How To Extend The Life Of Your BDS and Boost Solenoids

[imnprsd]

On this subject I yield to what Cbeirel and Morich have to share on subjects of this type, but I'm also having a hard time figuring out what is happening to my solenoids when they are being switched on-and-off and when the BDS is "Latched" and on-or-off?

And if you all are saying... when the engine is running the alternator will be charging the engine and house battery somewhere between 13.0-14.1V; and that voltage is what is energizing the BDS and Boost Solenoid on the high voltage side, then I also accept the coil voltage will ride about -0.2V less since there will be voltage drops of various orders.

...And Cbeirel is saying he has extended the life of his BDS by adding either a resistor or diode to lower the voltage at the coil positive post.

* The point being, I think, is that there will be less wear and tear on the coils when lower voltages are used; and/or by lowering the voltage to the solenoid coils then they will be better protected against high alternator out voltages that can fry the BDS coil. Is that right?

Here's what I pulled from the Intelletec #01-00055-000 Data Sheet:

https://rvpartsexpress.com/product/i...-01-00055-000/

The data sheet says: "At the heart of the system is a unique latching relay... that requires NO power to stay open or closed. It only draws power during activation."

As for anyone who needs to replace their BDS or Boost Solenoids you all really need to make sure you are buying the silver contacts type! (Trombeta uses a "20" to denote silver contacts in their Boost Solenoid. And who knows what the OEM coach manufacture shipped with the coach, but often it's the cheaper solenoid type.

* So, maybe there are RVs out there that still use a BDS that are "on" all the time, IDK.

==> My 2004 Itasca Horizon BDS is not on as far as I know!

* Or maybe when an RV uses the B.I.R.D Relay this has something to do with energizing the BDS coils to join the high current sides of the two relays together so the BIRD can use the alternator to charge the house batteries. IDK.

==> My 2004 Itasca does not use a B.I.R.D. type relay. In fact, it came from the factory without this option.

Note: My RV is an early model 2004 Horizon vs. the late 2004 Horizons that did come with the B.I.R.D. So maybe Cbreil's wiring codes are for the later model Horizon since my wire codes appear to be different.

Note: In my RV, in order for the alternator to charge the house batteries, I use the Keyline VSR (Voltage Sensitive Relay) that joins the house and chassis batteries together. This is aka a "battery isolator" that works great and has nothing to do with my Solenoids or my ignition switch.

Below is a picture of my two 2004 Itasca Horizon Solenoids.

QUESTION: Is my BDS always "on" when I am driving or is it only drawing power when the Salesman Switch is pressed "up" or "down?"

LJ is always biased with 12V from the house batteries.
LH is part of the Salesman Switch (down).
LG is also part of the Salesman Switch (up).

[cbeierl]

The Battery Boost Solenoid and the Battery Disconnect Relay (what I believe you are calling the BDS) are completely separate and unrelated.

The Battery Disconnect Relay is a latching relay controlled by the 'Salesman Switch' (by the entry door on your coach). When turned off it disconnects (most) loads from the coach/house batteries. In normal use this relay is latched ON.

The Battery Boost Solenoid is activated via the wire LR from the Battery Boost Switch on the dash and when activated it connects the chassis and coach/house battery banks together. As previously discussed it should be activated whenever the engine is running or the momentary Battery Boost Switch is depressed.

The Battery Boost Solenoid is the one that typically fails, resulting in the coach/house batteries not being charged by the alternator.

The Winnebago Ultimate Advantage/Freedom coaches DID use a B.I.R.D. (a 'smart' device to connect the battery banks as needed for charging), as do some more recent Winnebago coaches, however the coaches of our era do not.

[imnprsd]

Yep... That's what the schematic shows.

My early model 2004 Itasca Horizon came with 2 solenoids and there was no circuit installed that would allow my alternator to charge my house batteries. So, I installed a Keyline VSR to accomplish this:

My BDS made by Intelletec has a fuse on top and is always connected to 12V from the engine battery.

My Boost Solenoid is made by Trombetta and this is the one you want to buy with the silver contacts or you will be replacing this part more often.

Late model 2004 Itasca Horizons came with a BIRD system. And maybe that means they came with 3 solenoids? IDK.

I found a 3 Solenoid System using a BIRD Charging System and now where some of the confusion comes from... that and the many ways of trying to explain this stuff in writing.

[cbeierl]

Originally Posted by imnprsd

...
My early model 2004 Itasca Horizon came with 2 solenoids and there was no circuit installed that would allow my alternator to charge my house batteries.
...

Our of curiosity, have you looked at the terminals on your Battery Boost Switch to see if it has a LLJ or JJX wire attached to it (as shown by the wiring diagrams)? If it does that wire should be providing 12V when the engine is running and thus activating the Boost Solenoid.

Originally Posted by imnprsd

...
Late model 2004 Itasca Horizons came with a BIRD system. And maybe that means they came with 3 solenoids? IDK.

Are you certain about this? I haven't seen anything to indicate that this is true and it is in direct conflict with Winnebago's published wiring diagrams. My Feb 2005-built Vectra (Winnebago 'twin' of the Itasca Horizon) certainly matches the wiring diagrams.

[imnprsd]

I am absolutely certain of my early model 2004 Horizon 40AD did not come with the BIRD wiring used in later model 2004 Horizon 40AD and 2005+ models. There are also a number of owners who have written about his gap in Winnebago's that did NOT come with any type of circuit so the alternator can charge the house batteries using a BIRD or some other form of battery isolator.

As for checking my Boost solenoid's "on" of "off" status, I can't check the voltage until I pickup my RV in April/May, but when I review my schematics, their is nothing connected to the Boost Solenoid other than a Boost Switch I control at my dash. Moreover, one side of the boost coil is positive and the other negative.

[imnprsd]

Is my boost solenoid "on" all the time? ...I'm not sure.

... Now I think it maybe "on" when I turn on the BDS by flipping up the Saleman Switch at the door.

I can't measure the voltage at the boost solenoid since my coach is in storage. However, I think it is possible that you guys are right!

I looked at a few pictures I took of my Boost solenoid, and maybe I color coded my wire diagram wrong:

* I assumed the boost switch was "hot" at the dash, but the more I think about it... the boost switches ground. (See white wire "MG" in my schematic.)

* If this is correct then the boost hot wire "LR" may be connected to the BDS "hot" post where "LG" connects.

==> Since the BDS is a latching solenoid, that may mean when "latched-on" the coil post "LG" is hot all the time... and if the yellow "LR" wire is connect at this point, then the BDS also turns on and off the BOOST solenoid.

==> So the Boost dash switch is a a switch to ground! Is that right?

==> If so, then you all are right and my BOOST solenoid is on all the time when I am driving and when I am camping, because the Salesman Switch at the door is "on" all the time to keep my BDS "on."

"WOOPS" ...I apologize for getting this wrong! ...But thank you pointing this out to me.

===== MORE SOLENOIDS MYSTERYS TO SOLVE ===

Cbeirel: I reviewed all 6 pages of that old (2008-2010) thread you referred us to, and now I can see you and other notable forum members like John Cantfield and MrTransistor tackled this same subject... sort of.

Back then, as I understand it... Trombetta was shipping 12V coils in their Boost Solenoids and everyone was burning them up because the alternator was putting out 14V+.

RESISTOR FIX

Then you came along and used a few resistors to drop the battery/alternator voltage by -2 volts and today you are saying that extended the life of your BOOST solenoid. Is this correct?

Then in ~2010, Trombetta redesigned their "Bear" Boost Solenoid and raised the coil voltage to 15V and are now shipping silver contacts.

The Trombetta Part# 14-1211-020 and the "20" denotes silver contacts.

However, I see in the picture you posted that your 2008 Edition Trombetta uses the same part number. So can you elaborate a bit on the need to drop voltage? ...Did Trombetta redesign this part but keep the same part number?

Specifically, I can see where the point of adding a few resistors was great fix for the older Trombetta's, but does this fix still apply to newer Trombetta's?

Note: MrTransistor used 3 diodes to accomplish the same thing. (See picture below.)

WHAT ABOUT USING Ignition Condensers/Capacitors which only cost $5-$7?

==> I think this is overkill at this point, because one can argue adding diodes to the coil posts are overkill, but if they provide a few more years of service, and they are so cheap, then what's the downside?

ADDING REVERSE BIAS DIODES ACROSS THE COIL POSTS

So what's left to improve? I guess I would have to say adding a reverse bias diodes to the coil posts are a good idea -- if in fact these diodes to reduce the wear on the coil burning out inside. Does it is the question?

Here's the link to a $7 pack of thirty SR560 (DO-201AD) Schottky Barrier Rectifier Diodes, 5A 60V.

https://www.amazon.com/BOJACK-Schott..._t3_B007Z7OQ5G

And because my BDS has one hot and 2 switched negative leads (at the Salesmand Switch) I will need to add 1 diode between "LJ" and "LG"... and 1 diode between "LJ" and "LH".

Note: My wiring diagram is probably not the same as your RV if your coach came with a BIRD System and/or has more than 2 solenoids.

[imnprsd]

So this this my updated solenoid schematic and I have included a picture of my Boost and BDS.

...I just can't tell where my Yellow "LR" wire goes? ...Does it connect to my "LG" BDS-On post or go somewhere else?