Battery monitor panel 400

AMac

In the 400, there are the following notations on the battery monitor panel located just inside the trailer door: 4 lights = "C", 3 lights = "G", 2 lights = "F", and 1 light = "L". Dealer says fully charged AGM battery is 13.4 volts and to never let it get below 11 volts. Has anyone correlated the monitor panel lights to specific battery voltages? [edited to change references to volts]

RollingBnB

That would be volts not amps.

AMac

RollingBnB said:

That would be volts not amps.

Thanks - using dealer's words. Would still like to know correlation of monitor panel indciator light to battery state of charge.

Sharon_is_SAM

AMac, do you mean you want to know how many amps the lights draw?

AMac

SAM said:

AMac, do you mean you want to know how many amps the lights draw?

No, I want to know what the lights mean - in the simplest terms, is it okay for the state of charge of the AGM battery to get down to one light ("L") before charging it?  

Sharon_is_SAM

Does the 400 battery monitor display voltage, amps or percent of charge?  Do you have a See Level monitor also with battery charge?

AMac

SAM said:

Does the 400 battery monitor display voltage, amps or percent of charge?  Do you have a See Level monitor also with battery charge?

We don't know @SAM - that's why the question above - monitor is 4 lights, labeled "C", "G", "F" and "L" from highest (4 lights) to lowest (1 light).  No explanation that I could find in the manuals provided with the tab regarding what the lights mean, and dealer could not tell me.  Not sure what purpose the monitor panel serves as it relates to the battery if we can't find out what it indicates.

Michigan_Mike

AMac said:

No explanation that I could find in the manuals provided with the tab regarding what the lights mean, and dealer could not tell me.  Not sure what purpose the monitor panel serves as it relates to the battery if we can't find out what it indicates.

I wouldn't place a lot of value on a light system personally.  If it were me, I would purchase a 12 V LED cigarette style plug in meter to at least provide a ballpark read on where the battery voltage is at.  If your trailer is equipped for solar you could also download a smartphone app that will give you actual real time voltage data.  In the interim, you can buy the LED meter noted above at Walmart or a local automotive store.  

AMac

Michigan_Mike

From the looks of the photo you just press on the respective button designated for Gray - Black - Fresh Water tanks and the display to the left will let you know whether it is 25% - 50% - 75% or 100% full or empty.  The same would apply for the battery, but without actually knowing the voltage output that will be a guess.  that's why I recommend a simple 12V LED meter or consider having a more sophisticated set-up like the Trimetric voltage monitoring system.   We do have members who use the Trimetric set-up.  

AMac

Michigan_Mike said:

From the looks of the photo you just press on the respective button designated for Gray - Black - Fresh Water tanks and the display to the left will let you know whether it is 25% - 50% - 75% or 100% full or empty.  The same would apply for the battery, but without actually knowing the voltage output that will be a guess.  that's why I recommend a simple 12V LED meter or consider having a more sophisticated set-up like the Trimetric voltage monitoring system.   We do have members who use the Trimetric set-up.  

Yep! Was just hoping somebody might already know what voltage the readouts correlated to. If we end up figuring it out using your tips on measuring voltage from the cigarette type outlet we'll post it here!

skwhee

Here's what we learned from nüCamp:
C - Charged
G - Good
F - Fair
L - Low

So far we do not know how any of that relates to voltage or depth of discharge. 

in a 400 with the solar package the solar controller monitors the voltage and is bluetooth capable. Although it is located under the bed the smartphone app is easy to use. For more information on that here's a link to a relevant forum discussion:
http://tabforum.nucamprv.com/#/discussion/comment/78113

If your unit did not come with the solar package, Michigan Mike's suggestion of a voltmeter that plugs into the 12V (round) receptacle to the left of the kitchen window is the simplest solution.

Hope this helps. If we learn more, we'll certainly share. 

Happy Trails!
Steve & Karen 

MuttonChops

As others have noted your best approach is to use a true voltage meter. That could be the '12v lighter' outlet and a multimeter solution like the INNOVA 3721 Battery and Charging System Monitor or a fancy 'dash mounted' display panel. Both types have manufacturers providing products over a wide purchase price range.

As for the TAB Panel Battery Light vs Battery Voltage.

Disclaimer: The following is speculation on my part. I have no direct knowledge of the TAB installed monitor panel.

TAB Panel operates like and appears to be similar to a standard KIB Electronics Monitor Panel. Perhaps it is a TAB branded variation of the KIB M21VW Micro Monitor System found at RV & Marine supply stores.

Some years ago I installed a KIB M21VW on my boat and obtained the installation & troubleshooting manual. Standard Battery Voltage levels across a number of Micro Monitor models are in the manual and are as follows:

Note: To measure the voltage the Micro Monitor compares a reference voltage to the battery voltage. The circuit to generate the reference voltage (per the manual) is stable between 9 and 35 volts. A battery voltage below 9V will cause the reference voltage to be unstable. Would think that 'low light' could be anything below 9V.

The table suggests you need to recharge when the 'Fair light' turns on. Waiting for the 'Low light' will place the battery well below recommended discharge levels.

rbrtm

Is there a voltage to % chart for the 400's dual 6v agms combo?

Sharon_is_SAM

I am not sure if anyone has corollated the voltage measurement to percent state of charge, yet. I believe the amp capacity is about the same for the single large AGM vs the two 6 v AGM.  So, the % of charge would equate to the same amount of available amps.

@AMac, have you collected some info yet?

Verna

I have not paid much attention to the built-in battery meter. The gauge provided is a common gauge that is used in my sister's Winnebago View, so it not an inexpensive gauge.  

My T@B 400 has been sitting in the driveway without being connected to electricity, and I have been relying on my solar controller to give me my battery status. 

WOW! The battery voltage has not been under 13.0V, is recharged to full daily by the solar panel that are pointing north, even though I have the Fantastic Fan on medium, and the fridge is on. Because I Boondock so much, I need to know exactly what the voltage is.  

So, if you need to know more than 1/3, etc., you will need to purchase one of the above mentioned battery meters to tell you exactly how many volts you have left in your battery to use. 

gooddogs74

This is what I have.
Stupid dealership let my battery die while they had it for warranty work because no one bothered to turn it off.  They insist it's fine to let that happen,  but I don't think it is.

Sharon_is_SAM

This should be based on resting voltage.

jpi68

We are true rookies, and have been boondocking for the past 8 days near the Grand Canyon. We do not have a volt meter, yet. Therefore the only thing we can rely on is the KIB monitor lights in our 2019 T@B 400. On our second or third day I noticed that the monitor light was on the “1” , “L” level. I became concerned, so after that I started running our Honda 2200 generator every day for 2 - 4 hours to charge our batteries. Charging with the Honda for that amount of time would move the meter up level ”3” , “G”. No mater how long we charge on the generator we could not move the meter above the “G” level. If we noticed that the meter went down to the “2”, “F” level we would start charging using the generator. I hope we haven’t caused any damage to our 2 lithium batteries, but it’s the only thing we could do given our current location, out in the boonies... When we get back to civilization we will invest in a volt meter.

TNOutback

By the time the stock monitor is showing “Good” on the panel, you’ve already gone too far with Depth of Discharge and hurt the life of your AGM batteries.  That panel doesn’t know your batteries and isn’t very helpful.  Invest in a good battery monitoring system.

Here is a very helpful battery and battery monitor overview by no less than a T@B 400 owner!
https://youtu.be/Bq_eDTSzRsE

N7SHG_Ham

@jpi68 have you upgraded your stock 400 batteries to LiFePo4? If so did you upgrade charging method via an upgraded converter or other? If still lead acid batteries, yes even AGM it takes a long time to get the last 20 percent into the battery and a few hours with a generator may not do it. When charging with generator is that via 110 output to a charger or 12v leads direct from generator? The Honda 2200i needs to have eco mode off for use of the direct 12v charging per the manual.

If you did upgrade to LiFePo4, then they take a charge much faster and because of built in BMS hard to damage. I would be suspect of the four idiot light system with upgraded batteries as LiFePo4 has flat voltage almost to depletion meaning a standard voltage system like the built in one can't correctly monitor charge state.

jpi68

N7SGH We have what ever batteries came stock on the 2019 T@B 400. The batteries are not lead acid type but the closed lithium type, they weigh a ton. There are two batteries in an unvented box with a cut off switch. Last night I ran the generator and the panel indicated “4” or “C”. We have been running our Norcold 2-Way refrigerator, with only minor draws from step light and Jensen. This morning at 6am we are down to “2” or “F”. We can’t start the generator until 7am as we are in a National Park. Generator hours are from 7 -9am and 6-8pm.

Verna

The T@B 400 batteries are two AGM batteries. My 2019 T@B 400 has a vent for the batteries on the outside of the T@B above the cargo door, as this was the standard installation from the nüCamp factory. 

Sharon_is_SAM

@jpi68, the stock battery monitor is inaccurate and does not reflect your true state of charge.  At a minimum, you should pick up a plug-in 12 v meter to measure your voltage - a good estimation of battery state of charge.  Any time the TaB is under load (frig running, using lights, pump, fan, etc) your voltage will be artificially decreased, so to get a true measurement, you should turn  off the battery switch and rest your battery at least an hour.  Then check your voltage before turning the battery back on.  If you are near an auto parts store or RV store they should have them.  Here is an Innova from Amazon:



I would also pick up a good smart charger (Deltran, Creek) and isolate and charge your battery the next time you get to a shore power site.  The converter will charge it, but it takes a long time.

jpi68

Thanks Sam, we have been out in the boonies for several days and now are at the North Rim Campground at the Grand Canyon, with no services... I have checked at every store that we passed but no meters... I am charging on the Honda 2200 running on full, no ECO boost. Will run for two hours this morning , 2 hours tonight and 2 hours tomorrow morning, Then tomorrow we leave to head back to Colorado and will be hooked up to the truck, so we will get some charge there, tomorrow night we will be at a KOA on shore power for a couple of days, then another 800 mile drive hooked up to the truck. By the time we get home I am assuming that we should be fully charged. I will then turn the battery cut off switch to the off position when we put the trailer into storage. I will order a meter from Amazon today, should be there when we get home.  Thank you everyone for your comments on this most confusing issue...

pthomas745

This cannot be stated enough:  if the battery isn't "rested", and things are running in the trailer, you will always get a low reading from a monitor (unless it uses a shunt, as in the Victron, etc)..  If your fridge is running when you hit that monitor button, that reading is next to useless. 

".....you have to be careful that you are not just measuring the surface charge. To properly check the voltages, the battery should sit at rest for a few hours, or you should put a small load on it, such as a small automotive bulb, for a few minutes....."

I bet just turning the fridge off and waiting five minutes will give  you a more optimistic reading.

So, turn everything in the trailer off , turn the battery switch off and give your battery a rest for an hour.  Turn the switch back on, and then immediately see what the "monitor" says.

Edit:  my quote is from this Battery FAQ:

https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/#Battery Size Codes

jpi68

pthomas et al, my cigarette stile meter that Sam suggested should be here today. What should the meter read when the batteries are fully charged? 12 volts or more? Another issue is that when we are dry camping as we were on our recent trip to the North Rim of the Grand Canyon, we have the Norcold two way refrigerator and therefore cannot shut it down to allow the batteries to rest after charging without allowing the contents to spoil. It has been suggested here and attached articles that in order to get a accurate measurement of battery voltage it must rest first. Any suggestions?

ScottG

@jpi68, a fully charged battery should read north of 12.6V in a resting (or unloaded) state. Once you get down to ~12.2V your battery is half depleted and should be recharged to prevent accelerated wear.

Note that these are just generalizations. Actual readings will depend on the age, condition, and type of battery.

ScottG

To address your second question. The requirement for a battery to "rest" applies when it has just been charged. In that circumstance, the battery voltage will read high until the surface charge has dissipated. However, applying a load (such as your refrigerator) to the battery will dissipate the surface charge much more rapidly. After that, you really only need to flip your fridge off just long enough for the battery voltage to stabilize--probably no more than a minute or so.

jpi68

Thank you ScottG

pthomas745

Here is a state of charge chart.  I have one of these printed in the trailer.

If my battery is reading 12.6 or near there when I unplug the solar panel, etc, I consider that to be 100 percent.  When you run on shore power or with a solar panel, etc, the battery will read higher than these totals as the battery moves through the different charging stages.

The issue here with trying to check the state of the battery while the battery is actually running things is:  any monitor will always read lower than the actual state of charge. Turn the fan on full power and watch that meter drop and drop.  Then turn the fan off and watch the numbers go back up.    When I used one of the plug in monitors, even when I knew that a battery in use will always read a lower state,  it still always flipped me out.  It made me conserve a bit of battery, which is good.

The trick I used was to count, in my head, approximately how many amp hours I was using.  I grabbed a copy of Jenn Grover's spreadsheet that listed how many amps per hour each device used.  I could use 35 amp hours before reaching the magic 50 percent mark.  The trailer is using 4 amps or so a day, no matter what.  On top of that, how many hours did I run the fan on low?  (The fan uses a good amount of power.)  Or the radio?  Or the lights?  (lights use hardly any power). 

I was usually rewarded, after resting my battery, with a nice number on my state of charge.  Like I said, it is a little disconcerting to see those "low percentage" numbers, but  you can think it through.

AWCA12a wrote a very nice guide for the 400, and on page 53 there is a 400 power chart that I am sure will be helpful.  Look for the Tab 400 Resource guide , here:

https://tab-rv.vanillacommunity.com/discussion/6371/t-b-owners-manuals#latest