Power distribution unit - on or off?

In my 2007 Nuevo there is a Power Distribution Unit with an on/off toggle switch under the offside seat. In the past I have left this switched on all the time. Recently I have noticed that it emits a soft humming noise when switched on. This is new and is rather annoying in the night when there are no other sounds in the van. Should it make a noise? - and what are the consequences of leaving it switched 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,
our 07 Nuevo has the power contoller under the offside bunk. I was told only to use this to charge the batteries for a short lengh of time, its not an "intellegent" charger, and would fry the batteries if used continuously! When on a hook up site, I take an "optimate" charger with us, and use that.
Mike.

So can someone advise: How much of the time should this be switched on to ensure adequate charging without "frying" the battery???

I have a Bonus PDU4M in my Sigma and I asked this very question of Mark Burdett of Autosleepers on Wednesday. 

His reply was that Autosleepers do not recommend leaving batteries constantly on charge.  Leisure batteries are designed to operate on a discharge/recharge cycle hence and leaving them constantly topped up can lower their life.

I have just replaced my engine battery and believe that leaving this on charge via PDU contributed to it's failure.

Hope this helps

Best wishes
Alan

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

Just about to use camper for a few days with no hook-up so revisiting this topic! Your explanation is very helpful Peter. In summary: When van in use on hookup keep charger switched on. If on drive for few weeks/months give a few hrs charge every week or two. 

Having been parked on drive without any charging my habitation battery charge is currently showing low. I assume it will charge from the alternator on my journey this weekend. Will that charge be sufficient for basic 12v services (I think that's just lights, water pump, toilet flush??) for a few days without recharging?

Generally, yes, provided you don't make extensive use of anything that is power-hungry (e.g. halogen lights).

However, if the battery condition is Low and the van has been used recently, or you have had the charger on recently, then something would seem to be wrong. The leisure battery should take many weeks to self-discharge to a low state of charge, so unless it really has been many weeks since used/charged it probably needs further investigation.

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

Hi Peter can you answer my quiery on our Broadway EB, we had been on hook up for 5 weeks in Benidorm everything working fine but on the way home the leisure battery read 69% full and after 650 miles of driving it only read 85% full and after that we were on hook up for 2 days and then the reading went up to 100%. Surely 650 miles of travelling would have more than fully charged the leisure batteries to 100%.

John.

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

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.

While parked up in the drive for a week I left an inverter (switched off) connected up directly to the leisure battery. 

The power unit was on but I hadn't hooked up to mains and it was winter so negligible solar charge. 

Both leisure and vehicle batteries went flat. Used jumper leads to start van and went for a run also put van on mains when we got home.

Now I never leave the inverter connected and keep the power unit off while not on mains.
Fred

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