Lithium Battery

Syd

I know this has been discussed a bunch of times, but I don't think I have found the specific answer I am looking for.

We have a 2019 400. It has the original dual 6 volt batteries. They will need to be replaced either this year or next (I will be testing when I dewinterize). When I change the batteries, I am looking at a lithium 12 volt (amp hours tbd). Do I need to install a new charger for that battery? If so, is it some type of add-on? Or do I have to replace the old charger completely? It is behind the breaker panel, yes??

Anything else I need to install / do when I install a lithium battery? Please describe it like I am 5. Thanks!!!

pthomas745

You can spin down the rabbit hole on this issue.  The "non lithium" charger of the WFCO will only charge a lithium battery to "about" 85 percent.  Your solar Victron solar controller, (or any decent solar controller) can charge a lithium battery to 100 percent.  Since I rarely use full hook up sites, or plug my trailer in at home, I don't see any point in changing my converter to add the "15 percent".  If I really wanted to charge my trailer on shore power without solar, I have a Noco smart charger that will do the job.

If your vehicle has actually been able to charge your stock AGM's while driving, a lithium would have the same sort of limitation: it will not charge a lithium "completely".  You can add a "DC to DC" charger to your vehicle to take care of this situation. 

So, this depends on your camping style: if you are always at full hook up sites, you really don't need a lithium.  If you always boondock, and you have a decent amount of sun, your solar setup will charge a lithium, no new converter necessary.  A DC-DC charger is probably useful for those times when the sun has not been good, and your battery is down a bit after a couple of days at a campsite.  Your vehicle will be able to charge you more efficiently while driving to your next site.

This is my own opinion, of course.  There are plenty of threads:

https://tab-rv.vanillacommunity.com/discussion/16698/switching-to-lithium-so-many-choices#latest

And a lot more:

https://www.google.com/search?q=lithium+converter+site:tab-rv.vanillacommunity.com&client=firefox-b-1-d&sxsrf=APwXEdegS788xM6-nLLVwHPQjTotczb8uw:1679699707002&ei=-i4eZKLnPPbLkPIP-4mk4AI&ved=0ahUKEwiizPWC2fX9AhX2JUQIHfsECSwQ4dUDCBA&uact=5&oq=lithium+converter+site:tab-rv.vanillacommunity.com&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQA0oECEEYAVDwCVibQmDpSGgEcAB4AIABOYgBjwuSAQIzNJgBAKABAcABAQ&sclient=gws-wiz-serp

XenanMe

I have a 2018 400 and changed to lithium 2 years ago.  I simply removed the old AGM and put in the new lithium.  Basically dropped them in and hooked them up. I didn’t need to do anything else to see the benefits.  However, as many people will most like tell you, the existing converter will only charge the batteries to approx 85%.  If you have solar this isn’t an issue (and maybe without solar it isn’t either depending if you boondock or not) since the panel will top it up the rest of the way.  I added the Victron Smart shunt so I could accurately monitor the battery charge level.

Syd

Thank you for your replies. We occasionally semi-boondock - that is sometimes we camp in a campground that does not have power hookups. I would say 30% of our trips so far have been to areas where there is no power hookup. I find that the current batteries tend to be OK for a couple of days, but seem to be struggling after 3 days, even with the solar panel being in direct sun most of the day.

If the TV can fully charge the battery with a DC-DC charger, and our DIY solar can also top it up, then I can definitely live with ~85% charge for the most part. What I really like is the idea of not having to vent any gasses for a lithium battery, which means I could put the solar connector in the vent spot as I saw in another thread.

elbolillo

Syd said:

Thank you for your replies. We occasionally semi-boondock - that is sometimes we camp in a campground that does not have power hookups. I would say 30% of our trips so far have been to areas where there is no power hookup. I find that the current batteries tend to be OK for a couple of days, but seem to be struggling after 3 days, even with the solar panel being in direct sun most of the day.

If the TV can fully charge the battery with a DC-DC charger, and our DIY solar can also top it up, then I can definitely live with ~85% charge for the most part. What I really like is the idea of not having to vent any gasses for a lithium battery, which means I could put the solar connector in the vent spot as I saw in another thread.

Unless you plan on running larger gauge wire between your TV and the Tab I don’t think you will find that the DC to DC charger will be able to efficiently charger the batteries in the Tab. 

techietab

elbolillo said:

Unless you plan on running larger gauge wire between your TV and the Tab I don’t think you will find that the DC to DC charger will be able to efficiently charger the batteries in the Tab. 

One other thing to note is that if you have a newer vehicle with a 'smart' alternator (typically found alongside the now-almost-ubiquitous auto start/stop engine idling feature), you may have to figure out ideal 'run conditions' for your alternator in addition to running large-gauge cabling to your DC-to-DC charger. My Outback, for instance, doesn't seem to push max power unless the headlights are on.

Syd

OK. So the TV will probably not charge to full, but the solar should? If so, not a problem.

And our 2016 Sorento does not have that engine destroying 'feature'. Stopping and starting the engine is extremely hard on the physical hardware. Similar to a computer, turning it off and on again significantly shortens the life of the hardware. Keeping it running 24/7/365(6) actually extends the life by possibly years. -source: me, 20+ years IT

RFraer

I think the Victron Orion-Tr 12/12-9A (110W) Isolated DC-DC converter ($68] could be wired to the 7-pin alternator wire to top off the lithium batteries when driving.

techietab

RFraer said:

I think the Victron Orion-Tr 12/12-9A (110W) Isolated DC-DC converter ($68] could be wired to the 7-pin alternator wire to top off the lithium batteries when driving.

Yep, it can be, and that's a popular choice.

The issue for most folks is that typical 7-pin wiring setups generally use puny wire gauges that are good enough to 'keep the lights on' (literally) and not a lot else, and the wiring bottlenecks power throughput. Hence most people get a 'trickle-charge' at best when on the road.

10 or 12 AWG wiring to the 7-pin harness is common in situations where you'd want at least 8 AWG wiring to keep voltage drop low enough to feed the DC-to-DC converter, and then you're facing the same problem on the trailer-side of the setup as well. Usually, the most effective way to set up a DC-to-DC converter in this situation is to bypass the 7-pin route for battery charging entirely, and install a dedicated connection running from alternator > DC to DC charger > batteries, which will involve a separate wire-whip between the tow vehicle and a connector sitting in front of the batteries. A lot of folks just don't want to deal with the hassle.

MarkAl

There's been comments on the inadequate wire size for charging high currents. That's true but it's irrelevant for the input to the DC-DC converter as the output adjusts to what it needs. In my case, I moved the 7 pin 12v from the trailer's junction box to DC-DC converter input and ran a heavy wire set to the battery directly. This then charges the battery with little loss and the rest of my system rarely pulls more than 4-6 amps worst case. I also have a networked Victron with the battery voltage / shunt condition sent to the controllers (2 solar and the DC-DC). This also effectively makes the system less dependent on the voltage drops of the wires. A bit like a 4 wire voltage sense system.

JamesC

Thought I would share my experience this week;
First outing with the 200ah Renogy battery. With no hookups and no solar, we stayed three day and two nights with the Alde running (temps in low 30’s at night, high 40’s and low 50’s during the day), fridge, lights when needed and water pump at times. We made no effort to conserve but we never were wasteful either. Started the battery at 100% and it dropped to 60% with use. We could easily have  stayed two to three more days. This is a great improvement over the original AGM’s performance even when new. With adequate sunshine and my portable solar connected our limiting factor is likely to be the tanks. 

I did change out my converter to WF8955 Lis and that is working well to get a 100% charge. $206 on Amazon and was a relatively easy task. I just took lots of pictures so I would remember where all the wires went!

KK1L

@MarkAlthe buck/boost DC-DC will make sure the voltage is what it needs to be, but that does not mean you don't need to scale the capacity of the wiring. There is power delivered to the charging battery and that comes from the alternator&battery of the TV. The power is delivered to the DC-DC converter and must flow through the wiring to it. As you correctly state the voltage is compensated for, but the wire size is not truly irrelevant. P=IV and that power is determined by the load of the charging battery and the inefficiency of the DC-DC converter. It is clear you understand the situation, so I am wondering what I am missing in your considering the TV side of the "12V" supply less relevant.

Thanks!

KK1L

@techietab I am unclear how the stock Lithium setup in the 2023 T@B400 is going to respond to the voltage from the TV when hooked to the 7 pin connector. The new single LiFe4 battery setup comes with WFCO "Auto Detect" converter/charger for shore (I did make sure mine has sensed LiFe4) and a Victron MPPT 75-115 Solar charge controller. I added a Smart Shunt to monitor the battery, and a second MPPT for external panels.

I am considering when I might need between the TV and the 400.

When I measure the open circuit voltage at the 7Pin of the T@B I see 12.0V. The battery is at 13.55V. So there is something between the two. I have asked NuCamp for a schematic or wiring diagram for the new 400, and am waiting for a response. 

techietab

KK1L said:
When I measure the open circuit voltage at the 7Pin of the T@B I see 12.0V. The battery is at 13.55V. So there is something between the two. I have asked NuCamp for a schematic or wiring diagram for the new 400, and am waiting for a response. 

Perhaps the converter stepping down and normalizing voltage? If you look at the wiring schematic for the 400 that user MuttonChops pieced together (see here: https://tab-rv.vanillacommunity.com/discussion/6406/electrical-resources#latest), the path to the battery and 7 Pin whip converges at the junction box, and has a fused connection on the converter upstream.

KK1L

I had not found that schematic...super helpful! Thanks for the link. It would be awesome to have access to the source of the PDF to make updates as the LiFE4PO are currently standard for the 400.

I have to dig in a bit and double check the measures. Stay tuned.

Horigan

I just went through a lithium upgrade and given that I have solar, I elected not to connect the TV 12V to the trailer. I did this by pulling the fuse installed under the hood when the brake controller was installed. The brake controller signal is separate and that still is in place. 

If I had relied on the alternator to help charge the lithium battery I would have installed a DC DC charger and up sized the wiring in the TV and possibly the trailer. This would prevent potential damage to the alternator when connecting the trailer with a deeply discharged lithium battery. Note that DC DC chargers activate when it senses the source battery is being charged, via higher voltage. At least my Victron on my boat does. 

There may be a reverse polarity protection diode in the trailer that would create a one volt drop between the battery and the trailer harness

KK1L

Turns out I made a mistake measuring the voltage at the plug. I was not measuring against GND, but the turn signals. That's what happens when ya go from memory (vague memory) rather than have the diagram in front of you. The voltage drop put that reading at 12.0V. Measuring correctly I see the battery voltage at the plug. So, yes, it is a direct ohmic connection without a charger or DC-DC or something else in-line.

I ordered a Victron Orion-Tr Smart 12/12-8 amp DC-DC Charger. Now just to decide where I will put it in the T@B.

techietab

KK1L said:

Turns out I made a mistake measuring the voltage at the plug. I was not measuring against GND, but the turn signals. That's what happens when ya go from memory (vague memory) rather than have the diagram in front of you. The voltage drop put that reading at 12.0V. Measuring correctly I see the battery voltage at the plug. So, yes, it is a direct ohmic connection without a charger or DC-DC or something else in-line.

I ordered a Victron Orion-Tr Smart 12/12-8 amp DC-DC Charger. Now just to decide where I will put it in the T@B.

Good to know!

I have an Orion-Tr 12/12-18amp sitting around waiting to be installed. Planning to mount it in the tongue box, where I've had a second Victron MPPT controller, Victron Smart Shunt, and Victron BlueSmart IP22 12-30Amp battery charger mounted next to my batteries without issues for about 8 months. Planning to pass through power from TV to DC-DC charger via jumper cable with 50A-rated Andersen connectors (and flush mount Andersen connector boxes on the TV and tongue box).

KK1L

I did some tracing with the endoscope and poking around this morning. The charging wire from the TV plug to the Glaso 40A fuse in the passenger rear compartment is 10ga. It would be quite easy to install the 12V-12V in that compartment right next to the fuse. Alternatively I could put it under the dinette where the wiring comes up through the floor from the junction box. I would have to splice to make this connection (no big deal), and it might give me a chance to have the Bluetooth signal be strong enough to reach the front of the TV to monitor the performance. Makes sense to get a measure of performance before doing any extra work to increase wire thickness, etc.

Comments welcome.

KK1L

 I found something which might be obvious to some, but I just discovered it. It makes accessing the solar charge controller and the wiring MUCH easier. As y'all know the drawers can be pulled out pretty easily, but so can the cubby underneath the fridge! Four screws and there is crazy good access as shown in the pics below. Wish I thought about this when I installed the solar charge controller for an auxillary panel. I installed it all through the tiny drawer opening (and I have the scars to prove it)!

elbolillo

KK1L said:

 I found something which might be obvious to some, but I just discovered it. It makes accessing the solar charge controller and the wiring MUCH easier. As y'all know the drawers can be pulled out pretty easily, but so can the cubby underneath the fridge! Four screws and there is crazy good access as shown in the pics below. Wish I thought about this when I installed the solar charge controller for an auxillary panel. I installed it all through the tiny drawer opening (and I have the scars to prove it)!

I am not a big fan of where they installed the rooftop solar charger. It really could have been installed under the bed near the batteries. That is where I installed my charger for auxiliary external panels.

RTWCTS

Interestingly, our rooftop solar’s Victron came from the factory mounted on the inside bulkhead (right next to the Alde). Also, using divergent thinking, I’ll be mounting the Victron for ground based panels on the other side of the trailer. It’ll be next to the battery switch. Currently waiting on cables to complete additional battery and SmartShunt install.

elbolillo

RTWCTS said:

Interestingly, our rooftop solar’s Victron came from the factory mounted on the inside bulkhead (right next to the Alde). Also, using divergent thinking, I’ll be mounting the Victron for ground based panels on the other side of the trailer. It’ll be next to the battery switch. Currently waiting on cables to complete additional battery and SmartShunt install.

 I mounted on this side to facilitate cables running out the bottom of the nautilus cubby without the door needing to be open.

KK1L

Mine is currently in an easy no-drill "temporary" location. I went with Anderson Power Poles as I have a bunch for my ham gear.

RTWCTS

KK1L said:

Mine is currently in an easy no-drill "temporary" location. I went with Anderson Power Poles as I have a bunch for my ham gear.

I have to admit, I missed the wiring when first looking at the picture. Great use of the existing layout!

RTWCTS

Here is a picture of the stock location of our rooftop Victron.  As I previously mentioned, It is just forward of the Alde.

KK1L

Interesting. The 30A automotive style fuse is also in a different location than in our '23 400. Ours is at the 40A Glaso breaker in the rear passenger compartment.

As a Quality Engineer I wonder how NuCamp keeps track of all the variations.

RTWCTS

KK1L said:

Interesting. The 30A automotive style fuse is also in a different location than in our '23 400. Ours is at the 40A Glaso breaker in the rear passenger compartment.

There are fuses at the PV side (that you see in the photo) and the battery side on the Glaso breaker (as you mention).

KK1L

My bad...poor memory. You are absolutely correct. There is in fact a fuse at the PV input.