Do you really need a new converter for LiFePO4?

[TTMartin]

I'm transitioning my trailer to 100% lithium. I added two 100ah LiFePO4 batteries dedicated to the inverter and had previously been only been charging off the solar charge controller.

Now I have purchased the 300ah Chins Smart Battery with internal heater to replace the two 6 volt flooded lead acid batteries in the front box of my Escape 19. I also purchased a lithium compatible replacement convert for the power center.

However, looking at the specs for the original PEC converter it shows a Bulk charge voltage of 14.4, which conforms to the Charging specs of my Chins battery.

So now I'm wondering if I need to change out the original convert or since the battery has an internal BMS can I just leave it in and save the $$$ for the 'lithium compatible' converter.

Specs for the original PEC converter:
Specifications:
UL® and cUL®-Listed. FCC Class B
Warranty period: 2-year warranty
Output power: 55 amps DC output
Input: 105-130 VAC, 60 Hz, 12.0 amps (950 watt)
Output:
- Nominal (Absorption Mode) 13.6 Vdc (includes charging and load)
- Boost (Bulk Mode) 14.4 Vdc
- Trickle (Float Mode) 13.2 Vdc (after 48 hrs.)

Lithium Compatible replacement converter I purchased, but, still returnable to Amazon.

WFCO WF-8955-AD-MBA Main Board Assembly for WF-8900-AD Series Power Center - 55 Amp

The only thing I am wondering will the original PEC Converter not go into bulk mode unless the battery is below a certain voltage that the LiFePO4 battery might not reach? Or does the converter enter 'Bulk' charging every time it is initially plugged in to shore power / generator? If it is the later why change it out?

[splitting_lanes]

What is the manufacture and part number of your original converter? With that, you should be able to find a manual and identify if it goes into bulk mode on connection, and how long does it stay in bulk mode.

You really just need a converter that supplies enough voltage for a long enough amount of time to fully charge the batteries, and stay there for a bit for balancing.

I think you won’t find a perfect combination for that high of capacity battery, as I have a 300ah lithium battery also. My converter does bulk mode for 4 hours upon connection to 120v. That’s not enough if my battery is drained, but I can easily restart the bulk mode by unplugging and plugging back in.

I have my solar controller set to AGM battery, as it gives a more desirable profile than lithium, when used in conjunction with the converter and DC-DC converter. So having a profile set to lithium isn’t always what you want.

Short answer to your question is: you should be fine with your existing converter, but get the specs for its bulk mode to understand how to use it correctly.

I did a couple edits.

[TTMartin]

Originally Posted by splitting_lanes

My converter does bulk mode for 4 hours upon connection to 120v. That’s not enough if my battery is drained, but I can easily restart the bulk mode by unplugging and plugging back in.
...

Short answer to your question is: you should be fine with your existing converter, but get the specs for its bulk mode to understand how to use it correctly.

Thanks for the reply.

What I think I will do is tomorrow I will take the battery out and hook the existing converter directly to it. Unfortunately, I've already pulled the converter out and disconnected the DC lines or I would just put the 300ah battery in the front box. However, the AC lines are still connected to the converter.

The Chins BMS has Bluetooth so I can monitor the charging from the existing converter. The Chins battery is at 46% state of charge per the BMS, so that should below enough to get an idea of the converter behavior.

I'll also see if I can find more specifics information online on the existing converter. Again, thanks for taking the time to reply.

I'll post my results after my test tomorrow.

[splitting_lanes]

I’ll be interested in hearing your results.

Keep in mind that you won’t see 14.4 volts (bulk mode) with a meter until the battery is charged, as it will pull the voltage down while it’s charging.

I think you’ll be happy with your battery choice. You’ll be looking for ways you can use all that capacity!

[TTMartin]

Originally Posted by splitting_lanes

I’ll be interested in hearing your results.

Keep in mind that you won’t see 14.4 volts (bulk mode) with a meter until the battery is charged, as it will pull the voltage down while it’s charging.

I think you’ll be happy with your battery choice. You’ll be looking for ways you can use all that capacity!

Here's what I found:

All WFCO power converters are automatic three-stage switching power supplies. The converter senses which mode it needs to be in by checking the RV system voltage.

The converter normally provides a constant target output voltage of 13.6 volts (nominal) to power all the branch circuits. However, it is current limited, and if the output (load) current reaches its maximum, the output voltage will drop as necessary to hold the converter’s maximum output current level (the amperage rating) without exceeding it.

If the output current reaches its maximum (normally caused by a discharged battery), this will cause the converter to go into Bulk Mode, which means the target output voltage will change to 14.4 volts and a timer will start. Although the converter is outputting 14.4 volts, you will not be able to read that on a voltmeter due to the voltage-current relationship.

From the paragraph above, as load current increases, output voltage decreases. The actual ouput voltage will not rise until the load current is reduced, which happens naturally as the battery charges or if 12-volt appliances are turned off.

Bulk Mode will be maintained until the current draw drops to approximately five Amps, or until the timer reaches four hours (whichever happens first). Then the target output voltage is changed back to 13.6 volts for Absorption Mode. Lights that are powered from the output may change brightness slightly at that time.

[splitting_lanes]

Ah, a WFCO, same as mine. If your battery is really drained, like after a capacity test, you might want to restart the four hour timer after four hours.

Since you’ll probably not be draining your battery in normal use, it will recharge the battery and do some cell balancing in normal use. Cell balancing isn’t a requirement for lithium batteries on every charge, but every now and again will help the battery maintain maximum capacity.

If you camp in the same spot with hookups for a week or more, you could unplug shore power and reconnect after a few days to (mostly) have the converter run in absorption mode. It probably doesn’t matter what you do much, but you will use some battery after it switches to float mode. 13.2 volts is below what the battery will be at if charged.

[TTMartin]

Originally Posted by splitting_lanes

If you camp in the same spot with hookups for a week or more, you could unplug shore power and reconnect after a few days to (mostly) have the converter run in absorption mode. It probably doesn’t matter what you do much, but you will use some battery after it switches to float mode. 13.2 volts is below what the battery will be at if charged.

I hadn't thought about that. It's not often I'm on shore power to begin with, but, I appreciate the heads up on that.

[fudge_brownie]

Quote: “If the output current reaches its maximum (normally caused by a discharged battery), this will cause the converter to go into Bulk Mode, which means the target output voltage will change to 14.4 volts and a timer will start. Although the converter is outputting 14.4 volts, you will not be able to read that on a voltmeter due to the voltage-current relationship.”

Unless WFCO has changed their device (unlikely) their Bulk Mode claim is incorrect. It is well established that their bulk mode does not exceed 13.7 volts. There are numerous claims that their product never goes into bulk mode. I have never read about or seen anything above 13.7 in bulk. This is the reason some lithium conversations are replacing the guts of the WFCO with an upgraded charging system (with a new set of problems). WFCO has recently released the WFCO WF-8950L2xxx as a solution, there are others.https://www.escapeforum.org/forums/f...tml#post431947

[Perry Butler]

Our previous WFCO charger decided to charge at 20.3 volts and fried our AGMs. Our replacement WFCO charger has been disconnected since then, except for when it was installed. In addition, I did replace the ETI supplied GoPower controller with a Victron 100/30.

So, for the past 1 1/2 years we've been charging only with our Solar (170 watts the first six months and 465 watts since then). Our 5.0 sits outside 24/7/365 though.

Although not lithium, our SiO2 batteries charge bulk at 14.6 and float at 13.55. We have no problem keeping our batteries full. Since you have solar, and it sounds like your Escape is outside most of the time, you might just keep your money and do your balancing with your solar.

We also don't have, or see a need for, a DC-DC unit to charge from our truck. YMMV! After all, our truck does provide a whopping 1-2 amps driving down the road.

We arrived home yesterday after a 17 day trip, most of the time in shade, and had no problems getting our batteries charged when we had sun. Like lithiums, it's nice not having to worry about sulfation, so don't have to reach full charge for a few days.

Again, I'd skip buying a WFCO lithium specific charger until you see if you really need the extra charging.

Food for thought,

Perry

[TTMartin]

Found this WFCO Training Video.

https://www.youtube.com/watch?v=gpuWClCBkCI

It specifically states that you can use the standard WFCO converter to charge lithium batteries to 80 to 90%. As Perry mentioned the solar can be used to top off and balance the batteries.

The video provides good trouble shooting information to learn or keep as a reference.

[Yakanaka]

You could also buy the converter that a forum member in Tacoma has for sale. It is lithium ready. It is under the post "WFCO Power Center WF-8955LiS".

They posted the same day as your original post

[splitting_lanes]

FYI - I get a 14.6 volt reading from my wfco 8955-ad when the battery is fully charged and the converter is in bulk mode. I have a see-level and a shunt that both give me voltage readings.

I will say that the WFCO doesn’t consistently go into bulk mode. I’m going to see if there’s any improvements to be had in the wiring between the battery and the wfco. I see a .3 volt or better difference between the voltage readings of the two devices when there is a load like the refrigerator running on dc.

[oldwave]

If you’re going down the road of a dedicated lithium converter, progressive dynamics make a line that now has two stage lithium charging modes. They are not super expensive and have excellent tech support. I also like their excellent inverter transfer switches. I’m equipping my new trailer with their equipment except for a victron solar controller and a dc to dc charger from my new truck which has a heavy duty alternator. If you don’t want to spend money, the suggestions of topping off with solar will work. Big money would to install the victron multiplus which has transfer/ charging and inverter all in one, there are also other brands that do that. A few owners have documented their systems like that.

https://www.progressivedyn.com/lithi...power-centers/

[TTMartin]

Originally Posted by Yakanaka

You could also buy the converter that a forum member in Tacoma has for sale. It is lithium ready. It is under the post "WFCO Power Center WF-8955LiS".

They posted the same day as your original post

Thanks for the heads up on that. I did spend the summer in the State of Washington, however, I'm back east now.

I just decided to keep the WF-8955AD, mainboard I purchased.

[BobG]

Originally Posted by Yakanaka

You could also buy the converter that a forum member in Tacoma has for sale. It is lithium ready. It is under the post "WFCO Power Center WF-8955LiS".

They posted the same day as your original post

I posted the WFCO WF-8955LiS in Classified. Since it hasn't sold, I wanted to edit the listing to lower the price. I wasn't able to figure out how to edit the listing. Can you tell me if this is possible?

Bob

[JohnE3]

I can confirm that at 13.6V, my 280Ah LiFePO4 battery will charge to 95% as compared to a full charge at the maximum voltage of 14.6. After building the battery, I did extensive testing to quantify the new battery and compare it to the old lead acid.

As for overvoltage, that is a bonus of the built in Battery Management System. If the charge system exceeds the maximum battery charge voltage (or current) the BMS will disconnect from the charge system.

I use the original WFCO WF-8955 (at home) and a solar charge controller set for GEL type batteries (while camping) to charge my LiFePO4 with no issues.

[SunChasers]

I just replaced my batteries to lifepo4, I have solar on my rv. I leave my converter off to let my solar charge the batteries and plan on only using it when there isn't enough sun for the bulk charging aspect. Even though it is powered off the light still blinks unless I press the the wizzard button where it will get solid for 4 hours then go back to float. So my question is even though I have the converter powered off and I'm charging with my panels is the converter still going to try to balance the batteries? I don't want it to since the built in bms is doing that.

[Vermilye]

Originally Posted by SunChasers

I just replaced my batteries to lifepo4, I have solar on my rv. I leave my converter off to let my solar charge the batteries and plan on only using it when there isn't enough sun for the bulk charging aspect. Even though it is powered off the light still blinks unless I press the the wizzard button where it will get solid for 4 hours then go back to float. So my question is even though I have the converter powered off and I'm charging with my panels is the converter still going to try to balance the batteries? I don't want it to since the built in bms is doing that.

If your converter is off, ie the breaker powering it is in the off position, it doesn't matter what the wizard LED is doing - it won't supply any power to the battery.

Once the battery reaches 14.4V or so, the battery BMS will do the cell balancing no matter what the power source. The converter does not do balancing.

One note - there is a jumper on the Progressive Dynamics circuit board that can be switched between lead acid or lithium. In the lithium position, the converter produces 14.6V continuously. The charge wizard has no effect on the charging cycles or output voltage. In the lead acid position, the charge wizard works as designed, switching between bulk, absorption & float.

Some of the latest models of the PD lithium converters switch to a 13.6V float after the battery is fully charged.

[oldwave]

Originally Posted by Vermilye

If your converter is off, ie the breaker powering it is in the off position, it doesn't matter what the wizard LED is doing - it won't supply any power to the battery.

Once the battery reaches 14.4V or so, the battery BMS will do the cell balancing no matter what the power source. The converter does not do balancing.

One note - there is a jumper on the Progressive Dynamics circuit board that can be switched between lead acid or lithium. In the lithium position, the converter produces 14.6V continuously. The charge wizard has no effect on the charging cycles or output voltage. In the lead acid position, the charge wizard works as designed, switching between bulk, absorption & float.

Some of the latest models of the PD lithium converters switch to a 13.6V float after the battery is fully charged.

With the latest two stage PD lithium charger to wizard pendant still functions to place the charger out of float to bulk or absorbtion as it’s sometimes called. I replaced mine with a victron multi plus. The victron chargers are much better suited to lithium as you can precisely match the voltage to the manufacturer recommended. For instance SOK likes 14.6 and 13.8
For charge and float. Battle born is a bit different. Victron does make standalone chargers also.