Coach 12 volt monitor

[Ted Couch]

 
Our 1989 Marquis 12 volt monitor is hovering around 14.8 and may be creeping higher. Are we burning up our batteries? An electrician friend said it should be at about 13.7 and stay there. Does anyone know if this is bad,should we buy new batteries when we return home in a month or so?

[Fred Brooks]

         Hi Ted,
   How old are your batteries and when did you service them last?. The inverter/converter on your coach tries to charge the batteries when it senses resistance. It is a 3 stage charger, bulk, absorption, and float. Bulk charge is high amperage charge rate meant to help the batteries recover from a deep discharge cycle, absorb rate is when the charger starts to ramp down the charge rate as the batteries start to recover and absorb the charge. Float charge is a maintenance charge rate to keep the batteries charged and to deliver any 12volt demand the coach is requesting to operate.
   It sounds like the charger is in the "absorption" mode which is typical of dirty battery terminals or old batteries that are resisting taking a charge. You can disconnect the cables after unplugging the coach and everything is turned off and let them sit for 8 hours and check the voltage with a voltmeter. They should be 12.7 volts each.
   Hope this helps, Fred

[Fred Brooks]

   Ted, Just reread my post and should clarify my response, 12volt batteries will read 12.7 volts and 6volt batteries should be 6.4 volts. Also check and refill your batteries with distilled water. If you are going to change the batteries, take a picture first. It is easy to miss a cable or create a new problem. Fred

[Ted Couch]

The batteries are about 9 years old. They are sealed type. What kind would you recommend for replacement of my old ones? I appreciate your input.

[Larry Dedrick]

Ted
        You may also have a sense wire that is faulty which will cause the alternator to put out too high of voltage. I don't know your system that well, but on our 2001 Beaver, I was having this issue and the electrical experts put on a new sense wire and that was the end of too high of voltage.

            Larry D

[LaMonte Monnell]

Ted, I replaced my 4 coach batteries as well as the 2 start batteries last year. I had two that were bulging on the sides and the other two were bulged by the terminals. They were very warm to the touch and figured that they were trying to charge too much. I have a 2001 Contessa.

[Ted Couch]

What brand/type of batteries did you purchase?

[Fred Brooks]

   Hi Ted, If they are the sealed type, they are probably "AGM" glass mat batteries. Life expectancy is 7 to 9 years. I recommend them because it removes one more thing from your maintenance "to do list" that overwhelms some owners. Drawback is the price of the batteries, Advantage is no water to add or terminals to clean and they last a long time.
      Regards, Fred

[LaMonte Monnell]

What brand/type of batteries did you purchase?

I bought two sealed start batteries from NAPA and the four coach 6 volt batteries from a local golf cart shop(T105 6 volt)