Replacing AGM with lithium in 2021 tab320 BD

immanence

I am interested in the new SOK 280ah battery to replace the two AGM I currently have, which aren't holding a charge so well. I have two questions here:

Is it a simple swap with the 2021 tab320 BD? I read that shore power will have trouble  charging to 100% but solar can top it off. Will that be true in my case?

Second, I am reading that people are relocating lithium batteries inside. Is there a reason for this other than storage/weight distribution? Does anything else need to be relocated if you do this?

Thank you all!

gulfarea

I put the SOK 203 ah marine battery in as I liked the fiber water tight case much better. Art

pthomas745

Yes, they can just drop in....if...there is appropriate space for the battery in your tongue box.  Sounds like you have a big set of batteries up there already.

You need to look at the WFCO in your trailer and see if it is "lithium compatible".  (Seems like it isn't.) The stock non-lithium converters in the trailer are capable of charging your battery up to about 85 percent.  It is that last 15 percent that is the entire issue.  Many owners skip any thoughts of the converter, configure the Victron solar controller (or whatever controller they have) for lithium charging and go on their way.  If you are always on shore power enough to be concerned about lithium charging...you don't need a lithium battery.

The 400's, which have dual 6V batteries and a converter, have always had "inside" batteries.  The newer 320's with the "lithium package" that includes a Victron Inverter/Charger have the batteries inside.  Owners of 320's with appropriate wiring skills have done it...but it isn't exactly easy.  Wires would have to be run from the junction box just behind the tub to the area next to the converter, and NuCamp does not make much room to do that easily, although it has been done.

There are....really....dozens of posts about this, so don't take my word for it!  There is lots of good discussion on whether to replace the converter, or not, and if you do, change to what...etc.

https://www.google.com/search?q=2021+converter+site:tab-rv.vanillacommunity.com&client=firefox-b-1-d&sca_esv=580377342&sxsrf=AM9HkKlRot7KD5uNN3cjvFOXj8EgYYYu0w:1699418477453&ei=bRFLZe6fG5b3kPIP1JmWyAw&ved=0ahUKEwiuirGVy7OCAxWWO0QIHdSMBckQ4dUDCA8&uact=5&oq=2021+converter+site:tab-rv.vanillacommunity.com&gs_lp=Egxnd3Mtd2l6LXNlcnAiLzIwMjEgY29udmVydGVyIHNpdGU6dGFiLXJ2LnZhbmlsbGFjb21tdW5pdHkuY29tSN06UNIJWKM0cAF4AJABAJgBOKAB8AmqAQIzMLgBA8gBAPgBAeIDBBgBIEGIBgE&sclient=gws-wiz-serp

This search is about moving the batteries inside.  https://www.google.com/search?q=move+lithium+battery+inside+site:tab-rv.vanillacommunity.com&client=firefox-b-1-d&sca_esv=580377342&sxsrf=AM9HkKnHCBFkDwU95jZ2n-EXidP5w-nvzQ:1699419171132&ei=IxRLZdzbB4qKur8Pw72o2Ac&ved=0ahUKEwic-ZPgzbOCAxUKhe4BHcMeCnsQ4dUDCA8&uact=5&oq=move+lithium+battery+inside+site:tab-rv.vanillacommunity.com&gs_lp=Egxnd3Mtd2l6LXNlcnAiPG1vdmUgbGl0aGl1bSBiYXR0ZXJ5IGluc2lkZSBzaXRlOnRhYi1ydi52YW5pbGxhY29tbXVuaXR5LmNvbUitV1CoCVjTT3ABeACQAQCYATSgAb0NqgECNDG4AQPIAQD4AQHiAwQYASBBiAYB&sclient=gws-wiz-serp

immanence

@pthomas745 thanks - yeah, I am not very interested in rewiring at the moment, particularly if there aren't big advantages of doing so. And as you say, my tub is already pretty full with the batteries that are in there now, so I have plenty of space if I replace them.

Where is the the WFCO located? I will check that. But from the other threads I have read I am guessing I have the one that charges to 85%. This doesn't sound like a problem for my use case though.

I think I might go with this less featured battery. Still well-reviewed by Will Prowse and half the price. I don't need all the Bluetooth bells and whistles of the other, but I'd be missing out on the heating pad: https://www.litime.com/products/litime-12v-230ah-plus-lifepo4-battery-built-in-200a-bms-max-2944wh-energy

That said I am not in a cold climate anyway.

pthomas745

Sorry, the "WFCO" is the company that makes the converter.  I could have just said: converter!

Many owners have the LiTime batteries in this group.  I bought one when they were still "AmpereTime".  Lots of Will Prowse fans here, obviously.  A couple of years ago, I was in the "I really don't need a lithium camp", but after a few Will Prowse videos.....I bought a lithium.  After I realized what all the fuss was about with charging and low temperature protection and all the rest, I realized that the workarounds for all these issues were pretty simple.  (Lots of good threads in this group helped, too).  I just picked up another 50 amp hour lithium for 140 dollars on Prime Day.   A great deal on a battery that could easily run a Tab with a propane fridge, for example. 

Find the Will Prowse video on battery heaters.  His take is they are not really needed, for various reasons.  An interesting discussion.

immanence

@pthomas745 ah thanks, good tip! I will look that video up.

Also after perusing the threads you linked about moving the batteries inside, that helped a lot. It does not seem like something I am particularly interested in as theft seems like the most compelling reason, but I don't ever really leave my trailer where this would be an issue. Of course, who knows, but it seems like there are easier antitheft measures.

immanence

Here is the video @pthomas745 mentioned if anyone is finding this thread later: https://youtu.be/EaiwxDUY9ho?si=hUw9avjtOai2Vvs6

I definitely don't need the pad right now. I am not camping anywhere where temps are freezing throughout the day, so it seems like the cheaper battery would be fine for me. And I could insulare if it were an issue, but I doubt it will be.

Thanks for the good questions to follow up on @pthomas745

Yoshi_TAB

Hi, 

I have a '21 320 and moved my batteries inside for the sole reason of increasing storage in the front tub.  I had two lead acid batteries inside the front tub which took up a lot of space and opening that space for items has been a big  storage advantage for me.  I placed two lithium batteries inside next to the Air 8 as that space had very limited access and  use for me.   We go on multi month trips and  the change in space allocation (more space in the front tub) has been big for me.  

If you put them inside (either by the Air 8 or side compartment), it's only a minor wire change on the inside  and the installation of a new ON/OFF battery switch to hook them up without the need to cut any holes in the TAB.  If your interested, I'm happy to send you a wire diagram of how to do it.

Because of the lightness in lithium batteries, IMO, the weight issue   is not a factor.  I just can't see how 40 lbs or so (with proper tongue weight)  makes a difference  of where they placed inside or out.

My experience with the my WFCO lead acid battery charger is it will charge the two lithium batteries past 85% and all the way to 100%, but extremly  slow.  I'm in the process of installing a victron lithium charger to help with that.

We do travel/camp in the cold  shoulder seasons.  I have not considered any type of heater because the battery BMS (if equipped) prevents any cold weather charging from solar.  I also will turn off the solar charging via the app. as an extra safe guard when in cold weather.   If camping/traveling in cold weather and on shore power, the batteries are now inside, warm and can be charged.

WayneW

It’s interesting how folks approach things differently. We have a ‘21 320 BD and chose to keep the AmpereTime battery in the front tub solely because we didn’t want to give up the inside storage!   Our tow vehicle is an F-150 so that affected that decision. 

I did not change the converter but did purchase a Victron smart charger that I use at home if I want to top things off before a trip, but the solar typically does a good job of that anyway. I did install a dc-dc charger in the tub and use that occasionally due to the unreliable solar energy and dense canopy cover here in the rainy/cloudy northwest.

We also travel/camp a lot in the shoulder seasons and I use a Victron Battery Sense to disable the solar charger if the battery gets below freezing. However, even with a low nighttime temp of 20, the battery never got below 37. 

immanence

@Yoshi_TAB I'd love to see your diagram. I don't mind a bit of wiring, I pulled all of the trim out of my tow vehicle to wire the 7pin, but I don't want to do a lot of wire fishing. I suppose it depends on how intrusive it is. I read threads about cutting to vent to the outside, but that should only be necessary for AGM batteries right?

Also do you turn off solar charging with the standard victron app?

@WayneW is the Victron Battery Sense to automate that process? I will have to look that up because I am unfamiliar with it.

WayneW

@immanence Yes, it is to automate it. The Battery Sense sensor is mounted on the battery (or wherever you want) and networked w the Victron solar controller. You can set the Battery Sense to disable the controller at whatever temp (in C) you want. I have mine to disable at 1 deg C. 

immanence

@WayneW awesome, thanks for the tip! Looks fairly cheap for peace of mind!

Yoshi_TAB

Hi, I’m not home til later today.  I’ll send the diagram then.  The changes are not intrusive at all.  I’ll describe it better when I send the drawing but it’s really just involves cutting the 10 AWG battery wire from behind the WFCO that  goes from the inside to the outside and to the front tub.  The one cut end (behind the WFCO) that comes from the WFCO would go to a new ON/Off switch and then to the battery.  The new neg. can be tied into the neg. bus bar by the WFCO.  There is no wire fishing as no matter where you put your batteries, everything is easily accessible via the inside.  

  

You still have to get power to the electric e brakes.   also did a slight modification to put power to the e brakes independent of battery switch so in the unlikely event the battery switch is off, the e brakes always have power. If it’s still fuzzy, it will be clear when I send the diagram.

immanence

@Yoshi_TAB awesome, I appreciate it! Good note about the e brakes too. I assume that is because they are wired from the tub?

Yoshi_TAB

Hi @immanence

Here is a method to bring batteries inside and wire them without cutting any holes in your TAB.  The top shows how the battery is wired if it's in the front tub and below shows how to wire if you bring it inside. 

You would cut the #6 wire behind the WFCO.  This is the same wire that exits from inside , goes outside through a penetration to the trailer junction box and  to the battery in the tub.

You would take the cut wire from the WFCO side and wire  (10 AWG) it to a new switch.  I placed a new  switch to the rightof the WFCO panel.  But you can put it any where.  From the switch , you go to the a new positive bus bar.  The bus bar has connections to the new battery inside and to the other cut end of the #6 wire that goes outside to the junction box.  This way , the junction box always has power , where the emergency brakes are also wired to and thus always are powered independant of a ON/OFF switch.   There may be a reason to remove power from the e-brakes, maybe for maintenance, but you could just remove the wire from the bus bar.  You could skip the busbar and wire the brake directly to the battery, but it's always a good practice to minimize connectionsto a battery.  

I'm not sure it's necessary, but I also put a fuse (not shown) between the busbar and the wire going out to the junction box.  I also put a very small  (pencil point size) LED light  downstream of the fuse, so I can see if the fuse should blow, the light would be out.  The light shows me, at  a quick glance.  that the e-brakes have power.

Hope this helps.   

immanence

@Yoshi_TAB My battery comes today, but I got the Li Time 230AH battery, so I'm going to have to see if I can fit it under the seat.

Rather than a bus bar, would it be possible to use a terminal block in this application? Something like this? https://www.mcmaster.com/products/terminal-blocks/terminal-blocks-11/

And do you need to put a ground in the interior?

rickpool

@Yoshi_TAB - pardon my interruption here, but hoping you can advise on the proper gauge wiring for two LiTime 100ah Mini’s that I am also wanting to install under my seat.  I am thinking 2/0 marine grade tinned copper… but is this complete overkill?

elbolillo

rickpool said:

@Yoshi_TAB - pardon my interruption here, but hoping you can advise on the proper gauge wiring for two LiTime 100ah Mini’s that I am also wanting to install under my seat.  I am thinking 2/0 marine grade tinned copper… but is this complete overkill?

I would definitely go with 2/0 awg. That is what I used in my 2x 100ah batteries in my previous '21 Tab 320. I also used that gauge for my 4x 100ah batteries in my current '23 Tab 400. It is a bit of a beast to work with, but especially for all the battery interconnects I think it is worth it.

Yoshi_TAB

Hi @rickpool,

The two things to consider when sizing wire is how much current it will carry and the distance run (both ways).  Do you (or plan to) have an inverter?  If so, that will impact the size?  If you do not have an inverter, you can go with smaller AWG wire.  If you do not have an inverter, your TAB max. current capacity is probably only 30 amps and you can size your wire for that current.  If you have an inverter, the first thing to do is size your fuse based on the wattage of your inverter, then size your wire based on the fuse size and distance run.

So, while bigger never hurts, it may not be necessary.

Here's a link to help.  

Circuit Wizard - Blue Sea Systems

Keep asking and good luck with your project...

Yoshi_TAB

Hi @immanence,

I'm not an expert in this but busbars and terminal blocks serve different purposes.  Terminal blocks are used to connect an incoming and outgoing wire while bus bars are used to connect wires to distribute wires to different circuits.  So which to use depends what you want to do with your wiring..if that makes sense.

Not sure what you mean by ground in the interior?  If you mean when moving your batteries inside , I wired the negative leg to the negative bus bar behind the WFCO.  

AnOldUR

Yoshi_TAB said:

If you have an inverter, the first thing to do is size your fuse based on the wattage of your inverter, then size your wire based on the fuse size and distance run.

@Yoshi_TAB is correct, but I took a different approach that I''m hoping doesn't leave my T@B in a pile of ashes. For my 2000W inverter, I used 2 AWG (not 2/0) copper wire that has a 125 service ampacity rating. I know this is small for the potential 166 amps that the inverter could draw. To compensate for the smaller wire I'm using a 125 amp fuse. It's not a good excuse, but after looking at different wire sizes, the 2 AWG was the biggest wire I was willing to work with for the run from the tub to the inverter.

SLJ

In my 2021 320S I did not replace the WFCO converter. I let it supply DC when on shore power and just switch my two 100AH lithiums off. The lithiums get charged with a Victron smart charger connected to shore power. When I disconnect from shore power I just switch the batteries back on. The Victron charger is cheaper and more reliable for charging lithiums than the installing a newer WFCO auto sensing converter. Don't really have a use for an inverter as only the AC runs off 120V and we spend most of our time here in the Northeast outside anyway and don't use it.

AnOldUR

@SLJ I've seen the picture that you posted above before. It's a very profession looking install and I never questioned it, but today noticed something that's confusing to me. When researching before installing my two LiFePO4's I found that I should wire the positive connections to one battery and the negative to the other. Here's a link to an explanation. Your installation isn't the same as connecting both positive and negative to one battery and then jumping that to the second, but draws from the center of the jumpers. Does the length of the wires going from the bus to the batteries being equal compensate for the voltage drop mentioned in the link? What is the reason that you didn't run a jumper from one battery to the other rather than going to the bus bar from each battery?

I also read something about the flow of electrons being a reason for connecting to opposite batteries, but can't find an explanation that I can understand. Maybe someone can clarify if that's a consideration?

elbolillo

@AnOldUR The following diagram from Victron might shed some light on the different ways to wire a battery bank.

Yoshi_TAB

Hi @elbolillo,

Is there another page to that diagram that describes why you would select one way over another?  If they are all "correct" there must be a reason one would choose one way over another?  i.e cost of components?  what you have on hand ?  or just how you feel that day

elbolillo

@Yoshi_TAB  Attached is the pdf that was taken from. I didn't see much in the way of explanation. I would have loved to have done the busbar route shown in the first example. However, it certainly would have made the installation more complex, and there isn't that much room in my '23 Tab 400. I just copied the install (Like the last image), more or less as Nucamp, and had it checked by Battleborn's tech staff.

AnOldUR

@Yoshi_TAB here's a link to the Victron webpage. Unless it goes from best to worst, there's no rating of methods that I can find anywhere on the page. The only comment is on the last method saying that there could be a slight difference in individual battery currents. Strange because most of the wiring diagrams I found use that method.

SLJ

AnOldUR said:

@SLJ I've seen the picture that you posted above before. It's a very profession looking install and I never questioned it, but today noticed something that's confusing to me. When researching before installing my two LiFePO4's I found that I should wire the positive connections to one battery and the negative to the other. Here's a link to an explanation. Your installation isn't the same as connecting both positive and negative to one battery and then jumping that to the second, but draws from the center of the jumpers. Does the length of the wires going from the bus to the batteries being equal compensate for the voltage drop mentioned in the link? What is the reason that you didn't run a jumper from one battery to the other rather than going to the bus bar from each battery?

I also read something about the flow of electrons being a reason for connecting to opposite batteries, but can't find an explanation that I can understand. Maybe someone can clarify if that's a consideration?

It's only two batteries, not a bank of them. The runs are so short and large enough gauge of wire between them it won't make any difference electrically. Wiring this way allows a switch/breaker on each battery for pulling an individual battery for maintenance or shutting one off if needed.

immanence

@Yoshi_TAB I checked to see if the new battery would fit under the seats, and I think I am going to put it in the storage across from the WFCO. Here:



I have seen that other people like to put it next to the AC unit, but there is plenty of space here and I'll even have some storage left over. I'll just have to run a couple of wires around to the WFCO/ground, but that looks easy, as there is pre-existing space to run wires through for the most part.

I think I'm going to order my parts from McMaster Carr. Am I leaving anything out? Going to list parts and prices, in case anyone comes back to this thread in the future wanting to do something similar.

Distribution Bar ($27): https://www.mcmaster.com/catalog/129/855/9290T12
Mini Rocker Switch ($5): https://www.mcmaster.com/catalog/129/1085/7395K28
LED ($5): https://www.mcmaster.com/products/led-lights/panel-lights-with-quick-disconnect-terminals-7/
Fuse block ($5): https://www.mcmaster.com/products/fuse-blocks/
10 ft black 6gauge battery wire ($23): https://www.mcmaster.com/products/wire/electrical-wire~/american-wire-gauge-awg~6/
10 ft red 6gauge battery wire ($23): https://www.mcmaster.com/products/wire/electrical-wire~/american-wire-gauge-awg~6/

Questions I'm left with:

I believe the wiring in there now is 6 gauge. Is that sufficient for this application? I see people suggesting 2/0 in this thread, but it looks like that is for putting batteries in parallel. Happy to increase the gauge if necessary though.

What size fuse did you put in there? I put in a fuse block that holds a 30amp auto fuse, given that the tab accepts a 30amp connection.

immanence

Oh, and I see your comment said 10 gauge. Maybe I can save a few bucks on the wiring there then.

Yoshi_TAB

Hi  @immanence.

2/0 AWG is not necessary for what you are doing.  Folks are using that size wire when installing an inverter.  10 AWG is fine for a 30 amp circuit if you are moving a single  battery inside,  If your wire length is  a bit longer you can use bigger wire such as the 6 AWG.  You are tying it into 10 AWG of the WFCO.  

Curious on a few things.

-What is is the mini rocker switch for? 

Will it act as a battery switch?  If so, make sure you get one that meets the amp rating (30 A ) of your circuit.  A little bigger again never hurts.  

-What is the LED for? 

Not shown in the bottom of the diagram I posted are two things.  One is a very small  LED light that I surface mounted in the board between the air conditioning outlet and the lagun table leg mount;  the second is  a 30 amp fuse.  These are spliced into the wire that goes  between the positive bus bar out to the trailer junction box.  The purpose of the light is for at a glance  I can see that I have power going out to the trailer junction box and the fuse serves to protect that circuit and allows me to remove power  to the trailer emergency DC brakes if they inadvertently activate or for maintenance.  

-What type of fuse block are you getting?  Again, make sure you get one rated for 12V/30 amps.

Other things you may need are wire butt conectors and crimper.

Are you making a drawing?  Always good to have one and leave in a plastic sleeve nearby to remember your wiring changes or for others to trouble  shoot.  I also marked my wires with numbers and names to help with trouble shooting.  Use small labels around the wires.

The pdf posted by @elbolillo is a great resource to look at.