What Charges the House & Chassis Batteries When

[scrubjaysnest]

After looking at house/chassis battery bird wiring diagram I looked under the hood and the magic black box, B.I.R.D, has only four wires. That explains why shore power/ gen set doesn't charge the chassis battery.
I'll most likely leave that alone as cranking batteries have totally different charging curves from deep cycle.

[Oneilkeys]

No... This is the four wire BIRD diagram from Eds post #49 above. The Axis uses the four wire BIRD and charges both battery banks both ways. The fifth wire is for the emergency start switch which Thor wires directly (not thru the BIRD). If your chassis battery is not being charged while on shore power or generator (like mine was when I purchased my coach) it is likely that the same bozo wired yours incorrectly as mine. Another possibility is that you have a bad BIRD (not as likely). You can test this by taking a voltage measurement from the coach battery wire and see if it is the same as the voltage on the house battery. If the voltages are not the same, that BIRD wire is not hooked to the coach battery as it should be. Therefore it is not receiving the correct information to operate. My fix was to hook the wire directly to the coach battery side of the trombetta (with a small fuse) so the BIRD got the correct reading from the coach battery and now it works fine. You can test the chassis battery - BIRD connection the same way. Your coach should charge both both battery banks either from the engine alternator or shore power/generator. If it does not, do thing is wrong.

[scrubjaysnest]

Based on that drawing, 4 wire, and since A: engine start works, B: alternator charges the house batteries, C: shore power/ gen set doesn't charge the chassis battery and none of the wires from the B.I.R.D match whats on the isolation relay; the wire between the B.I.R.D and the engine start switch is missing/gone astray. If that turns out to be the case this will be the second missing wire and I begin to wonder how many others are not there/or where they should be.

[scrubjaysnest]

Here is a pic of the isolation relay and B.I.R.D with some notes.


When aux start is pressed the line marked aux start, yel/blk, rises from 0 volts to chassis battery voltage then a second or so later rises to house battery voltage.

[Oneilkeys]

In the BIRD in my Axis, there are four wires. They are labeled black - ground, white - ignition coil, red coach battery, orange - ignition. Since Thor does not bother to match the color if any wire when they splice into a wire (they just seem to use any color they have at hand) it is difficult to follow the wires from the BIRD to their destination. The Trombetta isolator relay coil has four posts - two large and two small. The two large posts with the big red wires run to the chassis and coach batteries. The two small posts are a ground and power input. As I understand it, the way the system is supposed to be wired is the white isolator relay wire is supposed to go to the power input terminal in the Trombetta to power and open/close the Trombetta. The black wire from the BIRD goes to ground. The ground post from the Trombetta goes to ground. The red wire from the BIRD is connected somewhere to the coach batteries. The orange wire is connected to the right had large post in the Trombetta with a small fuse. When I pulled back the insulation from the wires coming from my BiRD, I found that Thir had spiced an orange wire to the white wire coming out of the BIRD and connected it to the power post on the Trombetta. The black wire from the BiRD apparently went to ground. The orange ignition wire was spliced to an orange wire which was attached to to large right post which is attached to the chassis battery. The red wire was sliced to some other color wire and disappeared into a wiring harness going back into the coach. The ground post at the Trombett was attached to a white wire leading to ground. In my four BIRD wires, three were wired correctly - black, white and orange, although their colors changed making it difficult to determine this. The red wire was not wired correctly. It should have gone back and been attached to the coach batteries. However, when I cut the red wire leading into the BIRD and measured the voltage it was different than the voltage in the coach batteries meaning that it could not have been wired to them, as it should have. My solution was to run the red wire from the BIRD directly to the large left hand post of the Trombetta (which is connected to the coach batteries) thru a small fuse.
On yours, I do not think that the orange wire from the BIRD that the diagram says goes to the engine start switch is missing. It is the wire coming from the large right post of your Trombetta with a small fuse attached. While I cannot be sure without looking at it, it looks to me as if the red wire from the BIRD does not go to the coach batteries as it should.

[Oneilkeys]

Originally Posted by scrubjaysnest

Here is a pic of the isolation relay and B.I.R.D with some notes.


When aux start is pressed the line marked aux start, yel/blk, rises from 0 volts to chassis battery voltage then a second or so later rises to house battery voltage.

When you push the emergency start button, it does the same thing that the Trombetta does - it connects the two battery banks for as long as you hold on.

[Chance]

Originally Posted by scrubjaysnest

Based on that drawing, 4 wire, and since A: engine start works, B: alternator charges the house batteries, C: shore power/ gen set doesn't charge the chassis battery and none of the wires from the B.I.R.D match whats on the isolation relay; the wire between the B.I.R.D and the engine start switch is missing/gone astray. If that turns out to be the case this will be the second missing wire and I begin to wonder how many others are not there/or where they should be.

If you notice from the 4-wire BIRD diagram, there is not a dedicated terminal on the BIRD for engine start switch. The engine start switch is hard-wired somewhere between the BIRD output and the isolator relay.

It's difficult to say how electricians run wiring, but since you say the wires don't match, it's very possible the electrician made the connection (think in terms of a splice without being a splice) at the emergency start switch itself.

I would look to see if there is a wire from the BIRD to the emergency-start switch, and then another wire (which could be a different color) from that same terminal on the switch running to the isolator relay.



On subject of converter not charging chassis battery, how do you know this is not happening at all? Since the BIRD has built-in time delays and also has logic based on voltages, I would think that it's hard to test whether it ever works right or not. I know how I would test it, but I'm not sure it would normally show up unless one was looking to confirm proper operation. I'm just curious what is occurring that doesn't seem correct. Obviously the isolator relay works based on your post, so it must be something else.

[Oneilkeys]

From Ed's first post in this thread.
When the BIRD senses 13.1 volts for 2.5 minutes on the chassis battery the relay isolator will close sending charging current to the house batteries (alternator providing charge to house batteries. Going the other way when on shore power or running the generator when the BIRD senses 13.1 volts for 2.5 minutes on the house batteries the relay isolator will close sending charging current to the chassis battery (generator or shore power charging the chassis battery).

It is easy to check if the system is working. If the charging system is working correctly, after About 2.5 minutes the Trombetta will open connecting both battery banks for charging. If that happens, the voltage at both posts of the Trombetta will read the same on a volt meter. If they do not, the Trombetta is closed. After the charging system is shut off, the voltage in the batteries has to drop to 13.8 v (I believe) and the Trombetta automatically opens. If you have a load on the coach batteries The voltage readings from the two large a Trombetta posts will quickly read differently.
I could be wrong, but i think that the way Thor has this wired, the emergency start switch plays no part in the BIRD/Trombetta operation. I think it is wired completely separately and physically connects the two battery banks with a wire running for one bank to the other thru the emergency start switch. When the switch is pushed, it physically connects the two banks and when the switch it let off, it separates them. The five wire BIRD has a wire that acts as that switch and closes the Trombetta, but in the Axis, I'm not sure the emergency start switch closes the Trombetta. I think it works separately from the Trombetta to connect the two battery banks. I am not sure of that, but from fooling around with the system, I think that is the way it works.

[scrubjaysnest]

To reply to several different comments.
With 14.8 volts on the house batteries from about noon time on, due to the solar system, the B.I.R.D has had plenty of time to sense this voltage if working/wired correctly; and if this is what has the time delay. The same thing applies for the two times we have been on shore power over night where the converter output has been measured at 13.2 to 13.6 volts on the house batteries.

The isolation relay I have verified works by pressing the aux start button and watching the chassis battery increase from 12.2 to 14.8 volts, again on solar to the house batteries.
From the diagram you of coarse can't tell where the white isolation relay wire is physically landed.

From the diagram a 5 amp fuse is supposed to be wired in, ours is actually a 15 amp.

Having worked with the bulb snatchers, electricians for 20 years I understand wires don't always get landed physically per the diagrams but are electrically correct.


The limited checking I have done so far indicates a missing wire or failed component.

[Oneilkeys]

You're right, the BIRD has had time to sense the voltage and since the system works from alternator to coach batteries, the BIRD and Trombetta seem to be working. My point is, pushing the aux start button may not verify that the Trombetta (isolator relay) is operating. I think that Thor has the aux start switch wired completely separately from the Trombetta and pushing that switch just hard wire connects the two battery systems without closing the Trombetta. For the BIRD to open the Trombetta when on shore power it has to sense 12.5 v at the house bank. It does that thru the red wire going into the BIRD. If the red wire coming out of the BIRD is not connected to the house bank the BIRD will not receive the information it needs to open the Trombetta and charge the chassis battery. It looks to me that my system had the same issue as yours. I solved it by rerouting the red wire.

[scrubjaysnest]

When I checked the isolation relay it had 14.8 on the house battery side and chassis battery side had 12.25 until the aux start button was pushed at that time the isolation relay picked up both heard and felt and verified by the chassis side going to 14.8V.

I did locate a copy of the TEE1071-2 battery diagram showing the interconnections between house and chassis batteries along with all breakers and the gen set wiring plus the other two relays.
The only problem with the drawing is the batteries them selves are not properly connected per: SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank Which has a very good explanation on why and how to connect multiply batteries.

Ours are wired correctly from the factory per the Smartguage site. The hunt continues; I've located the two 100 amp breakers and the 50 amp. For the temporary solar hook up I connected to the 50 amp.

[Oneilkeys]

Originally Posted by scrubjaysnest

When I checked the isolation relay it had 14.8 on the house battery side and chassis battery side had 12.25 until the aux start button was pushed at that time the isolation relay picked up both heard and felt and verified by the chassis side going to 14.8V.

I did locate a copy of the TEE1071-2 battery diagram showing the interconnections between house and chassis batteries along with all breakers and the gen set wiring plus the other two relays.
The only problem with the drawing is the batteries them selves are not properly connected per: SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank Which has a very good explanation on why and how to connect multiply batteries.

Ours are wired correctly from the factory per the Smartguage site. The hunt continues; I've located the two 100 amp breakers and the 50 amp. For the temporary solar hook up I connected to the 50 amp.

It would be interesting to know if the red wire going into the BIRD read 14.8 v as the coach batteries did or if it reads under 12.5v, as I bet it does. I'll bet you that if you feed above 12.8v into the red wire going into the BIRD, that the Trombetta will open and both banks will charge under shore power.

[vkb]

Originally Posted by bevedfelker

... well, one would hope someone can hook up some wires correctly -- like your radio was.

Thank you Ed for the clarification on a much 'labored' subject !

[bevedfelker]

It was interesting researching this. This appears to be one of the most common and perplexing issues involving our Axis/Vegas models -- battery not charging, bsttery going flat, or not able to emergency start engine.

I wanted to shine light on the charging system and dispel several urban legends involving what is supposed to charge what and under what conditions. The system when wired correctly is pretty simple and fairly sophisticated. I learned s lot researching this. Hopefully this long discussion had helped others.

[vkb]

Originally Posted by Ag&Au

Now that I think about what we did when my kids were growing up, and what I did when I was growing up, one of the purposes was to avoid most of those thing you mention. I guess modern camping is all about bringing as much of your home with you as possible to a different location. Not that I'm doing any differently, and at my age I would not want to go back, but somehow a lot of the fun and adventure has gone out of it.

In any case, sorry for the distraction. Let's get back to how to fix all the neat stuff we now have, and aren't sure how works, or what it does.

Ken

Agree...when we were young, we tent camped ! Trying to find a spot without rocks and tree roots, forget being level !! Ah...then came air mattresses and sleeping bags that kept you warm !! Coleman lantern for light !
Thinking about those long gone days...over 40 yrs ago...we made some awesome trips. We did a 4500 mile trip in 1980 (our longest trip)..such good memories !

We love our Axis !! (and previous rv's) ..
our OLD bodies appreciate the comforts of our 'home away from home' ...
the outdoors at our doorstep, the beauty of this wonderful continent, and NOT having phone service 24/7 nor tv 24/7 !!

[Chance]

Originally Posted by Oneilkeys

.....cut....
I could be wrong, but i think that the way Thor has this wired, the emergency start switch plays no part in the BIRD/Trombetta operation. I think it is wired completely separately and physically connects the two battery banks with a wire running for one bank to the other thru the emergency start switch. When the switch is pushed, it physically connects the two banks and when the switch it let off, it separates them. The five wire BIRD has a wire that acts as that switch and closes the Trombetta, but in the Axis, I'm not sure the emergency start switch closes the Trombetta. I think it works separately from the Trombetta to connect the two battery banks. I am not sure of that, but from fooling around with the system, I think that is the way it works.

The diagram posted above clearly shows that the emergency start switch operates the Trombetta (brand name) isolator relay. The emergency start switch sends control current to close the Trombetta relay. There is no way that engine starting current, which would be in the 100s of Amps, could go through the emergency start switch itself which is limited to something like 5 Amps.

The reason these Trombettas are used is that they are available to handle very high current. Some models go up to at least 800 Amps, which should easily start a V10 engine.

When you depress the emergency start switch, a very low current (less than 5 Amps) will flow from the house batteries to the coil on the Trombetta (brand) relay, which in turn CLOSES the main contacts that allows 100s of Amps to flow from the house battery to the engine starter (assuming you are cranking the engine).

[scrubjaysnest]

Originally Posted by Chance

The diagram posted above clearly shows that the emergency start switch operates the Trombetta (brand name) isolator relay. The emergency start switch sends control current to close the Trombetta relay. There is no way that engine starting current, which would be in the 100s of Amps, could go through the emergency start switch itself which is limited to something like 5 Amps.

The reason these Trombettas are used is that they are available to handle very high current. Some models go up to at least 800 Amps, which should easily start a V10 engine.

When you depress the emergency start switch, a very low current (less than 5 Amps) will flow from the house batteries to the coil on the Trombetta (brand) relay, which in turn CLOSES the main contacts that allows 100s of Amps to flow from the house battery to the engine starter (assuming you are cranking the engine).

This is correct, all the Trombetta does is tie the two battery systems together when called to do so. On ours from the chassis positive battery post are 3 wires, 1 goes to the starter, the second goes to the Trombetta( isolation relay), and the 3rd looks like it goes to the under hood fuse box.
Again this is for ours, the Thor battery connection drawing(house batteries) shows the isolation relay within the house battery compartment when it is actually under the hood next to the B.I.R.D.

The Intellitec drawing shows two latching relays and the isolation relay. But per that drawing I am unable to find the latching relay they show for the chassis battery. The house battery latching relay used to disconnect the house batteries from the coach load center on ours is somewhere between the kitchen sink and the load center( distribution panel) at floor level

[scrubjaysnest]

Did some more digging into this yesterday. Found many splices between the B.I.R.D and other stuff. Two things jump out at you, 15 amp fuse feeding the B.I.R.D instead of 5 and wires changing color at splices. B.I.R.D is also wired to chassis battery, not coach as the drawing above shows. When I get done I'll post an updated drawing for our Axis. Others may be different since it appears each is custom wired and not with standard loop diagrams.

[scrubjaysnest]

Originally Posted by Oneilkeys

It would be interesting to know if the red wire going into the BIRD read 14.8 v as the coach batteries did or if it reads under 12.5v, as I bet it does. I'll bet you that if you feed above 12.8v into the red wire going into the BIRD, that the Trombetta will open and both banks will charge under shore power.

When I dug into this yesterday the red wire went off into the harness and the 15 amp fuse connected to the chassis battery. White goes to the Trombetta coil and off to the emergency start switch. Black went to the Trombetta coil, ground, and off into the harness. The orange or ignition went off into the harness.

[petefoss]

Originally Posted by bevedfelker

Going the other way when on shore power or running the generator when the BIRD senses 13.1 volts for 2.5 minutes on the house batteries the relay isolator will close sending charging current to the chassis battery (generator or shore power charging the chassis battery).
.

So my chassis battery went dead. I'm plugged into shore power and my house batteries are now at 13.5 while on shore power. But the chassis battery is not charging. Sounds like a BIRD issue?

So best way to charge chassis battery for now is to get off shore power and put an external charger on the chassis battery? I don't want the BIRD to start supplying DC at some point to the chassis battery while the other charger is connected?

Pete