Key coincidence...A bit of a ramble.
Just a couple of days ago, I too had a message flagged up in my non-Morgan advising to change the battery in my key.
The car was not new when purchased, I had asked the dealership to replace the battery in both keys as a matter of preventative maintenance.
As with some modern vehicles/equipment it seems when the cars main battery is replaced, the on board systems may require notification of this, thus either the battery it`s self (as in some cameras..?) seem to be able to be identified as O.E or aftermarket... In the case of my car`s main service battery, the charging system requires to be informed that a new battery has been fitted in order that the cars digital charge control system can re-adjust it`s charging rates... Now whether that is just an elaborate ruse to ensure that the car manufacturer`s O.E. battery will be fitted as a replacement and thus supplied via the dealership network to maintain profits... I have no idea...
When the key`s battery was advised to be replaced by the car`s on-board systems, I wondered IF when both the key batteries had been replaced at the dealership that action might have been recorded by the dealership in the cars on board systems, as per the main battery requires to be when it is replaced, and that perhaps the warning to replace the key battery might be time based relative to the last recorded replacement....? Or just that the on board digital security systems detect a drop in strength of signal from the key... ? The key for my car does not require button pressing to allow me access or for me to operate the car, as the key system can also act on proximity of the key to the car, thus may be constantly creating a signal which presumably depletes the battery over time .. Obvious question... how much time..?
Sorry I have digressed as ever...
Back to the seemingly simple key battery issue... fortunately I had a couple of spares still in their plasticised packaging in the house... No problemo...Fitted one of the new batteries (CR 2032) and it did not even cause the led to illuminate in the key when any of the buttons were pressed, and obviously it also did not unlock the car.... Hmm..?
Checked the voltage on the new battery...3.096V. Checked the voltage on the second new battery it was much the same.
Checked the voltage on the original battery from the key, and which the car`s info system suggested required replacement.... 2.9V
In order to check the functionality of the key had not been compromised in the battery change over process :-
Replaced the old 2.9 V battery in the key... The LED illuminated when any of the buttons in the key were pressed, and the car reacted as required..!
Tried the second new battery in the key.... no LED lit when any button were pressed and no reaction at the car.....!
I had no memory of how old the two new batteries might be, though both were individually packaged and their voltage seemed to be as it should be when measured via my DVM.... confusing..?
I did wonder if age might play a part in that the voltage might break down when under load in the new/replacement batteries .... Hmm...
I have known of button battery terminals to come with a self adhesive insulation material stuck on one side, which requires to be removed prior to fitting to whatever device... No such insulating coating or material noted on any of the two replacement batteries... and that I was able to measure the voltage available on each of the two batteries, seemed to confirm there was no such insulating coating.
Generally there is some sort of spring action which maintains pressure in terms of the electrical contacts in the device, and when installing new barreries the spring action can wipe the area of contact between device and battery to assist in making good electrical contact.... Often battery operated devices left unused can fail to operate just due to dirty points of connection at the battery building up over time, either on the device or on the battery, or a mix of both...
With the above in mind, given the key`s operation was restored with the old battery re-installed, it seemed that the keys connection point to the battery was not in doubt,
Becoming increasingly dismayed with my electrical incompetence, I found some light grade steel wool and gave both batteries a gentle rub with it on both sides..... both battery`s now operated in the key when tested.
I now carry a spare new battery in the glove box of the car, along with a small piece of steel wool too...!
Whether the batteries picked up something from their time spent in insulated packaging, or had built up some sort of resistive layer on their contact surfaces and my DVM`s probes overcame that due to the pressure applied on the points of the probes when testing the batteries voltage...??
The main thing is that the key now operates s it should and I have a replacement procedure that may hopefully work if/when I might need to replace this type of battery again...?
Any comments on my trials and tribulations gratefully received as ever...
