Modern Batteries and newer cars

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Modern Batteries and newer cars

Post by Vespa » Thu Dec 06, 2018 2:44 pm

I was looking at the GEM website generally and noticed quite a few items of interest of which this article was about batteries in modern cars, particularly diesel versions. It may be of interest to some of you. ... care-tips/
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Re: Modern Batteries and newer cars

Post by Nevyn » Thu Dec 06, 2018 10:40 pm


Have a Google on 'Smart Alternators' as fitted to Euro 6 cars. Turns out that unlike conventional alternators with a fixed internal regulator which provides a constant charge current, smart alternators are controlled by the 'ECU' and will turn off to save engine power and hence emissions and improve fuel consumption. The system tends to maintain the battery at less than full charge, maybe as low as 80%.

The main reason for this is Regenerative Braking. This works by 'the ECU' detecting when you are decelerating (ie foot off the gas) and temporarily boosting the alternator output to whack some charge back into the battery. The extra load on the alternator also provides a bit of additional engine braking. Of course this will only work if the battery is able to accept the charge...
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