Trying to understand my Truma solar dual battery charger setup ...

[APScotland]

I have an Adria Matrix 590 morothorme, with a solar panel (65W) and Truma SDC which were installed as part of the package - just under 2 years ago. It used to be that when I clicked on the power panel, I could see when the leisure battery was being charged up by the solar panel. Recently, it just reads 0.0 - except when I deliberately put a load on, eg raising the bed, when it goes strongly negative, as you'd expect.
I've just been teetering inside the wardrobe trying to read the settings on the SDC. They're all at the default settings, ie Gel battery, 50:50 charging, @25 Hz.
It looks to me as though only the service battery has been connected to the SDC - see attached photo, in which case the SDC should be set to 100% of the charge going to the leisure battery. Though I'd prefer the 50:50 split if this can be easily retrofitted?
There's a green flashing light for the service battery - nothing for the starter battery. The light flashes once every 2 seconds or so. The manual is not hugely helpful here - it says if it flashes in short intervals, the battery is not being charged. If it flashes in longer intervals, it's fully charged. If it flashes, check connections. Does anyone know what it means when it's flashing at once every 2 seconds???
The power panel shows that the leisure battery was at 12.6V, ie 91% charged, and the starter battery at 12.3V ie 76% charged, and the sun was shining strongly yet the power panel showed no charge going to the leisure battery.
Any advice much appreciated! Thanks

 

[pappajohn]

I would say at 2 second intervals the battery is charged.....and the fact it reads as 12.6v confirms that.
Use a multimeter directly on the battery to confirm voltage.
Fast flash rate will be a constant on/off/on/off.
I would ignore the state of charge indicator as inaccurate

To configure charge to both batteries will need extra wiring from the controller to the starter battery but if that is conventional lead/acid and the hab is gel it will overcharge.

A 65 watt panel will only provide, in the real world, around 3 amps in full overhead sun.
I would consider adding a further 100watts or more of solar panel.

 

[Speve]

Make sure the panel is clean as they do gather a bit of muck and that will lessen the charge rate.

 

[APScotland]

Thanks Pappajohn and Alan. I'll check what sort of batteries they are and whether they're clean. We have been visiting the coast in North Aberdeenshire recently - perhaps the seagulls had a mass bombing raid on our solar panels! No sign of it on the sides of the van, but they could be experts at targetting On closer inspection of the manual, it says that if there's only one battery linked to the solar charger it will get all the charge, even if it's set to distribute it 50:50. I'll check if there's room for another solar panel up there too

 

[Jimbohorlicks]

if you want to charge your starter battery tfrom your set up then you would require a battery master which would be connected to the hab battery then the starter battery. There is no connection from your Truma controller as its only currently configured for one battery connected.The second battery connection is unused , the charge should default 100% to the one battery. You don't advise if you have a gel battery or not-sometimes the dealers who install the controllers don't always set them correctly.

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[APScotland]

hi Jimbohorlicks, rather inconveniently there's no indication on the top of the hab battery what sort it is, and I didn't have the energy to disconnect it and haul it out when I rummaged around looking for the info the other day! It's due it's annual inspection shortly so I'll ask the chap who does it to find out for me ... ditto for the main battery under the bonnet too!

 

[Jimbohorlicks]

I had a Truma sdc10 on my set up with a 100w solar panel, when I put up another 100w panel I was obliged to changed the sdc unit for something of a bigger capacity. On top of the units is a sticker with the sdc type either sdc10 or 20, If you check your instruction manual it will advise the max capacity of your unit, if you have an sdc10 and want to add another panel you may have to upgrade the controller also

 

[Lenny HB]

I think your regulator is faulty, if you read the instructions you will see the bulk charge will take the voltage up to 14.2v (Gel setting) and hold at that voltage for the absorbtion phase for 2 hours then drop to a 13.8v float charge.
If your battery is sitting at 12.6v with no load that would suggest that there is no output from the regulator battery should be reading 13.8v.

 

[Jimbohorlicks]

below is a copy of the function display, maybe it is a faulty battery as @Lenny HB advises, if the flashes are every 2 seconds-have you another battery you can try?

Display Cause / rectification
LED flashes in
longer intervals
Check connections from the device to
the battery and solar module, ensure
that they are connected to the right
terminals.
Test the fuse, solar module and the
battery.
LED flashes Battery is fully charged.
LED shines. The battery is being charged.
LED flashes in
short intervals
The battery is not being charged.
If necessary, replace faulty battery.
LED does not shine Battery not connected or over-voltage

 

[pappajohn]

LED flashes Battery is fully charged.
LED shines. The battery is being charged.
LED flashes in
short intervals
The battery is not being charged.
If necessary, replace faulty battery.

Define "short intervals".
My definition is equally spaced rapid on/off.

Normal fully charged flash would be off 2 seconds, on 1 second

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[Jimbohorlicks]

Define "short intervals".
My definition is equally spaced rapid on/off.

Normal fully charged flash would be off 2 seconds, on 1 second

The manual doesn't define the time interval-Its a "copy and paste" from the instructions, the op indicated 2 sec intervals, but the battery was only 12.6 volts

 

[Viennese]

@APScotland, hope if you try to use a 'Truma trained engineer' as listed on their web site, you do better than me. They gave me about 6 potentials to take my problem to (dead Truma Combi water/warm air heater) 2 never phoned back, 4 said 'we don't do motorhomes, only caravans', one said 'we only do caravans we have sold!' Finally found one who agreed to look at it, and he, surprisingly, seems quite good. Hope he gets the replacement PC board soon to fit before we leave for Holland on 6 May!

 

[pappajohn]

The manual doesn't define the time interval-Its a "copy and paste" from the instructions, the op indicated 2 sec intervals, but the battery was only 12.6 volts

The battery indicated 12.6v on the onboard panel which is why I said ignore the panel and stick a decent multimeter on the battery.
On another thread the op got two different readings off two separate onboard meters pointing to inaccuracy in one or both.

 

[Ron W]

my Truma sdc 10 is flashing on number 1 and my meter on the voltage tester reads 11.6v I only have a 100w solar panel I didn't do the wiring this was done by a conversion company which I certainly wouldn't recommend. The instructions for this unit is very vague and confusing. I have two leisure batteries connected to it plus my van battery, think I'll just start my van not ideal but at least it will charge all batteries

 

[Abacist]

Why not phone Truma UK and discuss with them rather than a dealer!

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