Flat Battery Problem

[4petedaniel]

I have an 1996 autosleeper Clubman and after 3days the battery is always flat. New Batteries make no differance . I have taken the camper to Autosleeper who said they could find no problem and suggested it could be an alarm problem, does any one have any experiance with this sort of problem, and is it possible to fit an ampmeter between the battery and the wireing and do you know where I can get one.

I have to leave the camper with the battery disconected which means I have no alarm and would proberly have a problem with the insurance if it was stolen

Petedaniel

[Terrytraveller]

It seems a pretty high standy current consumption/drain you have, you must have a drain of around 1.1 amps, so you can rule out a short circuit I should think, (85 amp/hr battery divided by 72 hours = 1.1amps).

 

So it's not the fridge, that's 8amps, what about fans on the roof vent or blown air heating system fan, SOG toilet fan, lights, inverter on standby, they could all be about 1 amp each. I had the built in charger in a caravan pulling down the battery once, the charging unit had some diodes which had gone leaky and the power drained through the PSU transformer.

 

Have a look at http://tinyurl.com/6b5rzp an Automotive Current Tester, easy and safe to use for the non electrician DIYer. Just remove a fuse,see what stops working then plug in the special fuse blade probes and take a reading.

 

You would need to look at the Alarm Manual to see what the standby current consumption is, but its only likely to be around 10 - 20 milliamps, a fully charged 85 amp hour battery would keep it going for around 150 to 200 days at least.

 

Hope above is helpful - Regards Terry

 

PS Just noticed the Maplins tester is either mini or maxi fuse blade probes, my camper has both types, mini for the vehicle electrics and maxi for habitation. If your vehicle fuses are mini, buy the mini blade blade tester and make up a converter - i.e a mini blade fuse holder to plug the tester into, and a pair of wires from the fuse holder soldered to a blown maxi fuse.

 

 

 

 

 

 

[4petedaniel]

Thanks for your interest Terry I should have been a bit mor explicet

Both of my leasure batteries are still well charged it is only the main battery that I have the problem with I have disconected the radio and any thing else That seems to be part of the main battery consumption and except for the clock and the alarm I can't think what else could be draging it down I installed a photo cell to try to keep the battery topped up but it does not seem to help, The Maplins meter sounds a good bet and I shall pop down too Greenbridge tomorrow and see if they have one. But what I realy need is a Amp meter to connect between the battery and the cables.

 

I have just had a thought The onboard battery charger is always left switched on could that be part of the problem?

Petedaniel

[onecal]

Hi,

What make is the motorhome ( VW, Ford Etc' ) I need this Info' to be able to advise you further.

Regards,

Brendan.

[davenewellhome]

onecal vw - 2008-06-30 12:35 AM

 

Hi,

What make is the motorhome ( VW, Ford Etc' ) I need this Info' to be able to advise you further.

Regards,

Brendan.

 

In the original post the motorhome is identified as an Autosleeper Clubman which, unless I'm very much mistaken means its on a VW T4 base. ;-)

 

D.

[Terrytraveller]

Hi Pete,

Just seen your location, we are neighbours then ? Most of the in circuit ammeters would not be accurate enough and only show charge and discharge whilst the engine is running, typically they show charge and discharge of around 30 - 60 amps. If you were to fit an ammeter on the battery permanently, it would have to carry around 200 or more amps whilst the starter motor was operated, so is not feasable. The ammeters you see fitted to vehicles, are disabled when the starter motor is operated.

 

The maplins meter I suggested you use, is probably your best bet to monitor (engine off, ignition on or off) the currant drain on your battery as it will pass 20amps. Another option is the digital voltmeter (DVM), but the typical cheapo and more expensive DVM's will only monitor up to 10 amps on their max setting.

 

You could fit a voltmeter or use a stand alone DVM, to monitor battery usage and these can be left connected all the time, even when the engine is started, the vehicle analog battery voltmeters typically have a full scale deflection (FSD) of around 4 volts, they show the battery voltage fairly accurately from 11 volts to 15 volts. A battery just off charge using the engine or standalone charger will show FSD (14.8 - 15 volts), monitoring the battery disconnected voltage after 24 hours, will give a baseline reading of in excess of 12.7 volts but under 13 volts - you can experiment with loading and readings from there, to give you some idea of what the battery is up to.

 

The DVM or Vehicle battery voltmeter can be left connected across the battery terminals while you start the engine, the DVM on current reading or Automotive Current Tester from Maplins should not be in circuit when the engine is started, but can be left in circuit with the ignition on, BUT DON'T ATTEMPT TO START OR RUN THE ENGINE, as I would still like you as a neighbour!

 

Re on board charger always left switched on, it depends where they have put the switch in the charger circuit as to whether or not it is completely isolated from the vehicle battery My sisters autosleeper cannot charge the vehicle battery, whereas my camper can. So - if you cannot charge the vehicle battery from the habitation charger, it is already isolated from the vehicle battery anyway, so can be discounted from your investigation.

 

If you have a solar panel connected to your vehicle battery, these can discharge the battery when the sun goes down if they don't have a diode or controller fitted, or they might even have gone bad, so another thing to check then.

 

Regards Terry

[tonyishuk]

Could be faulty diodes in the alternator / charging circuitry ?

 

Rgds

[4petedaniel]

Thanks again for your helpful tips. Reguarding the amp meter I need one that I can install tempory so that with the ignition turned off I can start to disconnect circuits unill I find what is draining my battery . It is only the main baterry that i have a problem with so if I can put it in line with the cables and the terminal of the battery, as you say the multimeter type do not take much of a load and I do seem to have quite a large load as I get quite a large spark when I disconect the battery and that is with every thing turned off stillhave to try Maplins,

Petedaniel

[Terrytraveller]

Hi Pete,

 

You will get quite a large current inrush when you reconnect the battery terminal. Probably due to the ECU refreshing (rebooting) itself, plus the car radio and not forgetting the existing current drain of possibly 1.1 amps.

 

You can avoid the intial current inrush going through the meter by the following proceedure.

 

1. With the battery connected, and the negative terminal lead finger tight.

2. Set a DVM on the 10 amp range.

3. Clip one DVM probe FIRMLY to the slack battery negative lead.

4. Clip the other DVM lead FIRMLY to the battery post.

5. Remove the loosened off battery negative lead and tie back with string.

 

The initial current inrush will have taken a path through the connected heavy battery lead, so the meter only has to support the quiescent current, which should be within the capacity of the DVM.

 

It doesn't matter which probe goes where with a Digital Volt Meter, a meter with a needle, an analog meter is a different matter, and can be damaged. I have a cheapo Maplins meter in the MH, I checked it against my posh company calibrated one and found the £4.99 DVM to be really accurate.

 

 

Regards Terry

[4petedaniel]

RE the DVM , Do you have any opinions on a clamp on meter as i have to purchase a meter any way. As mine only reads in milliamps, I had an idea that with a clamp on meter over the battery cables ,and I have 4 coming off each terminal I could test each one sepritly .I will still be faced with the problem of traceing each cable to see where it goes

Petedaniel

[Terrytraveller]

Mornin Pete,

 

I don't think you can measure DC amps with a clamp on meter, only AC amps/volts and DC volts.

 

Regards Terry

 

 

[rupert123]

If nothing obvious is draining battery it could be an earth leak. Simply disconnect the earth lead and put a voltmeter in series between lead and earth, if it reads you have a leak, pull out fuses one at a time to narrow down causes.

[4petedaniel]

davenewell@home - 2008-06-30 6:42 AM

 

onecal vw - 2008-06-30 12:35 AM

 

Hi,

What make is the motorhome ( VW, Ford Etc' ) I need this Info' to be able to advise you further.

Regards,

Brendan.

 

In the original post the motorhome is identified as an Autosleeper Clubman which, unless I'm very much mistaken means its on a VW T4 base. ;-)

 

D.

The campervan is a VW Petedaniel

[4petedaniel]

Thanks terry for the Suggestion of the Maplin current tester It works quite well as a amp meter as well you hold one side to the battery and the other to the terminal It think part of my problem may have been the Radio as with the removeable face in place it was draining .39amps and as there seem to be a .14 load which I suspect is the alarm which is what I find when I use the current tester as an amp meter between the battery and the terminal .45amps .39+.14. I also found that if I installed the soler charger after I disconected the radio I now have zero amps outgoing I am hoping this will clear up my flat battery problem . BUT i am almost certain that I have had the problem even with the Radio face removed.

Petedaniel

[Terrytraveller]

Hi Pete,

 

Well done on finding the fault, 0.45 amps drain would take the battery down in seven days, working on the following ;-

 

85 amp battery divided by 0.45 amps (current drain) = 188 hours

188 hours divided by 24 hrs = 7 days approx.

 

With some people not using their cars/motorhomes every day but cycling or walking, owners are going to find the vehicle starter battery is going to be drained and flat.

 

My motorhome usage has been cut right down, not using it for short journeys and shopping , but using my newly acquired electric bike or push bike.

 

I'm now exploring all the new cycle tracks around Swindon, have you been up to the new Blunsdon bypass yet? I can cycle from that bypass on cycle tracks right down to Walmart and beyond - sounds a bit like Buzz Lightyear (lol)

 

P.S. That 140 mA (0.14 Amp) quiescent load seems a bit high for standby or armed standby, my alarm quiescent load is 80mA, if you still have the manual, might be worth checking the spec - if you don't have the manual, put the make/type on the forum, perhaps someone else has a manual and can advise.

Regards Terry

[Derek Uzzell]

Doubtful that this has a direct bearing on the problem, but I remember a flat-battery, radio-related scenario being mentioned a good few years ago where the motorcaravan's base-vehicle wiring had been modified to permit the radio to be switched on/off remotely. A diagram of the wiring changes was provided in a motorhome club magazine and, on the face of it, the alterations looked uncontroversial. In practice, after the remote switch had been added, a significant current-drain persisted even though the radio was (apparently) switched off. This was on a Mk 5 Ford Transit and, from what I recall, the standard radio installation included some sort of 'amplifier' unit that would normally shut down when the radio was turned off by its original switch, but continued to function constantly once the remote switch had been introduced.

 

(Incidentally, in the unlikely event that there's anyone considering fitting a SOG toilet-ventilation system who might be put off by the idea that this needs plenty of 12V juice (Terry suggests "about 1 amp" in his first posting), SOG's manufacturer quotes the fan-motor's power consumption as a meagre 0.43W, equating to just 0.036A)

[4petedaniel]

Funny that you should mention a remote control for the radio probably not the same thing. as this is a hand held control not I think quite what you where talking about. I believe you ment a wired switch not exactly what I have. But I wonder if this may have been the problem Do you think that a switch installed in the circuit for the radio will solve the problem in the future.if I have a similar problem?

Pete daniel

[Derek Uzzell]

Yes, a 'wired-in' supplementary switch was involved.

 

Logically, if you can pin the problem down to the radio (which doesn't sound like the type that would have been fitted originally to a 1996 VW-based Auto-Sleepers), then isolating the radio should provide a viable work-around. You really do need to be sure, however, that it's just the radio that's pulling down the battery charge and that will involve a painstaking step-by-step analysis to confirm.

 

A vehicle radio should draw hardly any current when switched off and the current drain of an alarm system on stand-by shouldn't be huge: our 1995 VW Golf sits for weeks with its alarm activated when we are motorcaravanning and always re-starts instantly and with no sign of battery flattening.