Best replacement battery for T@B 320

kipwill

We have a 2018 320 CS-S with a rooftop solar array that was added after initial purchase.  Our current battery is an Interstate Group 24  with specs HD24-DP  405 CCA  505 MCA.  It measures 10-1/4" x 6-7/8”, and is rated for 64 amp hours.

The current battery is several years old, and does not hold a charge well.  We are trying to decide whether to replace it with an another lead/acid battery, or pay more and get a lithium battery.  We want to make sure we don't mess up the ability of our solar panels to recharge the battery or to power 12-volt use for LED lights and recharging cell phones.

We don't know much about electrical systems, but assume from our limited research that our T@B charging system is compatible with lithium batteries and can properly manage charging cycles.  Is that a safe assumption?

We can get a WEIZE 12V 100Ah 1280Wh LiFePO4 Lithium Battery, Group 24 Deep Cycle Battery that has good ratings and reviews.  It is now on sale for $210 (compared to $130 for another lead/acid battery like the one currently in our camper).

Can T@B users with more experience tell us if there's any reason we should not do this, or something that we should check before switching to a lithium battery?  [Or is there another make/model of lithium battery you would recommend over the Weize model described above?]

Finally, if we do buy a LiFePO4 Group 24 battery, can we simply drop it in where the old battery was, hook up the battery cables, and be good to go?

Thanks in advance to anyone who can advise us on this battery upgrade,
Will and Kristine

FishDoctor

I have one of those Weize batteries and it has worked fine for me. That looks like a good price to me -- as long as it is a trustworthy seller (I got mine through Amazon). Compared to the current lead-acid battery you have, the fully charged Lithium battery would approximately double or triple your usable capacity (80-90 AH (80-90% drain) for the lithium vs 32AH (50% drain) for your lead-acid). The stock converter on my 2018 320S (and probably your T@B as well) will not fully charge a LiFePO4 battery without an upgrade, but it will charge it to about 80% capacity -- even that would give you double the usable capacity. Depending on the specifics of your solar setup (watts of panels and the solar charger), you would probably get up to a full charge from 80% on sunnier days. So it can be a drop-in replacement if you are OK with that. Double check the battery dimensions to ensure the lithium would fit in your existing battery box. At the cost difference between the lead-acid and lithium, I would go for the lithium upgrade. In addition, the lithium will be way lighter and your back will thank you! If you don't already have one, you should also add a shunt to monitor the energy usage of your battery. The stock battery monitor in your T@B will not reliably tell you what the state of charge is for a lithium battery.

Sharon_is_SAM

How do you use your camper?  Always with electric hook ups?  If boondocking, for how long?  

If you replace with lithium and don’t change the converter, make sure to purchase a lithium compatible charger.  Lithium safe charging and discharging parameters are different from lead acid.  The Victron solar charge controller needs to be reset for lithium charging parameters and they recommend disconnecting the solar controller during storage as well.  

FishDoctor

Yes, I also should have mentioned that you should get a lithium-compatible charger to make sure you can fully charge the battery from time-to-time. That's what I do right now. I'm planning to do a solar upgrade to my trailer this spring and will probably add new in-line charger or upgrade the charger in my converter at the same time.

pthomas745

Your solar controller needs to be looked at.  If you have a Victron solar controller, you can set it up so that it completely charges your new lithium battery.

There are many examples of the Group 24 lithium batteries.  This Litime battery is well reviewed and has a bluetooth app that provides some info about the battery.

https://www.amazon.com/LiFePO4-Battery-Rechargeable-Lithium-MotorHome/dp/B0CYQ371X4?crid=1V301WHEMXEG9&dib=eyJ2IjoiMSJ9.lDaQhIH9qmIczhsbuppfdKajAIPhx4VO3xEanFU14DmanjaWnugEDfSQce5ojUQagAbukcrH__asvVTxJmDPil3kO6VoBmKjh7qNU1oQZmLk8ozEVmhTniDyv_yJ6IBBBwLgMNMvBIgxSK2-zq5vXGct2nIwVe44lFwDgfmpUt5GDARmx6RPuIUnL-_GUR_zZToXPhuNBdYFQ08QgFeKOfe3keziYH2DSRHOC1pO8o0.GUg4AIhf8ugnZbZ1iM32o501qHGVeoywymx1pwi1ppw&dib_tag=se&keywords=litime+group+24&qid=1739277138&sprefix=litime+grou,aps,150&sr=8-1&th=1

Slackers

We replaced our Interstate lead-acid with a LiFePo4 similar to your Weize candidate and have 0 regrets. You can probably drop in the Weize battery and change the Solar Charge Controller to a lithium setting (or charge voltage) and live with that.
You can [likely] go without a shunt if you limit your trailer electric usage as you did with the lead-acid battery. However, a shunt will take the mystery out of your battery state of charge and allow you to confidently power more devices and for a longer amount of time.
As mentioned by others, the internal trailer power converter won't top-off your battery, but there are alternatives for this (such as relying on your solar to do it) that don't require an expensive upgrade to WFCO power center. We use a NOCO Genius battery charger that we already owned (to maintain the battery of an idled tow vehicle). For charging the trailer's LiFePo4 it's as simple as plugging it into 120v outlet, changing the NOCO's battery setting to Lithium and connecting it to the battery terminals.

kipwill

Hello to everyone who responded to our questions - we really appreciate your input!

Administrator Sharon_is_SAM asked several good questions.  The answers are that we are hooked up to electric, or shore, power about half the time when we camp.  When we are boondocking, it's usually for no more than three days.

Fish Doctor is reassuring that we are on a good track.  We will be happy if we double our power availability and also eliminate the possibility of ruining our (lead/acid) battery by running it too low.  If our solar panels or shore power can safely charge the lithium battery above 80% of capacity, that would be an added bonus.

Several of you mentioned the charger.  We don';t have a Victron solar charge controller, the one we inherited is a CE RoHS Solar Charge Controller SR-HP2440-B.  I just got ahold of a manual for it and it does have a Lithium setting, so we will set it to Li.  (Apparently we also need to set the "over-discharge return" and "Over-discharge voltage setting," which I don't know at this point.)

A couple of you also emphasized the value of having a "shunt."  We understand that to be something that accurately measures the battery charge - is that correct?  If so, would that be accomplished by buying a Li battery with a bluetooth app that reads battery level more accurately than our stock wall-mounted battery meter (which also reads black and gray water levels)?

That brings me back to the choice of which Lithium battery.  Both the Wieze and LiTime get good reviews.  Wieze has a 10-year warrantee, compared to LiTime's 5 years, which instills confidence.  However, LiTime offers Smart Bluetooth BMS & Low-Temp Protection via an app on our iPhone, and that sounds like it will give us valuable accurate data on battery performance.

So we are now down to picking between the two batteries, making sure our solar charge controller is set correctly for a lithium battery, and making sure we know how fully the new battery is charged.  

We would welcome any further comments about those final decisions, or any thoughts about what I've described above.

Again, many thanks to each of you for sharing your experience!
-Will and Kristine

Cherokee

We simply placed two 6v AGM batteries and when we Boondock with 95w of solar in the California sun that's all we need for several days. We still have the the 3-way which we run on propane when Boondocking.

Grumpy_G

A LiFePo battery merely needs a constant 14.2-14.6V charging voltage, the internal BMS takes care of everything else, including the discharge disconnect/reconnect. If you get a battery with bluetooth monitoring you don't need a shunt, the BMS keeps track of charge/discharge state of the battery. A friend of mine has the group 24 size LiTime which I had my hands on for a couple of days and it worked fine. 

pthomas745

The "bluetooth" monitoring will not take the place of the shunt, as far as I can tell.  It will only provide voltage and charging info.  (I will need to examine this more closely today for the LiTime battery).

@kipwill a shunt sits on the negative battery post of the battery, and counts the number of "amp hours" the battery is away from the capacity of the battery.  It counts these amp hours coming in from any charging and any going out from usage of the battery. 

A shunt is preferred for lithium battery monitoring because of the way that a lithium battery voltage "discharge curve" is not the same as the discharge curve of a lead acid battery.  A lead acid battery voltage is pretty "linear" as far as the state of charge of the battery.  12.6 volts is fully charged, and 12.0 is 50 percent on a lead acid battery in practically every state of charge chart I've ever seen.

A lithium battery voltage is not "linear", and the voltage readings can be pretty misleading if you are not careful.  Voltage can be used to sort our a lithium state of charge, but the numbers get pretty "squishy" after about 50 percent state of charge.

For that reason, a shunt is preferred for lithium monitoring.  Monitoring your actual amp hours used and seeing any amp hour "deficit" from the battery's capacity is a clearer picture of your state of charge.

elbolillo

@kipwill There aren't any compelling reasons to choose any kind of lead acid batteries (AGM included) over LiFePo4 batteries.

I recommend purchasing a LiFePo4 battery(ies) with the amp hours that fits your needs.
A Victron 500 amp smartshunt is currently $96 on Amazon. Definitely worth it for battery monitoring.

AnOldUR

elbolillo said:

I recommend purchasing a LiFePo4 battery(ies) with the amp hours that fits your needs.
A Victron 500 amp smartshunt is currently $96 on Amazon. Definitely worth it for battery monitoring.

We bought the 500 amp SmartShunt a while back, but they now have a 300 amp version for a little less. It cost $71.

Just built a power station with 4X 100Ah LiFePO4's and used the 300 amp SmartShunt. Works identical to the 500 amp.

elbolillo

@AnOldUR Nice. I didn't know that they had come out with a 300amp version. That size should be good for most systems.

Cherokee

It really depends on how you use your T@B. If you typically camp with connections, any appropriate 12v battery with good cells will do:

However, if you wish to spend days boonbocking, then having a converter optimized for the battery you have and the ability to measure the amount of available power in that battery becomes far more important: 

This may explain why some people can simply replace a lead acid battery with Lithium; while others purchase new converters and a means to measure the power. I recommend only spending money on what you truly need and save your cash for trips. A few years ago, We met a couple camping in a 2018 T@B 320 in a Colorado State Park. After I answered a question about where we camped with our system, the man proudly announced that he had converted to Lithium. His wife added that they always camp with connections, and looking at her husband, she stated that their purchase was a waste of money. I changed the subject to the weather.          

Grumpy_G

pthomas745 said:

The "bluetooth" monitoring will not take the place of the shunt, as far as I can tell.  It will only provide voltage and charging info.  (I will need to examine this more closely today for the LiTime battery).

[snip] 

For that reason, a shunt is preferred for lithium monitoring.  Monitoring your actual amp hours used and seeing any amp hour "deficit" from the battery's capacity is a clearer picture of your state of charge.

Every monitoring app I've seen so far has a state of charge indicator in the form of a dial or bar graph. Some show remaining Ah as a number as well. The BMS uses an internal resistor to calculate Ah just like an external shunt.
The explanation of why a shunt is better than looking at voltage is correct but using a shunt with LiFePo batteries is only really needed if the batteries don't have BT monitoring. 

AnOldUR

For what it's worth, here's what AI has to say ....

pthomas745

I looked at the LiTime video on their "app" earlier, and it isn't clear to me if there is an actual "shunt" (like I understand the shunt).  Or: if the App is simply making assumptions based on the voltage readout?

https://www.youtube.com/watch?v=2WmQ0XXmg_A

Here is a "review" of the App.  I asked the same question in the comments, but who knows if I'll get an answer.

https://www.youtube.com/watch?v=fFyRMklaAr0

AnOldUR

@pthomas745 While waiting for a response, I asked AI again ...

Bottom line is that you shouldn't assume that the BMS uses a shunt resistor.
Ask before purchasing if it's important to you.

pthomas745

@AnOldUR Thanks...I noodled around their site a bit more, but I can't find a direct answer. 

Grumpy_G

Well "the AI" did caveat "unless integrated with a shunt". The batteries typically used in RV applications all have overcurrent protection and BT monitoring showing charge/discharge current which requires a shunt. 
A while ago I posted about LiFePo charging and as part of my tests I discharged various batteries. I used a simple Amazon capacity tester (basically a shunt with realtime data display) and the built-in BMS tracked the tester closely. 

Edit: Ok,ok, let me rephrase. 'requires current measurement'.  

AnOldUR

Tried to narrow it down to the size battery that @kipwill was asking about for replacing his. I also asked about the Weize battery, but there was no information available. The key takeaway is, "LiTime recommends using an external shunt-based battery monitor."

ReenieG

I see alot of people using the LiTime, but I have a couple of Eco-Worthy products (portable solar suitcase & battery) and I really like their products and customer service. One thing I double checked on ordering a lithium battery is that they are wrapped inside with metal. There are some that are banded with plastic only and those can warp from heat. Right now (time of posting) they have a $30 off coupon on THIS group 24 Eco-Worthy that I have. Also, the blue-tooth works great so you can see in real time what's happening to the battery.

SLJ

Tear downs for the EnjoyBot batteries with low temp protection looked great so I got them and have been using them (2x100ah) for over two years in my T@B with no problems. Built to take the bouncing around of a camper. Good price. Just bought three more for my new camper and charged them. Will be installing them in the next couple of weeks.  https://enjoybot.com/