2019 Winnebago Intent 29L battery/inverter problem

[Kruserz]

Hello! We bought our Intent new in 2019 after getting stuck near Salt Lake City in our used 2006 Sightseer which had broken down numerous times. We've put 20,000 miles on the Intent and have been pretty happy.

My husband needed to replace both the batteries recently (dried out due to lack of maintenance) so he put in closed cell batteries. He's also not one to get on a forum like this so forgive me if I don't explain this clearly. We do quite a bit of dry camping and have an electric fridge that requires the inverter to be on. We have solar panels for during the day which do a great job keeping the battery charged. Until the batteries needed to be replaced the Inverter would only beep when the charge in the batteries was getting low. The inverter (Magnum Dimensions CSW series Pure Sine Wave Inverter Sensata technologies) recently started beeping continuously even when the gauge on the wall shows the battery is fully charged and will eventually turn itself off. It's inconveniently located under the seat and the display can only be read with a mirror, but it appears that the voltage drops to a level that is too low. It happens fairly quickly after the generator is turned off or the solar is no longer producing. Reading the manual has not been helpful. He's going to get the batteries checked out from where he purchased them, but I'm wondering if anyone has had a similar experience and has any answers.

Thank you!

[Morich]

Some small important points which may help?

When we read the voltage of batteries it can often fool us if we are not aware. When reading the voltage, if we do it as the batteries are charging, we do not get the true state of the battery but instead only see the voltage which the charging is putting in! And to get closer to the true state of charge, we need to wait several hours and then check.

Maybe review what you are doing/seeing to see if you are actually getting as much charge from the solar as you think?

My thought is that you may be seeing the solar as doing all the charge needed but the battery itself is still gradually going down, then when the charge stops,the reading drops quite quickly.

Can I "mansplain" without seeming offensive? Sorry, not meant that way but batteries are confusing things!

They are a chemical reaction and might be compared to looking at a barrel of water. If we look in a hole at the top as we add black ink, it may look like the water is really black. That is something like checking voltage as we are charging. You only see what is right at the battery post!
But if we come back after a few hours of not adding ink (charging?) the chemicals will be stable and we may not see much black at all!
Techie term is "surface charge" and you may find much better explanations if doing a search.

I suspect there is a basic problem of the charge going in from solar is actually less than being taken out by use. So it appears good while you are putting charge in but over time the battery chemicals are really getting lower and lower until they no longer operate.

[Kruserz]

Thank you for your quick response. We understand how the batteries work and we have checked the gauge numerous times, even after overnight and they rarely went below the 4 lights showing fully charged. This situation with the inverter beeping and showing low voltage happens after using the generator, driving short distances and using the solar to charge. The only things plugged into the inverter are the fridge and 2 TVs which can't be easily unplugged. The batteries were just purchased a few months ago and worked fine the first time we dry camped for 3 days without using our solar (we always turn the invertor off while we sleep since the single beep we are used to when the battery level decreased will wake me up).

This recent trip was 3 weeks, mostly dry camping. It seemed to get worse each evening as far as how soon the inverter started showing low voltage and beeping and how soon in the morning it would start beeping after we turned it back on. When we got home I turned off the refrigerator and 12 hours later the inverter beeped when I just opened the refrigerator door and the light came on. The battery still showed fully charged.

This never happened with the original batteries. Even when they wouldn't hold a charge very well, the inverter only beeped once as the charge was dropping but the voltage output was still enough to run the fridge. Our understanding is there should still be enough voltage for the inverter with the charge down to 50%.

Anyway, it is a mystery and if you have any further insight, feel free to share it.