[Morphology]

After 18 years in a VW Autosleeper Trident, we took the plunge in April and bought an 06 plate Knaus Sun Ti 650MF, as it ticked every box we could think of and looked great into the bargain.

This is a rather more serious and complex bit of kit than the old Vee-Dub and I still don't feel I fully understand it. Particularly the electrics.

The last time we used it was just under 3 weeks ago. Since then it has been sat on the drive in the following state:

1) NOT on hook-up
2) All switches on the control panel OFF
3) Big red breaker switch next to the Calira Charger OFF
4) Alarm (Thatcham Cat 1) ON
5) Immobiliser ON
6) Nothing silly left on (interior lights, radio etc)

I just went to start it, and the VAN battery is completely dead. The leisure battery is fine.

Is there anything I am doing wrong? Does, for example, the alarm draw that much current that I need to leave the thing on hook-up continuously?

This is the third time it has done this since we bought it. I've had the battery tested with a dwell meter, and it's fine. There is something drawing current, but I can't see what. If the habitation side is all shut down and isolated, you're dealing with the cab and running gear of the base Renault Master. Surely you could leave a Renault Master locked with the alarm on for 3 weeks without the battery going flat?

I could leave the VW on the drive for 6 months, and it'd be fine when I went to start it (yes, I know, I should get out more, but it was damn cold in Winter).

Any ideas?

Richard

[Ian03/54]

Hi Richard,

Welcome to the Friendly motorhome forum.

I am no expert but for an idea on your problem: like you I wouldn't have thought that the alarm would flatten the battery on its own in three weeks but, as this is the third time, can you be certain that the battery is able to hold a good charge and not just show "all is well" just after charging? Having been flattened completely twice before maybe it shows good but drops very quickly? 06 is now four years so maybe it is time to replace it, I'm assuming it is the original?

I hope I may have helped you in some small way but no doubt someone more knowledgable will be along soon.

Regards,

[Supertractorman]

Hi, Also no expert on this but had a similar problem, and in the end resorted to connecting to the mains while in the driveway, and replacing both batteries at 3 years of age. Now have solar panel and no problems plus peace of mind. I think there are more things taking charge out of the battery than we realise, alarms with flashing lights, clocks etc. Also wonder on quality of batteries and how many months the van stood round before the body was put on, as looking in some of these storage compounds they don't seem to disappear fast.

David

[Whotsit]

Again no expert, but to help identify your problem you could charge your battery first then disconnect one of your battery terminals, place a multimeter between the terminal and cable with the meter set to load( amps) you will get a reading of your discharge rate, if you know what the Thatcham draws in current and if the reading is higher than that figure you will know that another piece of equipment in causing your problem (clock/radio/fan etc), and the difference in figures will help you identify it, if the reading is not higher then you probabley have a duff battery.

Don't try and start the engine with the multimeter connected otherwise there will be a big puff of smoke and no meter left.

Ken

[Mick H]

A Renault master can easily be left for more than 3 weeks without the starter battery loosing it's charge, even with a Thatcham Cat 1 alarm fitted.
Ours is almost 5 yrs old, now, and the original battery performs as well as it did when new.

As other contributors have already said, if you have already had the battery checked, then you need to establish what is causing such a large discharge. The only other thing that I can think of that would cause this problem is a possibility that the alternator either isn't charging correctly or that it's draining the battery because a fault has developed with it.

Mick H.

[Morphology]

Mick H, on 23 July 2010 - 06:57 AM, said:

A Renault master can easily be left for more than 3 weeks without the starter battery loosing it's charge, even with a Thatcham Cat 1 alarm fitted.
Ours is almost 5 yrs old, now, and the original battery performs as well as it did when new.

As other contributors have already said, if you have already had the battery checked, then you need to establish what is causing such a large discharge. The only other thing that I can think of that would cause this problem is a possibility that the alternator either isn't charging correctly or that it's draining the battery because a fault has developed with it.

Mick H.

Thanks all for your advice/suggestions.

@Mick H: That confirms what I suspected - I ought to be able to leave the van on the drive for 3 weeks without the battery going flat

@Whotsit: Good suggestion - at least I'd know for sure what the drain was.

@Supertractorman: I'm considering a solar panel, but that's probably a project for next spring. It's easy enough for me to leave it on hookup whilst on the drive, but it doesn't feel right to have to do so. I'll attack it with a multimeter first.

We're away in it this weekend, but I'll try measuring the current drain when we're back home on Sunday.

Richard

[enodreven]

Hi,

I don't know if its relevant to your vehicle, but ours has a fridge freezer and it is fitted with a heater to stop the condensation, which when i read the hand book, as you do ? it told me that this must be turned off when not on a electrical hookup, hence a continued flat van battery until i found the very small hidden switch situated under the main fridge controls and turned it off, not sure if similar heaters are fitted to other Dometic fridges and freezers but it may be worth a quick check.

The fridge/freezer was turned off (left on 240 volt no power connected) as the heater appears to work independent of the fridge itself.

hope that helps

[Morphology]

enodreven, on 23 July 2010 - 08:32 AM, said:

Hi,

I don't know if its relevant to your vehicle, but ours has a fridge freezer and it is fitted with a heater to stop the condensation, which when i read the hand book, as you do ? it told me that this must be turned off when not on a electrical hookup, hence a continued flat van battery until i found the very small hidden switch situated under the main fridge controls and turned it off, not sure if similar heaters are fitted to other Dometic fridges and freezers but it may be worth a quick check.

The fridge/freezer was turned off (left on 240 volt no power connected) as the heater appears to work independent of the fridge itself.

hope that helps

That's interesting. I'll dig out the manual for the fridge. It certainly has a switch that says something about heating the outside of the body to prevent condensation in hot weather, but it's on view so easy to see that it's off.

I also assume that the fridge would be wired into the leisure battery rather than the vehicle battery, and it is the vehicle battery that has gone flat.

Richard

[Stewart]

Hi Richard,

Just to add to other comments, we had an Autosleeper Symbol that could flat the battery in 3-4 weeks if not charged in between. Nothing wrong with it we just put it down to the alarm, radio etc. I just used to keep the mains lead plugged in via a timer that switched the power on for i day a week. That kept the leisure battery OK and had a Ctek conected to the vehicle battery to keep that OK. This worked great even when we were away in New Zealand for 8 weeks.

I use the same system in the new Chausson and this is OK too.
Regards
Stewart

[ralph-dot]

If I do not use the van for 3 or 4 weeks the battery is usually well down, if not flat, not the alarm (not got one) not the radio (no live feed when the ignition is off), and it is on hook up, I have never been able to find the problem.

[Morphology]

The Van battery died completely last Friday. It had been on hook-up for 24 hours, but it was completely dead and wouldn't start. We were planning on going away for the weekend, so I had to buy a new one from Halfords friday night.

130 quid later, but at least this means I know I've got a decent van battery!

Whilst I was changing it I measured the current drain with (as far as I know) only the Thatcham alarm on. It was drawing 0.075A, which equates to less than 8 weeks with a theoretically perfect 100Ah battery, so leaving it on hookup seems to be the only option. I haven't had time to dig out the spec for the alarm, but it'd be interesting to see if this is what it claims to draw.

@Stewart: I like that idea of putting it on a timer. Makes loads of sense. Thanks for the suggestion.

Richard

[Mick H]

Morphology, on 26 July 2010 - 09:24 AM, said:

The Van battery died completely last Friday. It had been on hook-up for 24 hours, but it was completely dead and wouldn't start. We were planning on going away for the weekend, so I had to buy a new one from Halfords friday night.

130 quid later, but at least this means I know I've got a decent van battery!

Whilst I was changing it I measured the current drain with (as far as I know) only the Thatcham alarm on. It was drawing 0.075A, which equates to less than 8 weeks with a theoretically perfect 100Ah battery, so leaving it on hookup seems to be the only option. I haven't had time to dig out the spec for the alarm, but it'd be interesting to see if this is what it claims to draw.

@Stewart: I like that idea of putting it on a timer. Makes loads of sense. Thanks for the suggestion.

Richard

Hi Richard,

Pleased to see that you have made some progress, but in your original post you said that the battery had been tested and found to be ok, so I would strongly advise keeping your eye on things. For example, if you have a charging issue, then your new battery could easily loose it's capacity to retain full Amp Hour capabilities. From what you have experienced, it could be that the original battery had often been allowed to become discharged, before you had the motorhome.

Opportunity permitting, you will now be able to camp in your Sun Ti next winter, even if it is very cold again. With or without hookup, we find ours to be nice and warm.

Happy Camping, Mick H.

[Morphology]

Mick H, on 26 July 2010 - 05:48 PM, said:

Hi Richard,

Pleased to see that you have made some progress, but in your original post you said that the battery had been tested and found to be ok, so I would strongly advise keeping your eye on things. For example, if you have a charging issue, then your new battery could easily loose it's capacity to retain full Amp Hour capabilities. From what you have experienced, it could be that the original battery had often been allowed to become discharged, before you had the motorhome.

Opportunity permitting, you will now be able to camp in your Sun Ti next winter, even if it is very cold again. With or without hookup, we find ours to be nice and warm.

Happy Camping, Mick H.

True, very true. I've written to the place we bought it from (Choose Leisure outside Canterbury) asking if they'll extend the 3-Month warranty (which expired on Friday), and complaining that they'd told us the battery was OK. Batteries do die, so that's not the end of the world, but it's going to take a while to fully test the charging and, importantly, to build up confidence in the van - at present I cannot imagine heading off for a couple of weeks in France as we're planning on doing in September.

Interesting what you say about winter camping. The winterisation features seem to be one of its strong points, so I'd love to take it skiing for a few nights. That'd be a hoot!

Update: Choose Leisure have said they're happy to extend the warranty until the problem is fixed to my satisfaction. So I wanted to make it clear that I'm not suggesting they mis-sold the vehicle!

[Morphology]

An update for anyone who is interested....

I wrote to Cobra and asked them for some technical specifications for my model of immobiliser/alarm, which is a Cobra 7928/26/HF The important bits are:

Operating Voltage: 9 to 16v DC
Quiescent Current draw - Disarmed state < 9mA
Quiescent Current draw - Armed state < 13mA

I'd measured the current drain from my Engine battery, which was 0.075A (75mA) so it looks like something else is drawing current in addition to the Alarm.

Not a huge amount more, but enough to drain a less-than-perfect battery.

Since I fitted the brand new engine battery, everything seems fine. It hasn't been on hook-up and I've checked the engine and leisure battery levels each evening and all seems well.

Richard

[Mick H]

Hi Richard,

Things are looking good. Another thing that draws current, is the Renault immobiliser, I believe. The Calira charger might, as well, but not certain, because I haven't checked.

Regards, Mick H.