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Mennoted · 11-28-2015, 03:41 PM

Sorry for yet another thread on this, but I've been surfing through past threads all afternoon, and can't seem to find just the right information, or when I thought I did, most of the links to tech info were not functional anymore.

I have a 2005 Damon Daybreak, and I'm trying to locate a schematic of the BCC, the relays and the fuse assignments. I have essentially two problems:

1. The disconnect switch/isolator for the house batteries isn't functioning. The relay is apparently stuck in the closed position. The house DC is on all the time, and operating the rocker switch doesn't disconnect the batteries. I'm on shore power now, so we're maintaining a charge, but that won't be the case when I get on the road...which leads me to problem number two:

2. I'm having what seems to be a very common problem - the house batteries aren't charging when the engine is running, but if I hold the emergency-start switch closed, we get a charge.

I've seen some photos of the BCC with the two solenoids, but the wiring and the fuses aren't clearly defined. On the lower (plain silver) solenoid the white control wire is ground, and when I jump 12v to the other small terminal (pink wire) the solenoid closes, and we get a charge.

So I'm assuming that the emergency start switch and the charging system/BCC at some point share the same conductor (pink) that actuates the relay and connects house and chassis batteries.

What I'd like is a wiring schematic for the BCC so that I can troubleshoot the problems. I understand that the BCC won't make the connection to the house batteries until the chassis battery is sufficiently charged, but where does that switching happen?

I also believe that the disconnect solenoid for the house is an intermittent type that toggles on and off, which prompts the question...how do I toggle it OFF?

Gary RVRoamer · 11-28-2015, 04:03 PM

Intelletec made several variations of their BCC, plus there are related products using their Big Boy disconnect solenoid or BIRD (Bidirectional Isolator Relay) device. If you could identify which one you have, more help would likely be forthcoming. The big Intelletec BCC (#769, #861, or #886) is a pricey piece of gear and usually found only in higher end rigs.

Here are some of the common Intelletec devices for RVs:
Products - DC Power Management - Intelligent battery charging -

And some other related products:
Products - DC Power Management - -

In basic configurations, a high capacity solenoid (like the Big Boy) is activated in two ways: (1) via the Emergency Start switch, or (2) when the engine is running (ignition switch on).

The battery Disconnect is usually a different solenoid than the Aux/Emergency start one. It is operated by the house battery disconnect switch.

chboone · 11-29-2015, 10:22 PM

What your describing sounds similar to an RV Customs Products BCC. You may want to give them a call to see if they can help you.

RV Custom Products
14000 Anson Ave,
Santa Fe Springs, CA 90670
(562) 921-8353

If you still have the Sea Breeze in your signature the attachment may be of interest for it.

twinboat · 11-30-2015, 05:28 AM

The interconnect relay ( big boy ) on most late model MHs will not connect, until the battery that is receiving the charge reachs 13.5 volts.

In a by-directional system, either charging source ( alt or charger ) will cross connect the 2 banks at 13.5 volts.

You mentioned one solenoid staying engaged. Have you unplugged the shore power and tested it ?

Mennoted · 11-30-2015, 07:40 PM

Thanks for the help everyone. I think I've found the details I need. There is a lengthy thread that covers the systems and relays/isolators and the BIRD system in great detail for anyone else looking for similar information: Let's Talk Batteries, Isolator and Voltages. A wealth of information in that one thread.
Boone, tks for the schematic, but I've since traded the National for the Damon. Sorry, I forgot to update that. Color me sheepish.

Twinboat, I hadn't checked that relay without shore power, but as soon as all this rain stops I will. I think I'm getting things sorted out. I'll let you know.

If anyone is looking for a service manual for the Intellitec BCC (or at least one variation) I found this online and it has been helpful: http://www.intellitec.com/assets/pdf/5301087new3.pdf

markmiiler · 12-01-2015, 06:10 PM

Intellitec CS number is 941-697-9927 or 800-251-2408 and have your BCC number

Mennoted · 12-03-2015, 06:24 AM

Thanks for the suggestion Twinboat. I disconnected the shore power and the house disconnect functioned normally. When the shore power is connected that isolator/relay/solenoid stays on, and the disconnect rocker switch just inside the door doesn't override that. All the DC circuits (lights, etc.) are on. So apparently you can't disconnect the house while on shore power. I can't believe that I never noticed that before.

Re the charging of house batteries...I'm getting 14+ volts to the chassis battery (engine running and SP disconnected) but no charge to the house. From what I've been reading, the BCC can switch that on and off intermittently, so it's hard to know for sure if the alternator is charging the house batteries. (the emergency start switch works, so I know that the relay/solenoid is OK)

twinboat · 12-03-2015, 07:06 AM

Some isolator circuits have an overvoltage protection. How much over 14 volts is the alternator charging.

It should max at 14.2 and drop back once the start batt is charged up.

Mennoted · 12-06-2015, 07:03 AM

Twinboat,

With shore power disconnected, engine off, I'm getting 13.2 volts at the BCC on the house circuit. (both terminals on the top relay, and the left side of the isolator (lower) relay.

I'm getting 12.7 volts at the chassis side of the (lower) relay. With the engine running the charging voltage is 14.2, which you said was the upper limit. If I jump 12 volts to the isolator relay (bottom relay, left small gauge terminal) the relay closes and the voltage is 14.1 all around.

I'm guessing that at 13.2 the BCC isn't calling for a charge on the house batteries. (?) Maybe I'll draw the house batteries down a few volts and then see if the isolator relay closes.

Thanks for the suggestion

jdauwen · 06-18-2019, 04:14 PM

As an electronics technician - both military and civilian - and an engineer - I have not yet figured out why there is no power to the ignition or dashboard of my Damon Daybreak motorhome after storing it over the winter, and this problem just cropped up!
Unbelievable - but it seems to be more common than you would think.
House power is good - battery cables/connections are good.

The driver's side fuses suck because they are barely accessible. Probably will remove the driver's chair to get access. I have eliminated pretty much everything on the +12 and ground side.

Now it is time to feel the pain, remove the chair, crawl, and beg for mercy...LOL

John Auwen
jdauwen@yahoo.com