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Old 05-06-2014, 07:41 AM   #94 (permalink)
paulgato
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Quote:
Originally Posted by RedDevil View Post
That is strange. I cannot see how charging on a low current could be bad for a battery, unless it is has a shorting cell.
Quote:
To play devils advocate: if they get you to buy an expensive charger for your battery they make sure you will buy another like battery if it goes bad, or you would have wased all that money on the charger...
I would like to see proof that you do need a big charger for a big battery.
At least it does have the benefit of fully charging your battery within a few hours, but that's it.
Well I agree that it seems strange RedDevil, but I can't see that Enersys have anything to gain by telling customers they need a powerful charger when they don't. Quite the reverse: if a customer knows they have to buy a more powerful charger in order to use an Odyssey battery then that increases the cost to them and they are less likely to buy an Odyssey battery in the first place. In fact I think they should make that high charging current requirement clearer up-front, rather than burying it in the user manual, which most people won't read until after they have bought the battery.

However, the guy in Tech Support I spoke to was clearly being truthful, and also was very knowledgeable, both from hands-on experience and from an academic point of view. He also said there was a range of opinion (i.e. nobody really knows but some people think they do) on why this particular battery technology happens to work better and lasts better with higher charging currents in a cycling application.

The technology behind the 'consumer' Odyssey batteries was developed for the SBS industrial battery range apparently, and the tech document for those SBS batteries specifies a minimum 10%-of-Ah-rating charge, and again, no maximum (e.g. a minimum 10Ah charger for a 100Ah battery) The Odyssey batteries are slightly different I guess, in that they are designed for high current output for engine cranking and therefore presumably have a greater number of thinnner plates, ...but the basic chemistry is the same.

So quite why the Odyssey battery only gives its full number of deep cycles with a 40%-of-Ah-rating current charger, I don't know, but I believe it to be true.

I kind of needed a new charger anyway because I definitely in any case need a 2nd temperature compensating charger for the 2nd battery. 40% of the Ah rating for my PC1220 battery would actually be 25.8A, but I'm going to compromise very slightly I think and get a CTEK 25A charger, as I can't find a decent charger that is both more powerful and even vaguely affordable. (The Ring 35A or 50A chargers are fairly cheap, and they look good on paper, but I'm not sure I'd trust them. The manual has glaring errors in it for example, and that's never a good sign. The CTEK chargers are well-respected and come with a 5-year warranty)
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