New WFCO power converter for Lithium

Gerald98053

WFCO very recently announced additions to their product line including a drop-in replacement for the T@G power converter. The WFCO-8725Lis gives full support to lithium ion batteries. It seems to be nearly identical to our 8725-P in the T@G.

The only trouble is that no one stocks this item yet (3/1/2021). When this becomes available, I will upgrade to Lithium. If anyone finds it in stock somewhere, please let me know.

JamesDow

Per WFCO, the item is on backorder until May. They do not have info on pricing.

F.Y.I. the existing unit WFCO-8725 will work fine with the limitation that it will only charge a lithium batery to 80-84% capacity. I intend to top mine off with solar.

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Gerald98053

What size battery will you use? I figure I need 500 - 600 WHr but with only 80% usage available and something to spare I think 100 Amp-Hours is needed. With the newer charger I might get by on a 50AH battery.

JamesDow

Here is my recent post with information. 100Ah Renogy.

Go larger than 50 if you can afford.

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https://teardrop-trailers.vanillacommunity.com/discussion/1278/changing-to-lithium-battery-with-standard-2018-t-g-non-boondock#latest

Otis_60

I'm planning on building my own LifePo4 battery. I have the cells on order, but nothing else yet. I ordered 280ah cells. I'm still collecting info on other items I need such as BMS, shunt, balancer, and a few other things. This info about the inverter is another piece of the puzzle that I have been looking for. Thanks.
Another concern I have heard about is about a lithium battery taking a charge from the tow vehicles alternator, in that it may damage the alternator. If anyone has any info on that. Damn. Should I put this in a separate post?

JamesDow

In general, a lithium battery can accept/require move power (14.6-14.6 Volts) than a lead acid wet cell battery (13.7-13.9 +Volts). Lithium batteries also have lower charge resistance than a wet cell. This results in the alternator delivering more current. The current is disproportionately allocated more to the lithium battery. This results in the alternator working harder which results in increased heat. Heat increases the output resistance, resulting in the alternator having to work even harder to produce the same output. A fully loaded alternator produces a lot of heat. Heat can damage electronic components as well as decrease bearing life.
The heat issue is compounded at lower RPM's/speeds where less air movement exists. (Long idle periods, stop and go traffic, long uphill climbs where the engine is working especially hard)
My tow vehicle (TV) is a 4 cylinder Rav4 with a stock alternator. My plan is to make sure my tow vehicle battery is healthy and to limit/avoid situations which may result in increased alternator heat.
I plan to disconnect my trailer from the TV when at idle for extended periods while connected to the trailer. I also intend to turn off my Renogy lithium battery (placing in shelf mode) when the battery is near full charge and traveling long distances or when expecting to be in extended rush hour traffic, running uphill for extended periods (especially at high altitude).
Another thought to help avoid issues may be a DC to DC charger. I am not intending to go this route as of yet. I have not investigated changes I would need to make verses the benefits.
Since I do not have a battery isolator, I now (since trailer lithium battery) will make sure that I disconnect my TV when at a campsite.
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Misterbee

I have a 2018 T@G xl, and thinking about upgrading to LiON next year. Can someone tell me where the power converter is located?

LuckyJ

@Misterbee said:
I have a 2018 T@G xl, and thinking about upgrading to LiON next year. Can someone tell me where the power converter is located?

Part of or just behind the fuse panel, kind of attached to it.

Otis_60

@JamesDow Very good info. I'm old and have CRS, so I think I will be disconnecting the ability to charge from the tow vehicle since "I will" burn up my alternator by forgetting to disconnect it at certain times. I will use AC and solar to charge, but still leave the ability to connect to the TV in a quasi emergency.

Gerald98053

WFCO just emailed me to say that the WFCO-8725 will not be made in an LiS version. To get full Lithium support, the next model up will be WFCO-8735-LiS. It will be shipping in 45 to 90 days. (~late April to June).

MrGGBrown

@Gerald98053 said:
WFCO just emailed me to say that the WFCO-8725 will not be made in an LiS version. To get full Lithium support, the next model up will be WFCO-8735-LiS. It will be shipping in 45 to 90 days. (~late April to June).

Before finding the posts on this forum, I discovered the WF-8725LiS on the WFCO website and exchanged emails with them confirming it's a direct replacement. They told me it should be in stock in the "next month or so". It's showing on their website.https://wfcoelectronics.com/product/wf-8725lis/

I also talked with support at Lion Energy. They reviewed the specs and said it would work great with their LiFePO battery.

JamesDow

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.

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MrGGBrown

The question I have is whether there's any long-term impact on a very expensive battery in not regularly bringing it to a full charge. We too have the Renogy 100W solar suitcase, and that's how I plan to get our new Lion Energy battery fully charged, but when we're on extended road trips, only TV charging would likely have the time to achieve 100%, via the built-in converter. Just like you, real world usage will tell us what's needed.

JamesDow

Here is a YouTube link from a contributor that I respect, that indicates that running a lithium battery in a range is better for long term battery life. Either way I will be typically keeping the State of Charge at less than 100% except when boondocking. That is when I would need it most. I would also think the TV may bring it close to 100% on longer highway drives.

When at home parked, I will likely put the battery in storage mode. (Press of a button on the Renogy Smart Lithium Battery Monitor Screen)

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https://www.youtube.com/watch?v=Yf9N9zBgyB8

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MrGGBrown

Thanks, that was pretty helpful. It sounds like keeping the standard lead-acid battery controller, which doesn't fully charge the battery, could extend the battery life. The only thing I wonder is what applies to Li-Ion vs LiFePo batteries, as much of his data/charts were for Li-Ion.

Gingerfam

I just spoke to the manufacturer. WF-8725LiS is no longer manufactured. If you want to change out your control center to handle LiPo4 battery, you want to use the WF-8725-AD. Wiring is the same. It will auto detect if your battery is lead acid or LiPo4. Easy replacement.

MrGGBrown

Thanks for the update. It seems to me the WF-8725LiS was never actually manufactured. They put out an announcement, but I don't think it was ever available. They developed the autodetect capability instead of having a switch for lithium vs lead-acid.

JamesDow

 
@Gingerfam - Good information to know. Thanks!
Apparently WFCO quickly passed their switchable converter and moved to an auto detect converter. Good for them. (I really respect WFCO and support staff)
I noted that Amazon has the WFCO WF-8725-AD (25 Amp / 3,000 Watts) for $165.87
They also show the 35 Amp (4,200 Watts) model (WF-8735-AD) for $193.19.
With a 2018 T@G, I see no need for anything above 25 Amps.
A short story about the function of my original converter (WFCO WF-8725) and my Renogy 100Ah smart lithium battery. Recently (10/2/22) came home (54% state of charge (SOC) in my battery) from an off-grid camping trip to Senator Wash. Unbeknownst to me, my wife disconnected my garage smart switch, so the trailer ran another 24 hours on battery with refrigerator on (33°). Finding my battery now at 37.5%, I corrected the smart switch in my garage and within the next 30 hours the battery (with refrigerator running) rose up to 97% SOC.
The key with my original converter and charging lithium is having another draw during the process, which cycles the converter through its various three stage charging modes. Bulk mode at 14.4 volts charges up a lithium battery just fine.
Before investing in an upgrade to an WFCO auto detect converter, I would suggest checking to see if the original converter will meet your lithium battery needs.

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