Coach battery overcharging

[oldxr]

I have a Rockwood Mini Lite 2109s . I have been using this trailer to live in at a work site away from home . The trailer is plugged in most of the time except for week ends when I go home . The original coach battery lasted almost 2 years and then started losing a charge over the weekend . Put in an interstate deep cycle battery and it lasted 15 months. I was going to sleep 1 night and the cooling fan for the coach 12v power supply came on . Checked the coach battery and it was warm and the plates had sulfated . My question - I thought the coach 12v power supply is supposed to keep the coach battery in the correct state of charge? Seems like it’s not a very sophisticated battery charger . I just got a new battery but it looks like I will have to not connect it while the trailer is plugged in .

[tomkatb]

Need to figure out if it is the battery or charging device. Converter is 55 amps.

A Voltmeter is the tool.

A fully charged battery that has been off the converter for a few hours should read 12.6 volts.

Most converters charge the battery at several voltages depending on how discharged it is.

When fully charged the trickle charge should be close to 13 volts. Converters charge the battery to about 90% then go on trickle for a day to complete the charge.

Highest charge is near 14.

Sort of sounds like the converter is damaged. Running too long at 14 boils the battery. Not good.

In 8 weeks of travel we heard the fan on the converter only once for 20 minutes. Max rate. Close to 14 volts. After being in storage for three months.

Do you have a voltmeter on the battery? A good idea. The BM 2 from Amazon is $40 or so. Transmits to your phone and records. Handy tool.