Apologies in advance for asking questions you've probably seen many times already.  I've seen some answers but all in different topics with slightly different situations.

I'm trying to determine if my 12V batteries need replacement.

I'm a relatively new (2nd camping season) owner of a 2018 RPOD 180.  We tend to camp boondock with it on about 50% of our trips.  Last summer was fine in terms of battery life.  we would get 3ish days without the batteries ever dropping below the 1/3 light on the panel.  I've read some opinions on here about those lights so I just bought a bluetooth voltage monitor, but the little buttons/lights are all I had last summer.

I took the batteries inside and had them on a tender/charger all winter.

This summer we did a boondock trip earlier in the season that was fine.  then a 3 day trip in June with plugin, so no worries.  luckily, I procured a generator just before our most recent trip.  

After that June trip the camper stayed unplugged for a couple weeks, possibly a month.  Then I plugged the camper in to charge the batteries. but at this point, I didn't check battery charge, just plugged in the camper.

On this most recent trip (early Aug) we had a full week with no plug ins.  but between the time plugged in at home and 5 hr drive, I'm confident the batteries were fully charged when we got to the campground.  but after the first day, they were drained down to 1/3 or less.  the water pump was making the lights dim when it went on.  we proceeded to spend the next 4 days plugging the camper in to the generator at least once a day, but watching the batteries drain down to 1/3 or less before we went to sleep.  2 nights they got so low the CO alarm went off and the lights on the radio panel went out.

so my question is... is it true that if the battery's voltage drops below 12.2, it sustains damage and needs testing?  I assume that means like at Autozone.  I'm going to take them in to be tested.  But I wanted to ask for confirmation that they shouldn't fall below a certain VDC.

We have two Everstart 24MS batteries.  I think that means marine starting amps as opposed to deep cycle, which sound like they're not exactly optimal for running camper electronics for as long as possible.  I think they are at least 3 years old but could be older.  But until I left the camper unplugged in July I'm confident they were properly cared for with a tender.

on this recent trip where they were dying, we didn't have any serious load on them other than the water pump.  fridge and water heater were on propane.  no roof fan nor furnace.  no radio and lights were used sparingly.

I was considering a swap to LiFePO4, doing the research on an updated converter any everything... but may just go with a pair of new interstate marine deep cycle lead acid.

Have you checked water levels in the cells? Low water level will cause low capacity.

Good luck sorting this out.

We have used several different battery makes,sizes  and configurations since our first R Pod in 2011.

Without question, the best solution for us has been 2 6v Trojan batteries. They are costly, but last long enough to make them well worth the extra cost. The extra amp hours(ah) are perfect for boondocking.

We did have to buy a new battery box as they are slightly taller than the regular 12v batteries that usually come installed.

 I just looked at the Trojan website-they currently list a T-125 6v lead acid battery at 240ah. This is the highest rated ah battery available in flooded lead acid batteries. 

Using 2 6v batteries in series will give you more ah capacity that any 12v single battery.

If you truly want to have power while boondocking, these are the batteries to use.

We use them in conjunction with a 100watt solar suitcase and a Honda 2200 generator and have been on the road for as long as 3 months with no hookups.

I am not associated wiith Trojan other than a very satisfied user for over 6 years.

Travel often and safe 

Vann

I've been using LiFEPO4 batteries for 3 years now. I would never go back to AGM or FLA batteries. Do your research and you will find you can get one in just about any size that meets your needs. You will also have to check your power converter/charger to see if has a Lithium setting. 

Exactly. Premium golf cart batteries should come with a gym membership. 

Impressive! Not sure I could do that at my age and I consider myself to be in pretty could shape.  

Back to the battery topic, the OP needs to consider their plans for their Rpod. I went through the same decision process with our 179 and eventually decided that the juice wasn't worth the squeeze to convert ti lithium batteries, and FLA and AGM batteries didn't fit our travel style. So we ended up with a different camper with a full solar-lithium-inverter setup.

I considered Lithium but decided to go with 2 GC batteries due to the cost and the 2 required side projects.  Wish I could say I was going to test them this week, but alas we have a plug in site so I may have to wait a bit to experience the joy of 255 AH of battery.