattery 170Ah LiFePO4's last summer and went with the Progressive Dynamics PD9160ALV because it has two charging stages. The second stage drops the voltage to 13.6 after the batteries have been fully charged. I have been pleased with its performance so far.

[sportcoupe]

Judge, last summer 2020 or this summer 2021?

The WFCO WF-8950L2 is also a two-stage lithium charger. There is 14.2v bulk and 13.6v absorption. It seems to pick one and sticks with it for the entire charge. I feel the PD operates the same way.

[Judge]

Originally Posted by sportcoupe

Judge, last summer 2020 or this summer 2021?

The WFCO WF-8950L2 is also a two-stage lithium charger. There is 14.2v bulk and 13.6v absorption. It seems to pick one and sticks with it for the entire charge. I feel the PD operates the same way.

Summer is over so last summer is 2021

I have seen my Converter charge at over 14.6V when the batteries have discharged enough and then drop down to 13.5V once they are close to being fully charged. I also have a Voctron Smart Shunt that I use to monitor the batteries.

[happy]

How do you like the Smart Shunt?

Is the bluetooth range for checking battery condition sufficent?

[sportcoupe]

13.6v isn't a full charge on lifepo4 lithium batteries. It's more like 70% SOC.

[Judge]

Originally Posted by sportcoupe

13.6v isn't a full charge on lifepo4 lithium batteries. It's more like 70% SOC.

Yes.... that is correct but you are missing the point....

Maximum charge voltage for my LIFePO4 batteries is 14.6V with 100% SOC being about 14.4V. The Converter / Charger is charging at 14.6V and when the batteries get to 100% SOC, it is dropping the voltage down to 13.6V.

You have to remember the LiFePO4's voltage does not decay like a lead acid battery and 13.6V is still 100% SOC. The Converter holding the voltage at 13.6V is keeping the batteries at full charge.

When you also factor in that many rigs have a BIM and the Converter applies voltage to keep the chassis batteries charged, it doesn't need to be and probably should not be sitting at 14.6V continually.

[Judge]

Originally Posted by happy

How do you like the Smart Shunt?

Is the bluetooth range for checking battery condition sufficent?

I am happy with the Smart Shunt. I installed mine under my Dinette seat and I can connect to it anywhere inside the coach and anywhere in the immediate outside vicinity of the coach. It might not have the range of my FireFly Bluetooth connection but close enough for me.

[happy]

Thank you, we are shunt shopping.

[Korey & Tana Jackson]

Last week I upgraded our 2018 Vegas 24.1 with a similar setup:
- two 100AH Dakota Lithium Batteries
- WFCO WF-8950L2- MBA
- Precision Circuits Li BIM225
- Victron Energy 500A Smart Shunt

We're leaving tomorrow to try the system out in Shenandoah National Park.

That MBA replacement was pretty straightforward.

The WFCO converter output is advertised as follows (and I have verified this per my observations with a multimeter and consistent with the smart shunt readings:

Absorption Mode:

This mode is designed with 1 purpose in mind. This purpose is to provide a safe operating voltage for all loads in the RV. This is accomplished by reducing (from bulk mode) the output voltage to 13.6VDC and remaining at this voltage until the power is cycled to the converter.

The absorption mode stage is the default or normal mode of operation, which has no timer associated with it. In this mode an output of 13.6 VDC is provided to the DC circuits in the RV. This voltage has a long term history as the acceptable voltage for all loads in the RV, and should not place undue stress (nor reduce the longevity) of the lights and appliances in the RV. This is not to say that all loads will have an issue with a constant higher voltage; however, some loads may have an issue. Please refer to the individual manufacturer’s specifications for acceptable operating voltage range of the connected load.

Bulk Mode:

This mode is designed with 2 purposes in mind. First, to quickly restore the energy back into the battery. Second, to ensure the lithium cells inside the battery remain balanced. This is accomplished by boosting the output voltage to 14.6VDC and allowing the maximum current to flow as required by the loads.

The bulk mode stage could last anywhere from 1 to 4 hours based on the battery and load current which is being used. For a full battery, the bulk stage has a minimum time requirement of 1 hour, which allows the lithium cells inside the battery the time required to “balance”. For an empty battery, the bulk stage has a maximum time requirement of 4 hours. If your application requires longer than 4 hours (such as a larger battery bank > 200 Ahr), a simple cycling of power will reset the timers.

As the energy is restored into the battery, the DC system voltage will climb and the current from the converter will decrease. If the total amperage draw from the converter reaches a preset point (within the 1-4 hour timer), the converter is designed to drop out of bulk mode.

Source: https://wfcoelectronics.com/wp-conte...REP-Manual.pdf

[sportcoupe]

You mearly quoted the manual.

The problem I see with the WFCO lithium converter is that it picks a mode and never changes until you unplug from shore power.

Example, the battery may be at 13.5v and the WFCO initializes in bulk mode pushing 45 amps and hardly dropping in amps as the voltage rises. The result is my BMS disconnects the WFCO.

Why doesn't it switch from bulk to absorption?

Then on a different day when plugging in to shore power, the battery may be at 13.2v and the WFCO starts off in absorption and it takes forever to charge.

[Korey & Tana Jackson]

So far, testing in our driveway, after plugging into shore power or starting the generator, our WFCO converter does start out in either bulk mode or in absorption mode, depending on the SOC of the lithium batteries.

With the batteries at full SOC, and plugging into shore power, the initiated in absorption mode, with the shunt reporting ~13.6VDC.

I then disconnected from shore power for a couple hours, running a television and the refrigerator (converted to a residential compressor type) off the inverter.
After a couple hours, with the batteries down about ~30 to 40AH (as reported by the Victron shunt), I plugged into shore power. The converter initiated in bulk mode (~14.6VDC), and was initially pushing a little under 40 amps into the batteries; over time the amperage reduced.
After about one hour, the voltage dropped to ~13.6VDC...the converter dropped to absorption mode.

So far, I have not experienced the BMS disconnecting when charging in bulk mode.

I'll observe over the next few days of boondocking to see if we have a similar experience.

[Judge]

Originally Posted by Korey & Tana Jackson

So far, testing in our driveway, after plugging into shore power or starting the generator, our WFCO converter does start out in either bulk mode or in absorption mode, depending on the SOC of the lithium batteries.

With the batteries at full SOC, and plugging into shore power, the initiated in absorption mode, with the shunt reporting ~13.6VDC.

I then disconnected from shore power for a couple hours, running a television and the refrigerator (converted to a residential compressor type) off the inverter.
After a couple hours, with the batteries down about ~30 to 40AH (as reported by the Victron shunt), I plugged into shore power. The converter initiated in bulk mode (~14.6VDC), and was initially pushing a little under 40 amps into the batteries; over time the amperage reduced.
After about one hour, the voltage dropped to ~13.6VDC...the converter dropped to absorption mode.

So far, I have not experienced the BMS disconnecting when charging in bulk mode.

I'll observe over the next few days of boondocking to see if we have a similar experience.

My Progressive Dynamics Converter works the same way as well. I have also not seen the built-in BMS of my Big Battery LiFePO4's disconnect either.

[sportcoupe]

Unless your BMS has a Bluetooth app, and it is setup to report exceedances, you will never know if the BMS disconnected, or the converter shut off.

A BMS typically does not limit charge current at all, it merely monitors and disconnects for any exceedance such as pack over voltage, cell overvoltage, all under voltages, temp, ect.... I can set the parameters to obtain best life of battery or max capacity.

I have a DIY 280Ah lithium pack with an Overkill Solar BMS. I also run an active balancer. No way I am paying preassembled lithium battery prices. My 280Ah cells set me back $499. The BMS was $127.


I would be interested to know if your WFCO enters bulk mode and switches to absorption near the end of charge. You'll know because bulk can be as high as 48 amps charging and tapers off to around 17 amps near the top of charge where my BMS just disconnects due to overvoltage limit exceeded.

Absorption mode would taper down to a trickle, say 2 or 3 amps and 13.6v.

[Judge]

Originally Posted by sportcoupe

Unless your BMS has a Bluetooth app, and it is setup to report exceedances, you will never know if the BMS disconnected, or the converter shut off.

While true, I would disagree to some extend...

If the BMS disconnects the battery, you would see a change in House Battery voltage readings (on my FireFly or Victron apps) as the Converter goes from providing a charging mode voltage to supplying voltage just for for the house demand.

Same with the Converter shutting down completely. You would be able to tell from the House Battery voltage readings based on load from the coach 12V appliances.

If you think you have a Converter issue, then you don't have much choice but to try another of the same model or switch gears completely to something like a PD converter. The other option is to pull the Converter and send it back to WFCO for testing.

I do have a couple questions for you.....

What gauge wire is run from your converter to the batteries and how long is that cable run?

I have seen Thor do a very poor job of using the right gauge wiring for the length of the run and the demand. If there is more than a couple feet distance between your Converter and the House Batteries and the wiring is insufficent, it will wreak havoc on the Converters ability to charge properly because of the voltage drop occuring.