Converting Wfco 8735p to 48-00-3194 Converter - 35 amp with lithium switch

JP2558 · July 23

I got a quote from Nucamp to convert/replace my existing Wfco 8735p to a 48-00-3194 Converter - 35 amp with lithium switch (that’s the description on the quote).

The quote also includes installing a 48-00-3108 solar/inverters - solar port - female connector (also the description on the quote).

My lead acid marine battery is close to six years old, so I’d like to go the lithium route. Other than a lithium battery, what else do I need to take into consideration?

Am I correct in assuming shore power will fully (and ‘quickly’) charge a lithium battery?

And if I were to purchase a 100w solar panel, would I need other accessories?

In the past I’ve heard of charge controllers, smart shunts, etc but I don’t know how those relate here.

Comments appreciated. Thanks!

MuttonChops · July 23

JP2558 said:
. . . 48-00-3194 Converter - 35 amp with lithium switch (that’s the description on the quote).
. . . 48-00-3108 solar/inverters - solar port - female connector (also the description on the quote).

Suggest you ask nüCamp to clarify what their Part Number items include in detail.
Expect the change-over is pricey so you should have all the details.

For example on 3194 Convertor. Are they changing out the WFCO Power Center if so to what model or are they only changing the Convertor Board and again to which WFCO type. Also, ask them to clarify if "lithium switch" means an auto-select or a physical switch. If auto-select request nüCamp to install the WFCO Jumper that holds/forces an auto-detect convertor board into Lithium only mode.

For 3108 consider asking for full parts list and a wiring diagram. Could be the "3108" part number includes the extra items a typical installation would have.

pthomas745 · July 24

It is a bit confusing what you are getting quoted: a new converter for the trailer? A "new" WFCO?

And, you are installing one of the basic SAE "solar ports"? And maybe a new Victron solar controller?

An "inverter" is a device that would allow you to run electrical items (like small coffee pots, etc) from the battery. Is this what you have planned to do?

All the names for things can get confusing, so if we could straighten those details on what you are wanting to install, that would be good.

Do you have solar panels mounted on your trailer? If not, and you are installing the port a Victron solar controller to support a new set of portable panels, that would be a good upgrade.

Many owners have completely skipped the changing of the non lithium WFCO units in their trailers, and use their properly configured solar controllers to charge the lithium battery. There are many very simple lithium battery chargers that can attach permanently to the battery and allow them to be simply plugged into an electrical outlet to charge your lithium when needed.

Something like this:

https://www.amazon.com/Anderson-Connector-Indicator-Rechargeable-Batteries/dp/B0DR8CM38K

drackus · July 24

A few things to consider…
1. You only need to upgrade the power converter, not the whole power center.

2. A 35 amp power converter will take about 3 hours to charge a 100 amp hour lithium battery and about 9 hours to charge a 300 amp hour battery.

3. What size lithium battery do you need? Depends on how many days of dry camping you plan. We have a 300 ah battery and it is good for 3 to 4 days to power fridge, water pump and lights, without any charging. Remember, you will get more useable power from lithium than from lead acid batteries.

4. You probably don’t need an inverter. A basic solar converter is relatively inexpensive. You need to pair your solar controller with the power output of your solar panels. We have 200 watt portable solar panels and find that these are sufficient to replenish our battery from daily use, given a good sunny day. Remember, your solar panels will only approach peak capacity when in direct sun. If you have a shady campsite, performance will be much lower.

ReenieG · July 24

@drackus the WFCO 8735P is one complete unit that cannot be taken apart. It's hardwired together unlike other WFCO larger amperage models. I had to replace the whole unit when I upgraded mine from WFCO 8735P to WFCO 8735AD (auto detect) I'd imagine that if @JP2558 is switching out his unit, he would have to switch out the entire power center because: 1. you cannot replace only the converter in the WFCO 8735P and 2. different manufacturers are in all likelihood not compatible components.

@JP2558 Do you have a brand name for the new converter number? It doesn't look like any WFCO component numbers and I've seen posts on forums whereby people are swapping out their WFCO AD with a Progressive unit. Also, I wonder if they are simply going to leave your WFCO 8735P in place and add that new part no to replace the converter only or remove the whole WFCO and replace it with another brand that contains a switch.

drackus · July 24

Fair point @ReenieG! Didn’t realize that WFCO part was a single unit.

JP2558 · July 24

First, thanks for the input(s)! Second, I should qualify that I know very little about solar so excuse my lack of knowledge going forward.

I should probably start by stating what my goal is: to find a cost effective, efficient method for utilizing a lithium battery in our 2018 Tab 320-CS that has a power center that does not support lithium batteries.

@pthomas745 last paragraph states: "Many owners have completely skipped the changing of the non lithium WFCO units in their trailers, and use their properly configured solar controllers to charge the lithium battery. There are many very simple lithium battery chargers that can attach permanently to the battery and allow them to be simply plugged into an electrical outlet to charge your lithium when needed."

This sounds like the solution I would like to pursue.

So lets say I have installed the Lithium battery with my existing power center and we are off-grid.

1) Would this power every device just like my lead acid battery? i suspect it would.

2) Would the tow vehicle with a 7-pin connection provide any charge while in tow? I suspect it would be very little (and slow) due to the power center not supporting lithium.

3) Would using a lithium charger such as the one suggested by @pthomas745 require the battery switch to be in the on position when be charged? (My current battery does require the switch to be in the on position but I assume that is because the 30 amp cord runs through the existing power center to get to the battery.) I suspect it would not since the power is connected directly to the lithium battery.

I think this solution would be a good starting point as it will introduce me to the lithium world and once I am comfortable with a lithium shore power solution, then we could move forward with an off-grid solar solution.

Does that make sense?

ReenieG · July 24

@drackus yes, I discovered that it was a single unit, but... I'm now wondering (edited my comment above to JP) if maybe nuCamp is planning on leaving the WFCO unit in place, disconnecting the converter only and adding another component with a switch. I'm curious now.

FWIW, I recently rewired my WFCO 8735AD to isolate my converter on its own circuit breaker, labeled as branch #1 so that I could switch it off and use an inverter without hardwiring it into the control panel.

Image: https://us.v-cdn.net/5021717/uploads/editor/vo/57uga9y0clf2.jpg

pthomas745 · July 24

@JP2558 These things get very confusing, and you are not alone. Inverter...controller..converter..WFCO...SAE...etc. Hard to keep straight!

1. Your lithium battery will work just like your current lead acid battery works. Plug and play.

2. Tow vehicle charging is a whole 'nother subject. Most vehicles, it seems, do not do a good job with charging any sort of battery. A lithium battery is even harder to charge, due to the higher voltage needed. Edit: there are devices that can be installed on your tow vehicle to the trailer that will do a good job of charging the battery while driving. Called DC-DC chargers.

3. With the charger I linked connected directly to the battery, the position of the battery switch would not matter. The charging current would simply go right into the battery. When you use the 30 amp cord connected to the trailer for charging, turning off the battery switch completely isolates the WFCO from the battery. No charging can take place in that case through the WFCO.

The entire discussion about the non-lithium WFCO seems to revolve around confusion about whether a non-lithium charger works for a lithium battery. The non-lithium WFCO, like the one in my 2017, can charge a lithium battery. BUT.....only to about 85 percent. Somehow, this gets twisted to mean "the WFCO cannot charge a lithium battery so I need to spend several hundred dollars to replace it". As others have noted, there are many ways to add a simple charger to the trailer that would handle battery charging with shore power. I have a couple of small lithium chargers at home that I can just use battery clamps to charge the battery. In most cases, however...my solar panels do about 99 percent of my battery charging.

JP2558 · July 24

@pthomas745 Thanks for answering my questions. Regarding tow vehicle charging, I already learned not to expect much. I like to leave home 100% fully charged.

I should also qualify our off grid requirements: Basic stuff such as water pump, inside lights, Alde for hot water (the alde is usually on propane unless we have shore power, then we might use both), but we do camp sometimes in colder weather so the circulation pump for heating will have a draw as well. We weren’t thinking of the fridge but another comment above raises that possibility. Most of our adventures are often only three nights and once or twice a year we might go for four or five nights. I would most likely go with a quality 200 amp only because I want to buy it once and hopefully it will last ten years, which is pretty much our remaining camping timeline. I doubt I would try running the AC on lithium. We don’t have a microwave nor does my wife need a hair dryer so we really don’t use ‘home’ appliances. We rarely use the telly or the Jensen, but both already have kill switches installed.

Three last questions (for now):

1) Were I to install a lithium battery and purchase a charger, how would I monitor the battery’s status? Would the existing lead acid battery monitor button (the one currently in our tab) work or would there be another method for monitoring the lithium battery such as an app installed on my phone?

2) And if we were plugged into shore power using the 30 amp power cord, is it possible to also use a solar panel connected directly to the battery simultaneously? My thought is to do so, I would need to turn the battery switch off, and let shore power run the tab, and let a solar panel just charge the battery? And if I forgot to turn off the battery switch would there be any consequences is having two charge sources (solar and shore power)? Or is the battery smart enough to detect and adapt to that situation?

3) Are the chargers waterproof or does the battery need to moved indoors to use the charger?

drackus · July 24

Regarding your last few questions:
1. There are several ways to possibly monitor your battery: buy a lithium battery with a built in monitor and bluetooth connectivity to connect to an app on your phone; install a shunt that measures battery voltage and usage; use a multimeter to check the voltage. The nuCamp installed monitor is only good for lead acid batteries.

2. I wouldn’t use both simultaneously. Chargers adapt their voltage or current based on the battery state of charge and having two connected and active at the same time will likely confuse them and not lead to optimal charging.

3. You can certainly find waterproof chargers that can be mounted outside.

bjn2 · July 24

JP2558 said:

So lets say I have installed the Lithium battery with my existing power center and we are off-grid.

1) Would this power every device just like my lead acid battery? i suspect it would.

2) Would the tow vehicle with a 7-pin connection provide any charge while in tow? I suspect it would be very little (and slow) due to the power center not supporting lithium.

3) Would using a lithium charger such as the one suggested by @pthomas745 require the battery switch to be in the on position when be charged? (My current battery does require the switch to be in the on position but I assume that is because the 30 amp cord runs through the existing power center to get to the battery.) I suspect it would not since the power is connected directly to the lithium battery.

I think this solution would be a good starting point as it will introduce me to the lithium world and once I am comfortable with a lithium shore power solution, then we could move forward with an off-grid solar solution.

Does that make sense?

1) Indeed your lithium battery would power all your DC circuits. You do not need to replace the WFCO converter to do that. A lithium battery can be a simple swap out from your lead acid battery using the existing wiring.

2) The 7-pin connector and its wiring deliver too low a voltage and current to charge a lithium battery. They won't even charge a lead acid battery. That has nothing to do with the power center's capabilities. You can install a DC-DC converter with separate wiring that can charge your trailer's battery while towing. I went with a Bluetti Charger 1, which wires with heavy gauge wire to the TV's battery. It has flexible output control, so I can use it to both charge my portable power stations and to charge my trailer's battery via a solar port I installed. My trailer has rooftop solar, but I wanted the ability to use portable solar panels. That lets us park in the shade and potentially use solar suitcases to harvest the sun nearby. Having the DC-DC capability means that we can use the tow vehicle to charge when it's cloudy.

3)I use a Victron Energy Blue Smart IP65 Smart Car Battery Charger,12V,15A to fully charge our 100AH lithium battery. We have a WFCO "autodetect" converter but it doesn't detect lithium batteries easily or retain that status. To have it work reliably, I'd have to remove the converter and send it back to WFCO for modification. You can get a quick disconnect connector with an inline fuse to quickly connect the Victron charger to your battery. That means you can use the charger for other vehicles when you're not using it to top off the lithium battery in your trailer. You plug the charger into an AC outlet while on shore power.

The simplest way to go lithium in your case is to replace your existing battery and use a separate smart charger. You'd immediately at least double your battery capacity with lithium of the same AH rating. From there, you could look at adding solar capability and/or DC-DC. I'd also recommend eventually getting a Smart Shunt that would give you a way to accurately monitor your battery's capacity and state of charge.

bjn2 · July 24

JP2558 said:

1) Were I to install a lithium battery and purchase a charger, how would I monitor the battery’s status? Would the existing lead acid battery monitor button (the one currently in our tab) work or would there be another method for monitoring the lithium battery such as an app installed on my phone?

2) And if we were plugged into shore power using the 30 amp power cord, is it possible to also use a solar panel connected directly to the battery simultaneously? My thought is to do so, I would need to turn the battery switch off, and let shore power run the tab, and let a solar panel just charge the battery? And if I forgot to turn off the battery switch would there be any consequences is having two charge sources (solar and shore power)? Or is the battery smart enough to detect and adapt to that situation?

3) Are the chargers waterproof or does the battery need to moved indoors to use the charger?

1) Some lithium batteries have charge indicators and/or Bluetooth capability that will let you checck state of charge. A smart shunt (I use Victron's Bluetooth unit) monitors incoming and outgoing current and an app lets you see graphs data.

2) You can charge your battery via a controlled solar source when the trailer is on shore power. You can have multiple sources of charge. Your converter won't provide high enough voltage to contribute past the 80% charge level. I have two solar charge sources, the WFCO converter, and the Victron charger and I can use them all simultaneously. It doesn't matter whether the power switch is on or off.

3) Many chargers are waterproof (the Victron I'm using is). Before I moved our battering inside the trailer for better cold weather performance, I would run the cord for the charger out the front window of the trailer - connected to the battery in the tub.

Marceline · July 24

Hi @JP2558
I have a 2013 CS-S and I installed a lithium battery way back in 2020 because I only camp with shore power a few times a year and I wanted to be able to run the 2way fridge.

I never changed the original WFCO converter. It only matters if you use shore power to charge your battery. I don't have power where I store my trailer. I mostly charge my battery from solar. So the converter is not important to me. Here's what I installed in my T@B - all up front in the tub.

1. 90aH LiFePO₄ battery (this was back in 2020 - if I were doing it now I'd go bigger)

2. Victron SmartShunt to monitor battery
3. Victron SmartSolar (solar controller) to provide power from solar panel to battery
4. SAE port on tub sidewall to plug in 160w portable solar panel
This arrangement has worked pretty well for me. I do run a little low on power during the winter when days are shorter, but I can usually make up for this by completely turning off fridge at night due to low ambient temperatures. Ambient temperatures over 95deg can also be a challenge as the compressor in the 2way fridge runs nearly continuously.

My advice would be that it's not worth the money to swap out the converter unless you generally charge your battery from shore power. And even if that's the case, an external charger is a cheaper solution.

JP2558 · July 25

@MuttonChops, @pthomas745, @drackus, @ReenieG, @bjn2, @Marceline
Thank you everyone for all your input. I really learned a lot in the last 24 hours.

Two other factors have come to my attention: We have the original fiberglass/plastic tub and the existing battery box is a for group 24 batteries. After eyeballing it this morning I'm not certain I can fit a group 27 box in there (to accommodate a larger battery. I was looking at the Renogy 12v 200Ah mini sized battery.) Also since it is is not a metal tub I don't think I can mount anything in that area without drilling into the diamond plate (which I am hesitant to do.) My only other thought is to relocate the battery to the interior but since my wife just made the bed, which we keep in place year round, I don't want to explore that option just yet.

Time to do more homework!

AnOldUR · July 25

JP2558 said:

My only other thought is to relocate the battery to the interior ...

Consider swapping out your plastic tub with a truck box. Ours came from Tractor Supply. Plenty of room for propane, two 100Ah LiFePO4's and other miscellaneous things.

Image: https://us.v-cdn.net/5021717/uploads/editor/kb/ywno7s1iyn35.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/7g/qdhz83ny6go1.jpg

ReenieG · July 25

@JP2558 I'm in the process of updating my plastic tub with a really nice center tub from Sea Biscuit Metal Designs. You can install it with or without a platform. I have a platform but with the plastic tub. You can order a platform from them or get the hardware to anchor the box without it. An added bonus for me is that I will be able to keep my sewer hose modification intact behind this tub. I had to cut the plastic tub in order to make it work. (pic below)

I ordered a battery box for my 2 100ah lithium batteries with blue tooth. I love these batteries. They are the same size as group 24. Here's the battery box I ordered. They fit perfectly in the new tub, which is not installed yet, but I've attached a pic (top pic) of the arrangement I'm considering. I'm also adding a simple inverter install which I posted about in this discussion, Easy Inverter Installation Setup. The video shows a similar example to what I'm doing. The blue tooth works like a shunt so you can see exactly what the charge is going in and out. I'll be installing this box and inverter when I get back from my camping trip this coming week.

Image: https://us.v-cdn.net/5021717/uploads/editor/og/u4uvu7qao6eb.jpg

MuttonChops · July 25

JP2558 said:
. . . not certain I can fit a group 27 box in there (to accommodate a larger battery.

Lots of folks have converted the nuCamp Group-24 in older plastic front tub to a Group-27. The most common approach is to place an ~1-inch filler board in the Group-24 frame base then mount a Group-27 frame or box or frame and box on top of the original. Being sure the filler board is screwed to the trailer.

One example:

Forum Thread for above

Marceline · July 25

JP2558 said:

@MuttonChops, @pthomas745, @drackus, @ReenieG, @bjn2, @Marceline
Thank you everyone for all your input. I really learned a lot in the last 24 hours.

Two other factors have come to my attention: We have the original fiberglass/plastic tub and the existing battery box is a for group 24 batteries. After eyeballing it this morning I'm not certain I can fit a group 27 box in there (to accommodate a larger battery. I was looking at the Renogy 12v 200Ah mini sized battery.) Also since it is is not a metal tub I don't think I can mount anything in that area without drilling into the diamond plate (which I am hesitant to do.) My only other thought is to relocate the battery to the interior but since my wife just made the bed, which we keep in place year round, I don't want to explore that option just yet.

Time to do more homework!

Something to consider: lithium batteries don’t need to be put in a vented battery box as they don’t off gas. Any enclosure will do. My group 24-size battery is in a plastic file folder box along with the SmartShunt.

Howdy, Stranger!

Quick Links

Categories

Converting Wfco 8735p to 48-00-3194 Converter - 35 amp with lithium switch

Comments