Quote:
Originally Posted by Laird Scooby
You are correct that we have debated it before Tony, however you are incorrect in almost everything else you state.
Firstly the nominally 12V battery fitted to most of our cars is 6 cells, each of 2.2V each = 13.2V. To even get those to charge, the voltage needs to be a minimum of 0.1V per cell above that, viz 13.8V but to get the battery to the gassing point which it needs to do to desulphate, it needs to be in the region of 14.4-14.0V consistently.
Using silver-calcium as a coating on the plates of lead-acid batteries instead of lead-antimony increases the gasing voltage by ~0.1V per cell so 15.1-14.7V to charge at the gassing point. Without reahing the gassing point, the battery will sulphate rapidly, rendering it fairly useless in very short order.
If i'm so wrong about this, why have so many manufacurers increased the charging voltages on their vehicles to cope with calcium technology batteries? They have been in use for ~25 years now and caught me out at first but i was 25 years younger then and found someone somewhat older that had already encountered them and was explained the facts to by them. These facts have not changed in a quarter of a century and neither have the laws of physics.
For other batteries that do not require any desulphation techniques during recharging, what you say is likely to be correct - however for automtive batteries and similar, it's not. 
As for calling the wiki article dodgy, there are many of them, each giving similar information, are they all dodgy? As for the YT guy saying he's going to ignore the science, i'd call him a congenital halfwit but that would be over-generous by at least 7/16! |
Gassing is the bit you need to avoid. Anything above 12.9V (2.15V per cell) is fine according to my research. 14.4V just happens to be the max stated for most batteries to avoid gassing. 12.9 to 13.3V isn't worth arguing about. A 940 charging at 13.3V would be slow charging and considered faulty at 13.3V.
The datasheets for Bosch S4 and S5 both state for standard charging (meaning continuous) that 14.4V is the "maximum". Sadly most battery datasheets are rather limited, it seems this information is privelaged, but I can say for certain that either Bosch batteries have reduced their charging range or they are perfectly compatible with old volvos despite them using Calcium.
https://www.ez-catalog.nl/Asset/3c4b...-S5-007-EN.pdf
My experience also says they work just fine, if you have a reasonably well working charging system, even over short journeys.
The reason I provided the halfwit link was to show a potential explanation for this "belief". Its more common now for old cars to have calcium batteries and faulty/poorly performing charging systems. Due to this type of misinformation rip-off mechanics will simply sell you a new battery, blame the calcium until you come back a year later with the same problem with a different battery that has calcium but doesn't state it.
There are also a number of different kinds, Yusas talk about Silver Calcium and Calcium/Calcium. It looks to me like all batteries now are Calcium instead of Antimony due to the reduced temperature aging characteristics, and increased voltage tolerance. The lastest types being AGM and EFB for start stop use, and you will want to drive those as hard as possible for recharging.
While it is hard to prove one way or another, I do think if there was a difference it would have to be stated in the datasheet. That is where the court will draw the line in a claim.