Power distribution unit - on or off?

Its the battery charger. The noise is the cooling fan and,as you describe it, is normal. If you leave it off you will flatten your habitation battery


Peter

Hi Fatima

The power supply/battery charger unit is designed to use a mode of battery charging called the Float Charge. When you are living in the van the charger will if necessary recharge the battery and will also supply the habitation 12v needed whist maintaining the battery charge and keeping the battery in perfect condition. You should therefore leave the charger on all of the time you are living in the van.

If the van is not lived in or driven for a period of over 2 weeks the batteries will start to lose charge due to alarms, monitors etc even if everything is switched off. After 3/4 months the batteries will be well discharged.

If a solar panel is fitted then that will maintain the batteries (including the vehicle battery if a 'battery mate' or similar circuitry is fitted) in a charged state without detriment to the battery even in the low light levels of winter.

If the van is not being lived in with the consequent use of the 12v facilities and the van power supply/charger is hooked up and switched on then the float voltage is too high for constant application to the battery. That will cause slight gassing of the electrolyte in the cells (assuming the most common lead acid wet cell battery is installed) and in 3 to 4 months the electrolyte will have dissipated allowing the metal plates to heat up and distort causing permanent damage to the battery.

So if the van is not being lived in and you want to maintain the condition of batteries you should hook up and charge for 6 to 8 hours very week or two but don't leave the charger on all the time or you will damage the batteries.

I hope the above is clear but if not just come back.

Peter

If it is a few months since the van has been used I would first check the fluid levels in the battery cells and when they are ok (and if you have the facility) charge on hook up for 24hrs before you set off.

It would take several hours driving to get much of a charge into the battery but as Mojo says, if you avoid lights, tv, etc and just use basic facilities - pump, fridge, etc. you'll probably be ok.

Peter

I've been scratching my head on this but now have a possible scenario - it depends on you having a solar panel fitted to be correct.

I've no practical experience of your power installation so am a bit cagey about the % indication of battery condition.

After 5 weeks on hook up the battery should have been fully charged and should have stayed that way while you were driving back.

It is possible that your charge was not switched on while you were at Benidorm and that the 12v apparatus was being fed by the battery that was being topped up with a solar panel hence when you left the battery was not fully charged.

I would be surprised if you drove the 640 miles in one go and guess you only drove 3 or 4 hours a day and camped overnight a couple of times so you would put some charge in during the day and then use some at night.

When the battery went up to 100% it could either be because you had switched the charger on or did not use any 12v for a couple of days allowing the solar panel to fully charge the battery.

If the scenario I imagine is completely wrong then describe in more detail your travels/installation and I'll have another think.

Peter

artheytrate wrote:Yes Peter the batteries were fully charged when on hook up, on the way home we used some 12 volt plus 150 watt inverter, the leisure battery dropped to 69%.We then travelled 650 miles in  2 days using very little power only led lights, and the display only read 85%. We then went on hook up and the display went up to 100% after a few hours.
Also we keep getting alarm on display saying cab battery is low especially when  running water from taps. We only have the 30 watt solar panel fitted by Auto sleeper. I will have to get in touch with our dealer or Auto sleeper.

John.

I think you will have to get it checked out. My first activity would be to carry out tests to understand the accuracy of the % indications by measuring battery voltage at the terminals with a meter.

Peter