Alternator
My alternator on my 2007 Discovery with a 330 Cat and Freightliner chassis quit charging when running. The Generator and shore power charges the batteries so I am assuming the alternator is faulty. It...
Forum Discussion
Hi,
Normally you should have the alternator output feed directly to the engine battery and perhaps the fuse panel at the same time. Then a relay should be installed to charge the coach battery, with that relay energized when the engine is on. One manufacture used a oil pressure switch that would apply 12 volt power to the relay when the engine was on. Others use the ACC position of the ignition, so just leaving the key on will charge it, should the battery need a charge from shore power inverter/charger.
If your alternator broke while on vacation, it is OK to run the generator all day while driving, and let the inverter/charger supply all the power that you require. The same relay that allowed the engine battery to charge the coach battery can let the coach battery charge the engine battery, via the generator and charger. No need to fix it until you are at home.
Sadly - even if you find the broken wire that a mouse might have chewed through, the alternator does not like being disconnected from the battery - ever! West Marine even sells a switch protection system, so that if a boat battery switch is ever moved to "Off" while changing from one battery to another, it will not ever disconnect from a load and prevents the alternator from going to full output and reaching well over 15 volts and melting the diodes inside.
I know a couple that went through a couple of failed alternators before discovering that the 'battery isolator' on their 1984 Bounder had caused the failures. The input terminal to the battery isolator melted, and was allowing the alternator to reach over 15 volts at times while the engine was running. Your motorhome should be new enough that they are not using the electronic battery isolator anymore (for this reason).
Of course wire damage is something that can start a fire. Even if the alternator is not putting out any amps to the broken wire, the wire leaving the break to the battery can carry well over 1000 amps to start sparking if the conditions are right. . .
HOpefully everything will work out well.
Have fun camping!
Fred.
Normally you should have the alternator output feed directly to the engine battery and perhaps the fuse panel at the same time. Then a relay should be installed to charge the coach battery, with that relay energized when the engine is on. One manufacture used a oil pressure switch that would apply 12 volt power to the relay when the engine was on. Others use the ACC position of the ignition, so just leaving the key on will charge it, should the battery need a charge from shore power inverter/charger.
If your alternator broke while on vacation, it is OK to run the generator all day while driving, and let the inverter/charger supply all the power that you require. The same relay that allowed the engine battery to charge the coach battery can let the coach battery charge the engine battery, via the generator and charger. No need to fix it until you are at home.
Sadly - even if you find the broken wire that a mouse might have chewed through, the alternator does not like being disconnected from the battery - ever! West Marine even sells a switch protection system, so that if a boat battery switch is ever moved to "Off" while changing from one battery to another, it will not ever disconnect from a load and prevents the alternator from going to full output and reaching well over 15 volts and melting the diodes inside.
I know a couple that went through a couple of failed alternators before discovering that the 'battery isolator' on their 1984 Bounder had caused the failures. The input terminal to the battery isolator melted, and was allowing the alternator to reach over 15 volts at times while the engine was running. Your motorhome should be new enough that they are not using the electronic battery isolator anymore (for this reason).
Of course wire damage is something that can start a fire. Even if the alternator is not putting out any amps to the broken wire, the wire leaving the break to the battery can carry well over 1000 amps to start sparking if the conditions are right. . .
HOpefully everything will work out well.
Have fun camping!
Fred.
