I wouldn't go buy batteries quite yet.... at least until I had a better idea what's wrong. If the problem is a bad battery, replacing them would indeed make the problem go away. But if the converter's bad, you'd be turning it loose on the new batteries once you do the exchange.
So..
1. What converter do you have? I see from another of your posts your Hawk hardside is a 2012. I don't know when FWC started using them but at some point they started using Iota DLS-30 converters. According to the video below (at 3:48), those have a port for a jumper wire to make the charger do a fast-charge. That wire will prevent your converter from going to float mode. I know the camper is new to you so I'm thinking perhaps the previous owner had occasion to plug in that jumper for some reason. It seems like a long shot but would explain overcharging.
2. Speaking of the previous owner, I'd give him a call and ask if he had noticed the problem. And if that jumper wire's there, you will want to know why.
3. You might also do some Google searches for your converter model and the word 'overcharging' for more hints. I've got to go but on a quick search found the following post where a guy had a similar problem which turned out to be the converter....
55 amp converter overcharging battery, sizzling!!
4. If nothing comes of that, I'd disconnect the batteries and test them individually. If you don't have any test gear you could take them to an Autozone, Advance Auto, Pep Boys, etc and take them up on their free testing offer.
Gotta go...
-OC
Edited to add:
The video above has troubleshooting info. There's a visual representation starting at 7:35 in the video above. And here's another version which presents the info a bit differently:
Page Not Found That last one also says you can get inconsistent voltages if the unit overheats (typically because of air-flow blockage-- something else you should check)
Other info- If you do indeed have a DLS-30 converter it may or may not also include the IQ4 add-on PaulT speaks of in post 40. Iota sold two versions, one without an IQ4 and one with an internal IQ4. If the paperwork that came with your Hawk doesn't tell you I'd think a call to FWC with your serial number could clear that up.
(Note: If, after reviewing the troubleshooting info, that looks like it's beyond your experience level, it's probably time to take it to a pro.)
Edited on 5/29 to say....
My post above is probably making this too complicated.
I think I'd try this more simplified (and generic) approach first:
- plug a digital voltage display into one of the 12V outlets and record current voltage (presumably full charge)
- double-check the converter isn't on shore power
- use the batteries to discharge it/them down to something like a 12.5 reading on the display or lower
- plug in to shore power
- watch and record voltages as the converter charges - discontinue if voltage is above 15
- monitor battery temperature while charging- discontinue if battery gets hot or smells
- watch for voltage to drop out of the 14s to float voltage (probably something like 13.5) published for the converter
- if charging behavior seems ok, suspect a battery problem. Disconnect and take batteries for testing.
Note- this is just how i would approach it. I don't even HAVE a converter! If anyone with more experience at this sees anything wrong with the approach, please comment or send me a PM