Chassis battery not charging using shore power

[Old Bounder]

Originally Posted by frede

I unplugged the power, still had 12.25v at the terminals. Ohm meter showed open, unless I reversed the leads. You're right I have no Fuse #22.

What you are reading, on the yellow wire, is the no-load output of the voltage sensing circuits on the PC board, with no active inputs. Unfortunately RV-CP does not provide a detailed schematic of just how that circuit works.

The explanation for the different readings, when meter leads are reversed, is that the solenoid coil is open and reversing the leads actually allows you to detect the diode in the circuit output stage. You are not reading anything forward through the open solenoid coil to ground.

When you install the new solenoid, that 12.25 volts should simply vanish, as it doesn't have the capacity to support any current flow, until a charging level input is applied from the alternator or converter source.

[TBray]

Our 2003 Fleetwood Expedition (DP) doesn't appear to charge the chassis battery from shore power. After reading through all this I started to doubt if this might not be correct.

First, I have managed to talk Fleetwood (or whatever they are called now) into sending most of the wiring and plumbing diagrams. It seems that they have many of the drawings in PDF format, you just need to ask, and possibly ask a second time to get the ones that are missing. They will email them to you.

In the Chassis wiring diagram it shows the Isolator / Emergency Start solenoid which does tie the two battery banks together. The two wires going to the solenoid coil come from the Emergency Start switch up by the driver, it doesn't appear to be driven by anything else. The switch by the driver is strictly momentary operation.

I also have two controls on the master control panel that allow disconnecting either bank, or both, from the MH. In testing I have found that they do seem to work as expected. I have used those primarily when working on the electrical system so I don't have to pull fuses.

Having said all that, the coach batteries and the chassis batteries are different and I would assume will charge differently. In my case there are 4 6V golf cart batteries for the house side and a pair of diesel rated 12V batteries for the chassis. Using a single charger to charge both banks is not optimal as one of the two banks will probably suffer from either over or under charging.

What I have done when the MH is going to sit for an extended period is to plug it into shore power to keep the house batteries charged. I picked up one of those little Battery Tender chargers (around $40 depending on where you get it) and put it on the pair of chassis batteries to keep them topped off. The Battery Tender isn't particularly powerful but it is a multistage charger and many of my friends use them to keep the batteries in their fishing boats charged.

Be aware that lead acid batteries will self discharge even when not connected to anything. Depending on the age of the batteries they can be damaged in as little as 3 months when subjected to temperature extremes and if new, in a climate controlled environment, may last almost a year before they can't be rejuvenated.

Tom

[normandlegra]

It seems that there are no standards in these crappy USA built mh's and that's a shame.
PITA is the word to buy one of them and I regret it !

[montyhp]

Originally Posted by Old Bounder

No, it's not normal at all. Frede's BCC circuit board (at release level E) does not have a fuse #22.

The board controlled solenoid pick voltage, (the 12.6), would Not appear on the small terminals (yellow wire) unless the BIRD function circuitry is signaling that charge voltage (13.2+) is available at the batteries. This suggested, correctly, that the coach was plugged in and the converter was running.

The "Boost" switch applies actual battery voltage, which would be 13.4+ with the converter running, directly to the solenoid.

Since all conditions seem to be present at the solenoid to close the contacts, I feel certain that it is defective.

Mea culpa, I thought he was talking about the main leads

[frede]

Originally Posted by Old Bounder

...When you install the new solenoid, that 12.25 volts should simply vanish, as it doesn't have the capacity to support any current flow, until a charging level input is applied from the alternator or converter source.

Should know this weekend, I ordered the new solenoid.

[Old Bounder]

Originally Posted by TBray

Our 2003 Fleetwood Expedition (DP) doesn't appear to charge the chassis battery from shore power. After reading through all this I started to doubt if this might not be correct.
Tom

Your Expedition was most certainly designed to charge both the house batteries AND the chassis batteries from EITHER the engine alternator OR the converter (most likely an Inverter/charger in your case). Fleetwood has used this technique for over twenty years.

The two battery disconnect switches that you mentioned, control two large solenoids (the actual disconnects) located in the Battery Control Center (BCC) Box. This box also contains the circuit board that directs the Isolator Solenoid, when to close, to connect the battery banks together for charging.

The BCC box is either manufactured by Intellitec or by RV/CP. If you need diagrams and/or troubleshooting/testing procedures, for either of those two boxes, I can provide them. Just determine which you have.

[frede]

Originally Posted by frede

Should know this weekend, I ordered the new solenoid.

Any helpful hints or things to watchout for when replacing the solenoid?

[Old Bounder]

Originally Posted by frede

Any helpful hints or things to watchout for when replacing the solenoid?

Just be aware of presence of power on those bus bars if you don't disable it beforehand.

I would remove shore power, and disconnect the negative battery cable from both battery banks.

Document the connections to the PC board that you may have to remove to gain access to the solenoid.

[TBray]

Old Bounder:
The BCC box is either manufactured by Intellitec or by RV/CP. If you need diagrams and/or troubleshooting/testing procedures, for either of those two boxes, I can provide them. Just determine which you have.

I need to remember that our Fleetwood is a 2002, it doesn't stay 13 years old when a new year begins.

Yes, I would appreciate any manuals, diagrams or troubleshooting information.

I think the BCC has a RV Customs label on it. The owners manual does say that the engine, generator, and shore system should charge both the chassis and house battery systems. I don't think the emergency start works and I know shore power isn't charging the chassis batteries.

I have noticed that sometimes there is sort of a relay chattering noise that comes from somewhere in the electrical area. That could be related. I haven't heard it since I put the Battery Tender on the chassis batteries.

[Old Bounder]

Originally Posted by TBray

Yes, I would appreciate any manuals, diagrams or troubleshooting information.

I think the BCC has a RV Customs label on it. The owners manual does say that the engine, generator, and shore system should charge both the chassis and house battery systems. I don't think the emergency start works and I know shore power isn't charging the chassis batteries.

I have noticed that sometimes there is sort of a relay chattering noise that comes from somewhere in the electrical area. That could be related. I haven't heard it since I put the Battery Tender on the chassis batteries.

Diagrams and test procedures sent in a PM.

Clicking in a defective isolator solenoid/relay is common.

[ga traveler]

Originally Posted by TBray

[I]Old Bounder:


I have noticed that sometimes there is sort of a relay chattering noise that comes from somewhere in the electrical area. That could be related. I haven't heard it since I put the Battery Tender on the chassis batteries.

As a 15 year tech on Fleetwood products, If the chattering sound is inside the coach and you hear it when you shut off the generator, It is the changeover switch chattering. This is normal for The box that Fleetwood uses.

[Old Bounder]

Originally Posted by ga traveler

As a 15 year tech on Fleetwood products, If the chattering sound is inside the coach and you hear it when you shut off the generator, It is the changeover switch chattering. This is normal for The box that Fleetwood uses.

This is correct, and can be explained by the fact that while the generator is cycling down, the TX switch will dropout, and then attempt to reactivate a couple of times, as the voltage from the generator decays to zero. Not the best design.

The chattering 12V relay that TBray is hearing (that can be suppressed by the battery minder) is the isolator relay. The usual cause of this is conflicting characteristics between the converter and the BIRD function within the BCC, in combination with the normal parasitic current draws in RVs.

Many modern converters use the 13.2vdc level as their chosen "Float" voltage. This is significant because the design specifications for a 12V battery is actually 13.2V (2.2V cells X 6 cells = 13.2V). The BIRD function also uses 13.2V as the threshold voltage to close the isolator relay.

Any negative variation or fluctuation in the converter output, or voltage sensing interpretation in the BIRD, can cause the isolator to drop out, and then close again, as the condition subsides.

The usual cause of this phenomenon is a weak chassis battery, that pulls the converter voltage below the 13.2V threshold, in combination with a weak or failing isolator relay, confusing the BIRD.

If the converter would immediately jump to Absorption or Boost mode, when the isolator closes, and charging current is drawn by the chassis battery, the conflict wouldn't present itself. Unfortunately, some actions, and reactions, are more instantaneous than others.

[frede]

Originally Posted by Old Bounder

Just be aware of presence of power on those bus bars if you don't disable it beforehand.

I would remove shore power, and disconnect the negative battery cable from both battery banks.

Document the connections to the PC board that you may have to remove to gain access to the solenoid.

The Isolator/aux start/charge solenoid is changed and my chassis battery is now charging

[Old Bounder]

Originally Posted by frede

The Isolator/aux start/charge solenoid is changed and my chassis battery is now charging

Good show! Fred. Happy camping