Replacing mppt but no power from leisure battery leads

[Juandeatatime]

Hi everyone, I wanted to replace the standard Trauma PWM with a more efficient Victron mppt on my Majestic 285. I thought if I just replaced one wire at a time from old to new I would be fine but I must have shorted it as there is no power from the leisure battery leads at all. I followed the battery lead as far as I could looking for an online fuse but unsuccessful and it looks like a bird's nest of wires behind the control panel. Two questions, does anyone know where the fuse could be or failing that could I run a positive and negative straight from the leisure battery to the mppt? Many thanks in advance.

 

[MichaelT]

What make battery? If lithium is discharging turned on? There will be a big fuse near battery is that blown?

 

[Juandeatatime]

No, it's a 105ah lead acid the only leads in the battery box are the normal battery leads.

 

[autorouter]

There should be a fuse on that red wire, within about 30cm of the battery terminal. That wire should go to a fuse block where there are other fuses, possibly one just for the solar input. Can you post a pic of the wider battery around the battery?

 

[Juandeatatime]

There should be a fuse on that red wire, within about 30cm of the battery terminal. That wire should go to a fuse block where there are other fuses, possibly one just for the solar input. Can you post a pic of the wider battery around the battery?

Hi autorouter and thank you for replying. I've just got home from a visit to family and my motorhome is kept in storage. The battery is kept in a battery box under a storage box. From what I remember both leads exit the box on the left (just outside photo). Probably be able to get back there next week and will have a good look.

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[pappajohn]

No power from battery leads.
Do any 12v services work ....lights etc

 

[MisterB]

ive just started my rear air suspension project, when i was connecting to the supply (pos/neg) i turned off the battery at the isolation switch i installed, ddi the connections and turned it back on again .... nothing! off and on again .... nothing, no lights, no panel etc, thought strangely the display to the heater was showing 'something' ..... i checked the connections, all is well, still nothing ...... so i did what all good diy experts do, went and had a coffee ...

it was then that i realised i had to actually turn the bloody panel on ....... back i went, and solved my problem with the lifting of one finger !!

Posting this on your thread Juandeatatime in case yours is also a simple 'forgetful' fix?

PS i am only up the road in Clacton if youre still having problems - im not a mechanic/auto electrician but if you need two sets of hands ....?

best wishes and good luck with solving your issue .,,,

 

[Juandeatatime]

No power from battery leads.
Do any 12v services work ....lights etc

Sorry, I've not explained my problem properly. The leads with no power are the positive and negative wires attached to the Truma PWM that go to the battery that haven't got any power - the rest of the 12v system is fine. There must be an online fuse somewhere but I can't find it.

 

[pappajohn]

I think they will go to the control panel, not to the battery.
Probably a fault at the panel.
Maybe an onboard fuse on the back or front of the panel

 

[Juandeatatime]

I think they will go to the control panel, not to the battery.
Probably a fault at the panel.
Maybe an onboard fuse on the back or front of the panel

Thanks for the advice, I'll try and check this out although the control panel still works and gives me the voltage of the leisure battery.

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[pappajohn]

Then the fault lies in wiring between control panel and mppt.
Broken/disconnected wire or an inline fuse.
Can't be anything else.
As a temporary measure run live and earth direct to battery to keep it charged from solar but connect solar panel +v wire last as the mppt may need to see battery voltage first to know if 12v or 24v.

 

[Jimbohorlicks]

Hi everyone, I wanted to replace the standard Trauma PWM with a more efficient Victron mppt on my Majestic 285. I thought if I just replaced one wire at a time from old to new I would be fine but I must have shorted it as there is no power from the leisure battery leads at all. I followed the battery lead as far as I could looking for an online fuse but unsuccessful and it looks like a bird's nest of wires behind the control panel. Two questions, does anyone know where the fuse could be or failing that could I run a positive and negative straight from the leisure battery to the mppt? Many thanks in advance.

You need to disconnect your solar panel firstborn you disconnect anything else connected to your controller.

 

[pappajohn]

I thought if I just replaced one wire at a time from old to new I would be fine

A tip for the future.
If you have a few wires to disconnect, use different coloured tape or felt pen to mark the individual wires then take a photo.
Remove the lot ensuring any live ends are taped.
Change the item then rewire using the photo to see what colour goes where.

 

[MichaelT]

A tip for the future.
If you have a few wires to disconnect, use different coloured tape or felt pen to mark the individual wires then take a photo.
Remove the lot ensuring any live ends are taped.
Change the item then rewire using the photo to see what colour goes where.

I always take a photo.

 

[BouncyBoatFolk]

No, it's a 105ah lead acid the only leads in the battery box are the normal battery leads.



View attachment 998762

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Mike.

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[Speve]

I reckon Jimbohorlicks is right and you need to restart with firstly disconnecting your solar and then connect your controller then reconnect solar panel.

 

[Juandeatatime]

I think they will go to the control panel, not to the battery.
Probably a fault at the panel.
Maybe an onboard fuse on the back or front of the panel

Hi pappajohn I managed to get to the motorhome this morning and attempted to feel for a fuse - unsuccessfully. I think my control panel is a "Denver", but do you know, or anyone, if the faceplate just prises off to get at the screws holding it in? With it removed I should have a much better idea. TIA