Using onboard charger for long periods

[redpen]

When my Van is parked on the drive I have been leaving the onboard charger on for days at a time to keep the engine battery fully charged and occasionally topping up the leasure battery. My query is, will I 'boil' or damage the battery if leave the charger on too long?

 

My Van is a Ford Autosleeper fitted with a GEC chaging unit; Output 13.8V. 12V, 162W.

It is stated as having 'overcurrent'/'short circuit' protection as well as reverse polarity protection

[Guest JudgeMental]

just an aside, does the 230-12v charger charge the vehicle battery as well? I was not aware of that :-S

[Robinhood]

JudgeMental - 2010-11-04 4:06 PM

 

just an aside, does the 230-12v charger charge the vehicle battery as well? I was not aware of that :-S

 

Depends on the circuitry of the particular van.

 

Current and last two vans provide(d) a trickle charge to the vehicle battery on hook-up (main charge to the leisure battery).

 

Previous van to these would charge the vehicle battery if switched to do so at the panel (i.e. you could choose which one to charge).

 

I wouldn't be surprised if your 'van also trickle charged the vehicle battery. If it isn't clear in the manual, putting a meter on the battery whilst hooked-up with the engine off will tell you.

[tonyishuk]

I take the view that an over used, and cooked, onboard costing a couple of hundred pounds if it went "phut".

 

It would be cheaper to buy and use a couple of Halfrauds maintenance chargers. (or push the boat out and buy a couple of Ctek chargers and know that its a job well done.)

 

Rgds

 

Rgds

[redpen]

I shouldof course have said this is with the Van on mains hook-up. There is a switch on the main elec panel to choose the charging unit to vehicle/off/leisure

[pepe63xnotuse]

I would be worth just checking that this switch isn't just selecting which battery you actually draw from during use(..as that was the case in our previous Compass) and it didn't have any bearing on the charging side of things...

[lennyhb]

JudgeMental - 2010-11-04 4:06 PM

 

just an aside, does the 230-12v charger charge the vehicle battery as well? I was not aware of that :-S

 

Our one does.

 

 

[Keithl]

Hi Redpen,

 

I'd go along with Tony that even a good CTEK charger is a lot less expensive than your built in charger if you cook it! (and a CTEK charger is designed to be left connected whereas your on-board unit is really more of a power supply than a charger).

 

But can I ask why you think you need to leave your engine battery permanently on charge? Unless you have something draining the battery it should easily last 4 weeks or more without needing charging. I have left our Merc for 6 weeks without touching it and it started first time.

 

Keith.

[747]

Why not just stick an 8 watt or 12 watt solar panel in the windscreen.

 

Free energy and it is not going to boil anything as it will just about keep up with any natural battery drain.

[Derek Uzzell]

Received wisdom is that motorhomes should not normally be left on 230V hook-up for long periods with the on-board battery-charger continuously running. Once the battery has reached a satisfactory charge-state, the charger should be switched off. Why would one want to keep on trying to charge a battery once it is fully charged and increase the possibility of damage occurring should an electrical fault develop when the vehicle is unattended?

 

I believe that, after a certain date (2004?) Auto-Sleepers introduced on all models the capability to use the motorhome's on-board charger to charge either the leisure battery or the engine battery.

[Travelling Tyke]

Hello Redpen,

 

For your information our Bessacarr is left on mains "hook-up" all the time and has been since we bought it. (Over 4 years ago.) I switch between "habitation" and "cab" approximately every two weeks to keep the two hab. batteries topped up and the Cab battery recharged. (The alarm system works off that.)

 

It only gets disconnected when we move out...........

 

It hasn't been a problem, I never considered that it would be......Hmm........

...... 8-)

 

I assumed that the batteries would be pretty well topped up when we returned from our travels and as such the charger would be ticking over rather than supplying the maximum current it is designed to do.....

[Robinhood]

Derek Uzzell - 2010-11-04 7:00 PM

 

Received wisdom is that motorhomes should not normally be left on 230V hook-up for long periods with the on-board battery-charger continuously running. Once the battery has reached a satisfactory charge-state, the charger should be switched off. Why would one want to keep on trying to charge a battery once it is fully charged and increase the possibility of damage occurring should an electrical fault develop when the vehicle is unattended?

 

 

Received wisdom, however, is by definition not always correct ;-) .

 

Whilst I wouldn't want to leave a lead-acid battery permanently attached to the output of *some* historical (particularly single-stage) chargers, the motorhome industry has typically (but not universally) been using more sophisticated technology for some considerable time.

 

My particular 'van (and the one before it) features a commonly used CBE charger which is multi-phased:

 

i) Constant Current to end-charge voltage, then

ii) Constant Charging Voltage for a fixed interval, (interval differs for gel and standard batteries), then

iii) Constant Holding Voltage for 10 hours (essentially a trickle charge). then

iv) Standby until voltage drops below 13V (at which point the cycle begins again).

 

All batteries suffer from a certain amount of self-discharge, and this protects against it. Needless to say, my 'van remains on hook-up permanently when at home.

 

So, it's worth understanding the nature of the electrical equipment fitted to your 'van.

 

FWIW, the charging units fitted to many current UK built 'vans also feature muti-stage charging (albeit a slightly different cycle to that above) and at least one of the manufacturers states in their literature that permanent connection is fine.

 

 

 

[Derek Uzzell]

Robinhood - 2010-11-07 11:51 AM

 

...Whilst I wouldn't want to leave a lead-acid battery permanently attached to the output of *some* historical (particularly single-stage) chargers, the motorhome industry has typically (but not universally) been using more sophisticated technology for some considerable time...

 

Interestingly, John Wickersham, in his book "The Motorcaravan Manual" seems to be suggesting the opposite - that it's more acceptable to continuously charge motohome batteries if the vehicle has an old-type charger incorporating a transformer, rather than the more modern 'smart' type that you (and I) have.

[Robinhood]

Derek Uzzell - 2010-11-07 6:21 PM

 

Interestingly, John Wickersham, in his book "The Motorcaravan Manual" seems to be suggesting the opposite - that it's more acceptable to continuously charge motohome batteries if the vehicle has an old-type charger incorporating a transformer, rather than the more modern 'smart' type that you (and I) have.

 

I find the physics of that somewhat difficult to understand. Does he suggest why he takes that stance?

 

(Though of course, the type of charger on my 'van *doesn't* continuously charge the batteries when left permanently on hook-up, as described above).

[Overdrive]

Our circuitry charges the vehicle battery when on the move until fully charged, then charges the habitation battery.

 

It does the reverse on hookup, charges the habitation battery until fully charged, then charges the vehicle battery if need be. We have a light on the panel showing when both are fully charged and of same voltage.

 

I usually connect to the mains at least once a month if we have not used the van for 3 weeks. I would not like to leave it on permanently and do not see the need.

 

David

[flicka]

Derek Uzzell - 2010-11-07 6:21 PM

 

Interestingly, John Wickersham, in his book "The Motorcaravan Manual" seems to be suggesting the opposite - that it's more acceptable to continuously charge motohome batteries if the vehicle has an old-type charger incorporating a transformer, rather than the more modern 'smart' type that you (and I) have.

 

Hi Derek

I think John's book may be a little out of date on this.

My copy is dated First Published 1998 & Revised 2nd Edition 2004, so Electrics & Chargers appear to have moved on since John's book was last revised.

 

Our on-board Charger has a Battery selection switch, but if both are low it will send the main charge to which Battery is selected whilst also giving a trickle to the other Battery.

 

[SIB]

I too have a 4 stage charger, the 4th stage of which goes into standby mode and only switches on again if the voltage drops below 13 volts.

 

Can any of you technical types therefore explain why this could be detrimental to my outfit.

 

I wish to keep permanently on charge as I have lost several batteries, both leisure and vehicle in the past due to under charging/overuse

 

Thanks

[Brian Kirby]

SIB - 2010-11-08 3:29 PM I too have a 4 stage charger, the 4th stage of which goes into standby mode and only switches on again if the voltage drops below 13 volts. Can any of you technical types therefore explain why this could be detrimental to my outfit. I wish to keep permanently on charge as I have lost several batteries, both leisure and vehicle in the past due to under charging/overuse Thanks

I assume the batteries that failed in the past were not in your present van?

[SIB]

Correct and don't want the expense and inconvenience again.

[Robinhood]

Well, I'm in the sixth year of leaving my 'van permanently on hook-up at home, with the type of battery charger I've described as above.

 

I've had dual leisure batteries in both 'vans I've owned over that time, and other than having to top-up the two in the previous 'van at the start of the season (nothing untoward, just a small amount of distilled water), I've had no problem at all with the batteries (about 5 years on the previous vehicle).

 

Current batteries are gel, so hopefully not even any topping up required (and I do hope THEY don't go off, at the price gel batteries are) :-(

[casey]

Hi all,

I have a Sargent EC200 control system on my autotrail, can anyone tell me if this also charges the engine battery when on hook up, and if so how do you switch the charger to do this? info i have is very vague.

thanks

casey.

[Keithl]

Hi Casey,

 

What year is your AT?

 

On our 2004 you turn on the control panel with the top left button then press the button to the immediate right of it showing a battery symbol. it will probably be very similar as ours is also a Sargent panel. The way to check if the engine battery is charging is to change the display to show engine battery volts then turn the 'battery' switch on and off.

 

If all else fails try giving Sargent electrical a call as they are very helpful. Sorry but you'll have to Google for a number unless you've got anything with their number on.

 

HTH,

Keith.

[Derek Uzzell]

Robinhood - 2010-11-08 4:23 PM

 

...Current batteries are gel, so hopefully not even any topping up required (and I do hope THEY don't go off, at the price gel batteries are) :-(

 

It's not a question of "hopefully" - you CAN'T 'top up' a gel battery.

 

If you are an optimistic soul, having your motorhome's battery-charger switched on continuously while the vehicle is standing idle at home will be fine. You will assume that your 'smart' battery-charger will perform exactly as the manufacturer has advertised and will only charge the batteries when they need it. You will also assume that a battery or a vehicle's electrical system has no likelihood of developing a fault.

 

A pessimistic (though "realistic" must surely be more apt where motorhomes are concerned) person will have in mind the possibility that the charger, batteries or electrical system may become faulty and will be (or should be) aware that this could have serious consequences. Such a person will naturally be uncomfortable with the 'permanently on hook-up' practice as the potential for such a fault causing damage is clearly greater if the vehicle is 'on charge' unattended for extended periods. He/she may also ask themselves why they should want to do this in any case, as (for example) a fully-charged 'inactive' gel battery will last for several months before a significant percentage of its charge is lost.

 

For me, this issue is like Pascal's Wager (Simplistically, it's more sensible to believe in God than not, due to the potentially dire consequences inherent in disbelief) in reverse. Thus, it's more sensible not to have a motorhome on permanent hook-up, due to the potentially dire consequences inherent in the practice.

[armstrongpiper]

Autotrail Tracker 2008 with Sargent EC200 charger/controller.

I have usually left this on 240v hook up with the charger switched to vehicle battery, since there is a constant drain on the battery for the alarm/immobiliser of about 0.1 amps. This is enough to make engine starting uncertain after 4 weeks inaction. However, the van is now in a storage compound and 240v is not avaiable, so I've bought a Maplin folding briefcase 13W Solar panel and put it under the 'Heki' rooflight and connected to the vehicle battery. When I next can visit my 'van, in three weeks or so, it will be more than interesting to see what state of charge the battery has.

 

 

Neil B

[Brian Kirby]

From which, redpen will by now have gathered that without detailed knowledge of his charger and how it performs, his question is, essentially, unanswerable.

His best remedy would presumably be to contact either Autosleepers, or GEC, with all the relevant details of the charger, plus details of his battery type (flooded, gel, etc) and size (in Ah), and seek their advice.

Alternatively, if GEC has a website (or other source)detailing the technical specification for the charger in question, it may be possible for someone to give him a proper answer.

In the meantime, his safest approach will be to disconnect the mains, and then monitor the batteries, only re-connecting when either shows loss of charge.