Leisure batteries [voltage] dangerously low

[Dorset Diver]

The solar regulator is built into the Sargent EC325 PSU / charger and to date has been very effective when we have used the van off EHU for extended periods. What I find strange is that whilst sitting on the drive with no 12v being used (lights, TV, etc.) it should suddenly be unable to keep the batteries up. Incidentally I have checked and I know that it is working. However, I take you points about using the EHU / PSU / Charger and it is currently running. Thanks for all your help and suggestions.

 

[wizzer59]

I wonder, does your van have an automatic dump valve on the boiler?? cos my Hymer has it and it has quite a draw on the batteries, and it has been recommended to me to empty the boiler then turn it off

 

[Dorset Diver]

I think I know what you mean and I think the answers is no. The boiler is a Truma C6002EH which I rebuilt earlier this year when the electric elements failed. Having removed it from the van, taken it to pieces, refurbished and reassembled it, I am fairly sure I would have noticed such a valve.

 

[peterc10]

I think I know what you mean and I think the answers is no. The boiler is a Truma C6002EH which I rebuilt earlier this year when the electric elements failed. Having removed it from the van, taken it to pieces, refurbished and reassembled it, I am fairly sure I would have noticed such a valve.

It is not part of the boiler, it is usually close by it, although my one is some way away. According to this schematic it does have one - it is bottom left of the schematic picture.

 

[Dorset Diver]

Okay I,m with you when I was working on the unit I did find a couple of wires that were not connected. I described them to Truma and they said they were for an electrically controlled drain valve; which what I now think you mean. In any event whilst the system electrics have the facility built in Autotrail in their wisdom chose to install a manual valve.

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[RowleyBirkinQC]

We fell victim to the Autotrail leisure batteries draining even with solar panels on board (purchased van in Sep 2014). It may have been due to reversing camera and entertainment system screen drawing power when not in use. To be frank, we were clueless of this in comparison to previous vans and had no idea why the solar wasn't keeping the leisure batteries topped up. A week after finding this out and disabling via the related switch hidden away in cupboard, the battery is still showing as 12.8v on the panel, so far so good...

But I am a bit nervous about how knackered the leisure batteries may be in respect of holding charge longer term, as the lowest voltage seen on panel before finding out was down to about 5v.

 

[Dorset Diver]

Hello RB QC,

You are on the nail. That is the problem to which I tracked my difficulty. It was all fine whilst we had good long days with some sun but as the solar light got less the drain on the batteries was too much. Have switched off now, recharged the batteries and all seems well.

DD

 

[Techno]

I thought I would quantify your quote. At 12.4 V a battery is 50% discharged.

Absolutely correct (the table) but it is very important to note that these readings refer to a battery with no load on it or charge going in and it must have equalised. Placing any load on the battery will immediately drop the voltage and that cannot be used to assess its state. Turning the load off will send the voltage back up.
Low voltage cut offs usually operate when the battery is under load so if that setting is at 10.5 volts that is usually a no load voltage of 12 which is FLAT. Off course you should be monitoring your battery so that that does not happen.

 

[Steve]

As an after thought ! I would be a little surprised if 2 flat 110 AH batteries were fully charged overnight. Do you know what the output is from your charger. ?

If i let my batteries get down to 70% which i do every now and then, on a self regulating charger of 15amp they take the best part of 3 days to get back to 100%

 

[mitzimad]

same as dave we have had batteries sitting around in the yard dead flat for months and they have recovered i cant say how good they are after but weve often put them on vehicles and had no troubles with them scientificallly they may be damaged but in the real world they are doing what they are supposed to

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[Lenny HB]

I wonder, does your van have an automatic dump valve on the boiler?? cos my Hymer has it and it has quite a draw on the batteries, and it has been recommended to me to empty the boiler then turn it off

The Truma dump valve only draws 35 ma, later dump valves fitted to C4 & C6 boilers are mechanical so no electrical draw.

 

[Lenny HB]

I think I know what you mean and I think the answers is no. The boiler is a Truma C6002EH which I rebuilt earlier this year when the electric elements failed. Having removed it from the van, taken it to pieces, refurbished and reassembled it, I am fairly sure I would have noticed such a valve.

All Truma combi's have a dump valve, C6000 it is electrical, C6 it is mechanical.

 

[tonyidle]

OK! That makes sense then. 10 hrs at 25 Amp equates to 250 A.H. Both batteries re charged.

Not really. The charger is capable of supplying 25A but the current will taper rapidly as the battery voltage rises - it could be down to a few amps after the first hour. A 'smart' charger will maintain a constant current for much longer but otherwise re-charging a 250Ah battery will take days rather than hours. Note also that to fully re-charge 250Ah requires around 20% more than the capacity suggests or approximately 300Ah.

 

[oldmanriver]

Did anybody resolve why the batteries went flat as my autotrail has done the same, fully charged everything turned of and batteries flat after 2 days ?

 

[peterc10]

Did anybody resolve why the batteries went flat as my autotrail has done the same, fully charged everything turned of and batteries flat after 2 days ?

See posts numbers 36 & 37 above. It seems you need to find the hidden switch they refer to which switches off the reversing camera and media stuff. Not having an Autotrail I do not know where it is.

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[Sidney]

Earlier this week I popped into the van and I think I switched on switched on the control panel to hear an alarm. I looked at the Sargent CPU and saw the leisure battery reading at about 10.6 volts. The van was on hook-up but the battery charger was not switched on. I normally leave this on but must have switched it off when using an inverter when we were away a few weeks back.

There is a 80w solar on the roof.

Current was shown at around -0.4 amps.

I checked all the fuse points with a meter and found only the 12v supply to the fridge (which was taking bugger all) and switched it off.

After charging the batteries I disconnecting the charger and Sargent CPU for a day or two the voltage stabilised at 12.7 volts. So fully charged

I must admit I thought with the Sargent control panel switched on that the solar panel was routed to the batteries with smart charging. In which case the 2 x 110a/h batteries should have lasted months without any significant drop.


Ooh I may have answered my own question - perhaps smart charging is not selected on the panel!!!


It might have been a light that had been left on but I'm not convinced so I'm going to get a meter on the battery so see if there is a drain.

 

[Abacist]

My AutoTrail Savannah of 2010 vintage has the Sargent 325 and is fitted with the optional media kit. The switch to turn off the media kit is on the front of the Sargent main box in the middle near the bottom of the unit and is a black button type switch and is clearly marked Media System.

 

[Abacist]

Also you ought to check that your TV signal booster/gain adjuster which is a white unit in the same cupboard as the freeview receiver and Sargent unit on my van is also switched off as this takes some current as well.

On my van if the 12v system is switched on and the water pump then those 2 alone draw between 0.5 and 1.0 amps.

Watch also that vehicle alarm will drain your vehicle battery unless you remember to switch the vehicle battery charging every 10 days or so to recharge the vehicle battery when the van is not in use.