another battery question

[riven1950]

We are on a 2 month +/- trip to Fl in a new 2019 TT, just purchased in November.

I checked the battery ( new battery ) water level and charge before we left and it was reading about 13 volts not plugged in to a/c power. I installed a led volt meter I had left over from a project directly to the battery and attached it to the battery cover to monitor the battery reading.

We just left a commercial campground after being plugged into a/c power for 30 days. I was surprised to see the volt meter reading @ 12.5 volts after disconnecting the the a/c power. Ever time I checked the meter while at the campground, while plugged in, it was reading 13.3volts so I was thinking it was keeping it fully charged.

After driving about 1.5 hours to another CG, connected to the truck of course, the reading was 12.8V. After plugging into a/c power at the new CG I noticed the reading was 13.7, so charging I guess?

A side note: the converter failed right after purchase and was replaced. Everything appears to be working normally on a/c and d/c except the frig sometimes decides not to stay on when turned on LP ( traveling )

Questions: I this abnormal? Does it indicate a problem with the converter or does it sound ok? Suggestions on what if anything to check?

I plan to disconnect the battery cables tomorrow and check the voltage directly with a multimeter. Can I do that safely while plugged into a/c power?

Sorry for the long post, just trying to give some details.

Thanks

[Harvey51]

I killed my first set of batteries using the voltage method of estimating state of charge.
No problems since getting a $25 battery monitor that counts amp hours going in and out. Better to measure energy than energy per electron.

[twodownzero]

12.6 is fine.

[riven1950]

2oldman wrote:
Fridge should stay on. What is the symptom of its not being on?

First fyi the frig control board was replaced when the converter went out. AC ripple from the converter knocked out the board. It would not work on ac or dc. Now it seems to work fine on ac but on dc / lp it is inconsistent, may run a few hours then check light comes on. Reset it and it will go again for a while, but to be honest we have been on ac at all CG's so only testing it when traveling, so not really developed a pattern yet. It's a Dometic frig.

Someone ask the converter model #. It is a WFCO wf-8955pec
I have read that WFCO converters are not the best but it was replaced under warranty, so their money not mine. I would have upgraded for a few dollars more but past that now.

I looked again last night and here at this CG it is reading 13.7 plugged in to ac. Voltage here is about 124 on my progressive ems where at the other place I noticed it as low as 116 so maybe that is a difference too.

Thanks for all the replies

[garyemunson]

The best way, bar none, to determine battery condition. Without a load, even a weak battery can read acceptable voltage.
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html

[1L243]

The 13.2v is what your converter is putting into the battery while your plugged in. When unplugged for a few hours you will get the true resting charge level of your battery. 12.6+ is fully charged. I don't like to let mine drop below 12.3 which is actually around 70%. You never want to fully discharge your battery. It starts getting critical at 12.2v

[MrWizard]

get an AC volt meter and motor your shore power in the RV

Low voltage on shore power can cause converter voltage to be slightly lower than Optimal
13.2v is considered 'float' maintenance voltage for many batteries, and a tad low for a system in use

[MrWizard]

get an AC volt meter and monitor your shore power in the RV

Low voltage on shore power can cause converter voltage to be slightly lower than Optimal
13.2v is considered 'float' maintenance voltage for many batteries, and a tad low for a system in use

[theoldwizard1]

riven1950 wrote:
After driving about 1.5 hours to another CG, connected to the truck of course, the reading was 12.8V.

That is because that is the voltage it was likely seeing from the tow vehicle !

donn0128 wrote:
12.65 is generally considered fully charged battery.

But also remember, to have to have at LEAST 13.2V to charge into a lead acid battery.

[donn0128]

12.65 is generally considered fully charged battery.

[time2roll]

Normal. Post the converter model number for best answers.

[2oldman]

riven1950 wrote:
..plugged into a/c power for 30 days. I was surprised to see the volt meter reading @ 12.5 volts after disconnecting the the a/c power.

Everything appears to be working normally on a/c and d/c except the frig sometimes decides not to stay on when turned on LP ( traveling )

Questions: I this abnormal?

..disconnect the battery cables tomorrow and check the voltage directly with a multimeter. Can I do that safely while plugged into a/c power?

Assuming the led meter is accurate, that's acceptable resting voltage. A little low for a new battery, but not a concern.

Fridge should stay on. What is the symptom of its not being on?

Yes you can do that while plugged in.

FYI- ac and dc power are abbreviated without the slash. The slash is used to indicate air conditioning.