I bought a new battery for my 2010 Luna Quasar approximately 18 months ago and for the last 7 months the vans been laid up with an EHU permanently connected. I was under the impression this would keep the battery topped up but when I checked it yesterday the voltmeter was reading 2 volts. So it looks like the batteries had it. Apparently (and I was not aware of this) the correct way to keep a battery topped up over a long period is to turn off the charging unit every month or so and leave a 12volt lamp on for 24 hours then turn the charger back on. I would be interested in your replies and whether you approve of this method or have any other ideas of how to keep a battery topped up
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I rang Coachman and asked the question about my 2018 caravan.
They said that the charger was a "Smart" charger and would be ok to left connected constantly.
It may be that your 2010 caravan does not have a charger of this type.
It could also be that the battery had just had it and it was nothing to do with the charger.
I had a 2005 Burstner,it was left on charge 24/7 365 and after 15 years it would still move the caravan whenever I needed it, the person who bought the caravan in 2020 has just this year bought another battery!
saxo1
Was the battery reading 2v across the terminals while connected to caravan charger & plugged into mains ? If so then charger has probably had it because regardless of condition of battery with charger connected it should be reading about 13v.
If battery & charger are ok then yes plugged into ehu permanently should keep it charged. If battery does not retain charge once disconnected then battery has had it.
A leisure battery kept on charge on a caravan will only produce about 80% of it's capacity to avoid it reaching the gassing stage, that's why they advise to remove it and charge the battery up via a smart charger once in a while. When we return to the storage after each trip I remove the leisure battery, take it home and keep it charged 24/7 via a smart charger which my Lucas 100 ah. battery is now 10 years old and still functioning effectively as I now check the voltage before each trip due to it's age.
However, what you need to do is to check whether the battery needs replacing or if it's the charger itself is defective and the latter is the first step. Turn of the mains power, remove the battery then with a voltmeter switch back on the mains power and put the prongs on the caravan battery connectors. The reading should be around 13.9 to 14 volts which will reduce in volts when the battery is re-connected. Secondly, check the battery voltage to see if it reads the same as the onboard battery gauge because in some cases (but very rarely) it has been known for the battery gauge that's at fault.
We don't use our caravan over winter so always take the battery off and take it indoors. I then put a smart charger on it from time to time to keep it topped up. The battery only goes back on the caravan when the risk of frost has virtually gone. April being the very earliest we are likely to use it.
Quote " Turn of the mains power, remove the battery then with a voltmeter switch back on the mains power and put the prongs on the caravan battery connectors."
This won't necessarily prove that the charger is faulty, most smart chargers need a base voltage present to start the charge cycle,a CTEC wont put out any voltage if the battery is at or lower than 2V many others need a higher voltage.
You need to have a battery connected to reliably test the charger,older chargers may work without a battery connected
saxo1
Thanks Guys Just supposing the van charger packed up when the battery was 80% charged would it drop to 2 volts in 7 months. If the charger did fail while the EHU was still connected would that encourage a rapid discharge.
As you can probably tell I know very little about van electrics but I'm learning--slowly. As Billy says no matter what the state of the battery if the charger has a supply from the EHU the voltmeter on the control panel should read 13-14 volts (In my case its zero) I used a voltmeter across the battery terminals while the EHU was still connected and its only 2 volts.
If it turns out the van charger is knackered and its just a basic charger I guess this can be upgraded to a smart charger. I doubt if the battery will recover but my local garage said he would put it on a booster charge and see if it retains a charge. Thanks again for all your help
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If i have the need to leave ours charging 24/7 it means its generally freezing outside. That being the case, i have the heating on to around 10 deg. That keeps the battery happy, as its got juice flowing in and out of it.And the fabric inside keeps aired as well.
It is quite possible that a battery left connected to a failed charger for 7 months could be discharged completely. The charger could be putting a load on the battery if it has developed a significant fault, or other equipment inadvertently left switched on could do it. An alarm or a TV aerial booster for instance.
I would say it is almost certain that the charger is knackered and I don't see any reason why it couldn't be replaced by a more up to date one. You may be lucky with the battery, but I doubt it. If a battery is left in such a low state of charge for any length of time that will usually finish it off.
Most battery chargers have a blocker diode to prevent the flow of electricity from the battery back to the charger, a faulty charger shouldn't add a load to the battery.
A lead acid battery self discharges over time depending upon the temperature on average 4% per month.
saxo1
If the battery is down to 2 volts would this be enough to switch on an internal light ?. I've just been told a smart charger will not work if it detects the battery has an output of less than 10 volts is this right?
------------- The longest sentence known to man is "I do"
Quote: Originally posted by saxo1 on 20/2/2022
Most battery chargers have a blocker diode to prevent the flow of electricity from the battery back to the charger, a faulty charger shouldn't add a load to the battery.
A lead acid battery self discharges over time depending upon the temperature on average 4% per month.
saxo1
One of the faults I was thinking of was a diode going short circuit. I agree though, under most circumstances a faulty charger wouldn't put a load on the battery.
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