Does the battery need charging yet?

Deb55

Our T@B 400 is parked in the driveway, with the battery disconnect switch off. We probably won't be taking another trip for about a month. Today I decided to check the battery, so I turned it back on, and checked it with the monitor, which read 2/3 full. I also checked it with a plug in volt meter that read 11.77, which seemed (to me) lower than 2/3. Which one should I believe, and does it need charging at that level or is it OK? 

pthomas745

Your battery needs to be "rested" to get an accurate reading of the state of charge.  So, if you turned the switch on, and then turned on a light or two, your 11.7 reading was not accurate, since the battery is trying to "work" and tell you its "state".  If it isn't "rested", it will always read low.  So, try: turn your battery off.  Leave it off for an hour or two.  Turn your battery back on, and then use your "plug in" meter first thing without turning anything else on, and see what it says.

You are correct:  11.7 is below 50 percent, and you don't want to be there, if that is a "true" reading.

Here is a chart showing "state of charge" numbers.

Sharon_is_SAM

@Deb55, I would not trust the KIB monitor to guide your decisions regarding your battery state of charge.  Recently, a member reported the KIB reading full and it was only really at 60%.  If I were you, I would get a smart charger that meets the specs of your battery and use it to fully charge your battery before storing in between trips.  Your battery needs to be charged.  You can get away with using the plug-in voltmeter as long as you rest the battery as pthomas745 has directed.  If you have the single, large battery, if it discharges too low, it can be difficult to charge from the converter.  If you have the circuit breaker next to the battery, make sure it stays closed as you charge with the converter.

Deb55

I checked again just now, after the battery had been turned off all night. It still read 11.7. I'm charging it with shore power now. It's the one large battery. I'm not familiar with all the terms (converter, for example), so what I've done is plug into my house with an adapter and surge protector. The battery disconnect switch is set to on. Question or two--on our last trip, we overnighted in a driveway, and used the battery for typical things like the fan, lights and fridge. When we drove home (about 2 hours), the battery never fully charged from the 7 pin connection (disconnect switch set to on). Plus it seems that it's still discharging in the driveway, even with the disconnect switch set to off. Am I doing something incorrectly? 

Sharon_is_SAM

Your TV, especially with a brief tow period, is not likely to completely recharge your battery.  It acts like a trickle charger - only 1-2 amps an hour.  Any battery will self discharge without being used (not under load).  If your battery is under charged at the time you leave it in your driveway, it will discharge even lower.  

rfuss928

Sharon_is_SAM

A properly wired TV should be capable of much more than a "trickle charge" especially if the trailer battery is substantially depleted. I have seen mine exceed 25A to the trailer after a long weekend with little solar. 

Folks running the 3 way fridge on battery while towing need ~10 amps just to keep up with the refrig draw.

The 1-2 amp estimate is much too low IMO and I would suspect a problem with the TV wiring if that was all it could supply.

Verna

@Deb55, nüCamp quit using the one large 12V AGM battery because of problems with it. If have dealt with two owners privately in the past few weeks who were having the same problem as you, and I’ll give you the same advice. 

I like Interstate Battery dealers (absolutely no compensation from them). Look for one close to you, and take the T@B to them to have them check your 12V battery for a bad cell. If it is bad, consider choosing two 6V AGM Golf Cart Batteries wired in series, to replace the one battery. You probably don’t have a plastic cover on your battery, so the Interstate Battery guy will just strap your new batteries to clamps on the floor. The new 6V batteries should last 4+ years if regularly charged with a smart charger, or solar panels as I do.  And, their labor is free, by the way. They do the heavy lifting, too—yeah!

Deb55

Our camper has the 2 way fridge, and the battery fully charged on our trip involving full days of travel. I don't think the TV is wired incorrectly. I'm still learning, and I suspect that the 2 hour trip didn't charge the battery enough and I should have plugged into our house when we got home. We're going to have an outlet installed close to the camper so that it will be easy to keep charged at all times. Thanks for the input--I'm glad to learn that I should trust the volt meter more than the monitor in the camper, and I'm glad I found that out before having to replace the battery after only 2 trips! 

Deb55

Verna, thanks for the info regarding the large battery. I'll keep it in mind about replacing it with the 2 golf cart batteries if we keep having problems with charging. 

Sharon_is_SAM

@rfuss928, we have a 10 g charge line and we run the ARB.  Lots of folks can’t keep their battery charged while running the 3 way frig on battery and resort to running on propane, so must be lots of incorrectly wired TVs out there.  You are able to generate 25 amps?  What’s your secret?

Deb55

Update--after fully charging the battery on shore power, I disconnected it with the switch and retested it about a week later. It's still holding steady at 12.82, using the plug in volt meter. I think all is well! 

Sharon_is_SAM

Sounds perfect @Deb55!

Sharon_is_SAM

@RangerTom - I believe @Deb55 has a 2 way frig.  The 2 ways in the 400 are pretty efficient on DC.