We didn't realize our charger had a problem until I tested it - it didn't seem to charge much. In three rounds of testing, we figured out that, after 5-7 minutes in bulk mode pushing 60Amps, it would overheat and shut down. When it came back up (always within 30 seconds) it would 'see' the battery amps at 13.4 and go straight into absorb or float mode. Tricking it back into bulk charge always ended up the same - it would shut down and come back up in float. We replaced it under warranty.
As to battery location, we have two 6Vs under the stairs and two more about four feet away in a storage bin. The charger sits between the two.