Care to help me diag BCC chassis battery charging issues on shore power?

[TT_Vert]

I know this topic has been beat to death around here and I did read pretty much every post on it. I've gone through a troubleshooting guide/manual someone has posted from here (I'm unsure if it applies to mine however). When reading it and discussing revisions however I don't know how to find my board revision. I don't see anything on the PCB indicating revisions number but on the fog light relay I see the (Intellitec 00-00287-001 26294 F/W BCC W/D).
Maybe that's revision D? In my situations I can jumper the bottom right solenoid (I believe this is the coach battery solenoid as it is fed by the +12 side of the battery.

I've included some pics of what I am seeing. Does anyone know what those two large gauge (8AWG ish) are that go behind the BCC PCB? The top one comes from the left side of the top left solenoid and the other comes from the right side of the top left solenoid

When doing testing my coach batteries were above the 13.6V threshold to actually charge the chassis battery. (If I'm actually on PCB Rev. D) It's 13.2V otherwise and I'm definitely above that. So I feel the criterial is met to engage this bottom right solenoid. I know this solenoid is good because I can power it and get continuity across it and also because when I use the aux start switch and monitor it also bridges the coach and chassis positive batteries (I assume w/ that solenoid on bottom right but im here alone so I cannot have someone in the cabin flipping switches for me.).

I feel I'm missing something or not fully understanding how this system works (This is true). If anyone knows for a fact what the top two solenoids do and If I'm in fact correct that the bottom left (Which goes to positive of the two 6V seriesed coach batteries) and the bottom right (Which goes to positive on the chassis battery).

I also have some random relay just sitting in here (not sure if it's a type A or B). 86 goes to chassis ground and 85 is a white wire that comes in from the wire loom on bottom of the housing. Pin 30 of relay comes from J10 which says spare on left and CHAS. BD on right of PCB and 87 Goes to pin44 on the bottom inline connector. Anyone have any idea what this is for? Had contacts wrapped in electrical tape and the relay was just sitting at the bottom of the housing, if that's factory it's pretty shoddy work. Also crimped all back wires for the last few inches so it looks like someone just bought a premade relay harness and spliced it in.

I'm not sure of the circuit breakers purpose but I do have continuity through it and all fuses are good at the BCC PCB.

Any help or insight would be so very helpful, i'm thoroughly confused on this one.

[Skip426]

I've been trying to help another member with issues and I'm seeing way too many variants in the wiring installs .

I'll pull down your photos and see what I can add , about the only thing I can say , is the two red wires going behind the board , are power leads to the two bolts through the fuse panel , suppling the long line of fuses.

His coach doesn't have as many options and the lower bolt and feed wire ( Red box ) isn't there to supply the unused fuses in his panel. ( Yellow box)

[Skip426]

Ok relay/solenoid identification .

Intellitec , latching relays; yellow box , chassis battery disconnect , red box coach battery disconnect .

Emergency start solenoid , green box .

Chassis battery charge solenoid blue box , Not 100% sure on that one as most of the wires from the larger terminals don't show in the picture .

The emergency start , could be a momentary solenoid , as only intended for use until the engine starts from the coach batteries .Controlled by holding button on the dash.
The charge solenoid would have to be constant duty , as it could be engaged for days on end while on shore power .
Now control of the charge solenoid , I have not been able to get too much info on this RV Custom Products circuit board , but I'm thinking the resistors, chip and transistor in the corner of the board are in place to control the powering of the charge solenoid .Orange box

[Skip426]

OK, after a careful re-read of your post and taking your photo to my DW's desk top with 23" hi-def monitor some different findings .

I believe you are correct about the dual function of the lower right solenoid . Emergency start and battery inter connect for charging the chassis battery .
The upper left solenoid , is an " Aux Ignition " solenoid , in place to take amp load off the dash ignition switch .

The Aux ignition solenoid ( yellow arrow ) , is powered from the chassis battery disconnect relay, ( copper strap ) and the wire from the same side (green arrows) powers fuses connected to the bolt through the board ( another green arrow ) . I think if you look carefully under the wiring connector ( blue box) , you'll see printing on the board saying chassis battery .
The heavier red wire ( red arrows ) connects to the circuit board at the bolt through the board at the red arrow with printing on the board saying IGN.

I'm still of the mind that the function of the resistors and transistors on the board , are to control the chassis battery charging , and the no charge issue will be somewhere in there .

[Skip426]

Question ?

With the engine running , is the yellow wire , to the lower right solenoid " hot ", ?

That would indicate that solenoid is also in the circuit to charge the coach battery from the alternator.

On the added relay connected to , pin 44.

Can you see enough of the printed circuit to figure out what fuse powers pin 44?
If I'm seeing the wiring to that added relay correctly , it's always active, unless the pin on the circuit board is somehow switched , to power the relay down.
I'll blow up the circuit board picture for a closer look.

[TT_Vert]

Originally Posted by Skip426

Ok relay/solenoid identification .

Intellitec , latching relays; yellow box , chassis battery disconnect , red box coach battery disconnect .

Emergency start solenoid , green box .

Chassis battery charge solenoid blue box , Not 100% sure on that one as most of the wires from the larger terminals don't show in the picture .

The emergency start , could be a momentary solenoid , as only intended for use until the engine starts from the coach batteries .Controlled by holding button on the dash.
The charge solenoid would have to be constant duty , as it could be engaged for days on end while on shore power .
Now control of the charge solenoid , I have not been able to get too much info on this RV Custom Products circuit board , but I'm thinking the resistors, chip and transistor in the corner of the board are in place to control the powering of the charge solenoid .Orange box

You are correct, the bottom right solenoid is a momentary (not latching). I guess I am confused how you would interconnect the coach to main battery for charging UNLESS the top right latching relay provides the charging current right from the BCC board rather than just paralleling the two positive battery terminals? I'll have wifey today so she can press buttons while I use my DVOM to see. So you think that that bottom right momentary switch is JUST for emergency start from the aux start switch on dash and nothing else? That'd make sense as it just bridges the coach to main hot terminals.

Originally Posted by Skip426

OK, after a careful re-read of your post and taking your photo to my DW's desk top with 23" hi-def monitor some different findings .

I believe you are correct about the dual function of the lower right solenoid . Emergency start and battery inter connect for charging the chassis battery .
The upper left solenoid , is an " Aux Ignition " solenoid , in place to take amp load off the dash ignition switch .

The Aux ignition solenoid ( yellow arrow ) , is powered from the chassis battery disconnect relay, ( copper strap ) and the wire from the same side (green arrows) powers fuses connected to the bolt through the board ( another green arrow ) . I think if you look carefully under the wiring connector ( blue box) , you'll see printing on the board saying chassis battery .
The heavier red wire ( red arrows ) connects to the circuit board at the bolt through the board at the red arrow with printing on the board saying IGN.

I'm still of the mind that the function of the resistors and transistors on the board , are to control the chassis battery charging , and the no charge issue will be somewhere in there .

I think you were on the right track originally as that solenoid would probably get very hot if you always had to apply 12V to it to keep the coach/chassis batteries bridge to charge the chassis batteries when the criteria to do so was met. As you said, it could be many hours (probably not days as I assume it'd switch back to charging coach batteries when below 13.2V).

That top left solenoid that you called aux ignition has the left side go to the back of the BCC and the right also goes to back of BCC. It also has the link bar to the top right solenoid but what is that solenoid for (Main switch).

What i'm starting to think is this.

1. Bottom right momentary is for aux start only
2. Bottom left solenoid is to isolate coach batteries (Aux switch in coach)
3. Top left is some type of ignition solenoid(I don't quite understand this one yet)
4. Top right solenoid is to isolate chassis battery (Main switch in coach)

I may be wrong but I'm thinking this for charging the main from inverter:

the bottom higher gauge wire from BCC goes to left leg of top right solenoid. That latching solenoid is engaged and charging current comes through bcc high gauge wire to charge the chassis batteries. This is pure speculation on my part but I first need to understand how it's SUPPOSED to work before I can determine why it isn't working.

I think you are right and there is probably some comparator in that top left U1 chip. Something like, if coach battery >= to 13.2V send pin 2 high which enables a relay to trigger the latching solenoid. And another to reverse this. This also is pure speculation and above my pay grade. it's a pretty simple coard w/ 1 what appears to be mosfet, 3 caps, 1 tranny and a few resistors./diodes. I really cannot see that any one of them would only drive or or the other given there is only one tranny and 1 mosfet they have to be shared by both solenoids IMO. maybe a bad diode? I'll have to go check that out.


As far as your last question, is pin 44 the white wire in that 8 pin inline connector bottom left? How do you find pin#s, etc? I'd like to see any doc you may have if you don't mind sharing them.
Dave

[Skip426]

Dave ; there are probably only a handful of members who would recognize the acronym MOSFET

I had to replace one in my rad fan control module .

I,m looking at the pictures and then trying to figure out the company relationship , between Intellitec ( your board manufacturer )and RV Custom Products the manufacturer listed on the board of the other member .

The boards have too many similarities for the companies not to be related .

EDIT: BTW , there are constant duty solenoids available to match the top left and bottom right , can you find a PN on them ?

RE-EDIT, Just found 12 volt 150 amp , continuous duty solenoid, as in your pictures , for $23 CD on Amazon CA.
Double the price of momentary Ford starter relay .

[TT_Vert]

Originally Posted by Skip426

Dave ; there are probably only a handful of members who would recognize the acronym MOSFET

I had to replace one in my rad fan control module .

I,m looking at the pictures and then trying to figure out the company relationship , between Intellitec ( your board manufacturer )and RV Custom Products the manufacturer listed on the board of the other member .

The boards have too many similarities for the companies not to be related .

EDIT: BTW , there are constant duty solenoids available to match the top left and bottom right , can you find a PN on them ?

RE-EDIT, Just found 12 volt 150 amp , continuous duty solenoid, as in your pictures , for $23 CD on Amazon CA.
Double the price of momentary Ford starter relay .

Yeah i know enough to get myself in trouble. I did get a pic and zoomed in (Horrible eyes) to get the PNs for these and one is a TIP42C transistor and i'm not sure of the other yet as it's folded over and the PN is on the other side but it looks like a bipolar transistor. HOWEVER unless a different tranny drives the solenoid on shore power vs. running I cannot see that being the issue as it is properly energizing that isolation relay (solenoid) when engine is running, just not on shore or generator.



I did get ahold of a very knowledgeable person at intellitec who sent me a service manual. So far it's helpful in that it has pinouts and a bit of theory of operation but still doesn't solve my issue. I'll include it here for others but it does appear that that momentary relay is actually used to tie the two positive terminals of the batteries together for charging both. And you were dead on that the 2nd non latching momentary relay is for ignition. What he told me is very helpful

In essence, if the Chassis battery is not charging it might be due to the manual resettable circuit breaker being tripped and it needs to be reset in or to deliver the charging potential to the Chassis battery or the printed circuit board is not sensing or measuring the voltage being supplied from the converter and is not activating the isolator coil drive output – referenced above at J1 Pins 5 & 6

So my response was

. So my next logical question is how is “charging potential measured or sensed” to power pin 5? This may be where my issue is, wherever the reference source used to determined charge potential to power pin 5 is. Although it’s weird that charge potential is being sensed when ignition is on. I’m wondering if that hokey external relay (sent a pic and wiring details in last email) I have in my box has something to do with this?

I have to agree that these boards are made probably by the same company and just modified as needed. There is no way there is a big enough market to have many companies engineering these systems.

I know the relay (solenoid) isn't the issue as it works fine when engine is running. It's just not getting energized on shore or generator.

Dave

[TT_Vert]

So I was right but am beyond my pay grade now. It's using a quad comparator BA10339 and i think the PNP TIP42C drives the isolation relay but my reverse engineering skills aren't great, especially bend over an RV. The yellow (+12V to isolation relay) going to the base of the tranny so I'm not sure how that'd work. There is also an LM431 driving something, not sure.

Looked at the datasheet for the quad comparator and pin 3 should be Vcc but I get nothing. Somewhere to start at least! Hopefully this tranny drives ONLY the isolation relay because if it drives both then I cannot set that being the issue. I'm also hoping this comparator is only used for shore power and not alternator power as that is working fine. I see that as highly unlikely also though as I'd more than likely have it charging w/ ign. on unless it detects current from the chassis battery side and opens up all relays since it thinks it's running. Again, doubtful but throwing it out there for those smarter than I.


Dave

[TT_Vert]

Originally Posted by TT_Vert

So I was right but am beyond my pay grade now. It's using a quad comparator BA10339 and i think the PNP TIP42C drives the isolation relay but my reverse engineering skills aren't great, especially bend over an RV. The yellow (+12V to isolation relay) going to the base of the tranny so I'm not sure how that'd work. There is also an LM431 driving something, not sure.

Looked at the datasheet for the quad comparator and pin 3 should be Vcc but I get nothing. Somewhere to start at least! Hopefully this tranny drives ONLY the isolation relay because if it drives both then I cannot set that being the issue. I'm also hoping this comparator is only used for shore power and not alternator power as that is working fine. I see that as highly unlikely also though as I'd more than likely have it charging w/ ign. on unless it detects current from the chassis battery side and opens up all relays since it thinks it's running. Again, doubtful but throwing it out there for those smarter than I.


Dave

Disregard the VCC issue, I'm getting 9VDC to Vcc of that chip.

[Skip426]

Dave , I'm wondering , if it isn't time to disconnect the batteries and remove the circuit board to examine the back side for signs of over heating, or a break in the printed circuit ; that's how I found my failed MOSFET .

NOW ; the alternative is , to set up a toggle switch to turn on the lower right solenoid when you're on shore power .

[TT_Vert]

Originally Posted by Skip426

Dave , I'm wondering , if it isn't time to disconnect the batteries and remove the circuit board to examine the back side for signs of over heating, or a break in the printed circuit ; that's how I found my failed MOSFET .

NOW ; the alternative is , to set up a toggle switch to turn on the lower right solenoid when you're on shore power .

I thought of the toggle bit a word thing happens when I do that

1. The mirrors don't work for a few minutes after removing the jumper that powered the solenoid.
2. The hydraulic jack controller board get no power

This is very strange to me as I feel that applying 12v to that site to energize the solenoid is what the bcc does so why does this occurs? I'm going to test the mirrors and jacks while the vehicle is running as the isolation solenoid is actually powered properly at that point.

I still want to find out what this extra relay just sitting in the box is for. I may pull that bcc board today but given I have no schematics I won't even know if I have a broken trace on the board

Dave

[TT_Vert]

Another update. I took the board out and reverse engineered and tested every component. The only one thing I could not test was the TIP42 transistor as it was RIVETED to the board and when trying to check it w/ my DVOM i get about 300mA reverse current on it. I'm sure that is because it's in circuit as i took out the other transistor r(LM431) which was exhibiting this same behavior and it tested fine out of circuit. I tested all diodes and resistors just to ensure something weird wasn't going on. I also reflowed each joint in hopes that maybe I had a dry or cracked joint but no love there either. Only one looked questionable but I had continuity through the via even before reflowing so I knew chances were low it'd fix anything. I'm out of now out of ideas. I notice the yellow wire (Pin 5 on J1 (Isolator relay "hot" terminal")) that should be +12V when the relay is on is showing 18 ohms to ground so no idea what that is about either. The source of 12V for that wire is the collector of the TIP42 (PNP). I suppose I could go back our there w/ my meter to see if the criteria is present to allow the transistor to turn on but i'm about done w/ this thing. I'm thinking of just going w/ this and wiring it to the isolator relay to let it control the isolator relay completely. Intellitec BIRD 00-00362-100. Any opinions on this? See any real issues pulling all BIRD functionality out of the BCC and using this stand alone BIRD to control the isolator relay?


Thanks much
Dave

[computerguy]

When you ran through the troubleshooting in the manual what were the results?
Did it say to replace the board?
If it were me and it said replace the board - I would replace the board.
I am guessing you like to tinker with electronics and looking deeper into a problem that is fixed by simply replacing a part.
Also, you never mention what year a model rv you have. This might help determine which revision board you have.
I don't think it is a good idea replacing a stock BCC with a different BIRD as the BCC does a number of other things than allow charging of both battery banks.