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Old 11-17-2009, 05:48 PM   #1
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Separate Electrical systems?

Is there anything in the cabin that could run down the coach batteries (2004 6.0 Frod diesel)?

Ever since I had the alternator replaced by a (certified Ford dealer) the (new) batteries run down in 48 hours just sitting in the driveway. My guess is they rewired something incorrectly when they replaced the alternator, but I can't prove it.

What could run down two large batteries that quickly? The ofther thing is that everything in the cabin works fine; while the coach batteries are dead.

(appologies if this topic has been addressed before, I did look through the forum before posting)

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Old 11-17-2009, 07:59 PM   #2
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Re: Separate Electrical systems?

From what SMB told us on our orientation. The only thing that can run the starter battery down is keeping the radio switch on an "ON" position. while the engine is off.



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Old 11-17-2009, 10:05 PM   #3
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Re: Separate Electrical systems?

Like Ray said the radio switch is the #1 culprit. Also make sure your dome lights are not on. I'm not sure if a 2004 has one of those under the hood lights, but that got me on my Chevy one time. The shop bent it down and it stayed on with the hood closed. I would also look at anything that runs off the starting batteries themselves with the key off. My backup lights will turn on with the key off, but I would think you would see something like that.
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Old 11-18-2009, 07:20 AM   #4
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Re: Separate Electrical systems?

Thanks for the replies. I've had several RVs and vans, I can't imagine anyone would design one that ran camper equipment off the starter batteries. I'm not the first owner of this SB but it is a pretty stock floor plan. The issue traces directly back to when they replaced the alternator.

I checked the radio thing and that made no difference. The lights would be visible in the dard. Checked that. I just want to check all my options before I pay someone $80 an hour to do diagnositics.
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Old 11-18-2009, 04:00 PM   #5
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Re: Separate Electrical systems?

Actually, the radio switch works about the opposite. When switched 'ON' it allows the radio to run off the house battery, when 'OFF' it returns the radio to normal factory operation - off the starting battery when the key is in 'RUN' or 'ACC'

It should not be causing your issues.

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Old 11-18-2009, 06:21 PM   #6
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Re: Separate Electrical systems?

I forgot, I think Mike is correct on that one; it runs down the house battery with the key off, at least that's what they told me when I picked up the van. But I also have an amplifier on the stereo that will knock down my starting battery when I use my stereo. For some reason SMB said it had to be wired that way. My sub woofer amp is wired differently though.
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Old 07-27-2010, 10:55 PM   #7
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Re: Separate Electrical systems?

UPDATED 30OCT10. Here's a 12V electrical schematic diagram of my 2010 SMB West based on hand over hand inspection, multi-meter testing, and help from an electrical engineering friend. Peter DelToro (SMB West system guru) reviewed it and said it was "good." A summary of component functions is listed below the diagram to explain system operation. Comments are welcome.

Electrical systems are getting more complex with use of electronics (i.e., programmable circuitry) for monitoring and control. Design choices are best communicated with wiring diagrams. For example, I asked for a battery disconnect switch, but got a manual circuit breaker installed upstream of the Automatic Charging Relay (ACR). That prevents the breaker from functioning as a battery disconnect switch because the batteries can not be isolated from all loads (e.g., the charge Wizard stays on no matter what position the breaker is in). Sometimes component line-up matters. The inadvertant good that came of this miscommunication was that I don't have to remember to close the manual breaker in order to allow the alternator to charge my house batteries and I can still remove all but the Wizard load from the house bank (e.g., CO and propane detectors).


1. The Battery Disconnect Switch must be closed to operate the Manual Override (Remote Control Switch) for a van starting battery jump.
2. Van accessories can add load to the house battery bank if the Automatic Charging Relay (ACR) is closed. The charging Wizard pulls power from the house battery bank (and van starting battery bank if the ACR is closed). Ford vans are already known for larger than normal parasitic loads (e.g., 0.3 - 0.85 amps/hour for the first hour after turning the key off, compared to 0.05 amps/hour for other vehicles). Just something to keep an eye on if you're not charging battery banks every couple of weeks or so... Ford's wet cell drains first and most.
3. Shore power converter/charger output can be fully powered by a 15 amp commercial outlet hook-up (1,000 Watts / 120V = 8.3 amps maximum need)
4. Water can collect in the house battery box via the Hydrogen vent located on the side of the van, and even though SMB West installed floor drains in each battery box you can still have a damp environment that invites terminal corrosion.
5. AGM batteries should not be charged above 14.6V @ 68 degrees F per Deka specification. The 2010 Ford OEM 155-amp alternator will stop charging @ 14.3V according to Ford. The charge Wizard tops out at 14.4V. Based on a Deka provided chart (see their on-line tech manual) you should avoid charging when the batteries experience temperatures above 110 degrees F.

AUTOMATIC CHARGING RELAY (ACR) FUNCTIONS[listen for the clicking sound... switch action]
Closes after:
30s @ 13.5V
90s @ 13.0V
remote control switch closes (10 min. delay before returning to auto function)
Opens after:
10s @ 12.35V
30s @ 12.75V
Lockout @ 16.2V
Lockout @ 9.6V
remote control switch opens (remains open for 30s after returning to auto function)

WIZARD FUNCTION (Total Charging Management System)
1 Normal. Converter output = 13.6V until battery @ 13.2V; LED flash once/second
2 Boost. Converter output = 14.4V until battery @ 13.6V; LED on (returns to Normal @ 90% charge in 2 - 3 hours) [this is also known as a fast charge]
3 Storage. Converter output = 13.2V if no battery activity for ~30 hours; LED flash once/5 seconds
4 Desulfation. Converter output = 14.4V for 15 minutes every 21 hours in Storage mode; LED on [this is also know as equalization]
Manual override. Press button on wizard to cycle through modes (may be superceded by automatic function and returns to Normal after 4 hours)

Supplies DC @ 13.6V
Tapers charging current as battery becomes charged [refer to charge Wizard functions]
Trickle charge when battery is full [refer to charge Wizard functions]
Current reduced or limited in case of terminal short detection
Power output decreased if over temperature condition exists (>110 degrees F?)
Input >=132V will shut down unit and it will turn back on when voltage returns to normal
Attached Thumbnails
2010 SMB West 12V System Diagram.jpg  
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Old 09-04-2010, 07:00 PM   #8
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Re: Separate Electrical systems?

Mayby they installed a Alternator that has a bad Diode .
Its very common to have a parasitic draw from a bad diode.

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