Charge Bridge Solenoid Blown Fuse

[jrb]

I have a 2020 Newmar New Aire 3541. On a recent trip about 4 hours after stopping and plugging in shore power I noticed the chassis batteries were low on Silverleaf. Silverleaf also showed that the batteries were bridged, but the voltages on house batteries and chassis batteries were different (13+ on house and only 10.7vdc on chassis). I suspect my chassis batteries are bad, but I have not had them load tested yet. My understanding through discussions with Newmar and the schematics I've received is that when bridged they batteries are directly connected together via the Charge Bridge Solenoid so they should read the same.

It was late so the next morning I called Newmar and talked to Erica. I talked to her in 2023 when I had a similar issue and she was very helpful then so thankful to get her this time.

I found fuse F10 blown on the printed circuit board in one of the basement bays on the driver side. I replaced the fuse, heard a click, checked the voltages and they matched. I'm not suggesting the chassis batteries are good, but just that the Charge Bridge Solenoid "ACTUALLY" engaged to bridge the house and chassis batteries together. This is the same problem I had in 2023 when I talked to Erica.

My question is whether anyone has had this same experience? If so, any thoughts on why the fuse would blow twice even though some time between occurrences? Or, anything else that may be helpful? As an engineer, I appreciate the in-depth discussion on how these systems work. I have not investigated who the "owner" is of this printed circuit board - Newmar, Silverleaf, or Xantrex. I'm just guessing that it would take some digging to find out any details on the F10 fuse blowing problem. I believe it is just a control circuit to operate the Charge Bridge Solenoid, so odd that it would blow a fuse - but the designers did put one it, so...

Any help would be appreciated!

 

[Kevin D Pem]

Fuses are there to protect wires.

Happened twice? Look for a wire that passes through some tin where it might short out while the coach is in motion.(Not protected with a bushing)

I will not explore any other possibilities.

 

[jrb]

Thanks for the reply. Fuses are to protect all electrical components. As far as a short somewhere, I understand. If you have not looked at the wiring in a Newmar RV (mine anyway) it is atrocious! Nearly impossible to trace a given wire from beginning to end. This is a huge complaint I have about Newmar in how they just stack last-in wiring on top of any previous wiring without any type of organization, bundling or labeling.

Thanks again and would still appreciate any comments.

 

[Kevin D Pem]

When rats nests are common, run a new wire.

 

[jrb]

That's a thought. When this happened the first time I was able to maneuver enough to get a voltmeter on the terminals of the solenoid.

 

[rebel112r]

I have a 2020 Newmar New Aire 3541. On a recent trip about 4 hours after stopping and plugging in shore power I noticed the chassis batteries were low on Silverleaf. Silverleaf also showed that the batteries were bridged, but the voltages on house batteries and chassis batteries were different (13+ on house and only 10.7vdc on chassis). I suspect my chassis batteries are bad, but I have not had them load tested yet. My understanding through discussions with Newmar and the schematics I've received is that when bridged they batteries are directly connected together via the Charge Bridge Solenoid so they should read the same.

It was late so the next morning I called Newmar and talked to Erica. I talked to her in 2023 when I had a similar issue and she was very helpful then so thankful to get her this time.

I found fuse F10 blown on the printed circuit board in one of the basement bays on the driver side. I replaced the fuse, heard a click, checked the voltages and they matched. I'm not suggesting the chassis batteries are good, but just that the Charge Bridge Solenoid "ACTUALLY" engaged to bridge the house and chassis batteries together. This is the same problem I had in 2023 when I talked to Erica.

My question is whether anyone has had this same experience? If so, any thoughts on why the fuse would blow twice even though some time between occurrences? Or, anything else that may be helpful? As an engineer, I appreciate the in-depth discussion on how these systems work. I have not investigated who the "owner" is of this printed circuit board - Newmar, Silverleaf, or Xantrex. I'm just guessing that it would take some digging to find out any details on the F10 fuse blowing problem. I believe it is just a control circuit to operate the Charge Bridge Solenoid, so odd that it would blow a fuse - but the designers did put one it, so...

Any help would be appreciated!

 

[rebel112r]

Not a reply but a question. I have a 2020 3341 NA, which I have had for a month. Where is the bridge solonoid? There is a solonoid above exhaust and behind the chassis shut off switch, and another on the drivers side, in the storage bay behind the battery bay. Just trying to get a basic idea of what does what. Thanks Dan

 

[SteveMA]

Unfortunately the bridge solenoid is fed B+ control from both the manual bridge switch on the dash and from the silverleaf system (i think the TN102 in power bay). The fuse circuit /relay board is from KIB. On mine the dash switch B+ and the SL>KIB B+ are both connected to the control coil of the bridge solenoid (as well as a white ground wire on the other side of coil)

There are led’s on the bottom of the board for several ‘remote’ circuits (IE water pump etc). You can find most of the schematics on Newgle however it takes some doing as most newgle searches return minimal info.

If your chassis batteries are below 11v the current will go up when charging - but unlikely that could be what is taking the fuse out since the dash/SL signal is only to drive the solenoid to activate.

New thought - what were the chassis battery voltages when you got to your stop. If they were below 12.3 then either they are not taking a charge from the alternator (off the engine) and Likely time to replace them. Gaffney replaced ours last time I was there at very reasonable cost.

My 2020 Mountain Aire has similar system to your NA I believe.

When I redid the house system with LiFePo i changed out all to victron and used 2 OrionsXL to fed bidirectionally from house to chassis and chassis to house and effectively took SL out of the loop.