Renogy battery failure after shore power charge during winter

Aubrey

I stored my 2018 T@B400 in the insulated garage this winter plugged in most of the time. It has a 200ah Renogy AGM that was purchased in Aug 2022. worked fine in 2023. This year it wont hold a charge, even when topped off with a smart battery tender. it will discharge in a few hours with only the fridge on.
I have seen many posts that say shore power is fine for winter, so I have to assume this is a battery failure. I managed to register the warranty and start a "case" on the Renogy site while on hold for a really long time with support.
They never answered and sent me to a "leave a message" ending.
Anyone else leave their camper on shore power during the winter?
Any battery failures if you did?
I really hope Renogy works with me on this, I believe the battery has a 2 year warranty. It cost over $400

pthomas745

Many owners store their trailers with the trailer plugged in.

What device is telling you the battery is "discharging in a few hours?" What exact fridge is it?

Battery failure is certainly a possibility.

Aubrey

Support is awful. Multiple session of listening to the most annoying version of "Memories" ever, finally got an answer, now they say they want a photo of a multi-meter showing discharged battery. What the heck does that prove? If I get any help it will obviously cost me a LOT of effort and time.
This is as bad as dealing with Amerigas, truly every effort to make a person give up at eat the loss.

Aubrey

NR751 NORCOLD 2 way if i remember. I have a thread from few yrs ago about its quirky "no cool" problems when switching from shore to DC power.
Got through to support. They want the photos of the multi-meter showing 100 percent charge as well as discharge state and description of the load time, etc..
I reckon we will see if they come through on this warranty case. Updates to come.
Not sure why I didn't buy from a reputable battery dealer in my state, duh...

Mickerly

Your Norcold NR 751 is installed as DC. AC is not a switchable setting, it's an installation choice. DC all the time is better.

Do you have a battery monitor (shunt)?

Aubrey

By "switching" I meant going from battery to shore power. It defaults to AC whenever it is available. And if you plug to shore without using the battery shut off in the camper it will stop cooling. I assume it has some protection in the control unit that senses a surge (theory)

Aubrey

No shunt but it worked well last summer. Now full charge is around 12.6V, wich drops to 12V immediately when the camper disconnect is turned on and only the fridge is running.
Within an hour its at 11.8V and fridge cant cool. It holds there awhile but if I turn on the ceiling fan and one LED the light flicker and the voltage is a mere 10.7V..

I have a case pending with Renogy and they have the pics and story. Ball's in their court for now. Hopefully the stand behind it.

vhollow

You might have a loose or defective connection, positive or negative, at the battery, nearby terminals or at the converter. This could be a source of rapid discharge or failure to charge. Trailers vibrate and jolt and these things happen. It would be worth checking to eliminate the possibility.

Aubrey

So after more than a week I get this response from Renogy...

1. Please provide us with your system wiring diagram, and please provide us with the specific load that is connected to the battery. 

2. Please confirm the battery depth of discharge as well as the approximate number of times of the charging and the discharging cycle of the battery. 

3. PLease confirm the specific charger you are using and the charging parameter that is set to the charger. 

4. Please confirm the ambient temperature where the batteries are placed. 

5. Please confirm the battery usage scenarios before the feedback situation, was in use, or in storage; if the former case, confirm whether there is the situation: the battery was over-discharged, and after the battery was over-discharged, but the battery was not charged in time; If the latter case,  confirm how long the battery was storage/what the battery open circuit voltage was before storage / whether the battery was connected to other equipment during storage period / whether the battery has been charged during storage period.

6. Remove all the wiring cables on the battery, then at the ambient temperature of above 41℉（below 122℉), to choose the charger that matches the 12V AGM battery, and the charging parameters of the charger matches the charging parameters of the RNG-BATT-AGM12-200 battery(as shown in the below picture①), and the charger has the charging voltage temperature compensation (matches the RNG-BATT-AGM12-200 battery temperature compensation coefficients in below picture②)，then use the above charger to fully charge the battery；(The key steps)The terminal voltage of the just fully charged battery is about 14.4V（at the standard temperature of 77℉)，then the battery is left to stand for four hours(no any wiring cables on the battery), and use the multimeter to measure the open-circuit voltage of the battery; Then if the measured the open-circuit voltage of the battery is above 12.9V（provide the measurement pictures), it means the battery is fully charged；Then the battery is left continuously stand for over night(no any wiring cables on the battery), and use the multimeter to measure the open-circuit voltage of the battery and provide the measurement pictures, in order to confirm whether the open-circuit voltage of the battery drops obviously; At last the battery is connected to the matched and known power of the DC resistive load（electirc heater and so on）to fully discharge (After the battery is fully discharged, use the charger that matches the battery to charge the battery in time)，in order to testing the power of the fully charged battery(The power of the resistive load multiplied by the time it takes for the battery to be fully discharged)，ann please provide us with the testing results. 

 

That seems like a BS response to a warranty claim.

Grumpy_G

Aubrey said:

That seems like a BS response to a warranty claim.

Yup, a little bit of googling beforehand would have told you that Renogy is extremely difficult to deal with. To be fair, lead-acid batteries are notoriously difficult to warranty because it's not a simple "doesn't work anymore" and that's why they ask so many questions. I just helped a fellow tabber through some issues with his LiFePo setup and it was merely user error/wrong expectations, the battery works perfectly fine.

Personally I consider most warranties useless and just buy "cheap" so I can buy another (different) unit if need be.

Aubrey

So the charger should be at or BELOW 10 percent of the amp hours of the battery? Wouldn't any battery tender be appropriate for a mostly charged result, which could be topped off to 100 percent with solar panels and mppt controller? 
And shore power should also be good enough to periodically maintain the AGM in the off season, no?
I tried to baby this battery and I need to prove that I didn't mistreat it.
I have it pulled from the camper now and topping it off today, but even after showing fast discharge using only the Norcold fridge, it sat unplugged for couple days and stabilized at 12.5V, again it drops below 12V within minutes of powering only the Norcold (around 4amp draw if I recall)
Quite a hassle..

Aubrey

BTW, when I did use my battery tender it would show the green light and start floating, I have read some folks would not see the green light.

Aubrey

Charged my new PowerUrus battery with its charger overnight. Charger started off pretty slow and really warm, but I was assured this was normal, today it was at 14.3v when installed, holding about 13.4v installed while the Norcold refrigerator runs at 5.2 amps according to the Roypow app.
Time to put the camper back together and do some real world testing.