Late last year we purchased a new supercharge gold battery for my sons 944 Porsche Turbo. It was a maintenance free battery MF 65 B that fits in the rear hatch area.
Last month he traveled to the US and left the car with me, I started it several times and ran it for him while he was away and when he returned it started and ran o.k. Last week he had an oil light come up on the dash display and put oil in the motor at night without checking the level - appears that it over filled, so he left it at our place for me to remove the excess.
When I went to start it up, the battery was dead flat. I pulled it out of the car and noticed that the battery indicator was showing red which usually indicates Do not charge, though there is another interpretation that it is still o.k. to recharge (black dot in middle) so I put it on 4amp charge for 24 hours over the weekend. usually with other similar supercharge batteries, that sort of charge would bring it back up to full charge. But in this case it was still showing the red indication!
I took it back to Supercharge and they tested it and showed me the test between terminals as "battery good", but the hydrometer reading after removing the charge state tube indicator showed almost dead flat. They told me it would take perhaps 3 days to come up with a 4amp charger, and that I should use my 10amp charger as a better option, but it would still take quite some time.
I charged it all day yesterday and the indicator was showing clear (no colour) but after a further overnight charge to 4pm today on 10 amp charge, the indicator finally showed fully charged (green) It was suggested that with their newer batteries (calcium content??) this was slower than I was obviously used to in the re-charging process.
I was also given a number to call if there was any problem as the battery does have a three year warranty on it from date of purchase.
Has anyone else come across this slow charge when flat. I have always had a good run with their batteries, but in the past would have chucked out a battery that didn't come up to charge in 24 hours! or one that came up clear on the indicator after 48 hours. I think that was the reason we replaced the last battery as he had stored the car in a country location for 12 months while he was in Sweden, and we had to jump start the car to get it going late last year.
Any definitive information would be appreciated as this is the first time I have encountered this.
I now have to check and see why it went dead flat - I did ask him if he was sure that it was an oil light that came on and NOT the alternator light, and I was told in no mean terms he knew the difference!!
Lucky he has another normally aspirated 944, so Dad can take his time!!
Any information appreciated!!