So recently I noticed that the fault LED on my EarthX ETX900 battery had gone on (steady), so I contacted EarthX and they told me to file a warranty claim.  Despite not being able to locate my receipt (it's somewhere...) they quickly approved my claim and shipped out a brand new battery.  Thanks EarthX!!

Not sure why that happened - I haven't used the battery or even connected it to anything (I bought it about a year ago).  Maybe sat too long?

In any case I decided I probably should get a proper charger/maintainer, so I looked on EarthX's website for their recommendations and decided on their top choice (they actually sell it), the Tecmate TM series chargers (not all models though), which are also called Optimate.  I got the TM-291 model.