Life of Tab 400 battery?

tbatakis · November 2025

How long does a Tab 400 battery live and how do you know if it is dead? Mine does not charge up anymore but could that be a problem with the charging system it is it likely the battery?
thanks

pthomas745 · November 2025

Welcome to the Forums!

Before we can answer this, or any question, we need to know what year your trailer is.

For the 400, there are many different battery setups: one giant 225 ah deep cycle lead acid. Two dual 6V lead acid batteries. Lithium battery setups started a couple of years ago, and there are many combos of batteries and inverters, etc.

If: you have a trailer that is about 5 years old or so, and it still has one of the "AGM" or "lead acid" batteries, even if they have been perfectly taken care of, they may be reaching the end of their service life.

"Not charging up any more" or hot holding a charge is a perfect example of a battery that may not be well taken care of, or just reaching the "end of life" that all lead acid batteries reach.

So, tell us what year the trailer is, and which battery you have. Tell us if you are using a multimeter or the Victron app to help get a status of the battery. And, get down there in the battery compartment and see what you have in there. A picture would be great.

There are many good upgrades for the original AGM's if that is what you have.

tbatakis · November 2025

Thanks! My rig is a 2021. We’ve kept it plugged it all the time except a few camping trips w/o hookups. I’ll get into the battery compartment next and see what type they are.

Can lead acid be replaced with lithium directly?

pthomas745 · November 2025

Great! A 2021 would have the "dual 6V 225 amp hour" lead acid batteries, if they have not be changed out since 2021.

A lithium battery can be a straight replacement. We would have to check the version of your WFCO converter. Earlier "non-lithium" converters could charge a lithium, but "only" to about 85 percent. Newer versions from around your model year might have had a WFCO with a "switch" that told the charger to use lithium charging profiles. Later WFCO's had "auto detect" chargers that were supposed to detect lithium batteries.

So, have a look inside your WFCO and check the model number. It will be something like "8735" and a designation of LiS for the switch model, or AD for the auto detect. (A 2021 "might" have the LiS version).

Even with a "non-lithium" converter, owners have used the solar charging to properly charge the battery, or a stand alone lithium charger to do the job when on shore power.

There is a ton of info about that when you start to look more closely at this.

tbatakis · November 2025

Thank you! I’ll be getting into it next week. Really appreciate your input!

pthomas745 · November 2025

Here is a picture of the label inside your converter. This one has the "AD" designation, which is the "auto detect" model. The other version is the LiS, or lithium switch model. Your 2021 may not have either designation, which would mean it is a "non-lithium" sort of converter. The "non-lithium" would still charge the lithium battery, but only about 85 percent.

Image: https://us.v-cdn.net/5021717/uploads/editor/73/ujo5hbrvw4yf.jpg

jdzioba · November 2025

I also have a 21 400 Boondock. Planning on upgrading to Lithium next year. Where is this converter located?

qhumberd · November 2025

@jdzioba your panel is always near the floor but can be near bed, or dinette area. The panel opens by a push to reveal the breakers and fuses.

In our 2019 it is under the closet, as we have the small fridge.

Okpete · January 12

I have a 2025 tab 400. 620 watts solar. 1BB 100 amp battery. Battery heater switch. 1200 watt power inverter. My question is, if I install 230 amp li-time litium, do I need to defeat battery heater connections ? Did not find litime with battery heater function. Could tape over switch in cubby and isolate connections by taping to avoid shorting anything. Thanks.

pthomas745 · January 13

The Battleborn heater is built right into the battery. The cable coming from the battery is simply wired to the switch to turn them on. So, your idea of simply disabling the switch or terminating the wire would work just fine.

Okpete · January 13

Thanks for help

TomCanada · January 16

As pthomas said above, you may be able to just use your old converter. I have an older converter in my 2021 Tab 400, and when the AGMs died, I replaced with lithium. While I can only charge to ~85%, since I have solar, the solar can 'top up' the battery all the way to 100% from there, so I never felt the need to go upgrade the converter.

westernstates · February 11

I have been doing a test of my battery to see if it needs replacing. I have a 2021 400 with the original single AGM battery. The test involved using the Tab as if we were camping without any solar gain and the battery went from 100% to 75% in 24 hours. That seems ok though I don’t really remember what it was like last summer and we did have some solar gain. Any thought? Thanks

pthomas745 · February 11

What were you running in the trailer? What device gave you this "75 percent" information? Lead acid batteries voltage readouts can be quite variable depending on several factors.

I'm not certain when the single AGM was discontinued and NuCamp installed the dual 6v batteries, but, if that is the original 225 amp hour battery, almost 6 years old, it sounds a bit like it is still working well. But, without specifics on how the measurements were taken, it will be hard to tell.

A 225 amp hour lead acid battery may have (generally) 135 amp hours of usable amp hours. So, 25 percent of those amp hours for 24 hours would be "about" 27 amp hours. The basic "parasitic" drain of the trailer will account for "maybe" 6 amp hours of that total. Depending on what was being used in the trailer, or if there was any solar input during the day, etc....that 25 percent of usage sounds reasonable.

So, tell us what you are measuring the battery with. What did you run during your 24 hours?

And: good for you for testing!

westernstates · February 11

Thanks pthomas745 for reaching out. I use a 'QWORK Battery Monitor Voltmeter Ammeter’ I bought on Amazon to read the battery percentage, voltage and current. My test was without shore power, only 10wh solar gain per the Victron solar app. I was running the 12v refrigerator, Alde heater and 2-3 lights only in the morning and evening just like we do when we camp and ran the water pump enough to mimic our average daily use. No tele or radio or charging by USB. No inverter use.

pthomas745 · February 11

I have one of those little monitors on my "spare" battery. Was your read out taken with the battery switch on or off?

And, from what you were using, I would say that "about" 25 percent of your amp hours sounds reasonable.

westernstates · February 11

The battery switch was on. We were camping last fall on a 7 day trip, stayed in one place the whole time, parked under a lot of shade. By day two I needed to boost my battery with a 2000W Honda generator we have to take the battery back to 80% or so from somewhere around low 60%/high 50%. It took about 2 hours a day to complete this recharge. I was thinking I would replace my present battery with a LiTime 12V 230Ah Plus Deep Cycle LiFePO4 and would hopefully not need to do this daily. I also like to make things last and at present the battery seems to be working better than I expected for a 5 year old battery.

pthomas745 · February 11

I know the "Qwork" device is a shunt, but things can get weird trying to measure voltage of a lead acid battery when the battery switch is on or any charging is coming in. Are you getting good measurments of the numbers of amp hours used? That would be a better piece of information. You can turn off the battery switch and turn off the solar controller for a few minutes while you have a look at the battery voltage with the battery "rested".

Instead of the generator, you might also consider portable solar. Trying to get good solar input from the panels on the trailer roof can be hit or miss, but a portable panel out there in good sun may be all you need to recharge.

And, yes, the LiTime upgrade would take your "usable" number of amp hours from that "135 amp hour" number to over 200 amp hours. It is a great and simple upgrade.

westernstates · February 11

The ‘Qwork’ device seems to be giving me good data but I will also look at the switch off, solar off and resting state to compare. It appears to be giving me a reading of the amps being used at any moment. I know some recommend the Victron shunt as it is considered the gold standard for battery monitoring. Maybe I should invest in one? Does it work with LiFePO4? The portable panels have been on my watch list but my experience has been that we either have excellent recharge from our rooftop panels when in the sun or there is no sun due to westher or too much shade so portables would not add much.

pthomas745 · February 11

Sounds like you have watched your battery closely. I have a Victron shunt, and I do like it, but the "qwork" like you have should give you a decent readout of amp hours used, if it is set up properly.

Have a good look at the battery voltage with the battery "rested" and see what you get back. No matter what, with the various monitoring devices and paying attention, you are doing all the right things here.

westernstates · February 11

Yesterday evening before I turned off the battery switch I checked the voltage on the ‘Qwork’ device and it showed 12.38v and 75.5% and this morning with the battery in rested mode it was the same. I don’t know if the ‘Qwork’ device records amp hours used, it seems to just show amps left in battery, just like the voltage percentage.

westernstates · February 12

westernstates said:

I have been doing a test of my battery to see if it needs replacing. I have a 2021 400 with the original single AGM battery. The test involved using the Tab as if we were camping without any solar gain and the battery went from 100% to 75% in 24 hours. That seems ok though I don’t really remember what it was like last summer and we did have some solar gain. Any thought? Thanks

Correction, I just removed the bed to access the battery and discovered that I actually do have 2-6V AGM batteries. Just wanted to circle back to that so as to not mislead anyone.

pthomas745 · February 12

Not an issue, these things always get a bit confusing. The good news is you got down in there and had a look. In either setup, it is still a 225 amp hour capacity.

AnOldUR · February 13

.... and the other good news is that you have plenty of room to replace the AGM's with two LiFePO4's.

westernstates · February 13

AnOldUR said:

.... and the other good news is that you have plenty of room to replace the AGM's with two LiFePO4’s.

Two? I am looking at one. A LiTime 12V 230Ah Plus Deep Cycle LiFePO4 Battery with Low-Temp Protection single battery.
Do you have any other suggestions? Thanks

AnOldUR · February 13

@westernstates
It's up to you and your wallet, but prices today (if you stay away from Battle Born) are pretty good. We now have two 300Ah LiFePO4's in the same space that once had two 125Ah AGM's. It depends on how you camp. We very seldom have shore power, so it's nice to know we can go a long time when solar conditions are bad.

edit to ask, WS100?

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