campingman55 wrote:
they are for the chassie and i dont know the name of the battery what is a good brand to use the reason iam getting them is when i check i have 11.9 or 11.5 and when i start it goes to 14.1 and after i shut down it drop back to 11 something
I'm very surprised that your engine will even turn over, much less start with only 11.9 or 11.5 volts....this is way below 50% discharged....if fact they should be dead! I suspect that you have to use your emergency start switch to allow your house batteries to do the starting.
At 14.1 volts...that just means that your alternator is working real hard and doing it's job.
As Brett mentioned (who by the way is a diesel engine expert and you can take anything he says to the bank), it sounds like your chassis batteries are not getting charged while on shore power. A good way to check is after you connect to shore power, measure the voltage on your chassis batteries...they should be up close to or over 14 volts. If they stay at 11.9 or 11.5, your coach may not have the capability to charge while on shore power.
There are fixes for this... Trik-l-start (or amp) or a 120v battery minder (or tender).
Good Luck..
Ron