Chassis or House Batteries?

[Redg]

Need some help from you guys! 2008 Monaco Dynasty, having issues with chassic batteries.....coach stays plugged in to 50 amp power here at the house when not going down the road. couple of weeks ago when taking off for a trip the coach would not start, but using the booster battery switch got things going. Pulled the 2 chassic batteries and had them load tested, good, re-installed, coach started and we decided to go, no problems for the trip. today we were headed out again (coach had sat idle for 21 days), coach won't start, used booster switch and were running. with the coach engine running I put a v meter on the chassic batteries and got 14.1 volts, which tells me the alternator is charging? Am I charging the chassic batteries when plugged into shore power or just the house batteries? I have an aux air compressor for auto leveling that comes back to life every 30 minutes or so to check air pressure and will come on briefly...could this be tied to my chassic batteries and be enough to drain batteries? I also have a motorcycle 12 volt lift that is connected to my chassic batteries and don't normally have the coach running when lifting a 900 lb Harley, but have the generator running.....thoughts?

[cavie]

Originally Posted by Redg

Need some help from you guys! 2008 Monaco Dynasty, having issues with chassic batteries.....coach stays plugged in to 50 amp power here at the house when not going down the road. couple of weeks ago when taking off for a trip the coach would not start, but using the booster battery switch got things going. Pulled the 2 chassic batteries and had them load tested, good, re-installed, coach started and we decided to go, no problems for the trip. today we were headed out again (coach had sat idle for 21 days), coach won't start, used booster switch and were running. with the coach engine running I put a v meter on the chassic batteries and got 14.1 volts, which tells me the alternator is charging? Am I charging the chassic batteries when plugged into shore power or just the house batteries? I have an aux air compressor for auto leveling that comes back to life every 30 minutes or so to check air pressure and will come on briefly...could this be tied to my chassic batteries and be enough to drain batteries? I also have a motorcycle 12 volt lift that is connected to my chassic batteries and don't normally have the coach running when lifting a 900 lb Harley, but have the generator running.....thoughts?

Turn off the battery disconnect and see what happens. Separate your coach from the chassis. Your coach has a number of predatory usage items. Stereo, clocks, CO detector, Microwave clock, etc. if you still have problems you will know it's not in the house.

[windsorbill]

Originally Posted by Redg

Need some help from you guys! 2008 Monaco Dynasty, having issues with chassic batteries.....coach stays plugged in to 50 amp power here at the house when not going down the road. couple of weeks ago when taking off for a trip the coach would not start, but using the booster battery switch got things going. Pulled the 2 chassic batteries and had them load tested, good, re-installed, coach started and we decided to go, no problems for the trip. today we were headed out again (coach had sat idle for 21 days), coach won't start, used booster switch and were running. with the coach engine running I put a v meter on the chassic batteries and got 14.1 volts, which tells me the alternator is charging? Am I charging the chassic batteries when plugged into shore power or just the house batteries? I have an aux air compressor for auto leveling that comes back to life every 30 minutes or so to check air pressure and will come on briefly...could this be tied to my chassic batteries and be enough to drain batteries? I also have a motorcycle 12 volt lift that is connected to my chassic batteries and don't normally have the coach running when lifting a 900 lb Harley, but have the generator running.....thoughts?

when my coach was new, I had the same problem. Chassis batteries were not charged from shore power. I installed a Xantrex echo charger and it's been fine since.

[Outbound]

Ditto on Xantrec echo charger.

[oldguy70]

I had the same problem with my rig, the isolator that Monaco had put in had been wired backwards. I put in an amp L start and that worked for a while until that burnt out. I have now made up own system that works great and is really cheap.

[cavie]

Pull the chassis battery and have it load tested.

[l1v3fr33ord1]

Reggie-

While waiting for someone who really knows what is going on, I can chime in with some bits and pieces.

See the attached picture of the rear run panel for a 2007 Dynasty. Item 11 is the solenoid that connects the chassis and house batteries for cross-charging. Item 8 is the circuit board that sends the signal to the solenoid to close the contacts and tie the two battery banks together.

See if any of this matches your coach, and if it does, perhaps you can figure out what might not be working. Typically, the solenoid no longer functions reliably, but it could be as simple as a fuse on the Item 8 circuit board.

If I have sent you on a wild goose chase, I apologize in advance.

[Ron Postma]

There is an easy way to check if you coach batteries are being charged when hooked up to shore power. You said you have a volt meter. Place the volt meter on your chassis batteries. Now with the coach not connected to shore power measure the voltage. The voltage should start at about 12.7 volts. Next hook up to shore power and re-check the coach battery voltage. If it it is charging the voltage should be over 13 volts. You might have to wait a bit because your house batteries have priority and the system will not charge the coach battery until the house batteries are fully charged.

[vito.a]

Your Dynasty should charge the chassis batteries after the house batteries are fully charged. Not charging is a common issue.
It's caused by the "Big Boy" solenoid not closing and making the proper connection. There are large copper contacts within the Big Boy (located in the rear run box on the right side of the engine bay) and they come from the factory with some not very good dielectric grease that tends to burn.
You can replace the Big Boy. They are about $200 on eBay but even a new one will malfunction over time. The best thing to do is to remove it, disassemble it and clean the contacts. Put the large copper washers in a drill and spin them while applying fine sand paper to the surface. Apply some quality Dielectric grease.
Reassemble everything and you should be good.
Be careful working in the rear run bay as there are lots of high amperage contacts in there.

Attached are detailed rebuild instructions courtesy of Mike Canter.

[MHROOKIE]

Oldguy70,
how about sharing your cheap fix for the rest of us. I'm interested since my AMP-L-START is not working and I cannot get ahold of them.

Thanks,
Kurt

[oldguy70]

I went to a electronics shop and bought 2 40 amp diodes and wired them in parallel between the house and chassis batteries so the current will only flow from the house
batteries to the chassis battery. I used the heavy diodes as I ski and when I start up
and if I forget to use the big boy I won't burn up the diodes. I always have the generator running while startup so I have all the amps that I can get. The Amp L Start I gather won't start charging the chassis battery until the house batteries are up. For me the chassis battery is the most important battery to be up so this way it is always being
charged.

[twinboat]

Originally Posted by oldguy70

I went to a electronics shop and bought 2 40 amp diodes and wired them in parallel between the house and chassis batteries so the current will only flow from the house
batteries to the chassis battery. I used the heavy diodes as I ski and when I start up
and if I forget to use the big boy I won't burn up the diodes. I always have the generator running while startup so I have all the amps that I can get. The Amp L Start I gather won't start charging the chassis battery until the house batteries are up. For me the chassis battery is the most important battery to be up so this way it is always being
charged.

The problem with this work around is if your not on shore power or running the generator and something is drawing down the chassis batteries, the diodes will let the house batteries pass their current thru to the chassis battery.

You then end up with all dead batteries.

That is why voltage sensing devices disconnect below 12.6 volts.

[Ivylog]

While dirty contacts in the big boy is a common problem it is not your problem because when using the boost to start the engine the big boy is providing that connection so the contacts in it are in good shape. 8 is pointing to the bidirectional board, acronym of bird and it is not telling the big boy to connect and charge your engine batteries. Your problem could be as simple as the fuse referenced above is blown. When energized the big boy is hot to the touch so if it is not hot, it is not charging the engine batteries when hooked to shore power by the inverter/charger. You do not need to add diodes or another charger, you need to fix the bird relay so that it energizes the big boy.

[96 Wideglide]

Originally Posted by vito.a

Your Dynasty should charge the chassis batteries after the house batteries are fully charged. Not charging is a common issue.
It's caused by the "Big Boy" solenoid not closing and making the proper connection. There are large copper contacts within the Big Boy (located in the rear run box on the right side of the engine bay) and they come from the factory with some not very good dielectric grease that tends to burn.
You can replace the Big Boy. They are about $200 on eBay but even a new one will malfunction over time. The best thing to do is to remove it, disassemble it and clean the contacts. Put the large copper washers in a drill and spin them while applying fine sand paper to the surface. Apply some quality Dielectric grease.
Reassemble everything and you should be good.
Be careful working in the rear run bay as there are lots of high amperage contacts in there.

Attached are detailed rebuild instructions courtesy of Mike Canter.

This ^ is my guess as well!

An '08 Dynasty, doesn't need a seperate trickle charger for the chassis batteries!