I only use my 1991 Eunos once a fortnight or thereabouts otherwise it is kept in the garage. I have a lead acid battery which is about a year old (fittted by the former owner) which was discharged to the extent that the car would not start the other morning. I have taken the battery out and fully charged it with a conventional charger. It now appears fine at the moment. However I understand that battery drain is a common problem on these cars due to the loss of dark current through the immobiliser etc. I was thinking of buying a trickle charger and leaving it constantly connected to the battery when not in use without disconnecting the battery terminals. These can be bought on ebay for less than £10. However I have heard this could damage the alternator. The other alternative would be to buy a battery optimiser charger for about £35.
Has anyone any experience of using a trickle charger for long periods on a connected battery? Is this likely to do any harm or should I pay the extra for an optimiser?
I tryed a cheaper trickle charger on my motorcycle but the acid levels in the cells kept dropping considerably and the battery was always warm to touch, I opted for an optimiser which constantly watches the battery and chargers as required, over a 6 month winter period I never had to top the battery up nor did it ever feel warm so can only advise on my experience, I would go for the optimiser.
I agree with Zippy, I bought one of these three weeks ago and it is excellent. The easy bit is connecting it to battery; you don’t have to remove any battery leads. I leave mine on all the time now and the battery is always fully charged. With mine I got two spare leads with a socket on the end that can be fitted permanently to my other diesel car so I can just switch the charger to the car as when I like, dead easy.
Thanks for the responses and advice. I shall definetly go for the optimiser. Interestingly I removed the centre consol today to fit a cubbybox I got for Christmas. I found an alarm underneath which I had been told by the previous owner had been disconnected because it was faulty. However the unit had a light which was still flashing so I disconnected the earth. I had an immobiliser fitted soon after buying the car so maybe with the alrm and immobiliser both drawing power this is causing the battery to drain quickly when the car is unused for more than a week or so.
I have ordered a multimeter through ebay and will be checking the dark current drain first.