Ok, since my battery was so dead last week that it wouldn't run my landing gear, I brought it home to charge it up.
Here is my Walmart special battery charger:
I bought this back when I had my pop-up. I didn't know what I was doing then an still don't! I normally don't pull my battery out and generally let my converter charge it and disconnect to keep it from being depleted.
I first checked my water levels (YouTube educated!). I think they're ok:
I think they look OK and not frozen (my book told me not to charge a frozen battery, so I was checking).
Finally, here's my battery. Can anyone tell me anything about it? It doesn't seem to have amp-hours listed. Being a starting + deep cycle battery, it doesn't seem best suited for an RV, but we so rarely use battery power only, I think it's OK for now.