Beginner Help - Key Fob / Battery / Cobra

Might he also have a geographical problem Peter, as I guess Scotland may not get enough sunlight in winter to keep the batteries topped up??

Peter Brown wrote: so I expect the original poster has a battery condition problem.

We've experienced non operational key fob in the last due to flat starter battery during the gloom of winter. Learned from Peter that current draw from so called smart charging, is more than our 80 watt solar panel can replace. Problem solved by switching off EC500 and AA solar panel positioned on dashboard linked to the EOBD. Van in storage facility.

Hi folks, so quick update on my situation, but before doing that want to thank everyone who has inputted onto this thread, certainly much to learn for me.  

So, I have a friend who manages a local tyres / exhaust place and he dropped off a Yuasa YBX5019 this morning just in case it was needed.

Opened the door manually and the alarm did NOT go off - vehicle battery had a reading of 2.3v, connected a battery charger then the alarm did go off but that's because the doors were open, however the key fobs were then working as soon as the charger was connected.  

Left on the charger for a while and could see the battery taking a charge, however on removing the charger and doing something simple like putting the blowers on the battery started dropping fast.

This reminded me when we arrived at Marquis the first time we went to see this van, we had a test drive planned, and the van had been sent from another location the previous day, yet the van was dead and the guy said oh the battery must have a problem - never thought twice when we went back and test drove it and it started, but it would appear this like the existing leisure battery was clearly not checked out during any servicing.

So recoverable or not, I just decided to just cut my losses with this battery and fitted the YBX5019

I also removed the emergency disarm Cobra code from the cab - DOH!

I still clearly need to learn more about this control panel, solar panel and charging, and I also need to replace the dodgy leisure battery at some point.

So, again thanks for all the input, going to digest these posts and see if I can figure out the solar panel charging via the control panel.

Thanks for reporting back. It will be appreciated.  

Not everyone does so, and it can be very helpful to other members.

Most annoying of all are those who come on and ask a series of questions in their first post, then disappear . . . without even bothering to say "Thanks".

I know some established members keep a black list of those they will never try to help again. Can't say I blame them - courtesy costs nothing.

Thanks Caraman, that's a good point.  I won't offer up much hope but it may be worth trying.  When I first talked to them about the failing leisure battery, I talked with one of their engineers done some basic multimeter tests and they said I sounded faulty, and if I drove it back to them they'd replace it.  The reality is it's a 200 mile round trip for me, so what I spend on the fuel I could just spend on the battery.

Certainly worth a try, that's both batteries within 90 days given up the ghost (granted I didn't help matters this week) but it was clearly well on it's way out.

Thanks again 

Separating out your issues: (I have the EC 328 and have had a similar experience but without the complications of solar panel.
It sounds as though the habitation battery was badly discharged to start with and running the engine for a shortish period won't have helped that. Also it didn't have a chance to put back into the vehicle battery what starting had used. I would guess that then leaving the van on vehicle battery with the two control panel LEDs alight plus any other possible draining accessories plugged in on the van side (usb charger, a light left on, wardrobe door not closed, etc then drained the vehicle battery down to a very low voltage. You said that you could see the control panel lit up. That should not happen - BUT it does on mine but, as far as I am aware only when I stop the engine. Then, the auto off of the.backlight often does not work but any button press will restore the auto off.
A dead vehicle battery will kill the central locking and the alarm - you can only get in through the passenger door and if you have deadlocks you cannot even open the driver's door. 
When that happened to me I panicked and instead of simply connecting up the EHU I found my battery charger and linked it up to the battery under the floor. My Lidl smart charger wouldn't work because the 2V that the vehicle battery had fallen to was not enough to wake up the charger. I had to use an old fashioned charger to start the process. I DON'T KNOW IF THE EC328 WILL CHARGE A REALLY DEAD BATTERY. Once the battery was charged I ran it through a few discharge/recharge cycles to see how it behaved and got back enough performance for it to last another 7 years, though it would be never go above 12.5 V.  I know that I have to charge both batteries from EHU about once every 6 weeks. I actually replaced my original vehicle battery in September 2020

Turning to solar - in winter an 80w panel is marginalti produced enough power to keep the batteries charged. Not only is there less sun but it is much lower in the sky. My home. 4kw solar array on a pitched roof has only generated 267Kwh in 3 months. Translated back to an 80W flat panel I would optimistically guess that you might have generated less than 3kWh which is equivalent to less than 250 ampere hours. Two fills of one battery in 3 months in very broad terms. That's half or less what I put in with my 6 weekly charges on EHU!
It may well be therefore that the underlying electronics are working as they are intended to but that your unknowing neglect has caused the problem, just as it did with me when I first had this van.
If you don't need to use the van urgently it might be worth trying to recondition the batteries but at £100 a time only you can decide whether immediate peace of mind is worth the £200.
The lesson I have learned is that my 2012 A/S van does not hold charge in its batteries as well as my 2001 Hymer did.

Oh dear, lots of posts while I was composing! Well done for getting it sorted. I haven't deleted my post as I think it still has revance, particularly regarding solar performance.

Similar to my problems last winter,fitted overall cover thus no solar power.Engine battery dead,no central locking.OK,key in habitation door,would not unlatch (strip down later revealed bodged repair with hotmelt glu)Round to drivers door,key out of Merc fob,turned but again didn’t unlatch (inner panel off later revealed short connecting link not connected,probably from original build)Decision time,couldn’t find any child to be wedged through external locker so cheapest option break rear plastic window.No,sleep on it,4 am Eureka moment,13 pin tow bar socket has constant 12 volt to engine battery.Linked up a charger,bingo,remote opened doors (come on,who checks keys function when you’ve got the lazy way)
This winter I’ve fitted a battery isolation switch that links the two together,through the towing socket a constant 13.8 volt supply pulling about .5 amp keeps all batteries on float charge.

First, if you know your battery is on the way out /duff , change it , using a battery that has had it will even after charge will if the battery starts to go flat when starting the vehicle will make the starter motor want more power , this will if you keep doing it will burn the starter motor out.
With regards to charging a liesure battery and vehicle battery via a solar panel mine was set up by an electrian to trickle charge the main vehicle battery and liesure battery when not using the vehicle