Electrical JHub BM Pro

simon Orr

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Jul 9, 2021
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Hi, just brought a 2017 Jayco and the JHub 102? only turns on for a second and then turns off
The power did run low, but not flat
I have managed to get into the reset section, but didn’t want to delete the settings?
Any ideas would be much appreciated
 

Boots in Action

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Hi, just brought a 2017 Jayco and the JHub 102? only turns on for a second and then turns off
The power did run low, but not flat
I have managed to get into the reset section, but didn’t want to delete the settings?
Any ideas would be much appreciated
Hi @simon Orr and welcome to the forum. At first thought, what do you call "low, but not flat"? If battery voltage drops below the Low Voltage Disconnect (10.5 volts under load) 12 volt power is disconnected and is not available again until battery voltage reaches 12.8 volts or higher by EXTERNAL charging means. No, the BMpro 35 will NOT charge the battery by itself if LVD is activated.. Have a good read of my post of 27th April, 2021 - " BMpro 35 - what happens when LVD activated and why you cannot charge battery" And your JHub monitors battery state. I think that will be your problem.

Electrical BMpro 35 - what happens when lvd activated and why you cannot charge van battery

 
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Drover

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To fix it just disconnect your battery/batteries and put them on a charger, make sure its a charger that is for your type of battery, once they are juiced up connect them back up and turn the 240 back on the BMPro and it will run happily............. its always wise when your van is parked up to plug it in to 240 and the BM will keep the batteries happy, turn off everything else thats not needed. Leaving the 240 plugged in will not damage the batteries but make sure you fridge and HWS are switched off and fridge doors ajar.
 
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mikerezny

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The BmPro has a external switch, mistakenly still called the "battery isolation" switch, since that was its function with the previous Setec ST power supply battery chargers.

NOTE: THIS IS NO LONGER THE CASE.

This switch has an entirely different function and the sooner it is understood by all owners of a BmPro J35, the sooner the incorrect information supplied by well meaning owners of Setec systems, the sooner it will be buried.

The function of the switch is to now isolate ALL 12V loads from the power supply system: A load isolation switch.

So, it has absolutely no effect on whether the battery is connected, it has no effect on whether the battery is charged, it has no effect on whether the battery is charged or trickle charged, it has no effect on getting the BmPro J35 to charge the battery once it is flat.

Time spent reading the various manuals is time well spent and will reduce the frustration experienced and camping trips ruined.

take care
Mike
 
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Drover

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Thats handy to know I thought they had done away with it all together, so even though you are running on mains the switch will just isolate everything from the BMPro ???? I haven't come across a switch as such just control from the stupid hub will have to have a good look around next time.
 

mikerezny

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Actually, I was mistaken. I have read the manual more carefully instead of relying on my memory and have edited my previous post accordingly.
Here are some snippets from the manual.

LOAD ISOLATION SWITCH
A pair of contacts, item (9) in Description of Parts, had been provided for connection to an external switch.

The Load isolation switch contacts allow for the J35 to enter into storage mode. When no sources are available all outputs and the CAN power are turned OFF when these pins are shorted. If this switch is open, all** outputs and the CAN power will be turned back ON.

**the Slide-Out output will only turn back ON if the Auxiliary is NOT present. See Slide-Out section (Page 7) for more details.

Battery charging is not affected by this switch.

J35-B “SLIDE-OUT”
The Slide-Out output is different compared to the other outputs. Unlike the others, the Slide-Out output is always OFF whenever the auxiliary voltage is present, regardless if AC mains is ON or OFF. This is a safety mechanism of the J35. To prevent from accidentally engaging the Slide-Out while caravan is in transit, J35 effectively inhibits the Slide-Out to engage if auxiliary input is ON. To operate the Slide-Out, turn OFF auxiliary input. Turning OFF the towing car engine should suffice.

Here is another useful snippet related to the LVD (Low Voltage Disconnect) feature:

J35-B “TABLET” (5A)
The TABLET output terminal is where the charger (12V input/5V output) for tablets or mobile phones can be connected to. When the caravan battery is running low and reaches 10.8V (Low Voltage Disconnect), all the outputs will turn OFF except the TABLET output. This means that in case of emergency, the last remaining charge from the caravan battery can be used to charge a mobile phone and ensure phone calls can be made.

take care
Mike
 
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poor but proud

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The BmPro has a external switch, mistakenly still called the "battery isolation" switch, since that was its function with the previous Setec ST power supply battery chargers.

NOTE: THIS IS NO LONGER THE CASE.

This switch has an entirely different function and the sooner it is understood by all owners of a BmPro J35, the sooner the incorrect information supplied by well meaning owners of Setec systems, the sooner it will be buried.

The function of the switch is to now isolate ALL 12V loads from the power supply system: A load isolation switch.

So, it has absolutely no effect on whether the battery is connected, it has no effect on whether the battery is charged, it has no effect on whether the battery is charged or trickle charged, it has no effect on getting the BmPro J35 to charge the battery once it is flat.

Time spent reading the various manuals is time well spent and will reduce the frustration experienced and camping trips ruined.

take care
Mike
Makes the old centurion system in my heritage sound just too simple for words ,thank god for old technology,I am past having to be a professor to go for a trip in a caravan
 

Boots in Action

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Actually, I was mistaken. I have read the manual more carefully instead of relying on my memory and have edited my previous post accordingly.
Here are some snippets from the manual.

LOAD ISOLATION SWITCH
A pair of contacts, item (9) in Description of Parts, had been provided for connection to an external switch.

The Load isolation switch contacts allow for the J35 to enter into storage mode. When no sources are available all outputs and the CAN power are turned OFF when these pins are shorted. If this switch is open, all** outputs and the CAN power will be turned back ON.

**the Slide-Out output will only turn back ON if the Auxiliary is NOT present. See Slide-Out section (Page 7) for more details.

Battery charging is not affected by this switch.

J35-B “SLIDE-OUT”
The Slide-Out output is different compared to the other outputs. Unlike the others, the Slide-Out output is always OFF whenever the auxiliary voltage is present, regardless if AC mains is ON or OFF. This is a safety mechanism of the J35. To prevent from accidentally engaging the Slide-Out while caravan is in transit, J35 effectively inhibits the Slide-Out to engage if auxiliary input is ON. To operate the Slide-Out, turn OFF auxiliary input. Turning OFF the towing car engine should suffice.

Here is another useful snippet related to the LVD (Low Voltage Disconnect) feature:

J35-B “TABLET” (5A)
The TABLET output terminal is where the charger (12V input/5V output) for tablets or mobile phones can be connected to. When the caravan battery is running low and reaches 10.8V (Low Voltage Disconnect), all the outputs will turn OFF except the TABLET output. This means that in case of emergency, the last remaining charge from the caravan battery can be used to charge a mobile phone and ensure phone calls can be made.

take care
Mike

Hi Mike @mikerezny, further to my report on what happens when LVD is activated with a BMpro 35 (A?) , I was able to read the instruction book for same at the time I was sorting out the lady's problem. In fact, there are two voltage cut out positions, one at 10.8v and the other at 10.3v. Both have different procedures for "turning on" any loads (when 12 volt power restored) that were connected at the time of disconnection. As a result of knowing that the switch isolated all 12 volt loads connected by any type of power, that is why I took the precaution of firstly switching OFF any 12 volt lights and appliances before turning OFF the "Battery" (really the ISOLATION ) switch, and then disconnecting the negative on the 12 volt battery so that I could charge battery in situ. Note that re-connection when battery up to speed at 14.35 volts (over the Low Voltage Reconnect threshold of 12.8 volts) was the reverse of above with a good pause in between each action too! Incidentally, seeing you brought it up, you will notice that I mentioned that the lady used the "emergency" power on her first night in the park (power only available to retract the slide out) and that is why she had NOTHING at all on the second night.
My last couple of lines say it all :

For those of us who have the superseded Setec Series II or III, we may be behind in technology, but we are ahead in practicality.
Sometimes I wonder if the BMpro 35 is progress!!!
 

Boots in Action

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To get back to the OP, @simon Orr if when you plug into 240 you can turn the lights on but once you disconnect the 1240 the lights go out it will be because your battery is flat and isolated from the BMPro, so just follow the actions I mentioned in my earlier post.......... if no lights when on 240 check microwave lights up it will show if 240 is working, also look at the led lights that are on where each cable connects to the BMPro are red one will show a circuit failure.
Hi @Drover , that is not what I found with the lady's van at Poona. Even with the van (and BMpro) connected to the 240 volt grid for more than 36 hours, there was NO POWER available to run the 12 volt lights (or charge battery) in her Penguin fitted with the BMpro J35 unit. All the 12 volt battery lighting and 12 volt outlets are through the BMpro and no lights (that I remember?) are just 240 volt. Because the battery had gone below the LVD of 10.8 volts, ALL 12 volts outlets/lights has been disconnected (isolated?) from the battery and indeed any power source . Until I was able to get the voltage over the LOW Voltage Re-connection level at 12.8 volts, the 12 volt outlets remained isolated whether van connected to grid power or not. The lady did not have any 240 volt lamps to connect into the 240 volt power outlets, so she was stuck with no 12 volt power for lighting.

I think this is what @mikerezny was trying to get across in his earlier post.

Incidentally, my 2014 Penguin has NO 240 volt lights. They are ALL 12 volt LED style. The ONLY 240 volt power in my van is from a separate dedicated circuit with the 4 or 5 separate GPOs which provide power for the stove (single hot plate) , fridge (when on 240v) , Setec ST20 Series III (battery charging and 12 volt power distribution) and GPOs for general use. Micro waves are always connected to the 240 volt AC circuit, but any LED lighting must come from the power distribution system which has changed the supply from 240 volt AC to 12 volt DC and would be controlled by the power distribution system of some sort.
 

mikerezny

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Just to be perfectly clear, once again:
If you have a BmPro J35 and a battery installed, AND the battery is flat:

THE BMPRO J35 DETECTS THIS AS A FAULT CONDITION AND SHUTS DOWN THE ENTIRE 12V SYSTEM:

If I can get this one simple message across, I will feel I am not stuck in a real life version of groundhog day.

And again, just one more time:
If you are at a site with 240V and you have a flat battery, you will have no 12V to any part of the van. You can however get around this: Disconnect the battery. The BmPro detects there is no battery, hence no flat battery, and will then happily supply 12V to the van.
The BmPro will not charge or trickle charge a flat battery. The battery needs to be disconnected and charged with another source to get the battery voltage up as explained in detail by @Boots in Action. Once the battery voltage has been restored, it can be reconnected to the J35 which will then happily supply 12V to the rest of the van AND maintain the battery,

Both @Boots in Action and I have spent a lot of time on the BmPro J35 reading and understanding how it works even though neither of us even has one.

take care
Mike
 
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Boots in Action

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Just to be perfectly clear, once again:
If you have a BmPro J35 and a battery installed, AND the battery is flat:

THE BMPRO J35 DETECTS THIS AS A FAULT CONDITION AND SHUTS DOWN THE ENTIRE 12V SYSTEM:

If I can get this one simple message across, I will feel I am not stuck in a real life version of groundhog day.

And again, just one more time:
If you are at a site with 240V and you have a flat battery, you will have no 12V to any part of the van. You can however get around this: Disconnect the battery. The BmPro detects there is no battery, hence no flat battery, and will then happily supply 12V to the van.
The BmPro will not charge or trickle charge a flat battery. The battery needs to be disconnected and charged with another source to get the battery voltage up as explained in detail by @Boots in Action. Once the battery voltage has been restored, it can be reconnected to the J35 which will then happily supply 12V to the rest of the van AND maintain the battery,

Both @Boots in Action and I have spent a lot of time on the BmPro J35 reading and understanding how it works even though neither of us even has one.

take care
Mike
Thanks Mike @mikerezny for setting out my reports in VERY CLEAR LANGUAGE. I did not cover the "no battery" position at all, as my main aim was to get battery charged up so lady could use electrical system normally and off grid. If people are not aware of the flat battery problem not being able to be charged, I did not want them trying to disconnect battery terminals and accidentally shorting any wires to metal parts of van, even if they had the tools to do it! !
 

Boots in Action

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Don't know where you got the 240v lights idea from, @Boots in Action , I thought it was obvious that I meant when plugged into 240v the BMPro would provide power for the lights (leds) but wouldn't charge the batteries for the reasons you stated, at least I'm sure we still had lights (LEDs) with batteries on the bench charging and van plugged into 240v....... but I'm not going to get the book out and read it up.....Always said the BMPro is a junk system.
The units I have looked at where the wires connect to the unit there would be a small led behind each terminal if looked at directly you would see a red or green led dot made it easy to locate the faulty circuit at the time.......charged batteries up isolated that circuit and all was good.

Now I know the discrepencies I was working on a later version with more whistles not the base line version........ seems they ahve more versions than you can poke a stick at......
Sorry @Drover , not quite right. But your observations are correct. Lights will work when connected to 240 volt power while batteries are disconnected. And you covered the battery problem by charging them before putting them back. But NO POWER will be available to charge batteries and work lights even while connected to 240 volt power if battery voltage is lower than 10.8 volts (LVD activated). Re-connection for battery charging and lights occurs when battery voltage reaches 12.8 volts or more and Low Voltage Reconnect activated. Hope this clarifies the matter for you.
 
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Drover

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I found that out a few years back with the first one I played with just didn't explain things clear enough I suppose.....
 

Case8120

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Hey guys I’ve just brought a 17 swan an can’t get 12v system to work, pervious owner must have left something on an battery down to 5v.
Have charged battery hooked back up an still nothing not even to the coast to coast monitor but if I hook to 240v all works just not charging……

only had just over a week an ready to get rid of it already……

thanks
 

Boots in Action

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Hey guys I’ve just brought a 17 swan an can’t get 12v system to work, pervious owner must have left something on an battery down to 5v.
Have charged battery hooked back up an still nothing not even to the coast to coast monitor but if I hook to 240v all works just not charging……

only had just over a week an ready to get rid of it already……

thanks
Hi @Case8120 , there has been EXTENSIVE conversations about this sort of problem. Suggest you first have a read through all before your post and see if any of your problems can be solved that way. If you have the BMPr0 unit, make sure that the battery voltage has achieved at least and the Low Voltage Reconnect has been activated by battery being above 12.80 volts before start switching on all the 12 volt loads. In fact, if I remember from the manual, it voltage went below the 10.3 volt range, battery has gone into "store" mode. I think after charging, you have to cycle the on/off disconnect switch and the do the same with all the loads for the system to get going again. On the other hand, the battery may not be able to be recovered (to reconnect voltage) as left too low for too long. Have a good read through the manual for your model which can be downloaded from BMPro site.
 

mikerezny

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Hey guys I’ve just brought a 17 swan an can’t get 12v system to work, pervious owner must have left something on an battery down to 5v.
Have charged battery hooked back up an still nothing not even to the coast to coast monitor but if I hook to 240v all works just not charging……

only had just over a week an ready to get rid of it already……

thanks
Hi,

before you get information unrelated to your particular problem, can you please post exactly what brand and model number battery charger / power supply you have?

Have you a copy of the user manual? If not, they are not hard to find online.

Lastly, have you got a digital multimeter?

take care
Mike
 
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Case8120

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Hey guys can someone tell me if this fuse is meant to be there? As it wasn’t but as soon as I put one in everything 12v is working……
BMpro j35A
7041DD63-1CE8-4A68-88B5-77608BA748B2.jpeg
 

mikerezny

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There are TWO 12V fuses to protect the BmPro and the battery as stated on page 11 of the BmPro manual:

For Reverse Battery protection, two battery fuses are installed. (Refer to item Battery Fusing). If one or both of the fuses need to be replaced, contact your dealer for assistance.

And on page 12:
BATTERY FUSING

Apart from the fuse along the Batt+ wire that is connected to the positive line of the battery, a 40A automotive fuse is also mounted in the PCB. In case there is a short circuit in the battery line, this may cause either (or both) the PCB mounted or the external battery fuse to blow. If the fuse/s need to be replaced, contact your dealer for guidance.


So, you should see two fuses one above and one below the battery connection terminals.

Mike
 
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