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-   -   Advice on electrical problem in motorhome (https://forums.motorhomefacts.com/49-tech-mech-chat/239947-advice-electrical-problem-motorhome.html)

Yvonne and Ward 14-10-2020 12:59

Advice on electrical problem in motorhome
 
Hi all,

So, we're new to our 2006 Chausson Welcome 9 and would really appreciate some advice from those who know more and better!

Here's our problem: our 12v control panel gets power when plugged into a hook-up or when the motorhome's engine is on, but not from the leisure battery. I checked our relatively new leisure battery with a multimeter and it was nicely charged. Next step was to replace the 20a blade fuse in the fuse box for the auxiliary battery-- but still nothing (and I couldn't find another fuse closer to the leisure battery).

Does anyone have ideas for what we should check next?

Thanks!

EJB 14-10-2020 15:03

The motorhome control panel normally has a 12v On/Off switch?

Yvonne and Ward 14-10-2020 16:26

Thx-- yes, the panel has an on/off switch, but it won't switch on (or stay switched on) via leisure battery.

jiwawa 14-10-2020 16:40

Is there anything working on 12v when not plugged into 240v? Lights? Water pump?

I have a Truma control panel that controls heat/hot water. I also have a panel that shows the state of the batteries and the water tank levels. It is this panel that has a circular knob to step thro the various monitors but when you PUSH that button it trips the 12v on and off.

Yvonne and Ward 14-10-2020 19:42

Thx for this, Jean. Nothing else works when not plugged in (or with engine running). Our panel shows levels of batteries and tank levels (when plugged in or with engine running), but the panel won't toggle over between different energy sources....

jiwawa 14-10-2020 22:05

Can you post a photo of any panels you have?

Glandwr 14-10-2020 23:42

They WILL be an isolation switch for the habitation 12v system somewhere. Have you found one?

Pudsey_Bear 15-10-2020 08:10

Could it be the switch is broken, can you post a picture of the panel, that might help us.

Yvonne and Ward 15-10-2020 12:49

1 Attachment(s)
Thanks all, very much appreciated. I'm attaching a pic of our control panel. It registers battery levels as fine and a multimeter also says leisure battery is charged at 12.8v-- but the panel won't toggle from engine or hookup over to leisure battery (I don't think our panel does that anyway?)-- and if I turn off engine and unplug hookup, the panel just goes dead.

jiwawa 15-10-2020 16:08

That's not one I'm familiar with. I assume you've pressed the extreme right button?

Yvonne and Ward 15-10-2020 16:19

Thank you, Jean-- yep, we've pressed that one 'til we're blue in the face (ha).

jiwawa 15-10-2020 16:56

I thought you probably had but best to check!

jiwawa 15-10-2020 17:01

What about your electroblok that controls all the 12v? Mine is under the driver's seat (LHD). Maybe a fuse gone or something popped out?

rayc 15-10-2020 17:07

1 Attachment(s)
Can you confirm you have a CBE DS300 type 12v distribution box?

jiwawa 15-10-2020 17:08

On page 4 of the manual available here

https://www.google.com/url?sa=t&sour..._6LBTErVqFvfrv

there is a pic of a 'tap' that governs all the 12v to the hab area.

It refers to an A class but it's possible they use the same system in others?

Yvonne and Ward 15-10-2020 18:01

Quote:

Originally Posted by rayc (Post 3117257)
Can you confirm you have a CBE DS300 type 12v distribution box?

Yes, we have a distribution box like this one, a DS304. Just in case the problem was there, I replaced all the fuses in it.

Glandwr 15-10-2020 18:05


rayc 15-10-2020 19:05

1 Attachment(s)
Quote:

Originally Posted by Yvonne and Ward (Post 3117269)
Yes, we have a distribution box like this one, a DS304. Just in case the problem was there, I replaced all the fuses in it.

Can you remove the cover and with your multimeter check the leisure battery voltage on the large screw connectors ?
Contact -B2 is common negative.
Contact +B2 is positive leisure battery.
[Contact +B1 is positive engine battery].

rayc 15-10-2020 20:02

1 Attachment(s)
This is the wiring diagram. As you can see there are two inputs to contact B2- and B2+. One is the leisure battery and the other the charger output. The fact that it works with the charger on but not the battery alone points to trhe leisure battery positive not getting to contact B2+. I would suspect that 50A fuse in the line from the leisure battery + to contact B2+.

Yvonne and Ward 16-10-2020 11:17

Quote:

Originally Posted by rayc (Post 3117285)
This is the wiring diagram. As you can see there are two inputs to contact B2- and B2+. One is the leisure battery and the other the charger output. The fact that it works with the charger on but not the battery alone points to trhe leisure battery positive not getting to contact B2+. I would suspect that 50A fuse in the line from the leisure battery + to contact B2+.

Thx so much for this Rayc-- when I multimeter test the leisure battery itself it reads 12.75 volts. When I took the cover off the distribution box as you suggested, the multimeter test of leisure battery through B2 bolts is only 11.37v. What does that mean to you? Again, really grateful for your know-how!

rayc 16-10-2020 11:54

Quote:

Originally Posted by Yvonne and Ward (Post 3117375)
Thx so much for this Rayc-- when I multimeter test the leisure battery itself it reads 12.75 volts. When I took the cover off the distribution box as you suggested, the multimeter test of leisure battery through B2 bolts is only 11.37v. What does that mean to you? Again, really grateful for your know-how!

I think that the control unit disconnects if the battery voltage drops below a pre set voltage [the drop dead voltage]. I thought it was 10.8v but with a cheapish multimeter a reading of 11.3v may be near enough.
In any event the question has to be where is the 2v or so from the battery being 'lost'? At the 50A fuse or the terminal connectors?
What I would do is run a wire directly from the battery positive to terminal B2+ and see what happens. It may be prudent to insert a 20A fuse in the wire.

Just a question, are you absolutely sure the battery voltage you are measuring as 12.7v is the leisure battery and not the cab one?

Can you confirm that when on EHU that the voltage from the charger measured at B2+ and B2 - is the same as at the battery terminals i.e. the charger is charging the battery.

Yvonne and Ward 16-10-2020 12:49

Quote:

Originally Posted by rayc (Post 3117395)
I think that the control unit disconnects if the battery voltage drops below a pre set voltage [the drop dead voltage]. I thought it was 10.8v but with a cheapish multimeter a reading of 11.3v may be near enough.
In any event the question has to be where is the 2v or so from the battery being 'lost'? At the 50A fuse or the terminal connectors?
What I would do is run a wire directly from the battery positive to terminal B2+ and see what happens. It may be prudent to insert a 20A fuse in the wire.

Just a question, are you absolutely sure the battery voltage you are measuring as 12.7v is the leisure battery and not the cab one?

Can you confirm that when on EHU that the voltage from the charger measured at B2+ and B2 - is the same as at the battery terminals i.e. the charger is charging the battery.

Thx again. Oh, wow, this time when doing the checks you suggested I realized what I hadn't thought about before, that I was checking the leisure battery at B2 on distribution box while the motorhome was plugged into EHU. When I check B2 without being plugged in, it is really low, like 3.65v.

You asked me to confirm I was definitely checking leisure rather than engine battery, and I can confirm that (it's a Numax DC25MF back underneath the bed whereas the other is an Exide Excell EB950 under the hood).

You made another suggestion: I haven't yet run a wire directly from leisure battery to distribution box. I could figure that out and get 'er done if that's the key to the secret, but I haven't gotten that far yet.

So it sounds to me like I've got two charged batteries (leisure and automobile) but am getting next to nothing from leisure battery at the distribution box...

Thx again

rayc 16-10-2020 12:56

Quote:

Originally Posted by Yvonne and Ward (Post 3117449)

So it sounds to me like I've got two charged batteries (leisure and automobile) but am getting next to nothing from leisure battery at the distribution box...

Thx again

That is why you should check the 50a fuse that should be somewhere between the battery positive and B2+

Yvonne and Ward 17-10-2020 12:02

Quote:

Originally Posted by rayc (Post 3117455)
That is why you should check the 50a fuse that should be somewhere between the battery positive and B2+

Thx to everyone who gave us such helpful information. I found and replaced the 50a fuse, but it's still doing the same (registering 12.7 v at the leisure battery, only 3.7 at the B2), so I think we'll give up, have a drink :wink2:, and see if we can get an auto electrician to look at it next week.

All the info shared with us is much appreciated. See you all out there sometime soon.

Best, W

jiwawa 17-10-2020 14:12

Will you come back n tell us what the solution was please? All good info for future readers.

Yvonne and Ward 17-10-2020 14:28

Quote:

Originally Posted by jiwawa (Post 3117629)
Will you come back n tell us what the solution was please? All good info for future readers.

Great idea-- yes, I will come back to post again once I sort it out.

rayc 17-10-2020 14:36

Quote:

Originally Posted by Yvonne and Ward (Post 3117633)
Great idea-- yes, I will come back to post again once I sort it out.

Before giving up and calling the electrician you could try a couple of things if you wanted to.

Can you confirm that the 50a fuse was definitely in the leisure battery supply and not cab battery?

Can you remove the fuse and test the voltage on the fuse holder contacts, with the meter negative connected to battery negative? What do you read on the contact coming from the battery? What do you read on the contact going to B2+? [with EHU disconnected]

Can you use a test wire from battery positive to B2+? [with EHU disconnected] Does everything spring into life?

Yvonne and Ward 03-11-2020 10:19

Hi everyone-- thanks again for all the very helpful ideas you shared here-- very much appreciated.

We've finally solved it: someone at some point installed oxygen free wires (like for a car stereo) between the leisure battery and the distribution panel. As these wires do, they'd oxidized and were no longer transmitting the electricity well-- only a bit getting through so the system had isolated the leisure battery from the rest of the system. We cut off the oxidized portion of the wiring and are back up and running as normal.

Thanks everyone!

Penquin 03-11-2020 11:14

Not a thing I have ever heard of before "oxygen free wires" - must see what I can find out about such things ! Thanks for letting us know, in simple terms "naff wiring" may cover it.

Have now read a couple of explanations and of course our dear friend Wikipedia - the general consensus is that it is used in "high end speakers and amplifiers" so that makes sense, however all the articles say that the difference is debatable, if any and unless extremely long wires are used (over 15 metres) any difference in conductivity is negligible.

So, I doubt that I shall bother even considering using it in the noisy environment that a motorhome represents I doubt that my naff hearing would even recognise any possible Improvement in clarity while tootling along the N21 or even the A89 if we were homeward bound.....

Just one link;

https://customcable.ca/oxygen-free-c...-applications/

Sounds like a liberal dose of snake oil to me... :grin2:

ErnieB 03-11-2020 15:36

Have you checked for an in line fuse near the battery? it will, if it exists, be thicker than the wire and black. Failing that do you have a large box with the charger in it, if you have check the cables in the bottom of the box, we had one made by sargent and it had a burnt out connector.

jiwawa 09-11-2020 12:19

Quote:

Originally Posted by Yvonne and Ward (Post 3120329)
Hi everyone-- thanks again for all the very helpful ideas you shared here-- very much appreciated.

We've finally solved it: someone at some point installed oxygen free wires (like for a car stereo) between the leisure battery and the distribution panel. As these wires do, they'd oxidized and were no longer transmitting the electricity well-- only a bit getting through so the system had isolated the leisure battery from the rest of the system. We cut off the oxidized portion of the wiring and are back up and running as normal.

Thanks everyone!

Excellent news! It feels good to solve a problem!


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