Chassis battery charging w/ shore power (again)?

Freds342 · 07-18-2011, 09:11 PM

Does anyone know if my 2005 342DS XL chassis battery should charge when plugged into shore power?

It ain't, and thought I'd ask before troubleshooting and modifying.

Thanx!

Fred

kenandterry · 07-19-2011, 06:31 AM

I've sometimes gotten confused (not hard to do) when people start discussing the two different types of batteries in RV units. Chassis battery, engine battery, coach battery..........whatever battery.

My definition is engine battery........

located in the engine compartment, and is no different (other than size or amperage) than the battery in any motorized vehicle (car, truck, etc.) and is charged by the vehicle's alternator when running. These days they are all 12 volt, but can also be charged through the 12 volt outlet (previously known as the cigarette outlet) using a variety of charging units IF this outlet is "alive" at all times, and does not become "live" only when the ignition is on.

The coach battery..........

is the battery or batteries used to power the "living part" of any RV unit. They are typically "deep cycle" batteries, and are charged by being connected to a shoreline power cord or through the generator (if equipped) when running.

The charging systems are typically isolated and apply to only one battery or the other...........unless someone knows differently.

jsutherl · 07-19-2011, 10:06 AM

On my unit there is a "battery connect center" located near the coach batteries. What it does is isolate the two battery systems with a large relay. When it senses voltage grater than 13.2 on either battery system it connects the two after a 15 second delay. Once voltage on either side drops to 12.7 it disconnects and isolates the two systems.

When plugged into shore power the converter will cause the voltage to go above 13.2, the relay will close and both battery systems will be charged.

When the engine is running the alternator will cause the voltage to go above 13.2, the relay will close and both battery systems will be charged.

Attached is the instruction sheet for the one installed in mine.
Also attached is a diagram of the same unit.

jsutherl · 07-19-2011, 10:13 AM

Attached are two pictures there you can see the view under the step of my Georgetown. You can see the battery tray (without batteries installed in this picture) and you can see the battery control center with it's white paper label.

The second picture is a closeup of the battery control center.

Freds342 · 07-19-2011, 10:32 AM

Thanks, guys!

Jsutherl nailed it. Mine has the same setup, and the chassis battery should charge when plugged in to shore power.

The schematic and block diagrams will be a huge help, and go in my very sparse folder. I got no paperwork with this coach, as it was a repo.

I gotta go figger out why it ain't. I'll report back when I get it done.

Oh, Jsuther, from the other thread, the difference between RG-59 and RG-6 is size and bandpass, not impedance. RG-6 is larger, so the factory "Technician" just peeled back the braid and used screw-on connectors over the foil. It would work until it got jiggled a few times.

jsutherl · 07-19-2011, 10:40 AM

Quote:

Originally Posted by Freds342

Thanks, guys!
Oh, Jsuther, from the other thread, the difference between RG-59 and RG-6 is size and bandpass, not impedance. RG-6 is larger, so the factory "Technician" just peeled back the braid and used screw-on connectors over the foil. It would work until it got jiggled a few times.

Doh, I read that as RG-58 somehow. Sorry. Not sure how I did that. Probably because I'm a HAM radio guy and everything is 50ohm.

K7HUW

Freds342 · 07-19-2011, 10:45 AM

And I'm a just-retired Avionics Engineering Technologist, and for-damn-sure-not-knowitall!

I retired from Northrop Grumman in December, and still haven't caught up with the Honey-do's.

Agin, thanks for the schematics. I'm headed outside right now to fix the control center problem and install the rear TV.

jsutherl · 07-19-2011, 10:52 AM

Quote:

Originally Posted by Freds342

And I'm a just-retired Avionics Engineering Technologist, and for-damn-sure-not-knowitall!

I retired from Northrop Grumman in December, and still haven't caught up with the Honey-do's.

Agin, thanks for the schematics. I'm headed outside right now to fix the control center problem and install the rear TV.

Good luck on your changes! Let us know how it goes.

I'm a systems engineer at Earthlink. And I'm a long way from retirement. I do care and feeding of high end servers in datacenters. Datacenter power systems (big UPS's, big battery banks, big inverters and big generators) and datacenter cooling.

Thankfully a lot of that applies to fixing my motorhome. No professional experience in plumbing but thankfully my step-father taught me that.

cfsoistman · 07-19-2011, 11:06 AM

Quote:

Originally Posted by jsutherl

On my unit there is a "battery connect center" located near the coach batteries. What it does is isolate the two battery systems with a large relay. When it senses voltage grater than 13.2 on either battery system it connects the two after a 15 second delay. Once voltage on either side drops to 12.7 it disconnects and isolates the two systems.

When plugged into shore power the converter will cause the voltage to go above 13.2, the relay will close and both battery systems will be charged.

When the engine is running the alternator will cause the voltage to go above 13.2, the relay will close and both battery systems will be charged.

Attached is the instruction sheet for the one installed in mine.
Also attached is a diagram of the same unit.

You're 100% correct. Just went through the whole Battery Charging check last weekend. I had an Inverter installed a few years ago and recently noticed that my Low battery Indicator light came on very quickly after disconnecting from shore power with very little running off of the Inverter. After checking everything we found that the Installer left the Converter in line with the Inverter so I was using battery Power to run the Inverter which was running the Converter to charge the batteries I was using to run the Converter. Unplugged the Converter and problem solved. I still have a Charger with the Inverter, 3 Stage, and still have my 12 volt system in tact. it was interesting hearing the relays kick on and off as we disconnected from shore power. We had meters on everything and found out the system worked as describe once the Converter was Unplugged. I now have a spare charger if my primary goes up.

jsutherl · 07-19-2011, 11:30 AM

That's the same thing I did. I left the converter in place and just pulled it's plug. My thinking was the same, if the charging circuit ever fails in the inverter I can use the converter instead. Maybe someday I'll remove it and reuse those wires to run something more fun.

Freds342 · 07-19-2011, 02:55 PM

Okay, if anyone's interested, I found f-5, a 5-amp fuse blown on the control board. It is the aux start fuse, which is for sure why I couldn't get the house batteries to help me start the engine, but I have no idea why (or if) it had anything to do with the lack of charge of the chassis battery from shore power.

When I replaced the fuse, the chassis battery started charging, though.

May have been an air bubble in the line somewhere.

I'm certainly going to keep an eye on it though! Gonna do a shakedown cruise to the Kern River next week, a 120 mile trip with some really steep, winding mountain roads. We'll see what else we can find!

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